Power Plant Ductwork Design

[tdunaway]

I have heard several times that ductwork in power plants should be designed for +/- 35" H20 pressure. Can someone point me to the NFPA standard and section where that requirement is mentioned?

Is the 35" requirement in addition to other design loads (i.e. dead load, live load, wind load, etc...)?

Thanks,

 

[tdunaway]

Update, I located the section in NFPA 85 I was looking for. I believe they are actually saying the duct need NOT be designed for more than 35", but should at least be designed for the test block capabilities of the fan (if less than 35").

The section is uploaded here: