FireNet Community
FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Technical Advice => Topic started by: Benzerari on December 22, 2008, 07:51:53 PM
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Guys;
Have you ever seen a different level of protection in each floor of the same building, i.e. the basement has L3, while all the rest of the floors with L1?
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not on each floor but different parts of a site
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Yes. Have seen it many times and would say of is quite normal in multi tenanted office block where , for various reasons ( insurers, risk assessments, corporate policy and/or fire alarm sales force) have resulted in differing categories of system.
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Well; two extremely opposites answers, the case I am referring to is some basement of some building, which is a plant area with detections and some other rooms open to the common area without any detections in the same basement, while all other floors are protected to L1, now you can see a better clear picture…, what do you think?
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Well; two extremely opposites answers, the case I am referring to is some basement of some building, which is a plant area with detections and some other rooms open to the common area without any detections in the same basement, while all other floors are protected to L1, now you can see a better clear picture…, what do you think?
I thought the level of protection is per building, not per floor! :)
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I would think now g whats days with fire risk assessments deciding whats required, we will see this more and more.
All depends on whats happening in each floor.
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Don't forget that it is likely that the basement will be compartmented off from the rest by 60 minutes. If this is the case then it could easily be assessed separately and looking at the lower level of actual life risk in the basement plant area an L3 standard could be appropriate.
An L1 may also be put in for compensation for something else like over-occupancy, extended travel, an atrium or accommodation stair. If this is the case, then if this issue doesn't affect the basement then why would you put extra detection in where there is really no benefit?
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Similarly... we're looking to replace an old system at an old building in London... the existing system is just the usual mish mash of call points and sparadically placed detectors.
It turns out the Beadle at this building has sleeping accommodation and there is also a separate flat as well... both on the top floor (3rd floor). There is no ASD on the staircases and a couple of mains detectors only in the accommodation areas.
We've said the building should be to L2 minimum including the accommodation... is this wrong ??
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Sleeping accommodation should be L1?
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What's the difference then between 'sleeping accomodations' and 'dwellings' which need part 6 systems?
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"sleeping accommodation" generally means a room that is used for sleeping, hotel rooms, hostel rooms, etc.
"Dwellings" are where someone lives. If they have such things on your planet.
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Sleeping accommodation should be L1?
Nope. L3 and upwards, depending on risk. CLG guidance generally suggests L2, but BS5839 states L3 as a minimum. (Although it almost hints that if the rooms are off a small corridor, then L4 may be suitable)
In buildings in which people sleep within rooms accessed by corridors, other than short lengths of corridor,
research has shown that passage of hot fire gases through a door crack can produce smoke sufficiently dense
and cool for a corridor to become smoke-logged before adequate warning can be given by detectors in the
corridor. In this case, a Category L3 system, in which detectors are installed in rooms that open onto the
escape routes, as well as within the escape routes themselves, is likely to be appropriate
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Lots of multi-occs have random cover - it is rare to find a premises that you can give a category to.
How to record this if it is one system is difficult and descriptions of areas covered rather than a category is more appropriate.
Sometimes you will find it's a P2/M, or more often if pressed to use a category you have to call it something like "an L5 system incorporating L4 cover plus detection to the 4th floor general floorspace, access rooms to the 2nd floor and the basement boilers" although it's not usually a risk based design, just historical anomalies.
It seems to be that 'someone' around the country wants L1 in all offices as the most common situation is that older floors have either:
- nothing
- access room cover
- heads to storey exits as part of an L3
& newly refurbished (or indeed refurb in the last few years) floors have heads everywhere with a heat where the tea point would be installed.
Yet offices could in theory only have 'M' cover (in multi-occupancies with different trading hours we suggest one of the L categories however, but not L1 unless part of a engineered solution for other defects).
It gets worse when different tenant's over the years put their own panels in to their floors creating coordination & maintenance problems, especially when they leave and someone else moves in and doesn't want to service it as they didn't install it....
This problem is understandable in some buildings where the landlord fell back on their OSRP MoE certificate to keep an ancient 240V 'M' system in the building, but a tenant or tenants wanted AFD - they would put in their own modern system and interface it to the landlords one.
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"sleeping accommodation" generally means a room that is used for sleeping, hotel rooms, hostel rooms, etc.
"Dwellings" are where someone lives. If they have such things on your planet.
In our planet there is no difference..., since there are no homes and/or sleeping accommodations, the notion of time doesn't exist either ;D
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"In bedroom areas, the design requirements are usually based on the recommendations for a cat L3 system. Detectors are, however, typically installed in most other rooms and areas, as a fire in almost any area of the building could pose a threat to sleeping occupants; the system is therefore Cat L2. In practise, few if any areas are left unprotected and the system is effectively L1."
And there was me under the impression it had to be L1 for sleeping accommodation.
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GregC, we all keep learning. There is always someone willing to trawl through a BS or guidance to try prove you wrong, that is the beauty of this forum. :)