1.1 Background of the study
The primary purpose of buildings is to provide occupants with conducive, safe, comfortable,
healthy and secured indoor environment to carry out different kinds of activities such as work,
study, leisure and family life as well as social interactions. A completed building must be able
to perform its functions in the manner that will ensure satisfaction to its occupants in order to
achieve this purpose, buildings are designed, planned, constructed and managed based on
standards and specifications established by governments, professionals and experts who are
supposed to have adequate knowledge of users’ needs and expectations. Studies have however
shown that sometimes these standards and specifications do not conform to the changing needs
and expectations of users; and thus users are not always satisfied with the performance of their
buildings (Kaitilla 1993, Ukoha and Beamish 1997, Zeiler and Boxem 2008, Meir 2009). The
consequences of these are manifested in building related illness and ‘sick building syndrome’
(Kian 2001), increase in the desire for remodeling or modifications or abandonment of
completed buildings (Kim 2005) which cause waste of resources, time, energy and even
damage to the building envelope components and the surrounding environment (Mitterer 2012).
Several reasons may be adduced on why buildings perform poorly in meeting users’ needs and
expectations. The chief among them is the lack of adequate knowledge of users’ changing
needs and preferences by architects and other professionals who design, construct and maintain
buildings. This is obviously due to inadequate research on this subject. Meir (2009) observed
that whereas designers in other fields of human endeavour spend considerable resources in
examining the actual functioning and user satisfaction with everyday services and products and
refining their design accordingly, professionals in the building industry do not. In the light of the above, Kim (2005) and Fatoye and Odusami (2009) suggested that one of the ways to
improve the overall performance of buildings is to explore and understand users’ needs,
expectations and aspirations through regular performance evaluation.
In Nigeria, existing studies (Ukoha and Beamish, 1997; Olatubara and Fatoye, 2007; Fatoye
and Odusami, 2009; Ilesanmi, 2010; Clement and Kayode, 2012, Ibem 2012;) focused on the
general performance of public housing in meeting occupants’ needs and expectations. From
these studies, it is established that the physical characteristics of residential buildings have a
significant influence on occupants’ satisfaction with their residential environment. This implies
that the dwelling unit component of housing plays a vital role in determining the quality of
residential environment in particular and the performance of housing projects in general.
However, only a few studies have specifically examined the performance of housing units built in public housing schemes with a view to satisfying the needs and expectations of the occupants in the Nigerian context.
The purpose of a building is to provide shelter for activities carried out by the building users.
The question is, do the facilities in the building perform well and appropriate for their use? A
completed building must be able to perform its functions in the manner that will ensure
satisfaction to its occupants and when this performance could not be met, it can cause excessive
amounts of damage, nuisance or even death; disserving building owners, occupants and
imposing large amounts of unnecessary costs.
Building Services is that aspect of building components that deal with the provision of facilities
that make such buildings comfortable, safe and convenient for human use. According to
(CIBSE), Building services constitute a significant portion of money within a building. In an
average building they account for around 20-30% of the total capital cost, and on buildings that have large volumes of building services installations like laboratories, hospitals and hotels accounting for about 40-50%. In addition, they are also responsible for majority of the running costs of a building post construction.
Building services play a central role in construction of any building. A building must do what
it was designed to do, not just provide shelter but also provide a safe, comfortable and livable
environment. Building services contribute immensely to the functionality of the
building. So, everything inside a building which makes it safe and comfortable comes under the
title of ‘Building services’.
A building as a basic structure only offers protection against adverse weather conditions, such
as rainfall, snowfall, sunshine, wind etc. For the convenience of the users of buildings, more is
required of this basic structure; these requirements include among others toilet facilities, this
brings up the need for collection, transportation, disposal and treatment of waste. The need for
water to make this modern toilet functional also makes it imperative to provide water. The
waste generated in addition to the collection and disposal of storm water also brings up the
issue of drainage systems in building. The heat generated by the sun’s radiation causes a lot of
inconvenience to building users in form of raised body temperature; this situation requires
adequate ventilation, good air circulation and movement. The natural form of circulation might
not be adequate hence the need for means of artificial air circulation that can only be made
possible by the use of energy the most common of which is electricity.
Closely linked to this is the need to provide lighting to a building. Building being basically a
boxlike enclosure usually requires lighting to allow for visibility of the interior, this is only
made possible by either natural lighting obtained by the creation of openings in building, or
artificial lighting obtained via the use of electricity or any other sources of energy. The
foregoing basically is what services to a building are all about. Put in a different form, building
services or general services are those provisions in and around buildings that make the use of
the built environment convenient for users.
Imagine yourself in the most fabulous building in the world. Now take away the lighting,
heating and ventilation, the lifts and escalators, acoustics, plumbing, power supply and energy
management systems, the security and safety systems. You are left with a cold, dark,
uninhabitable Shell. (Ref. CIBSE)
Everything inside a building which makes it safe and comfortable comes under ‘Building
services’. A building must do what it was designed to do, not just provide shelter but also be
an environment where people can live, work and achieve.
Building services systems are the electrical and mechanical installations inside a building that
provide the internal infrastructure for the proper functioning of the building. Major building
services systems include:
(a) Electricity supply systems.
(b) Air-Conditioning systems.
(c) Lighting systems
(d) Lifts and Escalators.
(e) Fire services systems.
(f) Drainage
(g) Water services
(h) Earthing system.
Post occupancy evaluation (POE) is a general term for a broad range of activities aimed at understanding how buildings perform once they are built. It is the process of obtaining feedback on the performance of building in use. The value of POE is being increasingly
recognized, and it is becoming mandatory on many public projects. POE is valuable in all
construction sectors, especially healthcare, education, offices, commercial and housing, where
poor building performance will impact on running costs, occupant well-being and business
efficiency. POE has been used by number of researchers over the years as a tool for
documenting, evaluating and improving a building as well as environmental condition.
Building services functionality is an important criterion in the post occupancy evaluation of any
building, hundreds of POEs have been conducted on a variety of building types over the last 25
years but only few focuses on building services performance level of the occupant’s. It is
important to note that building services is an integral part for building functionality in meeting
user needs, if services fails building also fails that’s why much consideration is required
because people stays in a building for a long hours, thus, features like internal temperature,
water services, drainage system, lightning directly affect their well-being in any residential
POE of Building services is a useful management tool for evaluating the effectiveness of the
building services systems in completed buildings, and helps identify improvement measures for
implementing building projects in future.
This research will be used to assess the building services performance feedback, operational
systems satisfaction level of installed building services facilities and occupant’s satisfactory
opinions. Through BSPOE, designers can discover how similar buildings performs once they
are in use, policy makers can also apply it to help in developing and improving on the existing
programmes and projects being delivered. BSPOE is also a valuable tool for assessing installed
building services quality, since building designers, owners and even the government, in the
case of state subsidized buildings are held accountable for the success or failure of the building
and policies creating the buildings, K.C. Lam (2004). BSPOE identifies ways people can use buildings and equipment more efficiently and more cost-effectively. BSPOE also eliminates
dysfunctional and seldom-used facilities in a building and mistakes can be corrected in future
design and policies, Marsh (2003). The greatest benefits from BSPOEs are determine when the
information is made available to as wide an audience as possible, beyond the organization
whose building is evaluated, to all sector and construction industry. Information from BSPOEs
can provide not only insights into problem resolution but also provide useful benchmarking
data to which other people projects can be compared, Armstrong (2008).
1.2 Statement of the Research Problems
Building services engineering installation is worth 30-60% of the total cost of a building
construction. There are certain criteria that building services installation should meet up with in
designing, Marsh (2003, p. 62) states that “The purpose of design is to construct a workable
arrangement of technology that will deliver the technical objectives of the project. Unlike
architecture, building services must deliver the described technical performance exactly. To
under-deliver leaves the client with a building that is unusable, to over-deliver leaves the client
with a building that is too expensive or complex to operate”.
Many building defect complaints are reported in public and privates estates buildings in
Gombe, such as constant tripping off of the Power Distribution board, Neutral and Earthling
failure which results in Electric shock and damaging of electrical appliances, backlash offensive odour from soil waste, leaking pipes in the toilet that causes moisture on the building
walls and inadequate water supply and storage provision and poor waste disposal methods.
Hence, Building Services Post-Occupancy Evaluation (BSPOE) can be seen as a multifaceted
tool to be adopted in solving problems of building services and facilities management in a
building, as it evaluates the performance of buildings and facilities systematically. BSPOE can
also be seen as a systematic way to collect data and information on a particular building
services installation performances. Among the benefits that can result from BSPOE is the
identification of successful standard design features that can be scrutinized repeatedly (Watson,
2003), identification of problems to mitigate or reduce accidents or disaster that can occur due
to installations error or sub-standard works, improvement of building services performance and
environment, identification of redundant or omitted building services features and
empowerment of users to negotiate building issues and reduce maintenance works and cost
(Vischer, 2002; Hewitt et al., 2005).
Hundreds of POEs have been conducted on a variety of building types over the last 25 years,
but all this researches focuses on general building defects while commensurate works have not
be done on building services.
Buildings have started using latest advances in information technology to enhance the way they
work and to deliver new standard of performances and profitability. There is tendency now for
people to go for intelligent building in order to have functional and efficient satisfactions of the
installed facilities which are control by computer and intelligent network.
There are Building codes and standards which set out the rules and regulations that all the built
environment must adhere to when designing and installing building services facilities that
makes them fit for human use for all new and refurbishment work and if these facilities fails the
building fails that’s why much consideration must be given to them. This system can be applied to identify problem areas in existing buildings, to test new prototypes and to develop guidance
and criteria for future facilities. The building should be designed with the aim of producing a
high-quality interior environment so that the health and safety of the occupants are not
When considering purchasing a house or apartment or any dwelling for residence, one of the
major issues should be that it is electrically safe to live in. To this end personal safety and that
of other residents should be assured in the knowledge that all appliances, electrical systems and
components are functioning correctly. This safety aspect if checked on a regular basis also
combines to save the purchaser in energy costs during the lifetime of the system.
The problem this research wants to solve is to define means of tracking performances of these
installations since there is no enough practical information on operational function of installed
facilities in residential estates in Gombe State and to generate information as feedback
mechanism to the designer and explore how this can be made on regular features in building
construction industry to become in comparative that buildings to follow suits.
The outcome of this research is to provide information to the building industry about buildings
in use and abilities to determine how well a new concept of POE of building services works for
the government and public sector.
1.3 Significance of the Study
Current literature indicates that the poor condition of domestic mechanical and electrical
installations throughout Europe has raised concerns in respect of the safety of the
owner/occupier. The awareness of the public in regard to mechanical ; electrical safety seems
to suggest that a greater understanding may be needed and further input from the institutional
bodies in charge of mechanical ; electrical regulations be intensified, Noel Masterson (20I2).
The greatest danger of under-maintained electrical installations is fire. An investigation of the
Merseyside Fire and Rescue Service (UK) from 17 April 2008 to 8 December 2008 showed
that 79% of the accidental primary fires were caused by faults in the electrical installation
(Leonardo Energy, January.2010)
Building Services Post-occupancy evaluation (BSPOE) of buildings is vitally needed to ensure
that building perform its function and life of occupants and the appliances or the installed
facilities are safe and sustained after the building has been occupy. BSPOE of buildings is of
utmost importance in building performance evaluation, as it comprises the technique that is
used to evaluate whether a building meets the user’s requirements and possess ability to
perform function it was originally designed for. By using occupants as a benchmark in
evaluation, the potential for improving the performance of building services installations is
enormous. When reviewing the safety of a domestic installation of building services there are
quality requirements which must be attained, the main starting point would be the previous and
current condition of the installation if it was ever maintained or renovated. The point being,
safety at all times must be to the forefront of the occupants thoughts. One good reason for
prioritizing electrical safety in the home is the increasing use and abundance of modern
electrical appliances. Overloading of circuits in a house is now a serious concern for most
households due to the fact that when the house was designed the electrical outlet condition was
never perceived to have the growth that it has achieved, Noel Masterson (20I2).
BSPOE is a useful management tool for evaluating the effectiveness of the building services
system in completed building and helps identify improvement measures for implementing
building projects in future. It is also use to evaluate the maintenance and performance of
buildings services installation after they have been occupied. In addition, BSPOE provides a
mechanism for understanding the mutual interaction process between buildings and users’
needs and for recommending ways of improving the environment necessary to accommodate
these needs. Building Services Post Occupancy Evaluation involves systematic evaluation of
opinion on building services installation of buildings in use, from the perspective of the people
who use them and the provision of facilities in the buildings that make such buildings
comfortable, safe and convenient for human use. It assesses how well buildings match users’
needs, and identifies ways to improve building design, performance and fitness for purpose.
Having BSPOE as a measuring tool in any building will be able to detect which elements in
building performs or which elements in building underperforms and affecting the user’s
satisfaction and productivity, according to Riley, (2006), POE is used to consider the extent to
which a building meets the needs of its end-users while also recognizing ways in which design,
performance and fitness for purpose can be enhanced same also applied to BSPOE.
It is important to conduct a POE of building services installation in the residential building or
any other building so that the results can be used to gauge the level of satisfaction of designers,
occupants and owners of the building, and to determine whether the occupants are happy or
not. As the purpose of the building is to serve the needs of the occupants and it is critical that
the building should be evaluated from time to time to ensure that it is serving its intended
purposes. The building is an immovable asset, and it is affected by external factors such as
exposure to the climate, which leads to the necessity for maintenance.
Building should be designed in such a way to provide an environment where people can feel
comfortable, work, live and achieve. To have a satisfactory building services installation, every
building must follow design criteria which are the explicit goals that a project must achieve in
order to be successful, but in most cases the reverse is the case. Building services have certain
design criteria given by regulatory bodies such as CIBSE (Chattered institute of Building
services Engineers), National Building code, ASRHAE (Association of refrigeration, heating
and air condition engineers), British Standard (BS Standard) est., which serve as the
benchmarks against which success or failure in meeting design intent is measures in building
services, it is also a basis against which to evaluate success without any challenges.
This research will be of significance to the owners of public and private housing estates and
occupants, shedding light on the need for adequate provision of building services installation in
line with regulatory body guideline to serve end users better and provide comfortability and
safe environment. It will also provide a mechanism for understanding the mutual interaction
process between buildings services facilities and users’ needs and for recommending ways of
improving the environment necessary to accommodate these needs. It will serves as a tool to
account for building quality because M & E services installation is what makes building to
achieve the purposed it was designed for.
BSPOE is used not only to determine clients’ or users’ satisfaction, but also to fulfil other
objectives, including determining recurrent building services defects, supporting design and
construction criteria, supporting performance measures for asset and facility management,
lowering facility life cycle costs by identifying design errors that could lead to increased
maintenance and operating costs, clarifying design objectives and improving building
performance. The idea of BSPOE is to establish in relations the problems arising from the
building industry, more especially in the care facilities such as mental hospital, nursing homes,
school residence and residential buildings and estates.
Conducting POE of building services in residential estates buildings will assist with the
knowledge base which will be utilized by the owner of the residential estate to improve the standard of the facility. The knowledge base that the POE provides, will serve as the
benchmarks for continuous improvement, instead of waiting the Post Occupancy Phase to kick
and to reduce cost of recurrent maintenance.
This research has the broad aim of developing a general guideline for the BSPOE practice,
specifically for government and public buildings in Nigeria. The objectives were first, to
review and analyze government and public estates building performance, secondly, to
determine the occupants’ satisfaction level and thirdly, and to determine the correlation between
building performance and occupants’ satisfaction level.
1.4 Aims and Objectives
1.4.1 Aim
The aim of the research is to carry out POE in selected residential building estates in Gombe
Metropolis with a view to assessing the factors that affect the comfortability, functionality;
efficiency and safety of building services installations and to generate data as an input for
future installation.
1.4.2 Objectives
The specific objectives of this research are;
1) Identify and rank building services POE indices and measures.
2) Perform Evaluations of Building Services installation.
3) Determine the operational effectiveness of building services installation in residential buildings.
To develop measure for improving services design and installation for future
residential building projects.
1.5 Research Methodology
The data to be use in this research to be derive from both primary and secondary sources. The
primary data to be obtain through the survey method, while the secondary data to be derive
from the review of literature and archival records. The primary data to be obtain through the
use of a structured questionnaire survey, oral interviews and measurements.
1.6 Scope and limitations
1.6.1 Scope
The scope of this research is to evaluate building services performances of residential building
and it is confined to multi blocks estate of public and private estates within Gombe and
environs. The research is to cover services installations which are the technical components of
building only to determine level of comfort and functionality and safety of any built facility.
1.6.2 Limitation
The study is therefore limited to;
I. Narrowness of the subject.
II. Unavailability of occupant’s as at when needed.
III. Availability of technical information from the occupant’s.

