Lecture 2 & 3 THE PROCESS OF FEASIBILITY
The aims of this lecture are:
To identify the primary and secondary functions of a building
To identify the factors affecting performance expectations
To discuss the term ‘a successful design’
To consider design constraints
To appraise the content of a feasibility study
To consider the economics of construction
To consider the implication of design legislation
To consider the external environment
To consider aspects of low-maintenance design
On completion of this lecture, the student should be able to:
Produce a feasibility study incorporating to the requirements of the client, and offering the client a viable proposition
Introduction
This handout considers the functions of a building, how these are incorporated into a design, and then represented in the feasibility report for the client. The issue of cost and legislation are considered. Finally, aspects of the external environment and maintenance are discussed.
Functions of a building
Buildings are designed to satisfy a wide range of requirements and perform a number of functions. Perhaps the most fundamental function is that of providing shelter. Shelter from the natural environment is one of the most basic of human instincts whether it is shading under a tree from the hot summer sun or sheltering behind landscape features from the prevailing wind. Understanding how a building design can modify the natural environment for the benefit of its occupants is fundamental to building designers.
From this basic sheltering function we have developed buildings in response to an increasingly complex set of performance requirements that have been modified by each succeeding generation. Modern buildings have become, in effect, comprehensive and multi-functional life support machines.
Primary functional expectations of buildings
The primary functional expectations of modern buildings can be summarized as arising naturally from human needs. These are as follows:
1. Provide immediate necessities for human metabolism
· clean air to breathe
· clean supply of water
· treatment/disposal of waste products
· storage of food
2. Create necessary conditions for thermal comfort
· control of mean radiant temperature
· control of air movement
· control of water vapor
· control of surface temperature
3. Create necessary conditions for sensory comfort, efficiency and privacy
Secondary functional expectations
The following functional expectations arise largely from needs created by the building itself and are secondary to the basic human requirements.
· To distribute services around the building to convenient points.
· To provide stable support for occupants, furniture and belongings and provide structural resistance to the physical forces of snow, wind and earthquake.
· To protect its own structure, surfaces and internal finishes/furniture from wetting by precipitation or other water.
· To protect its occupants, contents and itself against damage by fire.
The factors that shape performance expectations
The performance expectations are affected by a number of factors that a designer has to consider. These include:
Climatic conditions – it is important to consider the implications of the sitting of a building as topography, climate and orientation all have major influences on building form. These factors affect the choice of a building’s structural system, materials and construction.
Geographical factors – Soil type affects type and size of foundations and drainage of ground, topography will also affect foundation type, the building configuration and relationship to ground plane. Site microclimate affects wind patterns, temperature and solar radiation.
Man-made environmental conditions – the building designer may have to consider conditions such as noise either generated within the building or in the neighborhood outside the building, vibration (e.g. if building close to roads or railways), pollution generated in inner cities or from surrounding industry, and vandalism.
Legislative factors – Legal standards have been laid down over the past century to ensure minimum standards of performance are achieved. These standards have been regularly reviewed and modified to meet changing human expectations. The Building Regulations cover a range of performance standards, largely related to health and safety and include minimum standards relating to matters such as energy conservation, ventilation and access for disabled persons. (see later)
What is a ‘successful’ design?
A building design may be considered ‘successful’ for a number of reasons when measured against certain criteria. For the end user, for example, success may be measured by how well the building functions to enable activities to be carried out in it. For the client, who may not be the end user, the perception of success may be based on financial matters such as whether the building was designed and constructed within budget, or whether the building offers a profitable return through rent. The general public, who may have no vested interest in the building, may judge it purely from external appearances from the street. For the building designer all these criteria are important and in addition there may be other benchmarks such as how environmentally ‘friendly’ the building is or critical acclaim from other design professionals.
A 17th century writer, Sir Henry Wotton, defined the essential qualities of good building as ‘commodity, firmness and delight’. It is very difficult to improve on this definition even today.
‘Commodity’ or the ability to accommodate is the primary function of most buildings. In order to accommodate the activities which go on inside them buildings must enclose enough space in a suitable configuration. They must also provide a suitable environment for those activities in terms of temperature, humidity, acoustics etc.
‘Firmness’ obviously means structural stability but may also mean durability and even fire resistance, both secondary but very important functions of buildings.
‘Delight’ equates perhaps with quality of life. Most of us spend most of our lives in or within sight of buildings so their aesthetic quality is of utmost importance.
The Design Process
An understanding about how designers work might be gained by considering the process from beginning to end. This will be of limited value as much design work is intuitive and it is difficult to understand the thinking process in the designer’s mind. The REBA practice and management handbook considers the design process in four phases:
Phase 1 Assimilation – The accumulation and ordering of general information and information related specifically to a project.
Phase 2 General study – The investigation of the nature of the problem and possible solutions or means of solution.
Phase 3 Development – The development and refinement of one or more of the tentative solutions isolated during phase2.
Phase 4 Communication – The communication of one or more solutions to people inside or outside the design team.
