4 hour fire doors …

So now we’re really upping the ante, so to speak, and talking about 4 hour fire doors. That’s a long time to provide protection from fire and smoke for, and implies something out of the ordinary about the environment in which the fire door will be situated.

It could be that the risk of fire is very great, and/or that the consequences of a fire in that environment would be terrible. Don’t let us leave you with the wrong impression here – all fires, where there is risk to life and property, are potentially terrible – but some are clearly more terrible than others. It’s a question of scale.

Let’s think back to the examples we mentioned a few weeks ago:

a fireworks factory employing hundreds of people
a small library with two members of staff
a school
a hotel
a hospital
a nuclear power station
a skyscraper
an old people’s home
an archive of vitally important or irreplaceable documents
a chemistry laboratory containing highly flammable and/or explosive chemicals
a Ministry of Defence site containing samples of the smallpox virus
the Louvre museum

As we said at the time, obviously the safety of the two library staff is no less important than the safety of the hundreds of people in the fireworks factory or the workers in the MOD site or the schoolchildren, but clearly the different environments necessitate different measures. Considerations include:

how many people would need to be evacuated in the event of a fire
what sort of building is it (e.g. skyscraper or small library) i.e. how quickly could everyone get out
what surrounds the building (e.g. isolated rural location or city centre)
what is IN the building that we wouldn’t want the fire to get to (think the Mona Lisa) , and/or if the fire does get to it what wouldn’t we want to get out (think smallpox)
overall, what would the consequences be of a fire breaking out in terms of human life, public safety, loss of property or material etc.

Don’t forget, also, all the regulations that we’ve mentioned on several occasions, and you’ll need to take into consideration additional requirements if members of the public may need to use the doors (think of public buildings, schools, hospitals etc.).

It boils down, as so many things do, to getting the balance right. There’s no point over-specifying the fire door and incurring unnecessary costs if it simply isn’t necessary. This in no way implies that we should take shortcuts on safety – simply that we get the right door for the job. Take the small library with two members of staff. It’s unlikely that a fire would break out anyway, and even if it did the staff could escape very quickly. So there’s no need to install a very high specification 4 hour fire door there.

So when would we want to install a 4 hour fire door? Let’s answer this by first reminding ourselves about the difference between hazards and risks.

Hazards and risks

The terms are often used interchangeably, but it’s helpful in this context to think of them as different.

A hazard is a potential source of harm or adverse health effect on a person or persons.

So, if there was a spill of water in a room then that water would present a slipping hazard to persons passing through it. If access to that area was prevented by a physical barrier then the hazard would remain though the risk would be minimised. So what is risk?

Risk is the likelihood that a person may be harmed or suffers adverse health effects if exposed to a hazard.

Health and Safety experts tell us that “the level of risk is often categorised by the potential harm or adverse health effect that the hazard may cause, the number of times persons are exposed and the number of persons exposed. For example exposure to airborne asbestos fibres will always be classified as high because a single exposure may cause potentially fatal lung disease, whereas the risk associated with using a display screen for a short period could be considered to be very low as the potential harm or adverse health effects are minimal.

Control measures

What we call control measures are often used to remove the hazard or to reduce the likelihood of the risk of exposure to the hazard being realised. There is a six-tiered hierarchy:

eliminate the hazard
substitute the hazard with a lesser risk
isolate the hazard
use engineering controls
use administrative controls
use personal protective equipment

Thinking back to our fire doors then, clearly if the hazard and the risk of a fire is substantial, then it may be advisable to install a 4 hour fire door, sometimes referred to as an fd240 fire door (i.e. providing protection for 240 minutes).

Apart from the extended protection from fire and smoke, such heavy duty doors will also provide enhanced security.

Talk to the experts

Enfield Doors have been manufacturing acoustic doors for many years for numerous satisfied customers – and we can give you expert advice and guide you through all of the regulations and complications that you need to be aware of.

As always we’ll be delighted to help and advise you.