2.1 Concept of Post Occupant Evaluation
Post occupancy evaluation (POE) is a general term for a broad range of activities aimed at understanding how buildings perform once they are built, and how satisfied building users are with the environment that was created (Chikezie et al., 2013). Over the years many theorist and practioners have grown uncomfortable with the term ‘POE’. This is because the literal meaning of the term seems to suggest that it occurs after people leave the building and it seems to emphasize evaluation done at a single point in the process. Despite the diversity of the practice, the term ‘post-occupancy evaluation’ remains common for historical reasons and it will be as such be used in this research. In this guidance, the term POE is to be used as an umbrella term that includes a review of the process of delivering the project as a review of the technical and functional performance of the building during occupation (Chikezie et al., 2013). A complete residential building should be able to function in such a way that it satisfies the occupant’s needs. Once the building has been completed and it is occupied, maintenance commences to ensure that the elements or facilities in the building function to their maximum capacity. Occupants of the building will then evaluate the facility to determine whether the building is functioning in accordance with its intended purpose.
Having POE as tool in the residential building will help facility manager to determine the level of satisfaction of occupants in terms of comfort, functionality, efficiency and conduciveness with respect to usability of the facilities. POE can be used to assist with upgrading an existing facility. It is often very useful to conduct a POE before planning for any refurbishment or renovation because user’s expectation, requirements and needs are addressed and the design term is properly informed. POE is the process whereby a building has to be evaluated in an accurate manner after it has been built and occupied for some time, (Jiboye. 2009). POE has come to represent a broad range of activities aimed at understanding how buildings perform once they are built, and how satisfied building users are with the environment that was created.
Study by Ukoha and Beamish (2001) examined the resident satisfaction with public housing and the relationship of satisfaction with specific housing features to overall housing satisfaction. The authors sampled 1,089 households in public housing units in Abuja. Residents expressed dissatisfaction with their overall housing situation; they were dissatisfied with structure types, building features and facilities, mechanical and electrical installation, housing conditions, and housing management, however they were satisfied with the neighbourhood facilities. The study of Ibem, Adeboye, and Alagbe, (2014) on the evaluation of public housing in Ogun state revealed that most of the residents perceived high levels of adequacy and dissatisfaction with the housing.
2.2The Review of POE Related Literature
POE was derived from the “occupancy permit”, a document that is issued once the building has been inspected and is declared free from all defects and ready for occupation. According to Riley et al (2006), POE was introduced as a result of complaints from the building occupants’ regarding problems such as Health and safty, security, disability, leakage, poor signage, lack of storage and privacy, halfway blockage, aesthetic shortcomings, inadequacy of designed space for equipment such as copier, the maintenance of glass surfaces such as skywalks. POE is a systematic collection and evaluation of information about the performance of the building in use (Chikezie et al., 2013).
POE is the evaluation of the performance of a building after it has been occupied. Using POE as a tool and interacting with the occupants will provide an information about how the building performs. This useful information will be used as the benchmark when new or future projects start. It plays a very important role in the interaction between the users and the building, and is intended to be used for improving on the shortfalls that existing building currently used by the occupants. POE also fulfills other objectives, such as identifying the building’s defects as well as providing the design team with alternatives on how to prevent similar mistakes from happening in future projects. With POE in place, the quality of building management will improve by using cost-effective strategic methods, (Eziyi, Akunnaya, Albert and Dolapo 2013). It is important to conduct a POE in the residential building or any other buildings so that the results can be used to gauge the level of satisfaction of designers, occupants and owners building, and to determine whether the occupants are happy or not. Nawawi and Khali (2008) define POE as systematic evaluation of opinion about buildings in use, from the perspective of the people who use them. Implementing POE in an estate building will help to identify measurable link between the building quality and performance outcomes of the occupants.
2.3 Post Occupancy Evaluation (POE) Methodology
2.3.1 Design Quality Method (DQM)
The Design Quality Method (DQM) is a tried and tested, independent, post occupancy evaluation (POE) method used by all UK auditing authorities, and many funding bodies.
The DQM assesses design quality, building performance feedback and operational efficiency in a quick and economical fashion – using expert opinion; professional judgement; user opinion; and scientific measurement. The DQM database includes over a hundred buildings, evaluated over the past decade, to form industry benchmarks for all building types and portfolios. The Design Quality Manual; improving building performance, by Martin Cook, was published by Blackwells in 2007. POE is recommended by the RIBA and CABE
The Design Quality Method (DQM) covers all aspects of design quality and building performance, such as architecture; environmental engineering; user comfort; whole life costs; detailed design; and user satisfaction. DQM results are benchmarked against industry standards, as well as Good and Best Practice. The Audit Commission, Northern Ireland Audit Office, National Audit Office, and Audit Scotland have all used the DQM to audit the design quality and value-for-money of educational and health buildings. The Scottish Funding Council is currently using the DQM to assess new college and university buildings.
Table 2: Six Matrix of Design Quality Method
Architecture Including the more functional qualities of specification, site and space planning, as well as the relatively subjective area of aesthetic merit
Environment Engineering Including objective and scientifically measurable aspects such as lighting, noise, temperature, and air-pollution levels
User Comfort Internal comfort conditions are scientifically measurable and links between them and productivity are increasingly evident
Whole Life Costs Including occupancy costs and the whole life performance of building fabric, components and services. Assessment of the balance between capital and running costs that affect future building performance
Detailed Design Including assessment of the maintenance and occupancy costs arising from aspects of detailed design and specification
User Satisfaction Building occupants are asked to rate their satisfaction with their building by responding to structured questions
Source; BRE DQM

