A burning issue

Fires in non-residential properties cause an average of 36 deaths and 1900 injuries every year in the UK, according to government fire statistics. To help address the problem, Building Regulations contain a raft of fire safety rules for the construction and fitting out of buildings. An m&e contractor’s role is to ensure installations are not part of the problem, but part of the solution, by fitting firestopping products that are fit for purpose.

Whether they carry flammable gas or digital information, every pipe and cable running through a hole in a wall or a floor is a potential conduit for fire and smoke.

To pass regulations, buildings must be divided into compartments by walls and floors that will stand up to fire and smoke for a specified period of time. This will stop a fire spreading through a building, giving people a greater chance of escaping and often limiting damage to property.

Penetrating a wall between fire compartments with pipes and cables reduces how long it will stand up to flames and smoke if a fire breaks out, significantly increasing risks. Firestop systems provide a secure seal, stopping the spread of smoke and flame into the next compartment for the specified time period and restoring the wall’s fire rating – a legal requirement of current Building Regulations.

A recent change in fire safety legislation means that if containment precautions fail to slow the spread of a fire effectively, fire services can investigate the causes and apportion blame to specific subcontractors along the supply chain. If it is found that a poorly fireproofed installation exacerbated the spread of a fire, the subcontractor that installed it can be individually prosecuted.

With these changes in legislation, and with commercial buildings requiring increasingly complex installations to facilitate technological advances, it can be challenging for contractors to keep up to date with fire safety measures.

Intumescent compound-based products expand quickly and powerfully when exposed to flames and, when installed correctly, can be used to automatically seal combustible pipes and cables in a fire.

For stopping plastic pipes, fire protection system manufacturer Hilti has developed intumescent pipe wraps, collars, plugs and pillows in materials ranging from PVC to lead. Wraps, collars and plugs can also be used to close single and bunched flammable cables, while pillows can render cables in trays fire safe.

To be effective, these products must be used only for the applications for which they have been designed, and they must also be correctly fitted. Ask the following questions when carrying out an installation.

1. Has the product been tested to do the specific job required?

Caution should be exercised before choosing a product for a specific application as the fire rating stated on the packaging may not apply to the particular situation. Contractors often have an unrealistic idea of the level of fire protection they are providing for installations.

Those using any firestop product should look for or request an official assessment that details the specific applications for which the product is tested and suitable. Where Hilti products are concerned, technical information detailing exactly which circumstances each product has been tested for is available online, in-store and through sales teams.

To give an example, an expanding wrap for closing pipes might typically advertise that it achieved a four-hour rating when tested on plastic pipes. Users need to be aware, though, that the quoted test may have been carried out on a thin PVC pipe passing through a small hole in a thick blockwork wall.

Used on a larger pipe made of more resilient material and running through thin drywall, the same product may fail completely, making the fire rating achieved in the test irrelevant.

The same caution should be exercised when using fire-retardant foam in aerosol cans. These foams are very commonly used in installations to plug the gaps around penetrating pipes and cables and are often advertised with ratings of up to four hours.

Again, the product may have lasted four hours when tested on a very small opening in a thick block wall, but applied to wider apertures in less substantial walls, the foam is much less effective. A foam-filled 50 mm opening in a 100 mm thick wall can burn through in less than five minutes.

An alternative to aerosol foam that has received positive feedback from the trade is graphite-based intumescent mastic. This is an expanding sealant that will not only form a permanent watertight and airtight seal around single or bunched combustible pipes and cables but will also expand to close them in a fire. The mastic, applied with a standard sealant gun, is as easy to work with as an aerosol, but is suitable for much more heavy-duty applications.

It is also possible to complete firestopping in drywall with this product without the need for time-consuming framing out of the aperture.

2. Is the product installed correctly?

Contractors can ensure they are fitting products correctly by undergoing training from one of the many UK regional bodies.

Such training will provide an underpinning knowledge that may be required for third party installer certification schemes such as FIRAS or the scheme run by the Loss Prevention Certification Board (LPCB), now part of BRE Certification.

Seeking certification can make good commercial sense as it can present a real competitive advantage in the construction industry’s increasingly safety-conscious and litigious climate.

3. What is the lifespan of the product?

While the wish to do a good job that will last a long time is motivation enough for most contractors, in many cases there is also a financial incentive to use products with good longevity.

In government projects such as hospital Private Finance Initiative (PFI) schemes, each subcontractor is responsible for the quality of their work for the lifespan of the building. The durability of the firestop product being used is therefore an important concern when carrying out installations under a government contract.

Using a product that degenerates over time will not only introduce safety concerns but could also mean the contractor is called back in to fix the problem at their own expense, possibly several years later. This can be avoided by looking for products that have been age-tested.

The range of firestop products available has expanded dramatically in recent years.

Where there is any doubt that a solution is fit for purpose, manufacturers should be happy to provide full details of the specific applications for which the product is appropriate and has been tested.

Effective firestop measures protect end-users and clients by increasing safety and reducing property damage should a fire break out.

From the contractor’s viewpoint, though, it is the limitation of liability offered by effective firestop measures that means that they are also a wise investment commercially.