Memorandum by the Fire Safety Development
Group (ROF 26)
1. INTRODUCTION
1.1 On 11 June 1999 a wheelchair-bound man
died in a tower block fire in Irvine. We believe that the fire
started in a room on the 5th floor and burs out through the window.
Within about 10 minutes the fire had spread up seven floors but
was contained within the area of the cladding. The fire broke
through into the building, possibly by means of the area beneath
the windows or the windows themselves, and engulfed the upper
nine floors.
1.2 There may have been special circumstances
relating to this fire but nevertheless we consider it highlighted
a number of aspects of fire safety which need to be addressed.
These are:
1.3 Firstly, a distinction between products
that conform to the Class 0 standard inherently, or through modification
by additives.
1.4 Secondly we seek urgent action from
the DETR to regulate the use of plastics and to reduce the threat
to life from toxic smoke and burning droplets. We have assumed
the Committee will be professionally advised, and have therefore
written our evidence accordingly.
1.5 We have been informed that the windows
at the corners of the tower block had been letting in cold and/or
moisture. In order to eliminate these problems and also to improve
visual appearance, new window frames of unplastised polyvinyl
chloride (uPVC) were fixed. The exterior wall around the window
was covered with glass reinforced polyester plastic sheet. This
gave a picture frame effect around the window. The glass reinforced
polyester sheet was also extended below the window. We do not
know if the fire was spread by means of the surface of the plastic
sheet or whether the fire spread within a cavity that may have
existed between the cladding and the original external wall.
Memoranda
2. "WHETHER
A RISK
IS POSED
BY SUCH
CLADDING"
2.1 Regulations in Scotland, England and
Wales specify that exterior cladding should be Class 0 fire performance.
Class 0 is the highest category for surface spread of flame of
a material and is defined in the Approved Document B Fire Safety
to the Building Regulations (England and Wales 1991). This definition
is also used in the British Standard (Scotland) Regulations.
2.2 We believe that there is confusion about
the Class 0 standard for two reasons. Class 0 materials refers
to the performance of the surface of the material, but applies
to the total product, ie the facing plus any coating, adhesive,
paint, etc plus the substrate to which the facing is bonded. Clearly
these other elements will affect the performance of the cladding
in a fire, and will vary with the nature of the coating, the thickness
of the adhesive, the type of substrate etc.
2.3 A material of limited combustibility
can achieve a Class 0 rating as defined by the regulations but
a Class 0 material is not equivalent to a material of limited
combustibility. A material of limited combustibility is generally
a material which is totally non-combustible or which contains
a small amount of combustible material. Combustible materials,
like plastic, wood, etc are not materials of limited combustibility
but can achieve Class 0 performance by adding fire retardant chemicals
or facing the combustible material with a metal foil or sheet.
Thus there is a fundamental difference between products that are
inherently Class 0 and products modified to enhance their performance.
This serves to undermine the integrity of the regulations and
therefore reduces fire safety.
2.4 Confusion often occurs because some
manufacturers refer to Class 0 products without due consideration
for the way the product will be used or treated. The performance
of an external cladding sheet which, when tested alone and meets
the requirements of Class 0, could easily be downgraded to an
inferior level by painting the sheet with the wrong type of paint.
2.5 We believe that both methods can suffer
from technical problems, particularly for products used for exterior
applications, when the additive may not be durable. With time,
the performance will fall to a lower level. If a facing foil or
laminate has been used on the plastic material, this could be
damaged with time or delaminate due to loss of adhesion between
the foil and the substrate. These types of products still remain
combustible and will contribute to fire load in the event of fire.
Higher levels of smoke will be developed when combustible materials
burn than for materials of limited combustibility. Furthermore,
in the case of thermoplastics, they could drip in the event of
a fire and this will exacerbate fire spread.
2.6 It is well known that fire and smoke
can spread unhindered in cavities and for this reason, regulations
specify cavities should be divided at certain intervals depending
on the nature of the cavity. If the requirements had been followed,
we do not think the fire would have spread as described in the
newspaper reports but further investigation should show if cavity
barriers were lacking.
2.7 The cladding appears to have helped
spread the flame over the surface and may also have been consumed
by the fire. However, it may not have been considered necessary
by the designers/specifiers to use a product with Class 0 performance
as the sheet may have been classed as a window frame rather than
an external cladding. If the plastic cladding used on the building
had a lower spread of flame than required by regulations or insufficient
cavity barriers were used, then we consider that this system presented
a fire risk.
2.8 We understand that the uPVC window frames
made a big contribution to the rapid spread of the fire and its
entry into the upper parts of the building. This would help to
explain how the fire could burst out of the flat where it started,
and then manage to get back into the tower block to destroy the
floors above the fifth floor.
2.9 We are concerned about the increasing
use of plastic and combustible materials on the face of buildings
and consider that their use should be examined in more detail.
Building regulations do not pay sufficient consideration to the
effect of fires spreading by external means. Smoke and flames
issuing from windows can be very severe and easily affect other
parts of the same building.
2.10 There is an increase in the use of
plastic products and in particular uPVC for renovation work on
the exterior of buildings and we consider their use should be
examined in more detail. As the work is frequently for small repair
and maintenance work, detailed planning permission may not be
required and the application is unlikely to be covered by any
fire regulations.
2.11 The uPVC window frames in the Irvine
fire were stated to have melted. This is a common occurence with
this type of thermoplastic and has occured in other fires. We
have had experience of a plastic soffit lining board melting and
molten plastic falling on fire fighters below. The molten material
also helped to spread the fire within the building although the
product had been used for an exterior application. In this case,
the plastic soffit board was destroyed which then enabled the
fire to enter the roof space and spread throughout the building.
