Design Concentration

[zubinsha]

Hi Every one ,

On what basis do we select the design concentration for room to be protected with FM 200. Normally we used to take the design Concentration as 7% at 20 C .Please provide an answer on the basis of NFPA 2001.

 

[cdafd]

http://www.ttlcompany.com/pages/kiddeproducts/softwares/FM200Cal/index.htm

??????

 

[zubinsha]

The Link which you provided does not work..No result is shown .No where does the link gives an answer to my question..

 

[cdafd]

Sorry not a designer

But per 2001 looks like you need to decide what you are trying to protect and than use the manufacturer to design the system to,

And appears that is what the calculator does just need to plug in the numbers

Also can seek the help of a FPE

 

[DM2]

Some consideration needs to be given to the manufacturers approvals, however most system are based on a Class A or C hazard. In the US the MDC (Minimum Design Concentration) is based on the manufactures listing. During the Halon 1301 days, the MDC was specified in the standard. For countries following ISO standards, the MDC is specified in the ISO standard. NFPA 2001 requires the MDC to incorporates a 20% safety factor above the MEC (Minimum Extinguishing Concentration). It should be noted that those following the ISO standards use a MDC which has a 30% safety factor.

Most Manufacturers have the same design concentration for Class A and C hazards set at 6.25%. This assumes that the system will be automatically activated rather than manually activated. A Manually activated system is required to have a MDC which is 30% above the MEC. The logic follows that the system wouldn't be discharged until someone was somehow notified of the fire, at which time the fire would be considerably larger than what it would be if it were to discharge automatically.

Basing the MDC on 20°C is more dependent on what the end user intends the protected space to operate at, under "Ambient Conditions".

Class B hazards (engine rooms, etc.) require yet a higher design concentration based on testing that the manufacture has performed on the specific fuel.

Regards,
DM

"Real world Knowledge isn't dropped from a parachute in the sky but rather acquired in tiny increments from a variety of sources including panic and curiosity."

 

[cloa]

The link works for me.

http://www.ttlcompany.com/pages/kiddeproducts/softwares/FM200Cal/index.htm

http://www.eng-tips.com/threadminder.cfm?pid=1529

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