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2.3.2 Building Research Establishment (BRE) Design Quality Method
2.3.3 Basics of DQM
DQM is a balanced scorecard that measures the whole performance of all building types, at design stage and post-construction. The DQM uses expert opinion, professional judgement, user opinion, and scientific measurement to assess design quality and building performance. Six matrices with defined levels of quality and performance cover the key areas of: architecture; environmental engineering; user comfort; whole life costing; detailed design; and user satisfaction. A seventh matrix is often added to cover specific aspects such as school grounds; safety and security in prisons; and clinical aspects in health buildings.
2.3.4 Useful where?
The DQM is a tried and tested, independent, POE method and design review tool used by all UK auditing authorities, and many funding bodies. The DQM was first developed by Martin Cook in 2002, to assess the design quality of new schools in England and Wales for the Audit Commission, and was subsequently used by other public and private clients to review other buildings types. The Scottish Funding Council uses the DQM to conduct POEs of university and college buildings, and the Scottish Prison Service uses it to assess the Scottish Prison estate.
2.3.5 In what sectors?
The DQM is suitable for all building types and has been used in most; educational buildings remain the core sector, with over a hundred schools, colleges and universities on the DQM Database. Hospitals were reviewed for the NAO and prisons are the latest building type to use the approach. Partnerships for Schools is using the DQM, in combination with extensive user surveys, to assess BSF secondary schools.
2.3.6 The Scope of DQM
The Design Quality Manual helps give an objective evaluation of the qualitative aspects of design. Matrices with six defined levels of quality have been developed that cover the key areas of architecture, environmental engineering, user comfort conditions, whole-life costs, detail design and user satisfaction. These can be scored by a visual survey and professional judgement and then augmented by scientific measurement where possible (e.g. temperature, lighting and sound levels). The resultant scores allow comparisons in terms of overall and specific aspects of building performance and design quality.
The Manual covers schools, hospitals and housing and offers a set of criteria by which to judge a broad range of design values; it focuses the design team on the needs of the end user and on the overall building performance
2.3.7 The Six Matrix of DQM
BRE’s DQM consists of the following six matrices, over-arched by a summary matrix
2.3.8 Matrix 1 – Building Architecture
Building Architecture is a general term to describe buildings and other physical structures. The art and science of designing buildings and (some) non-building structures. The style of design and method of construction of buildings and other physical structures. Building design refers to the broadly based architectural, engineering and technical applications to the design of buildings. All building projects require the services of a building designer, typically a licensed architect or structural engineer.
Since the 1980s, as the complexity of buildings began to increase (in terms of structural systems, services, energy and technologies), the field of architecture became multi-disciplinary with specializations for each project type, technological expertise or project delivery methods. In addition, there has been an increased separation of the ‘design’ architect from the ‘project’ architect who ensures that the project meets the required standards and deals with matters of liability. The preparatory processes for the design of any large building have become increasingly complicated, and require preliminary studies of such matters as durability, sustainability, quality, money, and compliance with local laws. A large structure can no longer be the design of one person but must be the work of many.
DQM Architecture Matrix covers the relatively subjective area of aesthetic merit, and also the more prosaic qualities of specification, site and space planning. All integrated aspects of a building’s artistic and scientific performance are covered by the term ‘architecture’ – the use of a discrete matrix is not intended to marginalize the term, but establish it as an over-arching definition of design quality.

2.3.9 Matrix 2 – Environmental Engineering
Environmental engineering is the branch of engineering concerned with the application of scientific and engineering principles for protection of human populations from the effects of adverse environmental factors; protection of environments, both local and global, from potentially deleterious effects of natural and human activities; and improvement of environmental quality.
Environmental engineering can also be described as a branch of applied science and technology that addresses the issues of energy preservation, protection of assets and control of waste from human and animal activities. Furthermore, it is concerned with finding plausible solutions in the field of public health, such as waterborne diseases, implementing laws which promote adequate sanitation in urban, rural and recreational areas. It involves waste water management, air pollution control, recycling, waste disposal, radiation protection, industrial hygiene, animal agriculture, environmental sustainability, public health and environmental engineering law. It also includes studies on the environmental impact of proposed construction projects. It more objective and supported by scientifically measurable lighting, noise, temperature, and air-pollution levels. Sympathetic integration of environmental services with architecture is crucial, not to mention appropriateness, maintainability and replacement sourcing.

2.3.10 Matrix 3 – User comfort

Comfort in buildings
Building better is not only about avoiding problems, it should also be about creating positively pleasurable and healthy living places. Comfort is about the physical environment in its totality. The issues which are most obviously associated with comfort are:
Temperature Humidity
Temperature and Humidity:
Human beings operate and feel better when they are at temperatures which are comfortable. It is now well understood that in the workplace, accidents increase as temperatures go outside the zone of 16 to24°C. However, temperature is also strongly linked to humidity levels as regards comforts the chart below indicates.
In the section on health, controlling humidity and temperature was seen as a method of controlling pollutants. Interestingly the levels of humidity and temperature which are healthiest are also the most comfortable. There is no conflict between health and comfort. In addition to temperature and humidity, acoustic isolation is also very important for comfort. There were 313,000 complaints in England and Wales to Environmental Health Officers about domestic noise disturbance in 2004, up from155,000 in 1999 and from only 31,000 in 1980. As a result of the growing number of complaints and the potential litigation arising from these, building regulations have considerably improved acoustic insulation requirements since 2002. Testing is now mandatory if robust details are not used. However, there are still a number of problem areas, and many building systems which have been designed for good thermal performance will not necessarily be good from an acoustic point of view. This applies particularly to lightweight structures. Certain types of thermal insulation can actually be bad for acoustic insulation, by increasing noise reverberation and flanking sound.
The point to note with regard to acoustics is that this is all about getting the shell of the building right in the first instance. It is extremely difficult, if not impossible to retrofit proper acoustic performance.
Lighting can have either a positive or negative effect on health and wellbeing. The effects may be felt immediately or only in the long term. There are four types of effect: light as radiation, light acting through the visual system, light acting through the circadian system and light as a purifier.
Generally natural daylight is understood to be beneficial both to health and wellbeing Maximizing good daylight in housing is therefore an important consideration. Gooday light means levels of daylight which are sufficient to see properly without glare or excessive contrast. Too much direct sun can actually cause discomfort and ill health, particularly with highly reflective surfaces.
On the other hand, darkness is also an important source of wellbeing. Our bodies require a regular cycle of light and darkness for both physical and mental health. Bedrooms need to be dark and quiet for most people to receive proper rest. Psychologically it is also important that the outside is also dark, wherever possible. Light pollution is now a commonly accepted problem in many built up areas.
Building better means taking the quality of lighting, particularly natural day lighting, seriously. It is not just the conservatory on the back of the house, but a strategy for the whole house, to bring in good natural light without glare, too much contrast or overheating. This also saves energy and money.
As regards artificial lighting, issues of radiation, glare, contrast, and flicker are all crucial for health and comfort. Although lighting is an important consideration from an energy point of view, health and comfort should not be sacrificed for low energy strategies. From both an energy and a financial point of view this is short sighted, as ill health and lack of well-being have huge environmental and financial consequences. However just as with humidity and temperature, with proper understanding and good design there is no conflict between energy and health in the area of lighting. A strategy to maximize the benefits of daylight, along with well-designed low energy lighting will provide the best solution for health and comfort and the lowest impact on the environment.
Substances that enter the nasal cavity maybe sensed either by the olfactory senses or by the limbic system. The first is responsible for odour detection, the second is sensitive to irritants. On the whole people adapt to odour relatively quickly, whereas irritant scan get worse the longer exposure continues. Furthermore, many of the irritants are at levels where they are not detectable as odour.
On the whole when building well, the objective should be to eliminate odour and air borne irritants of all kinds. There are some “natural” paints and other decorating materials which utilize natural essences such as citrus oil. The pleasant smell is often seen as a selling point, but it should be noted that many people have extreme allergic reactions to citrus essence, and furthermore that It will react as a VOC with other chemicals to produce low level ozone, which is a danger to asthmatics and those with respiratory problems.
The main ways of dealing with odour are outlined in the TM40 document in order of importance as follows:
Eliminate contaminants at source
Substitute with sources that produce non- toxic or less malodorous contaminants
Reduce emission rates of contaminants
Segregate occupants from potential sources of toxic or malodorous substances
Improve ventilation
Provide personal protection
It is obvious from this that the most important strategy is reduction of the problem at source. From a building point of view this means the use of non- odorous substances wherever possible, i.e. materials without VOCs, which are commonly used in many paints, glues, composite products, preservatives etc.
It may also be noted that certain types of material and certain types of construction are able to absorb odour and neutralize them. In particular, unfired clay products (as used in boards, blocks and plasters) and protein based products such as sheep wool (as used in carpets, furnishings, and insulation) have proven absorptive qualities. Internal comfort conditions are also scientifically measurable and links between them and productivity are formally established by peer-reviewed research. Integrating art and science creates ideal environments – e.g. the quality of daylight is just as important as the measurable quantity. For example, optimum environments are critical to successful residential building design and often reflected in the enhanced comfortability of the occupants.
2.3.11 Matrix 4 – Whole life costs

