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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Fire Safety => Topic started by: ST1878 on December 02, 2008, 01:13:18 PM

Title: BS 9999 / ADB - Discounting of Stair rule
Post by: ST1878 on December 02, 2008, 01:13:18 PM
Has anyone come across the apparent anomoly for the discounting of stairs in sprinklered buildings yet?
BS 9999 para 18.3.2 states "the stair discounting process DOES NOT APPLY to a building fitted with a sprinkler system".
This appears to be at odds with the earlier DD 9999 para 8.8.3.2, and the current ADB para 4.20 which state "stair discounting ALSO APPLIES to a building fitted with a sprinkler system, unless the staircase is lobbied or pressurised".

We have requested clarification from the relevant bodies, but have yet to receive an explanation to the difference, and we have now had proposals from an AI referring directly to the para in the new BS.
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: wee brian on December 02, 2008, 01:18:11 PM
I'm not sure if that counts as an anomoly, The are different codes - they will say different things.
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: jokar on December 02, 2008, 06:27:59 PM
Sprinklers are invoke and the answer to all our prayers.  As above, different code, different standard, its out there for use and people will use it.
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: colin todd on December 02, 2008, 11:57:19 PM
if the nat west tower is sprinklered it would probably only need one 530mm exit for compliance with BS 9999.
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: Galeon on December 03, 2008, 12:23:19 AM
It is
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: wee brian on December 03, 2008, 09:27:36 AM
You would still need to discount a storey exit wouldnt you?
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: Davo on December 03, 2008, 12:22:27 PM
What does BS 7974 have to say on this dilemma? ???

I for one would not want a designer to put one less stair in because you don't need to discount (IMO)

Davo
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: wee brian on December 03, 2008, 12:27:35 PM
Well if you need two storey exits then I think you will need a stair next to it. Iether that or issue parachutes.
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: jokar on December 03, 2008, 06:15:11 PM
As we are all aware fire safety is joined up thinking and stair discounting is not a subject of its own, it also includes travel distance and numbers of people.  What 9999 does is limit in some circumstances the numbers of exits and stairs that are needed and substantially in some areas.
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: colin todd on December 04, 2008, 01:04:23 AM
Parachutes, brian................ HMMMMMMMMMM Could that be a new business opportunity?
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: wee brian on December 04, 2008, 01:52:27 PM
No mate - Fire evac parachutes have already been patented. They tried flogging them after 9/11
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: colin todd on December 04, 2008, 09:36:50 PM
Ah Brian, it just goes to show there is nothing new in this world. No wonder, I/Os keep rediscovering what we knew 30 years ago. Should I just keep my money in intumescent strip manufacturers then?
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: Thomas Brookes on December 04, 2008, 09:57:01 PM
Evacuchute. Do you think these would be suitable for old peoples homes





http://www.evacuchute.com/products_build_civilian.html
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: colin todd on December 04, 2008, 11:59:28 PM
Yes it would give the wrinklies the thrill of their (imminently ending) life.
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: Thomas Brookes on December 05, 2008, 08:21:58 AM
I would love to see someone write that in to a risk assessment.

Imagine the look on the IO face when he does an audit.
Title: Re: BS 9999 / ADB - Discounting of Stair rule
Post by: nearlythere on December 05, 2008, 08:36:26 AM
Am I also reading that the occupancy factor for doors is substantially increased?
An 800mm doorway in a medium fire growth rate can now accommodate up to 222 persons? This is a heck of an increase from the 50 for the same door size as contained in BS5588 Pt6.