Fire and security

There are 700 deaths every year in the UK due to fire, and 66% of these are smoke related. With these facts, the main point to consider when specifying firestop products is that if a fire breaks out, will the installation prevent the spread of smoke and flame into the next compartment for the intended time period? Mark Fort, chemicals product Manager for Hilti (GB), highlights five key points for consideration.

1. Has the product been tested to do the job for which it is being specified?

Unlike acoustic or air sealing, which can be physically tested on site, firestop systems must be pre-tested in a suitable laboratory mock-up. A product alone cannot have a fire rating. The tested fire rating is only applicable if the product is used and installed in exactly the same way as it was tested.

A number of tests are required to cover different wall and floor types, different pipes and cable materials and diameters.

For instance, a foam that is claimed to achieve four hours’ integrity and be tested to BS476 will have been tested on a very thick wall with a very narrow joint. If the gaps are larger or the walls thinner, the actual time will be dramatically reduced.

Look for or request an official assessment that will detail the different ways the product can be used.

2. For drywall, has a 3 m x 3 m furnace been used?

The cheapest testing is done in a 1 m x 1 m small-scale furnace. This is fine for solid walls, but drywall can deflect and distort in a fire. Since the pipes and cables are usually supported independently from the wall, the wall can move relative to the seal.

A 3 m x 3 m furnace should be used to test drywall penetration seals, and it is essential to show the system can survive such deflection.

3. How do I know that the product being used is the one that was tested?

Imagine a product passes a fire test and is put on the market. What is to stop the manufacturer removing the active ingredients? Even if you cannot specify a particular product, it is advisable to request one with third party approval from, for example, the Loss Prevention Certification Board (LPCB) or Certifire . These bodies check the manufacturing process to ensure the product leaving the factory is as it should be.

4. Will it be installed correctly?

Designers can easily help ensure that the product is fitted properly by stating that installation be carried out by trained people. Even the best intumescent mastic on the market will not work if there is just a smear on the surface of the wall. Knowing how much product to use is crucial.

A third party installer, accredited by FIRAS or the LPCB for example, will have undergone installer training. Its companiesmust provide the paper trail to show what products were used where, which will ultimately protect the designer.

5. Will the product degrade over time?

Fire testing is likely to be done on a seal that has been installed just days or weeks before the test, but reality dictates a fire could occur years after product installation.

Moisture and temperature changes can degrade chemical products, so an age-tested system should be specified. The seal will be installed and subjected to an accelerated ageing cycle, then fire-tested to prove it still works.

With current legislation, liability for poor firestopping is shared by all parties from the designer to the construction firm to the installer, yet forthcoming legislation means individuals will be responsible.

Designers need to incorporate firestopping as an integral part of their role. By adhering to these five points, any individual or firm is well on the way to protecting lives, property, and minimising liability.