Units of exit widths?

[PhilB]

So you see that most of the guides that some of you like to cling onto are based on the principle that there are only 3 classes of buildings based on primary construction only. i.e. no account is taken of the combustible linings.

Once you determine the class the number and size of exits is based on how many frenchman can fit through a small gap in the time it takes to play God Save the King when your a***e is on fire.

Carry on code huggers & don't forget the latest guide when determining the maximum travel distance for a cow.

[slubberdegullion]

when your a***e is on fire.

Phil,

Jim Slimmon told me that the correct phrase is, "when you are receiving unambiguous fire cues!"

Stu

[PhilB]

Stu, never trust a Scottish fisherman who once worked in London ........Jim once told me that the job was f****d.........and we all know that's just not true!!!

[jokar]

I think that was a quote about Jim, and that may be true.

[slubberdegullion]

I think that was a quote about Jim, and that may be true.

True indeed......                                                                                                                                                                                                                                              
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[Ken Taylor]

Hasn't there always been confusion around between published tables for numbers able to use particular exit widths and the concept of 'units of exit width'? I've tended to refer to whatever publication seemed to be relevant for the particular premises type at the time - but even ADs aren't law and we're now in the risk assessment age - aren't we?

[slubberdegullion]

we're now in the risk assessment age - aren't we?

Yes we are but we still need clues as to how many people can get out of a given exit width in a given time.

There are different figures in different guides but they're all roughly similar....... and that's the point - I've said this before - the figures, wherever you get them from, aren't exact and precise.  If a door is 10mm, 20mm or even 50mm narrower than it should be, no one is going to die because of that.  If it's 500mm narrower, they might.

No one evacuates in the way that ADB (or the other guides) assume anyway.

So let's just be happy with the "clues" we have, no matter where we get them from.  They have stood the test of time with more success than failure (and there have been tragic failures) and are usually conservative.

If you're really interested in the topic read DD9999 first, then move into evacuaton modelling and fire modelling.

Stu

[Ken Taylor]

Agreed, Stu.

[nearlythere]

we're now in the risk assessment age - aren't we?

Yes we are but we still need clues as to how many people can get out of a given exit width in a given time.

There are different figures in different guides but they're all roughly similar....... and that's the point - I've said this before - the figures, wherever you get them from, aren't exact and precise.  If a door is 10mm, 20mm or even 50mm narrower than it should be, no one is going to die because of that.  If it's 500mm narrower, they might.

No one evacuates in the way that ADB (or the other guides) assume anyway.

So let's just be happy with the "clues" we have, no matter where we get them from.  They have stood the test of time with more success than failure (and there have been tragic failures) and are usually conservative.

If you're really interested in the topic read DD9999 first, then move into evacuaton modelling and fire modelling.

Stu

History has tragically shown all too often that the width of a doorway is not as important as its ability to open.  
When risk assessing escape route capacities does one take into consideration people size eg Weightwatcher meeting.
Who would be brave enough?

[CivvyFSO]

You could disguise it under a "mobility co-efficient" and make it look like some random fire engineering calculation.

i.e. a) Weightwatchers meeting has a mobility co-efficient of 1.2. So work out normal door width required and multiply it by 1.2. b) Gymnast meeting has a mobility coefficient of 0.8. c) Colin Todd has a mobility co-efficient of 1.9

[nearlythere]

You could disguise it under a "mobility co-efficient" and make it look like some random fire engineering calculation.

i.e. a) Weightwatchers meeting has a mobility co-efficient of 1.2. So work out normal door width required and multiply it by 1.2. b) Gymnast meeting has a mobility coefficient of 0.8. c) Colin Todd has a mobility co-efficient of 1.9

What about racing snakes like me?

[kurnal]

Hey thats a very good point civvyfso - do the Post War Building Studies have any relevance to the current population with so many of us much larger than our fore fathers.

[CivvyFSO]

You could disguise it under a "mobility co-efficient" and make it look like some random fire engineering calculation.

i.e. a) Weightwatchers meeting has a mobility co-efficient of 1.2. So work out normal door width required and multiply it by 1.2. b) Gymnast meeting has a mobility coefficient of 0.8. c) Colin Todd has a mobility co-efficient of 1.9

What about racing snakes like me?

Clearly you would fall into the gymnasts?

[nearlythere]

You could disguise it under a "mobility co-efficient" and make it look like some random fire engineering calculation.

i.e. a) Weightwatchers meeting has a mobility co-efficient of 1.2. So work out normal door width required and multiply it by 1.2. b) Gymnast meeting has a mobility coefficient of 0.8. c) Colin Todd has a mobility co-efficient of 1.9

What about racing snakes like me?

Clearly you would fall into the gymnasts?

With a phased evacuation approach then those with a lesser MC (mobility coefficient) would get to the escape door quicker than those with a higher MC. Hence with the natural order of things by the time the 1.2 MCs got to the door the 0.8 MCs would be away.
Do you think that this is something Darwin missed when writing up his theories? If not, and as I thought about it first, I want ownership of it.
I will call it "The theory that skinny people can run faster than fat people".

[jokar]

Kurnal,

Why have you four fathers?