Power Transformer Fire

[Power0020]

a building is located with the fire zone of big power transformer (15 m) . The recommendation of fire rated design is achieved however the architect would like to put some windows into the subject walls. NFPA 850 recommends using automated louvers for such windows but no one will be happy with extra cost.

The transformer is protected by water spray system as an active FF. Does the introduction of such active FF system help reducing the required 15 m passive distance?

 

[chicopee]

Wired reinforced glass , while may crack under intense heat, will not shatter into pieces. Radiant heat on the other hand will transfer thru the reinforced glass.

 

[Power0020]

Thank Chicopee, would this be the case with a battery room?

 

[LCREP]

Check with the insurance carrier they may/will have additional requirements.

 

[stookeyfpe]

A battery room is a completely different scenario. The fuel load is much less and they don't contain a combustible heat transfer oil.

As to the use of a water spray system in lieu of separation distance, it's not possible to respond to the questions because the volume of oil isn't stipulated. From my cursory glance at NFPA 850, one can apply engineering judgement for transformers < 500 gallons of heat transfer oil for smaller installations and you may be able to justify the water spray system as a credible reduction variable. Installations = or > 500 gallons should follow the prescriptive spatial separation distances unless they transformer is separated from the exposure by a two-hour fire barrier designed in accordance with NFPA 850, Section 5.1.1.4.