It covers the occupancy costs of installation of services facilities and the potential whole life performance of building fabric, components and services. It provides an analysis of the trade-offs between capital and running costs that affect future building performance.
Whole-life cost, or Life-cycle cost (LCC), refers to the total cost of ownership over the life of an asset. Also commonly referred to as “cradle to grave” or “womb to tomb” costs. Costs considered include the financial cost which is relatively simple to calculate and also the environmental and social costs which are more difficult to quantify and assign numerical values. Typical areas of expenditure which are included in calculating the whole-life cost include planning, design, construction and acquisition, operations, maintenance, renewal and rehabilitation, depreciation and cost of finance and replacement or disposal.
Whole life costing (WLC) is a powerful tool for calculating the lowest cost options for the entire commercial life of a building. It encourages the use of best value building designs and reduces the costs and disruption of unplanned repairs and maintenance.
Best value design and specification
Knowledge of a building’s costs over its full life span is important in achieving best value from both the capital costs of constructing the building, and the related ongoing costs of operating it. WLC helps you to make well informed design decisions, and to select the most suitable building materials, components and systems.
Better building performance
Whole life costing will enable you to minimize disruptions from otherwise unforeseen problems, for example from unexpected failure of building components that must then be replaced or repaired. A planned and costed maintenance Programme (as part of WLC) minimizes the risks of unexpected costs, disturbance and loss of income.
Durability assessment
Our durability assessment service defines your requirements for the durability of a building, and assesses design, specification and construction proposals against these. This will help you to reduce repair and disruption costs, minimize waste and achieve more sustainable construction. Our services are supported by extensive knowledge and experience of building and component defects, and, where data on future performance is unavailable, our ability to gather and assess anecdotal evidence. They will help you make important decisions such as:
Rebuild or refurbish
Impacts of positioning and building massing
The design most appropriate, sustainable and efficient for the business
Best life-cycle value of specifications, for example, aluminum windows or timber
Best life-cycle value of component standard, for example, mill finish or pre-finished aluminum roof decking

2.3.12 Matrix 5 – Detail design

Detailed engineering encompasses the design and configuration of various engineering systems that form the internal workings of a facility, including:
Process design ; specification
Mechanical design ; specification
Piping design ; specification
Structural design ; specification
Electrical design ; specification
Instrumentation design ; specification
Control system design ; specification
Process Design ; Specification
Failures in building performance are often caused by poor detailed design or bad
workmanship. Rectifying and coping with such failures will increase maintenance and occupancy costs. Detailed design is the phase where the design is refined and plans, specifications and estimates are created.

2.3.13 Matrix 6 – User satisfaction

User satisfaction of a buildings is vitally needed to seek the opinion of the occupant and also to ensure that building perform its function and life of occupants and the appliances or the installed facilities are safe and sustained after the building has been occupy. User satisfaction of buildings is of utmost importance in building performance evaluation, as it comprises the technique that is used to evaluate whether a building meets the user’s requirements and possess ability to perform function it was originally designed for. By using occupants as a benchmark in evaluation, the potential for improving the performance of building services installations is enormous, (Bownass and Bownass, 2001).
Marsh (2003) defines User Satisfaction as useful management tool for evaluating the effectiveness of the building services system in completed building and helps identify improvement measures for implementing building projects in future. It is also use to evaluate the maintenance and performance of buildings services installation after they have been occupied. In addition, User Satisfaction provides a mechanism for understanding the mutual interaction process between buildings and users’ needs and for recommending ways of improving the environment necessary to accommodate these needs. Having BSPOE as a measuring tool in any building will be able detect which elements in building performs or which elements in building underperforms and affecting the user’s satisfaction and productivity, according to Riley (2006).

2.4 POE Results
If negative results are envisaged by managers, a POE study can be opposed or even sabotaged (Turpin-Brooks and Vicars 2006). For rented apartments that are fully let out, owners will be reluctant to endorse such a study that could potentially uncover shortcomings in their buildings and effectively reduce its market value in a competitive market (Zimmerman and Martin 2001). The same applies to the project team; it could be feared that results of the POE would portray the building as ineffective, and thus, the project as unsuccessful (Riley et al. 2010). Due to this possibility, POE results are not published, and thus, mistakes are not learned by designers, while managers and others commissioning buildings ignorantly help perpetuate the same mistakes (Leaman et al. 2010). The use of sophisticated statistical techniques could also make interpretation of the occupancy survey results difficult (Turpin-Brooks and Vicars 2006) and thus, less likelihood of its adoption as feedback or feed forward. POE results should not be presented as a tool to intimidate stakeholders that might be potentially affected. It should also be made simple since the aim is to benefit from its lessons, and not to showcase complex mathematical techniques.
2.5 Building Services and Provision
Building Services Engineering is the engineering of internal environment and environmental impact of a building (Wikipedia, 2013). It essentially brings buildings and structures to life, (Braithwaite 2010). Building services engineering involves the design, installation, operation and monitoring of Mechanical, Electrical and public health systems required for the safe, comfortable and environmental friendly operation of modern buildings (Wikipedia, 2013). Building services influences the architecture of a building and plays a significant role on the sustainability and energy demand of a building as shown by world Book Encyclopedia (2002) and goes on to enumerate that within building services engineering, new roles are emerging with some examples in the areas of renewable energy, sustainability, low carbon technologies and energy management. With building accounting for around 50% of all carbon emissions, building services engineering plays a significant role in combating climate change (Hatamura, 2006).
According to CIBSE (2014), Service Engineering is all about making the buildings meet the need of the people who live and work in them. Like all other engineered products buildings must do what they were designed to do. They do more than provide shelter from the heat and cold, or from sun, wind and rain; they must also provide a safe and healthy environment in which people can live, work and archive. Building Services Engineers are the people who make this happen. They creatively apply scientific principles to design the buildings we need and to do so they focus on aspects of buildings.

2.5.1 Field of Building Services Engineering
Building services engineering comprises of Mechanical engineering, Electrical Engineering and plumbing or public health (MEP) engineering, all of which are further sub-divided into the following: (Designing Buildings Wiki, 2013).
Communication lines, telephones and IT networks (ICT)
Energy supply-gas, electricity and renewable sources
Escalators and lifts
Fire detection and protection
Heating, ventilation and air conditioning (HVAC)
Lightning protection and Earthing system.
Low voltage (LV) systems, distribution boards and switchgear
Natural lighting and artificial lighting, and building facades
Security and alarm systems
Ventilation and refrigeration
Water, drainage and plumbing
Fire detection and protection

2.5.2. Building Services Design Layouts and Requirements for Building
Design criteria are the explicit goals that a project must achieve in order to be successful. In recommendation and feasibility reports, especially, the design and decision criteria determine the document final recommendation. It is the criteria that designers should meet up in designing some system or device “the job specification summarized the design criteria”. (Mathew, 2011) Building services design criteria define here informs the basis of the design for project in M&E Service works system. M&E service design criteria are the benchmarks against which success or failure in meeting design intent is measured in building services, it is also a basis against which to evaluate success without any challenges.
Major factors to consider before engaging designs are as follows;
The building should provide outstanding comfort to its occupant.
The design will consider the latest information technology.
The building will provide a high degree of flexibility for its occupants
The building will be carbon neutral.
The buildings will be green with a focus on indoor environmental quality.

2.5.3 Electrical Installations of Residential Building
Electricity was a luxury for houses in the past, but it is a necessity for each and every house, irrespective of the scale or the category of the household. Within the Nigerian construction industry, the installation cost of an electrical system in a building is significant.
Building services installations typically account for 20-30% of the total value of a project – and sometimes a great deal more, (Simon and Andy, 2012). The complexity of building services installations has increased in recent years as demand has grown for intelligently operated environments, driving innovation to improve occupier comfort and extend building performance.
Electrical installation in a general term means any fixed appliances, wires, fittings, apparatus or other electrical equipment used for (or for purposes incidental to) the conveyance, control and use of electricity in a particular place, but does not include any of the following; subject to any regulation made under Electricity (Consumer Safety) Act 2004 subsection (4) – any electrical equipment used, or intended for use, in the generation, transmission or distribution of electricity that is: (owned or used by an electricity supply authority, or located in a place that is owned or occupied by such an authority); Any electrical article connected to, and extending or situated beyond, any electrical outlet socket; Any electrical equipment in or about a mine; Any electrical equipment operating at not more than 50 volts alternating current or 120 volts ripple-free direct current; Any other electrical equipment, or class of electrical equipment, prescribed by the regulations.
Electrical wiring work means the actual physical work of installing, repairing, altering, removing or adding to an electrical installation or the supervising of that work. Also, Electrical wiring needs to be made of two main materials: a good conductor of electricity, usually copper, and; to prevent the wires inside a cable from connecting to one another – a very good insulator, usually PVC (poly-vinyl-chloride) or special rubber.
Electrical wiring composes of electrical equipment such as cables, switch boards, main switches, and miniature circuit breakers (MCB) or fuses, residual current devices (RCD), lighting points, power points, lightning arrestors, etc.
The electrical work in residential houses must be made, taking into account the particular interior design. In some cases, cables can be laid under the ceilings, while in others you will need to drill walls and floor. That is why execution of electrical works here requires an integrated professional approach that takes into account the requirements of operation, safety and aesthetic perfection as well.
Part P of the building regulations limit what electrical work may be carried out by anyone other than a professional electrician who is a competent person registered with an electrical self-certification scheme. An electrical license is required before any electrical wiring work can be undertaken, regardless of the cost of the work and regardless of whether the work is residential, commercial or industrial. When work is carried out by a professional electrician, they will deal with the necessary paperwork to comply with the Regulations.
Electrical symbols are used to show the lighting arrangement desired in the home. This includes all switches, fixtures, and outlets while the electrical plans display all of the circuits and systems to be used by the electrical contractor during installation.
Electrical installation for new construction occurs in these three phases: Temporary, that this, the installation of a temporary underground or overhead electrical service nears the construction site and close to the final meter location, to provides electricity during construction; Rough-in electrical- also known as simply “rough-in” or pre-wiring, this is when the electrical boxes and wiring are installed. Rough-in happens after the structure is framed and covered with roofing. The electrical meter and permanent service can also be installed at this time; Finish electrical, this is when the light fixtures, outlets and covers, and appliances are installed prior to occupancy. Finish electrical is one of the last construction phases.
The building regulations set out overall criteria and requirements to ensure electrical safety in and around the home. Approved document P (Electrical Safety) from the planning portal provides practical guidelines for validating this type of work. It should be bear in mind that any electrical work carried out within the home, garden, garage, shed and other storage buildings may need to comply with the requirements of the Building Regulations.
Essentially, electrical works falls into two categories: Non-notifiable and Notifiable. Non-notifiable electrical work, some work is classed as ‘non-notifiable’, and this work can be carried out by a non-certified individual without notification although, obviously, the individual does need to be competent.
Non-notifiable electrical work covers: Replacement of fittings such as sockets, switches and light fittings; Replacement of the cable for a single circuit where it has been damaged; Work that is not in the bathroom or kitchen and consists of: (Adding additional lighting, light fittings and switches, to an existing circuit; Adding additional sockets and fused spurs to an existing ring or radial main; Installing additional earth bonding).All this ‘non-notifiable electrical work’ is conditional upon the use of suitable cable and fittings for the application for which they are intended, that the circuit protective measures are unaffected and suitable for protecting the new circuit, and that all work complies with all other appropriate regulations. Notifiable electrical work, these are work which must either be carried out by certified individuals/companies or notified to the local Building Control before work begins, this includes: All new or modifications to the electrical wiring within bathrooms or shower rooms; Installation or modification of electric under-floor or ceiling heating; Garden lighting or power installation; Other specialist electrical installation, examples being, Photovoltaic Solar and micro CHP (Combined Heat and Power) power systems.
Electrical installation in general is basically subdivided into Electrical Supply/Power/Light systems and Communication/Security/Controls systems (Appendix B of Building Engineering Standard Method of Measurement, BESMM 3). The classification was based on functions of the installations which could be likened to elements in the case of building. Thus to measure installation that performs a particular function, requires a combination of trades. The trades covered in BESMM3 are in Work Group Y and includes among others; Conduit and Cable trunking (Y60), HV/LV Cables and Wiring (Y61), Earthing and Bonding components (Y80), switchgear and Distribution boards (Y71), Luminaries and Lamps (Y73) etc.
Lawrence listed five main categories of electrical accessories ( Keraminiyage, Amaratunga, Haigh and Perera, 2009) which are accessories in power circuits, accessories in lighting circuits, protective devices, accessories in other circuits, cables and other sundry items. Each of these categories comprise of several key accessories.

