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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Technical Advice => Topic started by: CJ on January 18, 2008, 08:08:02 AM
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Could someone please advise me whether a heat or smoke detector should be fitted in a photo processing dark room? I'm think it should be a smoke detector, but am not 100% sure due to fumes that may be given off from the processes within the room.
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Do the fumes contain CO? and if not then why not a CO detector.
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Could someone please advise me whether a heat or smoke detector should be fitted in a photo processing dark room? I'm think it should be a smoke detector, but am not 100% sure due to fumes that may be given off from the processes within the room.
It depends of the stuff of photo processing used in the dark room are they old stuff or new digital machines? these later should be OK to use smoke detectors, while the old once possibly could cause false alarms and therefore a heat would be ideal
This is my own opinion you still need to find out...
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Optical smoke detectors should be immune to the chemical fumes. They would be my first choice.
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they are old style not digital thanks for your comments
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a multisensor optical and heat
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a multisensor optical and heat
Yes, Multisensor (if Apollo one) in mode 4 or 5 would be ideal
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Also this remind me of a couple of times I have been blamed when changing the type of detector from smoke to heat detector, it was in a corridor and close to the shower room, each time the door is opened the steam sets false alarms, I have been told to recommend repositioning of the smoke detector rather than replacing it by heat detector, because the decision of what type of detector is the decision of the fire officer and it is not for the service engineer to take the decision... that's what I have been told if I am wrong please feel free to correct me.
this may apply to your case CJ
Thank you
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It's for the Responsible Person to make the ultimate decision in an FRA as to head types and their changing. A service company can act as a competent adviser to help the RP fulfil their obligations, but by doing so risk some liability if you get it wrong.
If it is a corridor head & a life system perhaps a multisensor would suit, rather than a plain heat or a costly repositioning of head & cabling (which could result in a variation with head spacing down the corridor)
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Also this remind me of a couple of times, I have been blamed when changing the type of detector from smoke to heat detector, it was in a corridor and close to the shower each time the door is opened the steam sets false alarms, I have been told to recommend repositioning of the smoke detector rather than replacing it by heat detector, because the decision of what type of detector is the decision of the fire officer and it is not for the service engineer to take the decision... that's what I have been told if I am wrong please feel free to correct me.
this may apply to your case CJ
Thank you
I don't think it is quite right to say that the type of detector is up to the Fire Officer, assuming the FO you refer to is from the Fire Service.
The type of detector is dependant on many variables and the decision would be up to the RP in consultation with the installer, taking into consideration the advice contained in the BS.
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The type of detector is not up to the FRS officer, it is the alarm company and occupier/owner and would be determied by which is most suitable and applicable after a risk assessment. Indeed we (the FRS) often mentiont o occupiers that the detector is wrongly sited, or of the wrong type, when dealing with unwanted fire calls caused by automatic detection. Ususally as a result of smoke detection in areas like kitchens, showers, laundry etc where heat should have been fitted. We do not specify the alarm detectors and the companies usually fit the most common and cheapest, ie smoke, leaving the occupier nad us to deal with the aftermath.
Ricardo, which planet mate? CO detectors are there to determine excessive concentrations only intended for its property as a toxic gas, due to faulty gas heating/cooking appliances. They are not suitable as fire detection in any circumstances.
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CO is produced by every fire and its value in fire detection is being increasingly recognised. CO detectors (Combustion gas) for fire safety have been around for some time- they are referred to in BS5839.
They offer particular advantages- in that CO diffuses in the atmosphere and therefore is not subject to the foibles of convection currents caused by heating systems - but because it diffuses it may generate alarms some distance from the fire- maybe even in another zone. They are also much more immune to dust, steam and cigarette smoke but respond much faster than heat detectors in these environments. They do however have a limited operational life due to the nature of the sensor device. They are particularly sensitive to smouldering fires or fires in which the air supply is limites- less so to flaming fires.
The technology is developing so recent recomendations has been that they should be used for specific situations and to supplement other conventional devices but things are moving forward. The Gent SQuad multi sensor head is available with a CO element to augment optical and heat sensors.
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Also this remind me of a couple of times, I have been blamed when changing the type of detector from smoke to heat detector, it was in a corridor and close to the shower each time the door is opened the steam sets false alarms, I have been told to recommend repositioning of the smoke detector rather than replacing it by heat detector, because the decision of what type of detector is the decision of the fire officer and it is not for the service engineer to take the decision... that's what I have been told if I am wrong please feel free to correct me.
this may apply to your case CJ
Thank you
smoke or smoke/combustion detectors in corridors no heat.
