Types of fires that can start at schools

[John Webb]

......It makes you wonder what it is about the magic 800mm in voids- at 799mm I need no detection in the void according to BS5839 and no sprinklers according to BS12845 but at 801 mm I need both. How on earth are you supposed to maintain the sprinklers in a void in any case? You need inspection hatches beneath each head  which effectively rules out a good fire resisting ceiling.

Voids are usually formed by suspended ceilings for lighting and other purposes below a fire resistant ceiling/floor so access to void sprinklers is simply by removing an appropriate tile. I think the 800mm depth is a quite old requirement, and is connected with the potential for a reasonable quantity of fire load in larger voids as there is more room for equipment, cables etc. than in a shallower void.

Is there any valid  reason why I should not subdivide my 1000mm void with a  fire resisting barrier in the horizontal plane into two voids stacked on top of each other each of 500mm and thus not fit sprinklers or detection? ( All non combustible construction and no fire loading within )  Does this proposal provide an equivalent level of fire safety for both life and property protection?
All advice gratefully received.

It would be possible, but I suspect it would potentially more expensive than detectors or sprinklers as the construction would be quite complex with much heavier supports needed than a simple suspended ceiling.

[Mike Buckley]

I would suspect that the requirement for 800 mm is based more on an original 3 ft which has been metrified to a round figure.

As for the query about 800mm you can also wonder what catastrophic event that happens every day at 8,00 am which means I can park my car on a street at 7.59 am but I can't at 8.01 am?

[azadeshamsi]

I am an architect and I am studing on evacuate during a school arson.so I appresiate you if you will give me some advise to get some resourses.I want to use path finder for simmulate so I need some databases . I know I shoud consider some senarios but without it can I know the minimum time that is needed for evacuate the school?is there any table or formulation for this?
another question is about "extinction coefficient" which is about visibility in smoke condition and  shoud be multiple by speed of occupants. how can I earn this ones?
best regards
azadeh

[kurnal]

Hi Azedeh
We need to establish your level of understanding and study so far - are you in the UK? Have you looked at fire behaviour and human behaviour,  the behaviour of buildingmaterials and structures in fire, tenability and the concepts of Required Safe Evacuation Time and Available Safe Evacuation Time?  Have you looked at any other fire engineering software apart from evacuation modelling? Your answers will determine where we recommend you look for the answers you seek.

[azadeshamsi]

Hi Azedeh
We need to establish your level of understanding and study so far - are you in the UK? Have you looked at fire behaviour and human behaviour,  the behaviour of buildingmaterials and structures in fire, tenability and the concepts of Required Safe Evacuation Time and Available Safe Evacuation Time?  Have you looked at any other fire engineering software apart from evacuation modelling? Your answers will determine where we recommend you look for the answers you seek.

Hi dear Kurnal
thank you for your attention.I focoused on human behaviour and studied on this but I didnot have so much information in fire. first of all I desided to do my simmulation by viswalk.one expret offered me pathfinder. He said I shoud Know pyrosim too.so I studied its mannual .but Iam not exactly familiar with such this .I have just two month to end my project . Because of my 1years old son,I dont have enough time to research.of course if you think I need it,  I would learn any software which is needed.   But I realy dont know how essentioal is that? I studied some texts about Aset& Rset  .and I Khow it might be in SFPE handbook, but I am trying to earn that book which still didnot.No I am not in the Uk.
I sincerely thank you again