[SML] Smoke vs Heat vs Rate of Rise detectors

[Bill Conner]

I have no expertise on mist fire protection systems but have to wonder if
they are as effective in the tall spaces in a theatre as they are in the
very low floor to floor spaces of cruise ship.

On Tue, Mar 8, 2022, 9:37 PM Dale Farmer via Stagecraft <
stagecraft at theatrical.net> wrote:

> On 3/8/2022 9:29 PM, Dale Farmer via Stagecraft wrote:
> > On 3/8/2022 9:35 AM, Dougherty, Jim via Stagecraft wrote:
> >> I'll second the recommendation to include your AHJ, your alarm system
> >> contractor, and your Powers That Be early in the process.  Demonstrate
> >> the atmospheric effects that you use in your space - fog and haze will
> >> false trip many systems.  We underwent an upgrade some years ago and
> >> the decision was made to try a camera-based system; it was meant to be
> >> able to detect fire and flame by analyzing the video image (not a fire
> >> system engineer, don't know the details) specifically to avoid false
> >> activations through what we do.  It was pricey, we were early
> >> adopters, and it was a big investment.  Long story short, it didn't
> >> work.  It thought moving draperies/fog/a patron fanning themselves
> >> with a program were all flame and we experienced many false alarms,
> >> mid-show.  However, because communication was good throughout we ended
> >> up with a solution that works.  They were able to pull that system out
> >> and replace with other compliant equipment - primarily heat and
> >> rate-of-rise based.  The!
> >   o!
> >>   nly trips we've had since were faulty sensors that were replaced and
> >> the troubles ceased.
> >>
> >> Regarding the mist systems mentioned, I like the idea but why
> >> distilled water? Is there a large reservoir somewhere in the building
> >> to draw from? I'd think any benefit of it being distilled might go
> >> away over time in storage.
> >>
> >> - Jim Dougherty
> >> Middlebury College Theatre Dept.
> >>
> >> _____
> >    the reason for the distilled water, and yeah there is a storage tank
> > that has to be periodically drained and refilled, is to make the system
> > safe for use on energized electrical equipment.  Once the tank is
> > drained, it switches over to regular water supply.   Regular water mist
> > will have enough trace chemicals in it to cause short circuits in
> > energized electrical gear. Especially if your area has hard water.
> >
> >    The systems are sized such that it will extinguish expected fires, or
> > contain them long enough for fire response to show up.  The huge benefit
> > is that unlike halon systems, it is perfectly harmless to the meat
> > machines that are also in the space, so you don't need to wait for the
> > people to evacuate and the fire to get worse before release.
> >
> > There is a video from a cruise line that was retrofitting these into all
> > their ships.  They had engine room fires on a ship with a conventional
> > halon system and one with the water mist system installed. Both very
> > similar causes, a leaking diesel fuel spraying inside the engine.   The
> > halon sysstem worked, and the fire was put put.  The ship needed
> > emergency dry docking and was out of service for three months while the
> > contents of that engine room got replaced.   Several millions in direct
> > damage repairs, tens of millions of refunds of cruise tickets for that
> > three month period.   The ship with the water mist system.  Fire was out
> > before the firefighting team made entry.   Damage was confined to one
> > cylinder of one of the two engines in that engine room, cleanup and
> > repairs were completed at the next port call, mostly because they had to
> > order the parts.  No lost time, repairs cost a few thousand bucks,
> > cleanup was done with mops, buckets and rags by ships crew.
> >
> > Here is the video.  They had a camera in the engine room that showed the
> > fire breaking out and being extinguished by the HI_FOG system.
> >   https://www.youtube.com/watch?v=tKXiNdJMhgA
> >
> > Also here is an article about a system installed in a historic property
> > in the US.
> >
> https://www.securitysystemsnews.com/article/thomas-jefferson-s-home-gets-marioff-water-mist-system
> >
> >
> > Dale
> > _____
> Memory fail.   only two weeks out of service and only eight million
> dollars in damages.
> Dale
>
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