You need to give early as possible warning of a fire in the escape routes before they become overcome by smoke and impassible.
The heat would mean that the corridor was on fire.
Multisensor as mentioned would have been the best option.
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Ricardo, which planet mate? CO detectors are there to determine excessive concentrations only intended for its property as a toxic gas, due to faulty gas heating/cooking appliances. They are not suitable as fire detection in any circumstances.
My apologies fireftrm, my initial words were meant as a flippant remark only, not to be taken seriously, I most definately didn't mean the type of detection I am looking at right now installed through in my kitchen, to warn me of a problem with my gas boiler.
I am aware that CO detection is newish technology and is recognised and discussed within BS 5839-1:2002. as is other new forms of detection, such as video detection/fire warning for the deaf and multi sensor.
And "in practice" the recommendations made within the code relate to carbon monoxide fire detectors.
As kurnal has said in his post no 12, CO is a product of a fire, ( when incomplete combustion occurs as a result of a lack of O2) I myself have have witnessed on many occasions, CO detection now quite widely being installed in sleeping accommodation of hotels and guest houses.
If you check the BS, it provides recommendations as to where such detection can be used, as opposed to areas where they cannot be used. It accepts the use of CO in rooms opening onto escape routes in a category L3 system, however I bow to kurnals and others when they say multi sensor may be more suited in this enviroment(oh how I wish I had said that instead now)
I was basing that on dark rooms in my experience normally being small in size, and that a CO if installed would/should pick of the products of combustion in that room, as opposed to it travelling away along a corridor and into another zone, prior to it responding.
We live and learn, as confucious he say, he who claims to know all is a fool, for his learning has ceased. He who knows nought, and knows he knows nought, is the enlightened one, it is he who will be great.
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He also said don't eat yellow snow!!
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Indeed I have learnt something today, and apologise in turn!
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Also this remind me of a couple of times, I have been blamed when changing the type of detector from smoke to heat detector, it was in a corridor and close to the shower each time the door is opened the steam sets false alarms, I have been told to recommend repositioning of the smoke detector rather than replacing it by heat detector, because the decision of what type of detector is the decision of the fire officer and it is not for the service engineer to take the decision... that's what I have been told if I am wrong please feel free to correct me.
this may apply to your case CJ
Thank you
I don't think it is quite right to say that the type of detector is up to the Fire Officer, assuming the FO you refer to is from the Fire Service.
The type of detector is dependant on many variables and the decision would be up to the RP in consultation with the installer, taking into consideration the advice contained in the BS.
and the installer in consultation of what? and who?
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Also this remind me of a couple of times, I have been blamed when changing the type of detector from smoke to heat detector, it was in a corridor and close to the shower each time the door is opened the steam sets false alarms, I have been told to recommend repositioning of the smoke detector rather than replacing it by heat detector, because the decision of what type of detector is the decision of the fire officer and it is not for the service engineer to take the decision... that's what I have been told if I am wrong please feel free to correct me.
this may apply to your case CJ
Thank you
smoke or smoke/combustion detectors in corridors no heat.
You need to give early as possible warning of a fire in the escape routes before they become overcome by smoke and impassible.
The heat would mean that the corridor was on fire.
Multisensor as mentioned would have been the best option.
multisensor with the selected mode that combine heat and smoke detection isn't it ?
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There is something new to me in this topic, to be honest!
thanks to the contributors
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Also this remind me of a couple of times, I have been blamed when changing the type of detector from smoke to heat detector, it was in a corridor and close to the shower each time the door is opened the steam sets false alarms, I have been told to recommend repositioning of the smoke detector rather than replacing it by heat detector, because the decision of what type of detector is the decision of the fire officer and it is not for the service engineer to take the decision... that's what I have been told if I am wrong please feel free to correct me.
this may apply to your case CJ
Thank you
smoke or smoke/combustion detectors in corridors no heat.
You need to give early as possible warning of a fire in the escape routes before they become overcome by smoke and impassible.
The heat would mean that the corridor was on fire.
Multisensor as mentioned would have been the best option.
multisensor with the selected mode that combine heat and smoke detection isn't it ?
that's the one. a optical/heat is still classed a smoke detector
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A fire alarm engineer can give advice as to possible changes to automatic detector types already installed. The Responsible Person takes responsibility if they accept and act on that advice. Responsible Persons would be well-advised to consult and receive agreement for such proposals, in advance, from interested parties such as the building user, the building owner, the building insurer and any authority responsible for enforcing fire safety legislation for that building.