6. APPLICATION OF FUNCTIONAL REGULATIONS
It has been afgued that the use of functional regulations means that the standardization
of requirements which the National Building Regulations was supposed to introduce has
not been achieved but this is not So. For reasons explained in item 4 of this commentary,
the choice of materials and methods of design and construction have deliberately been
left free. What has been standardized is the requirement that the element concerned
should be fit for the purpose which it was intended to serve. It cannot be too highly stressed
that the standard of performance is set not by what can be achieved by materials and
methods of construction which are regarded as conventional but by what is necessary
to ensure the health and safety of occupants of a building. In this respect the deemed-tosatisfy
rules, although representing one way of complying with the regulation, cannot be
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regarded as the standard by which other solutions are judged.
Any application of a functional regulation must therefore take into consideration that the
required standards of performance may change in accordance with the circumstances
and that any solution must be related to the basic philosophy behind the regulations.
It is thus important in each case to ask the question, "What are we trying to achieve in
applying this regulation?" Basically, of course, the answer will always be that the object
is to ensure either the safety or health of people but it must be borne in mind that this
object may often be achieved in a simple but unconventional way.
Factors which may have to be considered would include the use of the building, the
length of life which the local community would expect from it, the size of the site and
the environment in which the building is to be erected. In addition, it may be necessary
to take into account the availability and affordability of materials, ease of maintenance,
the degree of risk which can be allowed, the relative cost of different solutions and even
the background and aspirations of the local ccmmunity.
Life expectancy may have a considerable influence on the structural aspects of a building.
The probability of certain loads occurring or limits being exceeded is obviously much
less in a period of 5 years than it would be in a period of 50 years. A modern high-rise
office building in an urban area, because of its height is subject to high wind loads in
addition to large gravity loads and, by its nature, is complex and costly. It is therefore
required to have a long life. This is of course automatically achieved because its very
cost and complexity ensure that it will be carefully designed and built using only satisfactory
materials and proven construction methods which will provide satisfactory performance
in terms of the functional regulations. However, it can be shown that the typical
traditional "wattle and daub" hut built in the rural areas can comply with the same regulation
and one of the reasons is that the expected life is entirely different. This form of
construction will normally last without collapse or distress for at least 2 rainy seasons but
will then need major maintenance or replacement. This is known and accepted by the
local community and thus, given a life requirement of 2 years, the hut may be said to
comply with this regulation.
The two examples used above represent extreme cases but nevertheless illustrate the
principle involved. It might be argued that this obvious difference in performance should
not be allowed and that in a case such as the hut the regulations should be employed
to raise Third World standards to those generally accepted in the First World. Besides
the fact that this was never the aim of the regulations it is essential to take into account
the realities of the situation.
In many of the outlying rural districts it may not be possible to obtain the more conventional
building materials and if it were possible the people would probably not be able
to afford them or know how to use them. A similar situation exists in the urban areas in
the field of low-cost housing where, particularly with core housing, shell housing and similar
self-help schemes there is inevitably much work which is of a temporary nature and which
cannot possibly be judged on the same basis as the final product. In the case of any
incremental house the provisional authorization, which is of course subject to the limiting
area of 80 m2, would have to refer to the complete building. The first stage to be built
will, by definition, be smaller or incomplete in some other way, but some time limit would
have to be set for completion of the building and submission of an application for approval
in the normal way. Once this application has been approved the building would
no longer be regarded as an incremental building and any subsequent additions would
be treated in the same manner as in any other building.
Low-cost housing, by its very nature, can vary from the pure 'Shanty-town" through all
the variations of self-help and many other unconventional methods, to the strictly conventional
but small house. What they all have in common is that they are all domestic
housing units set on small sites (implying small boundary distances) in large low-rise developments
and in all cases initial cost is of paramount importance.
In the application of functional regulations these factors must be taken into account. For
instance, because of their situation in a relatively high-density urban situation with little
or no high-rise development in the vicinity, it is likely that the walls of these buildings
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will be subject to a lower wind load than might usually be assumed and thus strength
criteria or bracing requirements might be reduced without endangering the occupants
of the house in any way.
The treatment of fire risk is always a problem in the context of low-cost housing. To insist
on many of the conventional ways of ensuring safety would be to rule out the use of many
potentially cheap yet sound methods of construction so again it becomes necessary to
go back to basics. The object of the regulation is to ensure the safety of occupants of
the building and they will be safe from the fire if they are outside the building. The object
of the regulation may therefore, ir, many cases, be achieved by insisting on very short
travel distances to exits from the house in lieu of other protective measures.
While this sort of treatment may ensure the safety of the occupants of a house it does
not in any way help to prevent the spread of fire from one house to another which is an
ever-present danger because of the very small boundary distances which are imposed
by the small sites on which these houses are built. It may be necessary under these circumstances
to accept a slightly higher risk factor as far as property is concerned but
it is possible for the local authority to compensate to some extent by other provisions.
The most obvious of these would seem to be by ensuring a very low response time from
the local fire brigade and an insistence that any house with combustible walls should
only be built on a site between houses with non-combustible walls. The latter arrangement
does not fall within the scope of building regulations but could be controlled under
a town planning scheme.
To sum up, the standards for requirements under a functional regulation are controlled
by the requirements of the individual building as influenced by its siting, conditions of
use, etc. The local authority cannot enforce any particular empirical requirement as a
general rule since what may apply to one building may not apply to another. It is for this
reason too, that the deemed-to-satisfy rules given apply usually to a limited range of buildings
and, in most cases, tend to be very conservative. A further outcome is that a local
authority could only reject an application on sound technical grounds just as a designer
may be asked to produce sound technical reasons to justify his design. 原件下载： 
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