BWF fire door short video

[Tom Sutton]

CT I have never been accused of being too complicated; I have been accused of being confused on many occasions. 

I accept most of what you say but if you saying a nominal 20 minutes fire protected route is acceptable then I would disagree. Because fire and the actions of persons in fire are so unpredictable I would require a minimal 30 minute standard. As Fire doors normally fail by distortion rather than burn-through and controlling or accommodating this distortion must be the primary objective. I would require intumescent strips to counteract this distortion and increase the fire resistance of the doors to provide a 30 minute nominal standard.

[CivvyFSO]

I don't believe a word CT says any more. I started reading his book, got to page 2, found a blatant lie, and stopped reading in disgust. 

Seriously though, I think a valid point is that the 20 or 30 minutes is 20 or 30 minutes of the test, it is not 20 or 30 minutes of a fire.

Unfortunately, we don't have a British Standard fire, and the times that it goes awfully wrong it is often a string of unlikely occurrences all bolted together. I am sure that for many circumstances the good old door would suffice, but somewhere at some time that extra 10 minutes could make a considerable difference.

I would also suspect that the manufacturers submitting their doors for the test will ensure that everything is done with the best quality gear, by their best joiner, and the door that sits on the test rig is the best one that they can possibly make. All others that end up in-situ will be at least a little inferior, and possibly fitted by young Johnny the trainee.

[jokar]

Civvy, are you allowed to say that?  Surely you have been subjected FRS equalities policies!

Doors are doors are doors.  You are correct that no one will know whether any particular door will operate in any way shape of form in a fire situatuation.  The furnace puts 800 degrees on the face but who knows what temperature will be in the room or compartment and for how long.

[nearlythere]

I don't believe a word CT says any more. I started reading his book, got to page 2, found a blatant lie, and stopped reading in disgust. 

Seriously though, I think a valid point is that the 20 or 30 minutes is 20 or 30 minutes of the test, it is not 20 or 30 minutes of a fire.

Unfortunately, we don't have a British Standard fire, and the times that it goes awfully wrong it is often a string of unlikely occurrences all bolted together. I am sure that for many circumstances the good old door would suffice, but somewhere at some time that extra 10 minutes could make a considerable difference.

I would also suspect that the manufacturers submitting their doors for the test will ensure that everything is done with the best quality gear, by their best joiner, and the door that sits on the test rig is the best one that they can possibly make. All others that end up in-situ will be at least a little inferior, and possibly fitted by young Johnny the trainee.

"but somewhere at some time that extra 10 minutes could make a considerable difference."

Difference to what Civvy?

[Tom Sutton]

Civvy I accept all you say except that scandalous statement in the first sentence. 

I am not talking about certified fire door sets I am talking about nominal fire doors which in the opinion of the assessor the doors should hold back a fire for a certain time. I am aware that a substantial standard door should hold a fire for 20mins, although I didn’t know it had been subjected to BS tests and in my opinion by adding the intumescent strips, will increase the FR to 30 mins. What I cannot accept is the notion that fire protected routes can be less than 30 mins.

Jokar I think Auntie Lin may have something to say on you statement “Doors are doors are doors”?

[colin todd]

Tw what is magic about 30 minutes POST FLASHOVER for avoidance ofdoubt I will say it again POST FLASHOVER. Given that people will have gone before flashover in most of the ciucmstances in which the issue is debated, who cares whether it is 20 or 30 or 300. Over engineering is bad engineering, thats why there arent 3 engines on a 737. Why do you not have intumescent strips on the doors in TW towers, given that statistically you are about 10 times more likely to die there than in an old hotel with 25mm stops on the doors and no strips.

[CivvyFSO]

Difference to what Civvy?

The difference between someone who makes it out of a building and someone who doesn't.

Why do you not have intumescent strips on the doors in TW towers, given that statistically you are about 10 times more likely to die there than in an old hotel

Where are those statistics from? I am not totally disputing them, just asking the question...

In 2006 there were approx 25,000,000 homes in the uk, and there were 55,000 fires. That is a 1 in 454 chance of having a fire in any one home over the course of the year. A total of 342 deaths means that on average 1 in 73000 houses suffered a fatality. We have 1 death recorded in a hotel in 2006. If there are 73,000 hotels in the UK then it is a nice even balance of probability of the building having a fatality due to a fire. The chances of any particular person being involved is clearly dependent on the number of persons in the hotel, and the same can be said for houses. There is not just the chance of death to consider, but the chance of injury also. If we want to update the figures for 2008 and look at the three killed in the Cornwall hotel, among with any more that occured during the year, then the figures will look quite different.

I have found it hard to find that actual number of hotels in the UK, so if anyone could enlighten me I would be grateful. I think guest houses etc can be lumped in with hotels because the statistics do not seem to separate them.

Also, there is over engineering and there is building in a suitable factor of safety for when it all goes wrong.

[nearlythere]

"The difference between someone who makes it out of a building and someone who doesn't"

Not getting at you personally Civvy but do we not aim for an evacuation to be completed in a few minutes? Even up to 10 mins would be very generous when you consider the level of detection installed in building nowadays.  Twenty minutes might be useful if you were tied up on a bed or trapped in a time locked safe.
Why 30 mins?
Why not 25 or 35?
Is it necessary to link 30 min fire door protection and evacuation times?
What is the rational behind 30 min fire door protection for escape purposes?

