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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Technical Advice => Topic started by: Wiz on July 01, 2009, 02:01:52 PM
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I've seen fire alarm controlled gas valve solenoids installed in various situations. Mainly in schools, mainly in kitchens, sometimes in laboratories and even often in boiler houses.
Does anyone know the regulations in respect of the necessity of installing such devices, and in which document(s) can these regulations/recommendations be found?
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If it's in schools, I suspect the guidance being followed originates in BB100 and BB101.
Regards
Owen66
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BB100 does not mention this. There are circumstances that justify shutdown for example in a gas fired crucible in a steel works, or in a kitchen if people are evacuating due to the fire alarm and may forget to shut off the cookers, or bunsen burners in a school lab.
I cannot think of any guidance that requires it as a matter of course. It is sometimes used as a backwards way to shut down the HAV systems in a fire - this is used for convenience since all the contol gear and switching is often connected back to the flame failure device. It may also be a compensating measure- for example in shopping centres gass mains should not be routed through malls, I guess if a shut off was provided this may be ok.
It would be interesting to hear other opinions on this, it does seem to be happening almost universally these days and can be a real nuisance due to the time it takes to start up equipment again afterwards.
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I heard rumour from the kitchen fitters at one of our schools this is actually a requirement of the gas regulations....
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Thanks for replies guys.
I also look forward to anyone being able to confirm definitive requirements listed in authoritive documentation.
I wonder if this is another one of these 'we always do it, but we don't know why or who says we must' scenarios that crop up now and again!
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It seems to be one of those things that has fallen into common use regardless of the situation.
The hazard from high pressure natural gas feeding a fire is obviously high.
But how likely is it that the gas supply will become readily involved in a fire so as present a risk to life safety and escape such that a solenoid activated on any activation of the system anywhere in the building is required?
As Kurnal says there will be some circumstances where this is the case, but in the typical office building this is not necessarily the case. A local gas shut off to the main gas fed risk (the boilers) via a fusible link is normally always present and with this is a solenoid link to the main inlet always required?
In most normal situations a fusible link drop to boilers, plus a clearly signed main valve room & it's location marked in the evacuation pack plans should suffice - sometimes auxiliary shut-downs seem to go OTT
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I think it comes down to risk against the cost, and in this situation of shutting off the gas supply out weighs the cost. On projects to provide an interface to shut the gas supply off will be around £100, so against the risk of the gas supply increasing the fire risk is justified. In my opinion !
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I think it's mentioned in section 3.1.8 of BB100 - requirements to cut of the fuel supply? - that may be a slight misinterpretation of whats required if the fire alarm shuts down the gas valve rather than the emergency isolation stated, but its a justification I have heard from many sources
Regards
Owen66
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Owen66, my copy of BB100 doesn't have a section 3.1.8. Can you confirm what you are reffering to, please?
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Well I've just downloaded another copy from Teachernet and there is a section 3.1.8 which deals with boiler rooms (in the section entitled "Places of special fire hazard") - Page 39.
Generally it requires there to be (in new schools) a means of automatically shutting off the supply of fuel and also a means of emergency isolation. This should also serve to isolate the electrical supply to the plant. So a classic design solution would an EPO at the boiler room entrance and heat detection in the oplqnt space. These would then act (via an interface if required) to shut down the boiler panel safety circuit and cause total electrical isolation as well as de energising the gas solenoid.
Means of reset may be automatic subject to gas proving but the text also suggests that it is manual only if the incident is genuine
Regards
Owen66
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Another copy of what ???
I did find this re kitchens.....
If gas supplies are fitted, refer to advice given in
the Institute of Gas Engineers 2004 publication
UP11 Gas installations for educational
establishments. Where gas cookers are provided
in classrooms (eg, for home
economics/domestic science lessons), the room
should be fitted with a lockable isolating valve
to enable gas supplies to cookers to be shut off
at the end of the day.
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Another copy of what
Building Bulletin 100
Regards
Owen
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Well I've just downloaded another copy from Teachernet and there is a section 3.1.8 which deals with boiler rooms (in the section entitled "Places of special fire hazard") - Page 39.
