I will check your links tomorrow Nicky- they look interesting.
I've worked on several systems in Qatar. Qatar Civil Defense has very
detailed requirements for fire modeling these systems, and negative
impact on sprinkler activation is not mentioned. These small impulse
fans direct the car exhaust toward the huge exhaust shafts as part of
normal operation--- they have two speeds-- normal and emergency. The
10m/s is the emergency speed. If a signal from a flow switch is used
kick them to emergency speed, the sprinklers already activated.
Brad
Quoting Nicky Marshall <ni...@protechdesign.co.nz>:
Are Jet/impulse fans installed in basement carparks a serious
concern to the successful operation of sprinklers?
Example of the fans:
http://www.fantech.com.au/FanRange.aspx?AppID=P2&RangeID=2021 which
also discusses some installation recommendations with regards to
sprinklers.
We are starting to see more of these installed in basement carparks
as a cheaper option to ducted systems.
The velocity is around 10 m/s (32 ft/sec) at the fan discharge
point. But 1-2 m/s at chest height over car park areas.
Obviously this impacts air and heat movement and sprinkler
operation. But if they are installed in drive lanes only (where
there is no fire load) and shut down as soon as one sprinkler
operates, is the risk largely mitigated?
FM Global data sheets only discuss air velocities for storage
sprinklers. It appears to be silent for non-storage sprinklers.
I cannot find anything in NFPA 13.
New South Wales Australia, the Fire Service are asking for
additional smoke detection to shut the fans down (unless fire
modelling shows it is acceptable). Is this really necessary?
https://www.fire.nsw.gov.au/gallery/files/pdf/guidelines/impulse_fans_in_carparks.pdf
There was also a case study done based on fire modelling.
http://www.sciencedirect.com/science/article/pii/S2214398X13000034 ,
but every building and system is different...
We agree that it needs to be considered, but are unsure that an
additional detection system is necessary.
Your thoughts and input appreciated.
Nicky Marshall
Southern Regional Manager
PROTECH DESIGN LIMITED
Specialist Fire Protection Consultants
Phone: +64 (0)3 579 5577 extn 2 Mobile: +64 (0)21 433 488 Email:
ni...@protechdesign.co.nz Skype: nicky-marshall Web
:www.protechdesign.co.nz
Address:105A Alabama Rd, Redwoodtown, Blenheim 7201, NZ Postal: PO
Box 4022, Redwood Village, Blenheim 7242, NZ
"I always wondered why somebody doesn't do something about that.
Then I realised I was somebody" Lily Tomlin
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