[Clevelandfire 3]

So based on statistics Colin Todd are you advocating that shouldnt put strips and seals on fire doors, or that we should just consider substantial doors full stops or do you think that because those things are in place that is why we have low statistics in the first place?
Plus a 747 has 4 engines not 2 Colin so no over engineering to give it three engines would be likely

[wee brian]

What Colin is getting at, I think, is that the fact that a fire door doesnt have intumescent strips has a very small impact (if any) on the effectiveness of a fire door in protecting escape routes from real fires.  Given the small risk and the small impact of the strips it is hard to justify making somebody install strips in exisitng doors.

If you are replacing doors then, of course, you would use the latest spec.

Just out of interest, how many of you strip huggers check the spacing of fixings in the plasterbaord partitions around the doors?

[Tom Sutton]

What Colin is getting at, I think, is that the fact that a fire door doesn’t have intumescent strips has a very small impact (if any) on the effectiveness of a fire door in protecting escape routes from real fires.

The following is a extract from a guidance document on upgrading doors.

Behaviour of the stiles and rails framework

Fire doors normally fail by distortion rather than burn through and controlling or accommodating this distortion must be the primary objective (even purpose made fire doors can fail as early as 12 minutes due to distortion). It is also considered important that the doors prevent the spread of smoke just as much as the door remaining stable helps the spread of fire and this significantly. The fundamental performance of a door leaf will be a function of the factors listed earlier but the main objective must be to restrain the distortions that will cause a loss of integrity at the leaf frame interface.

Controlling distortion

The control that various items of hardware can provide should be used in combination with each other to ensure that the proposed upgrading measures work in unison. Similarly, the correct specification of the intumescent door seal is vital to ensure that they can contribute to the control distortion of the door if the analysis identifies this as a requirement. And also provide a gap-filling function between door leaf and frame.

Note: Intumescent seals come in various types, some providing high-pressure expansion, others offering low pressure, also the direction and nature of expansion varies. Use of the wrong type of intumescent material could potentially worsen the situation and also be a complete waste of money.

The balance between hardware and intumescent is particularly important when considering historical/joinery type doors. Correctly specified intumescent seals can greatly improve the performance of the doorset, even if no other measures are carried out.

[CivvyFSO]

Not getting at you personally Civvy

I never take it personally. It is all discussion, advice and opinions.

but do we not aim for an evacuation to be completed in a few minutes? Even up to 10 mins would be very generous when you consider the level of detection installed in building nowadays.

We need to consider the time between the alarm being raised and the time that persons will leave their room. In hotels and other sleeping risks this can be quite a long time. There have been some human behaviour studies done and an alarm siren/bell is not a particularly effective method of letting people know what is happening. Pre-movement times (time between hearing an alarm and actually moving) are quoted in PD7974-6 as >20 mins for a poorly managed hotel occupancy, (i.e. probably 'less competent' or no staff on site, no prior fire instructions, expecting you to evacuate yourself) and IIRC similar times are quoted in D.Canters book "Fires and Human Behaviour". Granted, not all hotels are badly managed, but being an FSO I always go for the worse case scenario for an example.  

(And also bear in mind that we may lose a few minutes before the activation of the alarm due to Toddy's heat detectors being in the affected room.)

Something to consider is that if I ended up in coroners court over a decision I made then I need to be able to justify that decision. "Colin Todd says it should be ok" is not a good defense, unless you actually are Colin Todd with your list of letters after your name and a head full of statistics and years of experience. (And good reasoned arguments of course.)

Just to append to this:

TW, I think the point Colin is making that the 20 or 30 minutes comes purely from the test, which pretty much starts at flashover conditions. There can be a considerable incubation/smouldering period before the fire reaches anything like flashover conditions. (A good excuse for SD if there ever was one, but thats a matter for 50 other threads entirely... ) so from the point of ignition there may potentially be 5-15 minutes before anything like good flames are produced and the fire starts to really get hold, and even then a delay until flashover which may even require a window to break. The old test either wasn't as severe, or had lighter requirements, and the old doors could survive THAT test for 30 minutes. They changed the test, and the strips became necessary for the doorset to survive the test for the allotted time. So where we have the tendency to think of a 30 minute corridor, it is not really a 30 minute corridor, it is a corridor made up of materials that survive various specific tests for 30 minutes, the actual time it survives in a specific fire will vary depending on many potential different situations. It could be less, it could be more.

[colin todd]

Wee B That was precisely the point I as making and Civvy appears to have taken on board the point about the difference between real fires and test fires, something we teach all  new inspecting officers, so that they do not end up as dinosaurs closely hugging the security blanket of a prescritpive code of practice with arbitrary numbers.
Re statistics as there is around one death per day in dwellings and 60 million people live in dwellings, the chances of dying from fire by spending a day at home is 1 in 60 million. For comparison, adults spend around 100 million nights a year in uk hotels. Hope this helps civvy.

[Tom Sutton]

Civvy I think I do understand what CT is saying but your explanation is much clearer. I must reread the thread again because I must be missing the point somewhere.

[CivvyFSO]

Re statistics as there is around one death per day in dwellings and 60 million people live in dwellings, the chances of dying from fire by spending a day at home is 1 in 60 million. For comparison, adults spend around 100 million nights a year in uk hotels. Hope this helps civvy.

It does help, thank you.

So adults spend 60 million x 365 = 21,900,000,000 nights a year in domestic dwellings. Out of those nights 342 resulted in deaths in 2006. So any one adult has a 1 in 64 million chance of dying in their home in any one night. Ignoring any factors such as people living in deprived areas and vulnerable groups.

Last year 3 people died in one hotel. There may be more to add once 2008's figures are released but lets just use those 3 for the sake of argument. So, from the 100 million nights people spend in hotels, that gives a 1 in 33.3 million chance of dying in a hotel.

Now that doesn't seem to point towards hotels being 10 times safer, it seems to point to them being twice as bad.