Generally it requires there to be (in new schools) a means of automatically shutting off the supply of fuel and also a means of emergency isolation. This should also serve to isolate the electrical supply to the plant. So a classic design solution would an EPO at the boiler room entrance and heat detection in the oplqnt space. These would then act (via an interface if required) to shut down the boiler panel safety circuit and cause total electrical isolation as well as de energising the gas solenoid.
Means of reset may be automatic subject to gas proving but the text also suggests that it is manual only if the incident is genuine
Regards
Owen66
Very interesting owen 66.
This is the link I am using to find BB100
http://www.dcsf.gov.uk/consultations/downloadableDocs/BB100%20July%2005%20-%20Complete.pdf
I wonder if it has been superseded? I notice the link address includes 20 July 2005.
Can you provide me with a link to the document that you have found?
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Here you go Wiz:
http://www.teachernet.gov.uk/docbank/index.cfm?id=12199 (ftp://http://www.teachernet.gov.uk/docbank/index.cfm?id=12199)
I think you may be looking at the draft for consultation - it did change in the final issue I believe
Regards
Owen
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And you should always get confirmation from the gas boys that their kit is flame failure , if you attempt to do this on an old system it tends to go bang.
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Owen66. thank you for the link.
I couldn't access it directly from your post but by messing around with the address I found it!
Just in case others have problems I've added the link I used here:
http://www.teachernet.gov.uk/_doc/12199/BuildingBulletin100_OnlineVersion.pdf
You are obviously right about the document I found to be just the consultation document. It's a shame no-one has removed this out-of-date info!
In the document on teachernet I would suggest that the guidance is still not clear and this raises a further issue.
Most of the gas solenoid valves interfaced to fire alarms operate on any fire condition. This causes so many problems in so many establishments whereby any unwanted alarm causes the boilers to shut down and usually requires someone (at cost and time) to reset them!
I believe that the guidance could be suggesting that it is only a fire condition detected in a boiler house that should shut down the boiler!
If this is the case, and if it also applies to hotels, then my failure to be provided with a hot shower and cooked breakfast in a leading hotel in Birmingham a couple of years ago because the gas had been shut off by a faulty corridor smoke detector and no-one knew how to reset the boiler was all down to mis-interpretation of guidance documents.
I'm still fuming about missing breakfast!
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Well yes, a global command will tend to shut down the solenoid for any activation of the fire system.
A simple addressable system however should be capable of selectively programming the I/O unit such that activation only occurs from pre determined devices operating - heating chamber heat detection and associated Break glass units.
Same goes for any building type I guess - part of the fire strategy.
Sorry about breakfast BTW - but that's Brum for you
Regards
Owen
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Owen66, thanks, but the question isn't how to achieve it!
My question is why do we do it, not how can we do it?
My last post was confirming that the document you directed me to also actually indicates that it is only the detector in the boiler house that should operate the gas solenoid valve and not any alarm condition from anywhere (which is often the case)
My original question stands.
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Not sure as to the why Wiz although I can see the logic in removing a fuel source in the event of a fire that is likley to be in close proximity to that fuel source (or perhaps in high rise etc where vertical gas mains exist).
The requirement does seem to occur with remarkable frequency in all sorts of documents but based on a few I've looked at it seems that the requirement is only for shutdown on local activation (the old thermal link approach ) - this seems to have evolved into a global shutdown situation for some reason. Insufficient time allowed to programme the fire panel perhaps - or vague requirements in the first place.
I would have thought a building fire startegy would define this in some deatil but sadly not usually the case.
Regards
Owen
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http://www.bsdlive.co.uk/story.asp?storycode=3060154 (http://www.bsdlive.co.uk/story.asp?storycode=3060154)
This document refers to the shuttingdown of the gas supply on ventilation failure within the extract hood....
I wonder if this is a case of chinese whispers over the years....
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....................I wonder if this is a case of chinese whispers over the years....
That's why I originally raised the subject.
Seems no-one knows. Even in this supposedly super forum.
Shame no gas monkeys have put in any input to the discussion. Or it could be that they don't know either.
