Drainage innovations provide built-in fire and smoke protection
Peter Jennings, Technical Director for ACO Building Drainage, looks at how poor planning of drainage systems can contribute directly to the spread of fire in large buildings.
Drainage systems, by their very nature, are fundamentally open systems that safely remove water and liquid wastes away from the inside and outside of commercial and public buildings. However, it is the intrinsically open construction of these channels and gullies that presents a significant problem when in comes to fire protection. This is especially true within buildings and closed spaces, as drainage channels between floors can provide an unobstructed, open passage through which flames, smoke and toxic gases can easily travel from room to room and floor to floor at an alarming rate in the event of a fire. Worse still, the relatively narrow aperture of a drainage channel can actually cause a venturi effect and dangerously increase the speed at which flames and fumes are sucked or blown through and therefore spread.
Indeed, in recent years there have been a number of high profile
disasters where public and commercial buildings have been destroyed
and lives lost as a direct result of fire and fumes spreading
rapidly via conduits and drainage systems. Take for example, the
devastating and tragic fire that killed 17 people, mostly due to
smoke inhalation, and left over 100 injured at Düsseldorf Airport
in Germany on 11th April 1996.
The fire was caused when hot glowing particles from a welding
operation dropped onto a part of the roof of terminal A where PVC
cables and insulation materials immediately caught fire. As a
result, flames, smoke and noxious fumes then broke into the cable
ducts and drainage gullies and spread throughout the entire
occupied building. On top of the loss of life and casualties, the
fire caused hundreds of millions of euros' worth of damage to the
airport, making it, at the time, the biggest public disaster in the
history of North Rhine Westphalia.
Critically, the key problem here was caused by the use of PVC,
which is extremely flammable and generates huge volumes of toxic
gases. However, the point remains that the ducts and gullies
running between the floors offered an unobstructed route for flames
and fumes to be sucked or blown through.
In the wake of the much publicised tragedy, the building was
completely modernised and, most importantly, all the PVC was
replaced with alternative materials. The fire also raised public
awareness of how a building's drainage system can cause the
problems of a fire to escalate rapidly, ultimately with
catastrophic effects. Accordingly, the danger is now widely
recognised in Germany and standards have been introduced that make
it vital for appropriate gully protection systems to be installed
in public buildings, such as hotels and offices.
Although the problem is understood in Germany, in other European
countries, including the UK, the dangers are still yet to be fully
appreciated. In addition, even though standards have been
introduced in recent years to provide design guidance for
minimising the risk of flames, smoke and fumes, such as the
Regulatory Reform (Fire Safety Order) 2005, Building Regulations
Approved Document B Fire Safety, April 2007, BS EN 1366-3:2004 Fire
Resistance Tests for Service Installations and BS EN 13501-2:2003
Fire Classification of construction products and building elements,
the task of specifying the correct building drainage remains
somewhat complex as there is still a lack of widely recognised and
appropriate universal standards for companies to work to. This lack
of guidance and understanding means that many specifiers are still
relying on traditional technologies, such as sprinklers or fire
barriers, to prevent the spread of flames and fumes, particularly
in older buildings.
Nonetheless, the design and installation of drainage systems is one
area that requires considerable thought, particularly when you
consider the dire consequences of not doing so. In order to address
this issue, some leading manufacturers, such as s ACO Building
Drainage, have been working to develop a new generation of
innovative technologies, including a series of revolutionary high
performance floor gullies that are essentially fire proof and,
perhaps most importantly, provide an unparalleled degree of
automatic smoke protection. Equally, this leaves contractors rest
assured that these systems provide high performance fire protection
and meet the associated standards, without compromising the ability
to carry out their primary task of water removal.
Traditionally, drainage products have generally been manufactured
using plastic and aluminium, which makes them unable to withstand
the high temperatures of up to 1,000°C that are often found in
building fires. By comparison, the latest gullies are manufactured
with cast iron bodies with a melting temperature of at least
1,120°C. Equally, to prevent the drainage gullies and connecting
pipework from providing a path for the passage of fire, smoke or
noxious gases, these gullies feature unique fire protection
cartridges.
Perhaps most importantly, the latest high performance cartridges
are tested and certified to meet BS EN 1366 Part 3 - Fire
Resistance Tests for Service Installations - Penetration Seals with
up to two hours protection, and are constructed from an intumescent
material that expands dramatically when the ambient temperature
reaches approximately 200°C. As a result, the rigid cast iron body
forces the cartridge to expand inwards causing it to block off the
gully outlet entirely from fire and smoke. Furthermore, the fire
protection cartridge can easily be retrofitted if the building
undergoes a change of use, where fire protection is later
required.
In addition, this latest generation of drainage gullies has been
designed in accordance with BS EN 1253 Gullies for Buildings
meaning that they can be installed without the need for further
performance and safety testing. Moreover, they offer specifiers a
broad range of grating styles, in either stainless steel or copper
alloy for use in solid or suspended concrete floors, and in both
new build or refurbishment projects. They are also compatible with
a wide range of floor coverings, including tiled, resin,
cementitious or flexible sheet flooring applications.
The latest building drainage systems have also been designed to
improve the flexibility and ease of use for specifiers and
installers still further, making them ideal for multipurpose
applications and allowing for easy installation with modern
building and construction techniques.
Some of the leading manufacturers, such as ACO Building Drainage,
are members of the Association for Specialist Fire Protection (ASFP)
and their fire protection drainage systems can be found in the ASFP Red Book, which is the definitive guide
to the provision of proprietary materials and systems used for fire
stopping and sealing of penetrations to comply with building
regulations.
Recent high profile disasters, coupled with the fact that 2008 saw
the highest UK peacetime fire losses of all time, has helped to
raise awareness of the importance of correctly specified and fitted
fire proof drainage systems in order to protect not only public and
commercial buildings from damage, but most critically, people.
Thanks to the introduction of the new generation of fire resistant
gullies, designers and installers can now rest assured that optimum
protection against flames, smoke and poisonous gases, as well as
effective water removal will be achieved at all times, maximising
safety, comfort and customer satisfaction over a long service
life.