Table 2.1-Electrical Accessories in main groups – Lawrence, (1993)
Group Accessories
Power circuits Accessories Socket outlets, Shaver Sockets, Cooker Controllers
Lighting circuits Accessories Switches, Light Dimmers, Lamp Holders, Ceiling Roses, Light fittings
Protective Devices Miniature Circuit Breakers, Residual Current Circuit Breakers, Earth Terminals, Distribution boards
Accessories in other circuits Telephone Sockets, Television Antenna Sockets, Bell, Switches, Electrical Bell Units, Ceiling Fans
Cables and other sundry items Wiring Cables, Conduits, Conduit Accessories, Enclosures, Cable Trunks, Junction Boxes, Sunk Boxes, Wiring Clips, Distribution boards
Source; Jiboye 2012
However, the priority of the list of these features varies with the situation and the characteristics of the person with the need.
Due to the diversification of availability of different types of accessories, a systematic approach should be adopted in the process of building the model. Several procedures can be adapted to this effect and the following three steps will be followed in building this particular cost model:
Identification of the Cost Variables
Collection and analysis of cost data
Representation of analyzed data in the model in a way that it reflects the cost variables of the system, while catering to the need of ease of use of the model and ability of simulating various combinations
2.5.4 Determinant of Electrical Cost
Adeniyi, (2004) and Chan, (1999) developed a models for determining building durations in Nigeria and Hong Kong respectively; also, Temitope, (2001) has also developed a predictive model for the determination of the final cost of construction project; Onwe (2012), also wrote a research work that deals with the measurement of electrical services in buildings; but there is yet not a research work or study carried out to determine the probable cost of electrical services in residential buildings, nor the development of a cost model for electrical installation in residential buildings.
Moreover, most architectural drawings for residential buildings such as those of bungalows and duplexes are not usually accompanied with its corresponding detailed electrical drawings which have led cost engineers such as quantity surveyors/estimators to find another way of determining the cost of electrical services through the use of provisional sums which is more of a guess work.
Also, the non-availability of electrical drawings for residential buildings could lead to variations and loads of claims by the contractors in situations in which the estimated allowances for such electrical installations is found to have been underestimated; therefore, the desire and requirements by the clients to get accurate estimate in order to enable them to take a right decision regarding the feasibility of proposed building services such as electrical works in residential buildings becomes unrealizable.
Therefore, a cost model will provide an acceptable solution within this scenario. As identified by Beeston (1987), “A cost model’s task is to estimate the cost of a whole design or of an element of it, or to calculate the cost of effect of a design change.” Authors have used this approach to solve the similar problems.
2.5.5 Daylight calculations and measurements
Illuminance is the measure of the amount of light received on the surface. It is typically expressed in lux (lm/m2). Illuminance levels can be measured with a lux meter, or predicted through the use of computer simulations with recognized and validated software (e.g. VELUX Daylight Visualizer). Illuminance is the measure of light currently used by most performance indicators to determine daylight availability in the interior.

Source; Venox 2013
Table 2.2
Luminance (cd/m2) is the measure of the amount of light reflected or emitted from a surface.
It is the measure of light used to evaluate visual comfort and glare in the interior.

2.5.6 Daylight factor
Daylight factor (DF) is a daylight availability metric that expresses as a percentage the amount of daylight available inside a room (on a work plane) compared to the amount of unobstructed daylight available outside under overcast sky conditions (Hopkins,1963).
The key building properties that determine the magnitude and distribution of the daylight factor in a space are (Mardaljevic, 2012)
• The size, distribution, location and transmission properties of the facade and roof windows.
• The size and configuration of the space.
• The reflective properties of the internal and external surfaces.
• The degree to which external structures obscure the view of the sky.
The higher the DF, the more daylight is available in the room. Rooms with an average DF of 2% or more can be considered day lit, but electric lighting may still be needed to perform visual tasks. A room will appear strongly day lit when the average DF is 5% or more, in which case electric lighting will most likely not be used during daytime (CIBSE, 2002).

Figure 1: internal lux of Residential Building
The amount of daylight in a building’s interior depends on the availability of natural light outside at that location, as well as the properties of the building spaces and its surroundings. The evaluation of daylight performance should, therefore, take account of the availability of daylight on site in addition to the properties of the space (CIE, 1970). Using recorded climatic data (outdoor diffuse illuminance), we can determine what DF levels will be needed to reach the target illuminance level over a given period of the year. The example below shows how the target DF is determined from climate data to achieve daylight levels of 300 lux for 50% of the year.

2.5.7 Useful daylight illuminance (UDI)
Useful daylight illuminance (UDI) is a daylight availability metric that corresponds to the percentage of the occupied time when a target range of illuminances at a point in a space is met by daylight. Daylight illuminances in the range 100 to 300 lux are considered effective either as the sole source of illumination or in conjunction with artificial lighting. Daylight illuminances in the range 300 to around 3 000 lux are often perceived as desirable (Mardaljevic et al, 2012).
Recent examples in school daylighting design in the UK have led to recommendations to achieve UDI in the range 100-3 000 lux for 80% of occupancy hours.

2.5.8 Earthing Resistance
The resistance offered by the earth electrode to the flow of current into the ground is known as the earth resistance or resistance to earth. The earth resistance mainly implies the resistance between the electrode and the point of zero potential. Numerically, it is equal to the ratio of the potential of the earth electrode to the current dissipated by it. The resistance between the earthing plate and the ground is measured by the potential fall method.
The resistance of the earthing electrode is not concentrated at one point, but it is distributed over the soil around the electrode. Mathematically, the earth resistance is given as the ratio of the voltage and the current shown below.

Where V is a measured voltage between the voltage spike and I is the injected current during the earth resistance measurement through the electrode.
The value of the earth resistance for different power stations is shown below
Large Power Station – 0.5 ohms
Major Power Station – 1.0 ohms
Small Substation – 2.0 ohms
In all other cases – 8.0 ohms
The region around the earth in which the electrode is driven is known as the resistance area or potential area of the ground. The fault current which is injected from the earth electrode is passing away from the electrode in all directions shown below in the figure. The flow of current into the grounds depends on the resistivity of the soil in which the earth electrode is placed. The resistivity of the soil may vary from 1 to 1000 ohm-m depends on the nature of the soil.

There is not one standard ground resistance threshold that is recognized by all agencies. However, the NFPA and IEEE have recommended a ground resistance value of 5.0 ohms or less. The NEC has stated to “Make sure that system impedance to ground is less than 25 ohms specified in NEC 250.56.
2.5.9 Earth Pit Construction as Per Indian Electricity Board
1. Excavation on earth for a normal earth Pit size is 1.5M X 1.5M X 3.0 M
2. Use 500 mm X 500 mm X 10 mm GI Plate (Plate may be use as big as possible to contact more and more area of Earth for low resistance ; best result)
3. Make a mixture of Wood Coal Powder Salt ; Sand all in equal part
(a) Wood Coal Powder use as good conductor of electricity, anti-corrosive, rust prove for GI Plate for long life.
(b) Salt use as electrolyte to form conductivity between GI Plate Coal and Earth with humidity
(c) Sand has used to form porosity to cycle water ; humidity around the mixture
4. Put GI Plate (EARTH PLATE) of size 500 mm X 500 mm X 10 mm in the mid of mixture
5. Use Double GI Strip size 30 mm X 10 mm to connect GI Plate to System Earthling
6. It will be better to use GI Pipe of size 2.5” diameter with a Flange on the top of GI Pipe to cover GI Strip from EARTH PLATE to Top Flange
7. Cover Top of GI pipe with a T joint to avoid jamming of pipe with dust & mud and also use water time to time through this pipe to bottom of earth plate
8. Maintain less than one Ohm Resistance from EARTH PIT conductor to a distance of 15 Meters around the EARTH PIT with another conductor dip on the Earth at least 500 mm deep.
9. Check Voltage between EARTH PIT conductor to Neutral of Mains Supply 220V AC 50 Hz it should be less than 2.0 Volts

2.6 Basic Layouts of Mechanical installation of Residential Building
2.6.1 Water service system
Water is one of the basic human needs of humanity. The needs of water cannot be over emphasized, the availability as well as quality of water is one of the major consideration in any built environment. What usually the problem is water quality, the sources, the supply of portable water after treatment and the form/convenience by which the supply gets to the users. Building services in this respect seek to create an understanding of the real meaning of water, the sources, the quality, the purification/treatment/storage and supply to ensure adequacy and availability all time round. (UNESCO, BLD 207) water services installation can be used to supply of cold and Hot water within the building, these includes supply to sinks, washing hand basin, baths, water closet, pipe. The water services and water distribution systems shall be designed and pipe sizes shall be selected such that under conditions of peak demand, the capacities at the point of outlet discharge shall not less than the required capacities of both the flow rate and flow pressure which is later discuss in this write up.
NBC (2006) reported that every building in which people live, work or congregate should be supplied with a clean, cool and portable water in sufficient quantity to maintain all water supply and plumbing fixtures in a safe and sanitary manner, and such other water supplies as are required for fire protection, air conditioning and all other services and equipment of the building or structure. The water services comprise of mains water supplies, cold and Hot water installations. The mains, cold and hot water distribution services can either be supply by direct or indirect system. The system to be choosing depends on the source of the supply water and they are classified as follows;
Surface water; water from river, streams e.t.c
Underground water; water from boreholes, walls dams e.t.c
Public main; treated water from water board authority
2.6.2 Factors to consider in Water Demand
Water demand depends on:
Type of building & its function
Number of occupants, permanent or transitional
Requirement for fire protection systems
Landscape & water features
Typical appliances using the cold water
Numbers of WC cistern, wash basin, bath, shower, sink, urinal flushing cistern
Washing machine, dishwasher

2.6.3 Water storage
This is the process of storing water within the distribution system according to the maximum peak demand of the building. Engineers are responsible for designing stable and durable reservoir that protects the quality of stored water, (Mathew, 2011). This comprises of two ways:
Elevated Storage; Due to the gravity.
Ground-level storage with high service pumping.