I pray for the day that there are one set of clear easily understandable set of rules and regulations for every building/room type and every situation (I don't believe that every situation has to be so different!). Then everyone would know what they are doing and why.
Until that day, bullsh*t will continue costing this country £Billions !
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The major kitchen fire suppression manufacturers all advise an automatic shutdown of the gas supply be linked to their systems then upon activation of the fire suppression system this would ensure there is not a build up of gas within the area once the fire is extinguished. Obviously there could still be a heat source in the area which could ignite any gas build up or if there are appliances not protected by the nozzles and are on fire they don't ignite the gas from other appliances. (What's that I hear you all say? Surely no :-X would place an appliance without protection??? Oh yes, sad to say 'tis oh so true - anyone need photo's?? There are some classics out there..)
It also ensures that if the evacuating staff forget or cannot physically get to the shut off valve/switch then the gas will be cut off upon their evacuation.
The shut off can be mechanical or electrical (which then would be linked to the F/A)
Which is nice if your a fireman type chap rushing in to a kitchen to check out the latest salamander or fryer in your local restuarant or Big Macs.
Some of the locations of the manual gas shutoff switches beggar belief. Try knocking off the gas at 2-3' from a blazing fryer.
The system manufacturers also advise them (the suppression systems) to be linked to the F/A via a n/o link. Both the gas shut off and F/A link are activated upon system release simultaneously.
That may answer the original enquiry. I'm no gas monkey, just a humble Ansul monkey working long nights this week and short of sleep.
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Thanks for the input psuedonym (is that really your name?)
I think we all understand the reasons why these shutdowns could be required.
But are you aware of any authorative guidance documents or recognised standards that state the specific requirements?
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No, of course not. Its a psuedonym you know.
I will get hold of the regs and let you know when I can dig them out. The kit is US and their info relates to the UL standards (UL300), but I'm pretty sure we have the equivalent standard over here. The insurance firms also advice the same so there must be somthing lurking around. I just can't remember what! It's old age.......
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Thanks for the input psuedonym (is that really your name?)
No, of course not. Its a psuedonym you know.
I'm obviously not as funny as I think I am! :(
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Well I had a chuckle, Wiz ;D
Owen
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Thanks Owen!
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I think as the discussion evolves we are seeing that:
a) Specific standards for specific situations (e,g, cooker hood supression, schools guide) mandate the use of an automatic gas supply shut off
b) However as far as an across the board requirement (i.e. independent of a specific risk situation in a building or part thereof) for gas valve shut off goes there is no actual requirement/recommendation, it's just something done because 'that's what we do'
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Wiz, the only regs regarding fuel i.e. gas/electric shut off to kitchen equipment from a fire suppression sytstem is LP1223 2.2 section 5. That with UL300 i.e. US equipment listings which as US kit we adhere to so as to be compliant,
The is no legislation for fire suppression - catering, for F/A link up or notification from installer/surveyor or the manufacturers' specification information advising links are possible and the procedures for installing switch gear in their control panels.
That plus pointing out to the client the advantages of a link. Most insurance firms, if aware of the possibilities, also advise a link.
Unfortunately "risk assessors" simply tick the Fire Suppression Installed? Y/N box. But that's another debate, one which I had with a duty manager this morning while the rest of sensible world was tucked up asleep!
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Thanks both to AnthonyB and psuedonym for their recent answers.
It seems that the fire alarm system operated gas cut-off solenoid valves commonly installed all over the place recently have been installed because of (i) 'findings' of a risk assessment (ii) recommendations from a manufacturer of a specific piece of equipment based on standards that may not apply to the u.k (iii) because it seems a good idea/that's what we did on the last job scenario.
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Wiz,
Another issue that comes up is the ressetting of the gas within the kitchen following a F/A cut off. I was told last Fri/Sat of a case where the staff had their fingers burnt on more than one occasion due to their lack of knowledge regarding this. Maybe fire training should encase possible gas/F/A problematic scenarios too??
Just think of the "expertise" required from an assessor now. Another box to tick without any prior knowledge of the subject!!!