Hi
A novice question I know but I am starting to look at taller commercial buildings as part of my role (having previously only dealt with lower risk, single storey accommodations). There's a few questions in this...
I am looking at the following situation;
Building constructed 1970/1980s with original design plans showing office accommodation only. But over the years, the usage has changed in areas.
Ground floor plus four upper floors (no basement)
Standard construction (Brick, mortar, reinforced concrete)
Occupancy details are:
- Ground floor = shop
- First/Second floors = offices
- Third floor = training centre (so members of public may be on site)
- Fourth floor = offices / meeting rooms
Max. occupancy levels in whole building is typically below 60.
There is one protected stair.
There is one means of escape to fresh air being at the front of the building. The shop of the ground floor does also have a second exit, but this is not available to the upper floor levels.
The approximate height of the building (from ground level to top of roof) is approximately 14m. But the height from ground floor to the floor of the fourth floor is approximately 11m (sorry if that doesn't make sense but I wasn't sure if you measured to the top of the building itself, or just to the floor level of the highest floor??).
There is one passenger lift (not firefighters) which is in a protected lobby (not in the protected stairwell). Occupants on each floor have to pass the lift to reach the stair. I think this is acceptable from looking at ADB and BS9999.
The accommodation spaces on each floor level are approached via a lobby of 2 x FD30s doors. Albeit, the previous assessment shows that only the door leading to the stair has to be FD30s??? Is this correct as I thought/read in ADB/BS9999 that any building with more than one floor above ground had to have a lobby approach?
My main question is, is one protected stairway enough?? The reason I ask is that both ADB and BS9999 appear to read that any floor above 11m should have an alternative means of escape. But is the fact that the floor level on the highest floor is 11m adequate for only one stairway to be accepted??
Any help on any of these questions much appreciated.
Number of escape stairs
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- Paul1979
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- Messy
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Re: Number of escape stairs
The bottom line is, you cannot apply ADB or BS9999 retrospectively, so you have to be creative to deal with what you have got.
Lobby approach is a start, but what about the fire detection system? is there one and if so (I hope there is!), what category is it?
I once dealt with a single staircase building which was basement, ground and 5 floors - Therefore 6fl & basement & well overheight for a single staircase. B & G were retail and the others were a multi occupancy offices. There was no space for an external staircase and no appetite for an agreement to escape via next door. Control measures included lobbied staircase, compartment floors and a Cat L1 detection (detectors everywhere!!). It worked, there were no alternatives.
Its so difficult to make any judgement on your situation from a blind point of view, but with a decent coverage detection wise, it might not be such an issue
Lobby approach is a start, but what about the fire detection system? is there one and if so (I hope there is!), what category is it?
I once dealt with a single staircase building which was basement, ground and 5 floors - Therefore 6fl & basement & well overheight for a single staircase. B & G were retail and the others were a multi occupancy offices. There was no space for an external staircase and no appetite for an agreement to escape via next door. Control measures included lobbied staircase, compartment floors and a Cat L1 detection (detectors everywhere!!). It worked, there were no alternatives.
Its so difficult to make any judgement on your situation from a blind point of view, but with a decent coverage detection wise, it might not be such an issue
- Paul1979
- Member
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- Joined: Mon Oct 24, 2016 4:19 pm
- 7
- Industry Sector: Property Management including H&S
- Occupation: Property Manager including reviewing of H&S assessments and implementing remedial actions...or trying to justify why they are over the top and an alternative solution can be found!!
- Location: London
- Has thanked: 204 times
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Re: Number of escape stairs
Hi Messy,
Thanks for the reply. Sorry - I should have said...it has got a L3 system! (L2 in parts where the tenants have extended their areas to include AFD linked to alarm).
So if it were a brand new building (or a redeveloped building) the 11m rule would apply?
Generally, is a lift (which I think was installed after the initial build but has been in for some years by the look of it) okay in the lobby as long as they upgrade the doors to FD30s level to the staircase and to the accommodation areas?
Thanks again for your help - much appreciated.
Thanks for the reply. Sorry - I should have said...it has got a L3 system! (L2 in parts where the tenants have extended their areas to include AFD linked to alarm).
So if it were a brand new building (or a redeveloped building) the 11m rule would apply?
Generally, is a lift (which I think was installed after the initial build but has been in for some years by the look of it) okay in the lobby as long as they upgrade the doors to FD30s level to the staircase and to the accommodation areas?
Thanks again for your help - much appreciated.
Last bumped by Paul1979 on Thu Jan 11, 2018 7:33 pm.
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