The phases of this plan are not necessarily sequential although they are arranged in a seemingly logical order. In simple terms the plan states that a designer has to gather information about a problem, study it, devise a solution and draw it, but not essentially in that order. For example, one may need to study a problem before deciding on the amount and type of information to be gathered. Markus (1969) and Mover (1970) developed a map of the design process related to the REBA plan. They suggested the need to go through a design sequence of analysis, synthesis, appraisal and decision at increasingly detailed levels of the design process.
Analysis – involves the exploration of relationships, looking for patterns in the information available, and the classification of objectives. Essentially this stage is the ordering and structuring of the problem.
Synthesis – this is an attempt to move forward and create a response to the problem. This stage is about the generating of solutions.
Appraisal – involves the critical evaluation of suggested solutions against the objectives identified in the analysis phase.
Before a decision is finalized there is usually an element of feedback at various stages where critical comments are received following the appraisal. This may take the form of further information, advice, recommendations, approvals or instructions that either confirms that the proposal is acceptable, or that some elements must be analyzed again in more detail. Further examination leads to a new synthesis, a new design proposal that can be re-appraised, that may result in further feedback. Thus the process is iterative, the design is constantly reviewed and refined.
This map was not thought to suggest a firm route through the design process as that process may be considered to be endless. Designing also involves finding as well as solving problems and involves subjective value judgments. The process of design also has to respond to a number of constraints from various interested parties both from within the design team and from outside.
Design Constraints
In the development of a building design the architect has to take account of many constraints. These include constraints imposed by the client, factors related to the site and environment, cost considerations, legal constraints, planning and building control legislation, together with constraints imposed by other members of the design and management team.
Feasibility Studies – the client’s report
Before the client proceeds with a building project, they must be certain that the project is feasible, in other words – is the scheme possible? This process needs to be quick yet precise – a client is not prepared to wait several months for the results or incur unnecessary consultant’s fees.
Before a decision is taken to build (extend or renovate), clients will consider their needs carefully -
· Why is it necessary to incur expenses?
· Are there other solutions?
If the client decides to proceed with development, the client will then negotiate directly with all those concerned or have representatives to undertake the negotiations on their behalf – this is INCEPTION. The architect or other consultants will formulate a brief. The minimum points required by the architect are:
1. Time limit,
2. Preliminary details of the building type, size, etc.,
3. Solicitors information – boundaries, covenants, easements, etc.,
4. Finance available,
5. Extent of land or property,
6. Ownership of the land,
7. Is there outline planning permission?
The architect can then begin to give the client options / types of solutions. If these are suitable the next stage is the FEASIBILITY STAGE – an extension of the brief. During discussions new ideas and options will cause the brief to be modified to suit the client’s exact needs. It is the architect’s responsibility to study all aspects of the proposed project. It will be necessary to visit the site and begin consultations with the local authority and other bodies.
The report requires the architect to carry out an environmental impact study – a study concerned with the way in which a building performs in a particular location. The positioning and orientation of the building on the site with regard to the land and existing vegetation will be considered along with the way the building reacts and interacts with the elements of sunlight, wind and rain. The following factors will affect the way a building is designed and used:
1. Location, size and topography of the site. A soil analysis of a site will identify the type and extent of the soil and the minerals contained. From this the water table can be established and also the movement of surface water.
2. The orientation of the site with regard to sun path. The sun path of both the summer and winter sun has to be positioned, and combined with the topographical slopes of the site, the position of the building on the site can be fixed as well as its orientation. Following from this, the location of certain rooms can be positioned. Today all house types should be within 300 of facing south (in this country) and within 150 if using a solar panel.
3. The direction of prevailing winds – this affects the use of windows and doors in certain areas and also external seating and walkway arrangements. Prevailing wind can increase noise pollution from nearby roads, etc. as well as carrying polluted air.
4. Existing trees and vegetation, shelter and natural shade. The latter is important depending on the aspect of the building or garden and on the requirements of the occupiers.
5. The buildings within the surrounding area.
6. The existing services provided, etc.
Costing
The client will be concerned with the economic viability of the project. In all cases the cost of the scheme must be balanced against income:
1. Developments for profit. Cost targets for profit developments are related to free-enterprise economics. The location and quality of a scheme will reflect rental levels / selling price. Cost targets can easily be set.
2. Social development. Cost targets are difficult to set as rules vary. Constraints are at a high level (Government) or the amount of money that can be raised. ‘Yardsticks’ are used for education, hospitals and social housing. Often the restrictions of tight constraints deviate from the social purpose of the whole exercise.
The total project cost will be much higher than the cost of the building fabric and will comprise:
1. Cost of land.
2. Legal, etc. costs of acquiring the site.
3. Demolition or other physical preparation of the site.
4. Building cost.
5. Professional fees in connection with above.
6. Furnishings, fittings, machinery, etc.
7. Cost in connection with disposal – sale or lease.
8. Cost of financing the project.
9. Cost of management, running and maintenance where building is to be retained or managed by the client.
Building Legislation
One of the main issues present in the design process is the legislation as it applies to the planning, construction and operation of a building. Such legislation is usually there to protect the public. Most dominant in the process are the twin consents necessary for almost all new development of any size: PLANNING PERMISSION and BUILDING REGULATION approval.
