Fire

[cliffed]

Our company just installed fire alarm system into garden centre warehouse,problems with alarms going into fire state.Smokes installed on ceilin purlins,it seems that the centre sprays the plants/flowers with water,hence a damp humid atsmosphere,any suggestions to fix this frustrating problem cheers.

 

[Spazz]

Put heat throughout - but thinking it will take alot of heat to set these off - with the big space

Put the smoke alarms higher up so the spray has more room to disappear before it hits the alarms

Other option is work out the risk areas and miss the locations which the spray is activating the alarms - I dont know the layout, but a flat internal roof is an advantage as the smoke spreads across the top of the roof setting smoke detectors a few meters away off.

If you have peaks then you need smokes in each peak.

Pictures of the location would be a great benefit!
Different situations different options with fire alarm systems

 

[Guest123]

What make of kit have you installed???

Special marine environment detctors are aviailable from most manufacturers for situations like this one


Your risk assessment of the area should have highlighted this.

 

[i=p/u]

twists in it all if your in expierienced..

sorry for jumping in , hi lenny or any other artful electrical dodger, im looking at a drawing and they have put two smoke alarms in the same hall way,

isnt it a smoke alarm shouldnt be more than 5m from any bedroom (domestic)???

 

[cliffed]

What make of kit have you installed???

Special marine environment detctors are aviailable from most manufacturers for situations like this one


Your risk assessment of the area should have highlighted this.

All done to spec,problem not thought of at start,google marine detectors c what comes up cheers 4 advice

 

[tazz]

Would suggest beam detection in open warehouse situations, they are more controllable and more cost effective than smoke sensors. They work on the method of percentage of obstruction in air, and can be calibrated to suit different evoiroments. ie 30%, 40% or 50% set to activate fire, wher 100% will always activate fault. Fire Beam is possible the best on the market. At around £250 covering upto 100m x 14m its a bit cheaper than installing 20 optical smokes with cabling and labour.
Hope this helps

 

[i=p/u]

just looking at my drawing, the architect has said smoke alarms to be on deticated ciruit and before rcd, but have seen some posts saying smokes and heat on rcd is fine.....

 

[tazz]

Bit old school to ask for fire circuit to be before rcd, would suggest asking him the question in a RFI. Normal standard is to follow wiring regs, with dedicated MCB or RBO for the fire alarm panel, and wired in enhanced fire proof cable to a lockable switched double pole fused spur adjacent to control panel. This way you are covering both regs.

 

[bradso]

i ve had a smilllar problem in a big warehouse where there were misters to keep dust down which was setting off detectors we changed them to heat still had problems mist/water causing shorts on system and setting devices into fire due to when the voltage drops to a certain range it goes into fire thia is done in normal circumstances by there being a 470 ohm resistor or a zenner diode built into the smoke or heat detectors being put across the head once the optical head being set off or the thermister in the heat detctor being activated. anyway we eneded up using linear heat trace cable being used not ideal but done the trick

 

[Guitarist]

Sounds like a job for a specialist firm, rather than ideas from a public forum tbh.

 

[alarm man]

id go for ror heats,if smokes are being set off beams will too if the steam is causing the problem.you could go down the vesda route but will mean ripping the system out and starting again,no doubt at your company's expence

 

[Spazz]

I take your firm didn't do the design for the Fire Alarm circuit

If the design company specified what you should put in and you did it to spec then sorry your job is done -if it does not work because of a problem with the wrong equipment in the spec (from the sound of it this is the case) the design company is responsible.

Throw it back at them and tell them to redesign it as their system is not working to the customers spec and it is not fit for purpose!

Then if they change the system they are responsible for meeting the costs encored, if they dont pay up then that's a claim against their PI.


As this post is now a few days old have you sorted it yet?

 

[tazz]

Vesda, or airsense can be a problem in this situation, water evapourators can help, but the filters dont really like water.
Beams are the only answer in hostile situations.
As to public forums, I would like to think i joined to help others

 

[alarm man]

Vesda, or airsense can be a problem in this situation, water evapourators can help, but the filters dont really like water.
Beams are the only answer in hostile situations.
As to public forums, I would like to think i joined to help others

steam is not a problem for vesda and the small amount of steam which could arise in this situation would pose no problems at all.most ir beam manufactures say not suitable for areas of dust and steam..

 

[tazz]

Alarm man, see were your coming from, with the amount of steam or water when it condistates, but would wonder how much a vesda or airsense could function over a long period in such evoroments, and to what extent. The old fixed beams being a pain in the rear have now been sorted with programmable beams such as Fire beam made by my old company Lemtronics. In areas of dust or high combustion would certainly go for the fast response of vesda.

 

[alarm man]

Alarm man, see were your coming from, with the amount of steam or water when it condistates, but would wonder how much a vesda or airsense could function over a long period in such evoroments, and to what extent. The old fixed beams being a pain in the rear have now been sorted with programmable beams such as Fire beam made by my old company Lemtronics. In areas of dust or high combustion would certainly go for the fast response of vesda.

id compare vesda to a fine car,needs looking after and regular tuning for the filter and airflow,if looked after never false alarms and provides the best protection around..

 

[tazz]

Certainly would not disagree with that, air sampling has always showed a faster response time, always found it the best solution for closed cieling voids.
Just checked with vesda, Airsensense, recommended use of water traps, evapourators in high humidity so your answer is correct, vesda is suitable if well mentanained

 

[Guitarist]

Vesda, or airsense can be a problem in this situation, water evapourators can help, but the filters dont really like water.
Beams are the only answer in hostile situations.
As to public forums, I would like to think i joined to help others

I think most of us signed up for that reason. There are times though, especially on something of this scale and importance, where a forum is really not the answer imo.