FEMA and the Red Cross recommend that a minimum of one gallon of water to be stored per person per day, which will only cover most basic needs: drinking, some cooking, and minimal hygiene (think sponge bath). For anything beyond that, additional water to be stored. And don’t forget water for pets and other domestics’ purposes.
Store as much water as possible; aim for two weeks of stored water. Start small-enough for just one day-then build up to three days, one week, etc. elevated or ground water storage tanks were recommended to store waters.
2.6.4 Water Pressure
Each tap or shower will be rated with a minimum required pressure rating, typically between 0.1 and 3 bar. It’s first worth talking about where the pressure comes from. Essentially, water will enter your house at the cold mains under pressure, i.e. at ‘high pressure’. If you have a gravity system, the pressurized cold water is stored in a tank, and heated on demand. As it is stored, it loses all of its pressure. So how does the water get from the tank to your taps if it is no longer pressurized? The clue is in the name of this type of water system – gravity.
So in gravity systems, every 1 metre drop from the water tank typically equates to around 0.1 Bar in pressure. So your upstairs bathroom taps will normally sit around 2 metres below your tank, resulting in a water pressure of 0.2 Bar, and your kitchen taps will be around 5 metres below your tank, supplying you with around 0.5 Bar of pressure.
There are other water systems, other than gravity and combination boiler. For example, in new builds and for large houses it is common to see what is called an ‘unvented’, or ‘megaflo’ system. In this case, water is still stored in a tank, but it is stored in a pressurized environment so it doesn’t rely on gravity to create any motion. If you have a gravity system and no pump, you very likely have ‘low’ water pressure, and should be looking at taps and showers with a 0.2 bar rating or less. It’s important to note that you shouldn’t expect too much, even with suitable taps. There’s only so much pressure being created, and therefore so much water flowing past a certain point (litres per minute) available. If you want a ‘good’ shower, you might be disappointed. For a few hundred pounds you could install a pump, which would mean you suddenly have a much wider range of options when it comes to choosing your taps. If you’re renovating an entire bathroom, this isn’t much in the scheme of things.
If you have a combination boiler, and it is relatively modern, they tend to have a reading on the front to show you what water pressure you’re getting. Generally, this is around 1-1.5 bar, although it can sometimes be more. The majority of taps and showers can be chosen with this kind of pressure.
If you have a pump, or if you have a megaflo-type system, you can pretty much have anything you want – body jets, big rain heads, 2 or 3 outlets on at the same time – the works.
Always remember that this is just a guide. There are many other factors, such as the direction and bends of the pipework; the size of those pipes; or the contents(!) of them, and so on.
If you are unsure about what water pressure you have, it’s always best to have your plumber take a look and let you know before you purchase. A plumber will have a pressure gauge tool to work out exactly what pressure you have in your home, giving a much better idea of what taps will be suitable.
2.6.5 Gravity System
As mentioned previously, a gravity system is a low pressure system with a cold water storage tank (usually located in the loft) as well as a hot water cylinder. As the name suggests, the pressure supplied around your household is based upon the height in which the cold storage tank sits from the location of the taps around your house.
Generally speaking, the water pressure supplied to your upstairs bathroom will be around 0.1 or 0.2 bar and the pressure supplied to your kitchen will be somewhere around 0.5 bar. This type of system limits your tap choices significantly and the installation of a water pump should be considered to give you access to a wider range of tap options.

Figure 3: Hot & Cold Water Gravity supply

2.6.6 Design for Water Tank
When we want to find out that how much water are required for an estate, city, village, hospital, house, town etc. So first of all we have to find their water requirements how much water they are using per capita in per day. After that we are able to find the population of the estate, city or village etc. then it’s easy to find the total volume of water for them. When we complete this survey then we have to find out the volume of the water tank for the water which are required for the estate, village or city peoples, then we add the factor of safety in that water because F.O.S can give us a lot of benefits.
Here we have a small family and we have to find the volume of water required for a house. So we have total nos of population in this house just 12 nos. Now we have to find the volume of water and volume of water tank for the 12 members of family.
First of all, to find out volume of water Requirement for One person / day. 120 liters of water is the average of water for one person/day
1: Drinking = 5 liters
2: Cooking = 5 liters
3: Bathing and Toilet = 70 liters
4: House Cleaning = 10 liters
5: Cloth washing = 30 liters

Total Water Requirement for 12 members per day = 12 x 120 = 1440 liters/day
We Know that: – Density of Water = 1000 liters/Cu.m
Now: 1 cu.m = 1000 liters
1 liter = 1/1000 = 0.001 cum
Our Water Requirement is 1440 liters
So 1440 x 0.001 cum
Volume of Water = 1.44 cum
Now Assume Height of Water Tank = say 1.2 m
Now Find The area of Water Tank = 1.44/1.2 = 1.2 sq.m
Now we have to find out the length and width of water tank
so Take under Root on the Water Tank Area
?1.2 = 1.095 m
So Now
Height of Water Tank = 1.2 m
Length of water Tank = 1.095 m
Width of water Tank = 1.095 m
Note: when you want to design a water Tank so Water tank design it depends on the population and also that how much water they are using depend on the person nature. And after that we have to find out the volume of water average and then we are able to Design the water tank after the Given Data The above water Tank Design of Water is just for one days it means this water tank is just work for one day for 12 members’ family

2.6.7 Purpose of Water Storage
Provide for an interruption of supply
Accommodate peak demand
Provide a pressure (head) for gravity supplies
2.6.8 Maintenance of Water Supply Systems in Estates Housing Buildings
Poor Water Quality – Causes and Solutions
Corrosion in the plumbing of buildings and dirty roof tanks are the main causes of turbid and discoloured water:
Air bubbles which sometimes form in the plumbing systems of buildings make the tap water look milky white. But as they disappear after coming out from the taps, the water becomes clear again. This has nothing to do with the water quality Slight discolouration of the tap water should not pose health hazard to human, although it might be aesthetically unpleasant.
Discolouration is most prominent when the water has been stagnant in a water pipe for some time, or when it is first drawn out from the tap in the morning. Under normal circumstances, the water should become clear after the tap has been turned on for a short while.
If the discolouration is persistent and serious, the consumer should employ a licensed plumber to check the pipework of his flat and to replace the corroded pipes if necessary. He should also request his management office or the registered agent to check the communal plumbing system of the building and to arrange remedial action as necessary (Water Supplies Department, Hong Kong).

2.6.9 Other Water Supply Problems – Causes and Solutions
Apart from discoloured water, many other common water supply problems might also be caused by lack of proper maintenance of the plumbing on the part of the consumers, the management offices or the registered agents. For example, poorly maintained water pumps often lead to disruption of supply, while corrosion in water pipes might cause choked and lead to weak pressure. Regular checking of the plumbing can identify small defects before they develop into major problems (Water Supplies Department, Honk Kong).

2.7 Drainage System
2.7.1 Excrete/Sewage disposal methods
Excrete/sewage disposal methods or option can be classified as on-site or off-site. The former refers to those in which the waste is collected and disposed of on or near the plot while the latter is where the waste is disposed away from the site. The options may also be classified as dry or wet, depending on whether water is intended to be used for their operation or not (Pacey, 1978). All the available options can simply be classified as;
Dry, on-site treatment and disposal (e.g. pit latrine, compost latrine)
Dry, off-site treatment and disposal (e.g. bucket or vault latrine)
Wet, on-site treatment and disposal (e.g. wet pit, aqua privy, septic tank, cess pit)
Wet, off-site treatment and disposal (e.g. conventional sewage).

2.7.2 Conventional Method
Sewage systems
Septic tank
Cess Pits
2.7.3Sewerage systems
Sewerage systems are designed to collect excreta and domestic wastewater and transport them away from homes to a treatment and/or disposal point. This system is ideal for urban areas. The system however requires large volume of water to transport the waste away. Unless a reliable water supply is available a conventional sewerage system will have many problems. Conventional sewerage is a high- cost sanitation option; it is usually deep-laid and must be maintained by professional staff (Smith, 2000). Such a system is thus appropriate only where funds are available for operation and maintenance by trained staff All sewerage systems should be linked to a treatment plant, as the raw-faeces they carry represent a public health risk.
Modified sewerage systems are also designed to transport waste away from the home, but work on different principles from conventional sewerage systems. They do not require high-volume flush toilets, but do need significant amounts of water for flushing (Smith, 2000). Small-bore sewers are designed to carry only effluent, and each home requires an interceptor tank to collect and store solid material, which must be regularly emptied by mechanical means (WHO, 2003). Modified sewers are larger-diameter sewers that carry both solid and liquid; wastes. They differ from conventional sewers in that solids deposited in the pipes are re-suspended when water builds up behind the blockage. To ensure that enough water is available to move the solids, all household wastewater should be disposed of into the sewer. (WHO, 2003)
While both small-bore and shallow sewers have problems, they have been: successfully managed by communities and have far lower water requirements than conventional sewers (WHO; 2003). The modified technologies may be appropriate in larger villages that have water supplies close to, or within, the homes.
2.7.4 Septic tanks
A septic tank is a form of on-site sanitation that provides the convenience of a sewerage system as well as partial treatment of sewage. It is usually linked to flush toilets and; can receive domestic wastewater (or sludge). Since flush toilets tend to use large amounts of water, septic tanks are usually appropriate only for households with water piped into the home (WHO, 20.03). The tank is offset from the house and linked to the toilet and domestic wastewater by a short drain. The septic tank consists of two chambers. The solid part of the waste settles at the bottom of the primary chamber in which aerobic bacteria acts on to breakdown the waste. The effluent is discharge from the primary into the secondary chamber in which the action of anaerobic bacteria renders it less harmful. The effluent is the discharged into the soil. The two chambers are sometimes constructed separated, with a soak away serving as the secondary chamber.
Septic tanks generally require relatively large amounts of land and periodic emptying by vacuum tankers. This is often expensive and the trucks will need easy access to the tank. Septic tanks thus tend to be high-cost sanitation option (Smith, 2000), Septic tanks are suitable in communities that have access to water supply within the home, have land available and who can afford the cost of emptying the tanks. Communal septic tanks may be feasible if a large number of households close to the tank can be connected with very short lengths of sewer pipe. For such a system to work, however, each household needs sufficient water to flush fasces into the septic tank effectively (Smith, 2000). This approach will probably be effective only when water is supplied to at least one tap on each plot.
2.7.5 Cess Pits
This is also an on-site method and may be designed to hold both excreta and domestic wastewater. Cesspit is used where the septic tank is not suitable, either due to ground condition (impermeable ground or high water table) or limitation of space. The pit is constructed of impermeable walls and holds the waste temporarily before evacuation. The frequency of emptying will be more than in septic tanks and vacuum trucks are more appropriate for this purpose.

