Peter Jennings, Technical Director for ACO Building Drainage, looks at existing standards relating to fire safety in public sector buildings and explains how the latest drainage technology is helping to reduce the risks.
It goes without saying that fire safety is a critical consideration during both the specification and construction of public buildings, such as office blocks, retail outlets, places of assembly, hospitals, schools and hotels. As a result, one area in particular that requires considerable thought is the design and installation of drainage systems. These are intrinsically open systems designed to allow liquids to drain away from restaurant kitchens, shower rooms and from rainwater or flooding. However, the open nature of these systems presents open channels through which flames, smoke and toxic gases can easily spread from room to room and floor to floor in the event of a fire. Indeed, in the worst case, the relatively narrow aperture of a drainage channel can actually act as a venturi, increasing the speed at which flames and fumes can travel and therefore spread.
While 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 a challenge as there is still a lack of widely recognised and appropriate universal standards for companies to work to.
To address the problem, leading manufacturers, such as ACO Building Drainage, have developed innovative new technologies, including a range of high performance floor gullies that are effectively fire proof and, perhaps as importantly, can provide a high degree of automatic smoke protection. These new systems have also been designed specifically for multipurpose applications and allow for easy installation with modern building and construction techniques.
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, these new cartridges are tested and certified to meet BS EN 1366 Part 3 Fire Resistance Tests for Service Installations Penetration Seals, 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 nickel bronze 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. For example, the latest gullies from leading manufacturers are supplied with membrane clamps as standard, while a wide range of gully tops are available for various floor finishes, including insulated floors, eliminating the need to specify additional raising sections. There are also options for gullies to be supplied with wetroom gully tops, which incorporate an integral, hermetically sealed polypropylene fleece to ensure watertight connections with proprietary roller or brush applied tanking systems, as well as rodding eyes for use with all types of floor finishes and double seals on the covers ensuring air and watertight access.
Naturally, fire safety plays a key deciding role when planning, designing and building both public and commercial facilities. In particular, it has always been critical to prevent the risk of flames, smoke and toxic gases spreading through conduits and drainage systems by specifying and installing appropriate solutions. With the advent of new building drainage technology, the pressure of this task can be somewhat alleviated, leaving contractors to rest assured that these systems provide highly effective fire protection and meet the appropriate standards, without compromising on the ability of gullies to carry out their primary task of water removal.