[SML] Smoke vs Heat vs Rate of Rise detectors

[Dale Farmer]

Caveat.  I have not kept up with current technology in fire detection 
systems.

Beam detectors have their place, but not any place that is likely to 
have helium balloons.  You really want to have a way to shut them off 
for special events.   You want to consult with a locally licensed fire 
protection engineer and spend the bucks and the time to educate them on 
the special aspects of theater. Local codes will have great influence. 
Make friends with your local fire inspector and ask for advice. 
Finding one who already understands theaters is a pearl of great rarity.

Also, why does the university insist your existing system needs to be 
replaced?   Is it broken?  Did the insurance carrier inspector say so? 
Presumably the existing system was legal when installed and likely 
grandfathered in.

plain heat detectors are cheap and reliable.  They are literally a disk 
of metal or glass ampule that melts or bursts at a set temperature to 
activate an alarm.   My big issue with rate of rise detectors is that if 
you have serious winter at your location, they also detect that you just 
closed the door to the outside, and as the heating system warms the 
place up, they go off.  Rate of rise detectors will alarm faster than 
the heat detectors in a fire situation.

Sprinkler systems are a wonderful thing.   Also, if there is money for 
sprinkler system upgrade, take a real close look at those micro fine 
water mist systems.  They are catching on in europe, on ships, and the 
hotel industry.   Basically they spray out distilled water at high 
pressure to create a mist or fog.  This mist of micro droplets stay in 
the air for a long time, and as the fire sucks in air to burn the fuel, 
the mist gets sucked in with it and extinguishes the fire.   The 
advantage is they use about ten percent of the water compared to a 
conventional sprinkler system.  This greatly reduces the amount of water 
damage.  Cleanup uses rags and wet vacs instead of pumps and shovels. 
The other large advantage is the distilled water mist works on A, B, and 
C fires, and can be used on energized electrical equipment.

Dale

On 3/7/2022 8:28 PM, Bill Conner via Stagecraft wrote:
> Most modern heat detectors are both rate of rise and fixed temp, so just 
> avoid particle (smoke). (In US, no option in return air other than 
> particle. Am working on a code change to fix that.)  I've not formed a 
> strong opinion on the beam detectors.  Had one that shot across a 
> catwalk. Move past that point fast and no problem, but stop a second and 
> alarm activates.  Another project helium balloons in house set it off.  
> But maybe with thought on placement they'd be OK.
> 
> On Mon, Mar 7, 2022, 7:29 PM Riter, Andrew via Stagecraft 
> <stagecraft at theatrical.net <mailto:stagecraft at theatrical.net>> wrote:
> 
>     The university has said our entire fire alarm system needs to be
>     upgraded.____
> 
>     __ __
> 
>     When designed in the late 90s (opened in 1997), the designers put
>     heat detectors in the venues, but missed the “shared” areas that
>     look like separate rooms on the drawings but actually share the same
>     air (they put smoke detectors in the pit, Front of House Cove, venue
>     light locks, and air return system).____
> 
>     __ __
> 
>     I’d love to take this opportunity to replace a bunch of the smoke
>     detectors with Heat detectors, but I believe there is a difference
>     between Rate of Rise detectors and “set off at x degree level of
>     heat” detectors.____
> 
>     __ __
> 
>     Can anyone give me a quick primer on these types of heat detectors,
>     and advantages / disadvantages of each?____
> 
>     __ __
> 
>     Thanks everyone.____
> 
>     __ __
> 
>     *Andrew M. Riter*
>     Assistant Technical Director, Head Lighting Technician
>     Chan Centre for the Performing Arts
>     The University of British Columbia | Vancouver Campus
>     6265 Crescent Road | Vancouver BC | V6T 1Z1 Canada
>     Phone 604 822 2372
>     andrew.riter at ubc.ca <mailto:andrew.riter at ubc.ca>____
> 
>     UBC E-mail Signature____
> 
>     __ __
> 
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