2.7.6 Non-conventional Method
Cartage Pit latrines
VIP latrine
Aqua privies
2.7.7 Cartage
Cartage is the most basic form of excreta disposal faeces are collected in a container and disposed of daily. An example is the bucket latrine, in which household wastes are collected in buckets under a hole in the floor of a specific room. Each day, the bucket is emptied into a larger container and the contents disposed of. Bucket latrines should not be promoted because they pose health risks to both users and collectors and may spread disease (WHO, 2003). If cartage is considered for your community, a vault latrine (a latrine where wastes are stored in a sealed container) that is mechanically emptied on a regular basis is a better choice (Smith, 2000).
2.7.8 Pit latrines
These provide the simplest form of latrines and are widely used because of their simplicity, low cost and ease of construction in suitable ground conditions. It basically consists of a pit dug in the ground and a platform, usually of traditional materials, laid over the pit. A squatting hole is provided on the platform. The walls of the pit are normally unlined if the soil is stable. The superstructure can be made of local materials such as mud, timber posts, thatch and the like. (Mbamali, 1990);
A volume of 0.06- 0.1m3/person per year is often used to estimate the life of a pit (Tebbutt, 1992). In most pit latrine systems, faecal matter is stored in a pit and left to decompose. Unless specifically designed, pit latrines do not require periodic emptying. Once a pit is about two-third full it is filled with soil and then sealed, and a new pit dug. If faecal matter is left to decompose in dry conditions for at least two years, the contents can be safely emptied manually and the pit reused. The pits are normally unlined. However, if there is the possibility of ground water contamination, the pit should be lined with an impervious walling material. Fig. 1 shows a typical pit latrine. Other designs use two alternating pits, reducing the need for new pits.
Pit latrine provides a very cheap means of excreta disposal. However, a number of problems have been experienced with simple pit latrine; these include nuisance from flies, mosquitoes and cockroaches, and unpleasant smells (Smith, 2000). Unlined pits also have the tendency of polluting ground water, especially where the water table is high. Another disadvantage of the pit latrine is the visual nuisance due to sight of the excreta.
Some pit designs are meant to be completely dry, while some use small quantities of water. Ventilation to remove odours and flies is incorporated into certain designs, while others are very basic and use traditional materials and approaches. Some variants of the pit latrine which incorporate certain improvements over the traditional pit latrine are described below:
2.7.9 Sanplat
The Sanplat is the cheapest and most basic improvement of the pit latrine. It consists of a small concrete platform (usually 60 cm 60 cm or smaller), laid on top of logs or other supporting material traditionally used to cover the pit. The purpose of the sanplat is to provide a sanitary (san) platform (plat) which can be easily cleaned to limit the presence of helminths such as hookworm (WHO, 2003). Once the pit is full, the sanplat can easily be moved. However, the sanplat design does not overcome problems with odours or flies and may not be acceptable to some community members. The sanplat is best used when there is very little money for improving sanitation and where odours and flies will be tolerated.

2.7.10 The VIP latrine
The VIP (ventilated improved pit) latrine was developed by Morgan (1977) and is designed to overcome the problems of flies and odours in pit latrines (Smith, 2000). It has a vent pipe from the pit to above the roof of the building. When air flows across the top of the vent pipe, air is drawn up the pipe from the pit and fresh air is drawn into the pit from the building. Offensive odours from the pit thus pass through the vent pipe and do not enter the building. The location of VIP latrines is important: unless a clear flow of air is maintained across the top of the vent, the ventilation system may not be effective. VIP latrines should therefore be located away from trees or high buildings that may limit airflow. A dark vent pipe also helps the air to rise. The top of the pipe is usually covered with mosquito meshing. If the inside of the building is kept partially dark, the flies will be attracted to light at the top of the pipe, where they will be trapped and die. Fig. 2 shows a typical VIP latrine.
When the VIP latrine is constructed and used properly, it provides great improvements in fly and odour control, but may not eliminate either completely.
A VIP latrine is designed to work as a dry system, with any liquid in the content infiltrating into the surrounding soil. Although some liquid inevitably will enter the pit, it should be minimized. For example, it would not be appropriate to dispose’ of household wastewater into the pit as this may prevent decomposition of the contents. VIP latrines are most appropriate where people do not use water for cleaning themselves after defecating, but use solid materials such as paper, corncobs or leaves. VIP latrines may be designed with single or double pits. Double pits may be used, for example, when cultural taboos prohibit the mixing of male and female faeces (WHO, 2003). Twin pits may also be used to facilitate emptying and composting. When one pit is full, the other can be emptied and reused (Mbamali, 1990). The pit of a VIP latrine is usually located directly beneath the slab to prevent fouling of the chute, which would lead to odour and fly problems, and require regular cleaning.
The VIP latrine is more expensive than either traditional designs or the sanplat and this should be borne in mind when considering its use. In some areas, traditional latrines or sanplat latrines can be improved by providing ventilation (WHO, 2003). Installing a vent pipe on an existing latrine may damage it. When considering a VIP latrine as an improvement on existing sanitation, it is important to be aware that this may require the construction of a new latrine, not simply the upgrading of an existing one (WHO, 2003).

2.8 Air Conditioning System
Air Conditioning system is the process of treating air in an internal environment to establish or maintain required standard temperature, humidity, clines and motion. The air-conditioning system in a building controls the environmental parameters, including air temperature, relative humidity, air movement and cleanness of the building space to provide the occupants with a comfortable indoor environment. The purpose of Air condition is thermal cooling for human comfort which is the expression of mind that expresses satisfaction with thermal environment and across by subjective evaluation (ANS/ASRAE STAND 55).

3.1 Research Design
Casual and scientific observation is the best technique to use in investigating the relationship between human activities, installed facilities and physical settings in the housing estates. Data were to be obtained from both primary and secondary sources.
The primary data to be collected using structured questionnaires from the resident occupants of the selected building of the (GSIPDC) estate in Gombe, Gombe State. Interviews were to be used also to explore the impulse of occupants and their expectations about their buildings with regards to building services installation; Archival Retrieval approach would also be employed to retrieve documents such as original site as original site plans, building services drawing (M&E) and building construction techniques from Gombe State Investment and Property Development. The final step to be employed is the evaluation of elements that influence building services installation based on a theoretical frame work of building services quality indicators such as; air content, heat, ventilation, lighting and acoustics.
It will comprise of testing and measurement of parameters such as; temperature, earth resistance, trip test, ELCB check, pressure testing, in-services and luminous testing, and the following was calculated through information obtained from the occupants, Peak Hour Demand (PHD), Maximum Daily Demand of water supply (MDD)., water storage capacity.
The reason for this test and physical inspection/assessment was based on several complaints from the occupants of estate building in Gombe metropolis for high level of maintenance of building services installation works. The complains usually emanated from poor workmanship of the contractors and government bureaucracy between allocation and time of completion of the building which results in dilapidation of some installed facilities and data were to be collected from our respondents using checklist developed from existing standards.
The research was carried out using both quantitative and qualitative data. The primary data for the research was obtained through field survey, using structured questionnaire, interview and measurements of parameters while the secondary data were obtained from extensive literature review of relevant seminar paper, reports, textbook, journals and the research. The descriptive statically method was used to obtained data.
In this research, probability sample technique was adopted according to De Vaus cited by Uji (2009), is one in which each person/object in the population has an equal, or, at least, a known, chance (probability) of being selected. The research deemed it fit that most commonly acceptable way of providing an equal probability of selection of samples from populations was to use principle of systematic sampling. In this systematic sampling, the researcher worked out a sampling fraction by dividing the required sample size by the size of the population (n/N) then selecting one case out of every (n/N) case in the population. This enabled the collection of information from a representative group good enough to permit conclusion to be drawn about the large study group.
The perception of the occupants was properly examined by measuring their responses to certain questions regarding their comfortability in their built environment. This questionnaire contained some qualitative questions structured to be responded within 10 minutes and was ranked accordingly to their level of agreement and comfortability. Checklist, Test and Measurements were used and sorted out. After sorting out, the result was collated and analyzed using SPSS software.

3.1.1 Population of the study.
The study area is Gombe State. It is located in the North-Eastern part of Nigeria; it is one of the country’s 36 states with Gombe capital. Gombe State was created in October 1996 from part of the old Bauchi State by the Abacha military government. As a young developing state, the demand for quality residential and commercial housing is high.
Therefore, Gombe State has mandated Gombe State Investment and Property Development Company (GSIPDC) to address the accommodation problems in the state. To strengthen the company, government has transferred ownership of all its housing estates to the company.
The estate includes;
Table 4: Names, Types and Number of Estate Buildings in Gombe
Name of Estates Type of the building No. of building
Orji Estates 2 Bedroom with BQ 300
Shongom Estates 2&3 Bedroom bungalow semi detached 500
Investment Quarters 2 & 3 Bedroom bungalow semi detached 450
Buhari Estate 3 Bedroom bungalow with 2 Bedroom BQ 350
Dukku Road Estate 2 & 3 Bedroom bungalow semi detached 400
Labour Quarters 2 & 3 Bedroom bungalow semi detached 300

The target population of this study are occupants of these housing estates belonging to Gombe State Government and managed by Gombe Investment and Property Development Company (GSIPDC). The estates are categorized into two sections: based on period of occupants; occupants from 1985 to 2000 and till present.
3.1.2 Sample size and Sample Technique
According to Gombe Investment and Property Development Company (GSIPDC), there were a total of 2300 housing units from the five (5) estates. The sample size for the study was obtained from the 2300 housing units using the equation (1) below;
n= N
Therefore, n= 2300
1+2300(0.052) =340
Where N=study population of 2300
level of precision (e) = 5%

Since the population of the study is homogenous, purposive sampling method was adopted for questionnaire administration to the occupants using simple random sampling in order to eliminate the incidence of bias. The questionnaire was administered with some characteristics; those who are the true owners of the building and those who rented the apartment.