One fatality occurred. A picture showing this fire is included.
2.12 Our understanding is that at present
the DETR have no plans to reconsider the relevant regulations.
We think this ill-advised. We also believe it is necessary to
consider that contribution made to the fire by burning plastic
building materials and in particular foam plastic cores of external
composite cladding panels.
3. "THE
EXTENT OF
THE USE
OF EXTERNAL
CLADDING SYSTEMS"
3.1 External cladding systems are widely
used both in new building and in refurbishment work. We understand
the type of plastic cladding used on the property in Irvine is
widely used throughout Scotland. However, we believe the fire
spread and re-entry to the building was probably a consequence
of the PVC window framing and sills. We do not think this type
of alteration is widespread but it should be looked into.
4. "THE
ADEQUACY OF
THE REGULATIONS
PERTAINING TO
THEIR USE"
4.1 We believe the present regulations in
England and Wales were revised in 1991 to ensure that cladding
systems did not spread fire and present a risk. As a result of
the experience with a fire that spread within the cavity behind
an external cladding system, the Approved Document B was changed
to specify that combustible insulation was precluded from external
wall construction in buildings with a storey at over 20m above
ground level. The Scottish regulations were amended in 1997, after
fears that a fire could spread up a cavity. Since then, every
opening has had to have a seal.
4.2 We believe that not only should the
external face of the cladding be Class 0, in accordance with the
regulations, the Clase 0 standard should also apply to the inner
face of the cladding sheet where there is a cavity behind the
external sheet.
4.3 We do not consider there is adequate
regulation governing the use of plastic products on the exterior
of buildings. Responsibility for implementation may be split between
Building Control and the Fire Autorities and it is not always
clear which authority is responsible for renovation work.
4.4 We also wish to make a distinction in
the regulations between integral Class 0 materials and modified
products. This should reflect the different fire performance between
a non combustible composite cladding and one consisting of a metal-face
foam plastic.
5. "WHAT
ACTION MAY
BE NECESSARY
TO COUNTER
ANY RISKS
POSED IN
EXISTING BUILDING
AND TO
AVOID ANY
RISKS IN
NEW BUILDINGS
OR ALTERATIONS
TO EXISTING
BUILDINGS"
5.1 We do not consider there should be a
wholesale review of all external cladding systems, as we are sure
that the majority will have met regulatory requirements. A more
detailed study is, however, needed to examine the fire behaviour
of thermoplastic products when used in exterior applications.
When plastic window frames could be affected by fire as a result
of the design of external cladding systems, some form of fire
protection may be necessary to protect the frame. Alternatively,
fire barriers should be used to prevent fire ingress into the
building.
5.2 Thermoplastic products should not be
used in areas where they could melt or be destroyed by fire and
thus add to the spread of fire. It may therefore be necessary
to replace some of these plastic products with materials of limited
combustibility.
5.3 There is also widespread concern amongst
many fire fighters about the safety of external cladding systems
consisting of metal-faced foam plastics. These systems will generally
have Class 0 fire performance, but in real fires the foam plastic
lining can ignite and burn. This helps to spread the fire via
the building fabric and there will be an increase in the generation
of smoke and toxic fumes. Collapse is also possible. We believe
this subject is still being reviewed by the DETR and consider
more stringent controls a priority.
6. "OTHER
MATTERS WHICH
MAY ARISE
IN THE
COURSE OF
QUESTIONING"
6.1 We have highlighted some problems with
burning plastics which this fire has raised. There is at present
nothing in Building Regulations to require control of smoke, fumes
or burning droplets from building materials. This should be rectified
as the increasing use of plastic materials means there will be
further instances of burning or molten plastic helping to spread
the fire or cause injuries to fire fighters or building occupants.
The DETR should act to rectify this, especially as Home Office
Statistics consistently demonstrate how more people die in fires
after being overcome by smoke than any other cause.
6.2 We consider the use of Class 0 materials
should be more stringently controlled for external wall cladding.
Products which can only achieve this rating by means of surface
treatments, coatings, foil coverings or impregnation treatments
should not be allowed.
6.3 Apart from the specific recommendations
for improvement we have proposed in our Memoranda, there is an
overall broad but important point to make. The Irvine incident
once again illustrates the unpredictable and unexpected nature
of fire.
6.4 This view was well expressed recently
(FSDG Seminar on Fire Issues, House of Commons, February 1999)
by Frith Hoehnke, an architect who carried out the extensive revision
of Scottish fire safety building regulations which came into force
in 1997. Mr Hoehnke then said: "I would never advise a client
to cut anything to do with fire to the bone because, when I look
at the fire reports of actual fires, the most incredible things
have happened . . . So far as fires are concerned it is really
the unexpected that defeats us on many occasions. Indeed, it is
usually when not just one thing goes wrong but one, two or three
things go wrong at the same time that all our defences are breached
and disaster strikes".
6.5 We concur with this opinion. It raised
the question of whether regulatory decisions about fire safety
in buildings should be left as they currently are within the BRAC
or (in the case of Scotland) the BSAC remit. Clearly both these
bodies call in expert opinions but they do not always reflect
a full range of available specialist experience.
6.6 The Government is currently moving,
through the Home Office, to establish a Fire Safety Advisory Board
which should bring this wider experience to bear on all fire safety
matters. Logically BRAC and BSAC should work more closely with
such a body. It might, indeed, finally emerge as a Fire Safety
Commission reviewing fire hazards in a continuous and therefore
more sensible way. These are, as we said, wider issues but every
single incident has its lessons to teach and the Irvine fire should
be another providing support for such a broader move.
The Fire Safety Development Group is an alliance
of eight leading companies manufacturing structural fire safety
products within the UK and Europe.
July 1999
| 