Planning Legislation – Dates from the 1947 Town and Country Planning Act, the purpose of which was to ensure control over the use of land and provision of appropriate development. Zoning land for uses prevented housing and industrial being built side by side (as in the Industrial Revolution).
Whilst zoning has been abandoned, Local Authorities prepare Local Plans identifying ‘principles’ of land use in their area. To ensure that the aesthetic considerations of the surrounding area and of the building are kept in harmony, the planning officer requires a description of the proposed design. They will consider a wide variety of details from the number of car parking spaces to the color of the brickwork.
Outline consent – is granted where, in principle, the size and type of building is suitable.
Detailed consent – will involve examination of the design along with notes on the materials and finishes to be used.
Building Regulations – These are concerned with the well being of the public and not the building itself. The introduction to the building regulations state:
“The main purpose of the Regulations is to ensure the health and safety of people in or about the building. They are also concerned with energy conservation and access to buildings for the disabled.”
Some of the sections within the regulations cover: Materials, structural stability, thermal insulation, sound insulation, refuse disposal, ventilation, room heights, drainage, sanitary conveniences, etc.
Fire Precautions Act – Certificates are issued by the local fire authority and cover in particular – means of escape, means of fighting fires and means of warning (alarms). This implies that the design of a building takes into account planned escape routes with fire doors, the widths of corridors and openings, and the positioning of fire extinguishers.
The Construction (design and management) Regulations 1994 – These regulations are to ensure that all aspects of Health and Safety are not only considered and designed into a building, but also that when the building is maintained, the maintenance work is able to be carried out safely – without causing unnecessary health hazards, e.g. the replacement of certain types flooring requires the use of acetates – this could be in an enclosed space with poor ventilation.
The grounds, access and space, externally.
The grounds around a building should be designed with as much care as the internal aspects of the building. There will always be limited space that needs to be apportioned between designated areas.
Customer requirements: Appearance is everything, therefore areas need to be put over to landscaping and furniture, hard paving areas and lighting. The layout of the grounds and entrances to the building should ensure that customers, their cars and delivery lorries, etc. are kept separate.
Car parking needs particular attention as customers will expect to enter and leave easily, and leave their cars in a secure environment. The customer car park entrance should ensure that no bottlenecks occur. The parking area should:
· Ensure parking spaces are easily seen (and found),
· Ensure spaces are wide enough,
· Provide disabled parking spaces,
· Provide easy access into the building,
· The areas should also be well lit and safe for pedestrians.
Hotel requirements: The main consideration will be for the access of fire-fighting vehicles as stipulated by the Building regulations (B5). Access is required to a percentage of the perimeter of the building depending on the building’s height, services and fire fighting provision within the building. Even with a dry riser, a fire-fighting vehicle has to gain access within 18m of the inlet to the riser.
The goods entrance will take into consideration the size of the delivery vehicles and their turning circles. The access to the building will take into account the method of loading/ unloading and also the type of delivery i.e. Refuse, food, laundry, stationary, etc.
The economics of designing low maintenance buildings
A building is an asset that needs to be maintained to ensure its value is not eroded. If a building has been designed using high maintenance products, the client will have to pay for maintenance work during the life of the building.
Different elements of a building require maintenance at different times, e.g. Engineering services usually have a much shorter life than the structure and require regular maintenance to ensure they function efficiently.
It is important that the client is made aware of these problems during the design stage as there are many options to choose from at this stage:
· various wall construction,
· different roof finishes,
· door types, etc.
The Organisation and Management of Maintenance (to the structure of a building).
From the moment a building has been built and occupied, it will begin to deteriorate and maintenance will be required.
Maintenance is the combination of all technical and associated administrative actions intended to retain an item in, or restore it to, a state in which it can perform its required function.
All maintenance should be ‘Planned Maintenance’. Planned maintenance is organized and carried out with forethought, control and the use of records to a pre-determined plan. Some hotels, etc., have their own estates/ maintenance department, others rely on management consultants. Whichever is used, hotel management will need to know the maintenance that is planned, or request maintenance if necessary. Therefore maintenance of a building can be divided into two functions:
The ‘ORGANISATION OF MAINTENANCE’ where the estate’s department will need to priorities work. The maintenance manual will be used as the major source of reference to consider –
· what maintenance is required?
· where is the maintenance located (and quantity of work)
· what is the frequency of the maintenance?
The hotel’s ‘MANAGEMENT OF MAINTENANCE’ where the hotel management will liaise with the estate’s department to consider the following:
· when can the work be carried out?
· what disruption will it cause?
· will it affect income?
· how much will it cost?
From the above, a programmed for the maintenance work can be established which will include for:
· Regular maintenance
· Annual maintenance
· Periodic maintenance
This maintenance programmed will identify the type of maintenance and when it will be required.
Credit:ivythesis.typepad.com
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