3.2 Data Collection
The study obtains its data from both primary and secondary sources. The survey was conducted primarily through field investigation. Self-administered structured questionnaire and checklist on building services installation was used to obtain relevant data, also test and measurement was carried out on some installed facilities. Secondary data was obtained from written literature in form of textbooks, journal and past project on design guide and regulation, design criteria and standard approved by an authority such as ASHRAE, CIBSE, PROBE, BS est.

3.2.1 Data Collection Instrument and Method

The instrument used in collecting data for this research are field measurements and structured questionnaire. The field measurements involve data collected on temperature, pressure testing, earth resistance testing, general electrical load calculation and water demand. This was done to get variation measurement in terms of the installed facilities. Also, questionnaire was structured with qualitative questions which was responded within 20 minutes and it covers all the four objectives of the research. The method adopted was closed ended with options from which respondents were requested to select the ones that apply to them in order to seek their opinions on comfortability, efficiency and safety of service installation in their houses. The questionnaire was grouped into six (6) sections, which contains;
Personal details of respondents.
Building attributes of the built facilities.
POE indices and measure ranking some identifies variables on a five (5) point Likert scale to indicate their satisfaction and comfortability levels.
Building services installation evaluation ranking some identifies variables on a five (5) point Likert scale to indicate their satisfaction and comfortability levels.
Operational effectiveness of installed building services installation in Likert scale.
Measure for improving future design and installation.
The checklist also was grouped into two (2) section, which contains;
POE indices and measures with three (3) variables on Likert scale to state functional condition of installed facilities.
Condition and operational effectiveness of building services installation with three (3) variables on Likert scale to evaluate functional condition and operational efficiency of installed facilities.
The equipment used for the field measurement includes;
A thermometer for measuring temperature.
Pressure bucket
Ground Resistance/Earth Tester.
Test push button Switch of ELCB
Cable Tester.
Plier and Tester
Physical assessment.
No of occupants

3.3 Data Analysis
Descriptive analysis using Statistical Packaged for Social Sciences (SPSS) and Microsoft Excel are used in data analysis. Cross tabulation was used to establish the satisfaction and un-satisfaction variables. Presentation of the result are by means of frequency tables and simple percentage.
A total of three hundred and forty (340) questionnaires was administered and the analysis are based on the number of returns. The data obtained are processed using statistical tools. The magnitude of the responses to the questionnaire are obtained using the formulae below.

%= n ×100
n= number of responses
N= total number of respondents
Weighted mean
Where: f-weight given to each response
X-Number of responses
Xt-total number of responses.

Charts are used to express the statistical result concerning the satisfaction, comfortability and safety causes of the installed building facilities. This was achieved with SPSS.
Objectives one, two, three and four of the study are analyzed through the adoption of the Relative Agreement/Comfortability Index Technique.
In analyzing section C of the questionnaire, the Relative Comfortability Index technique was used in analyzing POE indices and measure and Measure for future design and installation. The data analysis was employed using the following steps:

Computation of the mean using the weighted average formula
X= Efx ………………………………….(eq. 1)

Where: X = mean
X=points on the Likert’s scale (1,2,3,4 and 5)
F=frequency of respondents’ choice of each point on the scale.
Computation of the Relative Importance Index (RII) for each item of interest, using the formula:
RII= Efx × 1……………………………….(eq.2)
Ef k

RII= X……………………………………………….(eq.3)
Where K= maximum point on the Likert’s scale(in this case, k=5)

Ranking of the items under consideration will be based on their RII values. The items with the highest RII value is ranked first (1) the next (2) and so on.

Interpretation of the RII values of the RII values is achieved through the following as recommended by Mbamali and Okotie(2012):
RII?0.60, item is assessed to have low rating.
0.60?RII?0.80, item assessed to have high rating.
RII?0.80, items assessed to have very high rating.

4.1 Preamble
The aim of this research is to carry out POE on Mechanical and Electrical installation in selected residential building estates in Gombe Metropolis with a view of accessing the comfortability and operational efficiency of these building services installations and to generate data as an input for future design and installation. The questions the study set out to answer were, “Do occupants feel comfortable with the installation of building services and how efficient are these installed facilities”? In order to achieve this, the research articulated a POE method consisting of six metrics with which the evaluation was done.
The specific objectives were to identify and rank building services POE indices and measures, perform evaluations of Building Services installation, determine the operational effectiveness of building services installation .and to develop measures for improving services design and installation for future residential building projects. Four approaches employed to accomplish this work were; a review of existing literature, personal observation of the installation using checklist, Questionnaire survey and field test / measurements of relevant variables (such as Earthing system, Trip test, ELCB Check, Pressure testing, temperature and daily water demand.)
This chapter presents the findings of the empirical work. The presentation follows the chronological stages of the research.

4.1.1 Frequency of Response
A total of three hundred and eighty (380) questionnaires were administered to occupants of selected residential building in Gombe metropolis cutting across six (6) estates of which three hundred and nine (309) were returned and analyzed as in Table 4.1. This represent a response rate of 81.3%.
Table 4.1: Questionnaire Distribution and Response
Questionnaire Frequency Percentage (%)
Number of return 309 81.3
Number of not return 71 18.7
Total 380 100
Source: Field Survey (2018)

4.2 Respondents’ Profile
Respondents were asked to indicates the demographic data which formed section A-B of the questionnaire. It comprises of the personal details of the respondent and the responses obtained were shown in the table 4.2 below.
Table 4.2: Respondents’ Profile
S/N Demographic Information Frequency Percentage (%)
A Gender
B Age of Respondents
31-45 Years
46-59 Years
60 Years above
C Marital Status
D Educational Level of Respondent
‘O’ Levels
E Years of Stay in the Apartment
1 Year
2-3 Years
4-5 Years
Above 5 Years
F Hours Spent in the apartment per day
2 Hours
3-4 Hours
5-8 Hours
Above 8 Hours
Source: Field Survey (2018)

Section A of Table 4.2 illustrates that the questionnaire was distributed to both male and female occupants with 55.7% of the male and 44.3% of female which shows that the questionnaires were distributed without bias.
Section B shows that majority of the respondents are 31-45 years of aged having 78.6%. This shown that the respondents were an active age group who makes adequately uses of installed building services facilities in the building.
Section C gives the marital status of the respondent, though the majority age of the respondents was between 31-45 years and this indicates that they were married with 50.8% while the single is 49.2%.
Section D shows that 61.8% of respondents are graduate while 25.3% are OND/NCE holders, 11% are O Levels while only 1.9% indicated none. This shows that the majority of the population are educated and they are elite group who have adequate knowledge of facilities and believed to be demandful in building meeting their needs most especially building services installation.
Section E establishes that the highest percentage of the people staying were people between 2-3 years with highest percentage of 35.9%, followed by the 1year with 35.6%, while 4-5 years is 26.5% and above 5 years is 1.9%. The table shown that the majority of the occupant don’t exceed 5 years of staying in their apartment.
Section F indicates the maximum hours spent by the occupants was 5-8 Hours in a day having the highest percentage of 36.9% while 3-4 Hours with 30.4%, 2 Hours 15.2% and above 8 hours was 17.5%. This table shows that the highest population spent 8 hours in a day which give better representation of this research to get a dependable feedback

4.3 Building Attributes
This section addresses attributes of the building and how well the building services installation meet the occupants needs of residential estate building in Gombe metropolis.
Table 4.3: Features of the Buildings under study
S/N Building attributes Frequency Percentage (%)
A Number of Bedrooms
2 Bedrooms
3 Bedrooms
4 Bedrooms
Above 4 Bedrooms
B Number of Occupants
1-2 Person
3-4 Persons
5-6 Persons
Above 6 Persons
C Source of Power
Generating Sets
Solar Panel
Public Power Supply
D Water Storage
Overhead Tank
Ground Tank
Source: Field Survey (2018)

Section A illustrates that 2 bedrooms’ flats have the highest percentage with 42.1%, while 3 Bedroom with 26.5%, 4 Bedrooms with 20.4% while above 4 bedrooms was 11%.
Section B shows that 3-4 people were majority resident in the apartment with 41.7%, 1-2 people resident are 33%, 5-6 people resident is 12.3 while above 6 is 12.9%. From the above table, it was established that more than a person resident in each apartment which would demand functionality of installed facilities.
Section C established that 97.4% resident has power supply to their building from different source which allow our evaluation of functional installed electrical facilities with 74.1% public power supply, 15.5% Solar Panels & Public, 7.8% Generating set while only 2.6% with no supply.
Section D established that 91.6% resident has provision of water supply and storage facilities to their building from different source which allow our evaluation of functional installed Mechanical facilities in each apartment with 70.9% Overhead Tank, 12.9% only ground tank, 7.8% have both Overhead and Ground tank while only 8.4% with no storage facilities
This section shows the agreement of POE Indices and Measures using Design Quality Method for Evaluation of User Satisfaction on Building Services installation
4.4.1 Building Architecture
Table 4.4: Ranking of Building Architecture POE indices and Measure
POE Indices & Measure
(Design Quality Method) Importance Level Sum Total Mean RAI Position Agreement Level
Building Architecture Frequency of Response
1 2 3 4 5 ?f ?fx
1 The building type 85 174 34 14 2 309 1253 4.06 0.81 1st VHA
2 General building design and layout 89 152 52 16 0 309 1241 4.02 0.80 2nd VHA
3 Physical condition of the building 88 135 48 34 4 309 1196 3.87 0.77 4th HA
4 Space in the building 80 155 40 26 8 309 1200 3.88 0.78 3rd HA
5 Construction materials quality 93 118 52 38 8 309 1177 3.81 0.76 5th HA

Source: Field Survey (2018)
Key: RAI