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According
to English Heritage, the body responsible for the protection
of a large number of historic buildings in England, on average
two historic buildings burn down each week. While loss of
life is not normally associated with these incidents, there
is clearly a perception that old buildings represent significant
hazards and accordingly the authorities here in Ireland have
been reluctant to accord any special consideration to historic
buildings when formulating regulations. Historic buildings
open to the public are frequently the subject of arson attacks,
while buildings are at significantly greater risk during the
course of any construction works. Spectacular examples of
fires during repair include the fires at York Minster and
Windsor Castle.
The
regulatory environment
All buildings open to the public are subject to the workings
of the Fire Services Act, which, among other things, sets
out standards for egress and stability in the event of fire.
These standards reflect the current technical guidance given
under the building regulations. Places of assembly and entertainment
and also apartment buildings are covered by this act, which
however, makes no allowance for the special requirements of
protected structures, but applies equally to all existing
buildings. Thus, requirements to improve fire separation or
to provide alternative means of escape may apply to all old
buildings.
Under the Planning Act, only work which does not affect the
character of a protected structure is exempt from planning
control. Anomalies arise when planning permission is not forthcoming
for works that may be required by the terms of a fire safety
certificate. Several of the typical Georgian buildings on
the main Dublin squares exist in a kind of regulatory limbo
for this reason.
The solution, as proposed by the Heritage Council and other
interested parties, such as the Royal Institute of the Architects
of Ireland and the Georgian Society, is for special status
to be given to protected structures in the context of technical
guidance for the Building Regulations. Such an approach has
been adopted in the recently issued revision of Part L of
the Technical Guidance Documents, which acknowledges the potentially
destructive impact of compliance with new standards on old
buildings, and accordingly exempts protected structures from
the requirement to comply. A similar approach with regards
to fire would allow the special circumstances of historic
buildings to be addressed, while maintaining safety standards.
Improving Fire Performance of Older Buildings
Fire
Engineering
One of the advantages of working with existing buildings is
that issues can sometimes be resolved by demonstration and
trial rather than theoretically. This use of a fire engineering
approach is acceptable to most fire officers. An extension
of this approach is the QDR, or qualitative design review,
approach, which allows that increased levels of management
may be credited in evaluating the fire performance of a building.
As many of the more important historic structures are open
to the public, and are therefore equipped with a curatorial
staff, this is an important element in establishing and quantifying
risk.
Thus, by means of testing, the enclosure of the important
cantilevered stone staircases at Dublin City Hall was averted
by demonstrating that a fire of a given size, which was lit
within the ambulatory of the ground floor, would not fill
both staircases with smoke within thirty minutes. In this
instance, the building itself assisted in arriving at the
solution: the large dome was seen to act as a reservoir for
the smoke.
Such fire engineering solutions may be necessary to overcome
a literal interpretation of the guidelines under the Building
Regulations. The requirement to provide lobbied enclosures
to staircases can be particularly intrusive: pressurization
of stairs may obviate the need to pressurise, in certain circumstances.
Similarly, it was possible to demonstrate in the crypt of
Christ Church Cathedral that adequate levels of lighting were
achievable from indirect floor based lights, a design which
would normally not be allowable, but following erection of
a sample series of fittings and measurement of the resultant
light, certification by a competent specialist was provided.
Certain improvements to the performance of buildings in fire
are easier to accommodate than others: compartmentation of
a roofspace may have little visible impact on a building,
yet may significantly reduce the rate of spread of flame or
smoke. The more the spread can be inhibited, the more time
available for the fire to be identified and controlled.
Active fire detection measures are of the utmost importance
in the reduction of the risk of fire. Provision of fire detection
and alarm systems to a standard higher than that which would
otherwise be required may be possible, attention being given
to reducing the impact of wiring on the historic fabric, perhaps
even utilising wireless systems.
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