Maximum panel area for explosion deflagration venting

[designsimply]

I check International Fire Code. It define the relieve pressure of 20 psf (usually 20 psf - 40 psf) for explosion deflagration (release) ventings. But it doesn't define how big size a venting can be. For example, is there a maximum area limit of 200 sqft or 300 sqft, whatever? I don't have NFPA 69 Standard on Explosion Prevention Systems which IFC refers. I don't have Factory Mutual (FM) 4440 Standards regarding the design of explosion deflagration venting. I am design an explosion deflagration venting of 20'x72' with 16 panels. I don't like to design every panel as a release unit because of cost like cables, connections, etc. I am trying to design every two or four panels as a release unit but I've got to know whether there is a maximum area limit before I give my design proposal.


By the way, I just got some information about NFPA 68. The recommended bound limit panel area is 33 sqft. For Factory Mutual (FM) 1-44, it looks like no specific panel area limit but usually 125 -150 sqft is used for cost efficiency. By the way, I still don't have NFPA 68 or FM 1-44 Data sheet.

Thanks for any response.

 

[riskengr]

I don't have it handy right now, but I believe there are size and weight restrictions for vents in NFPA 68. The problem is that the weight and the inertia related to larger panels can slow their movement and thus the relieving affect. This can increase the peak pressure experienced in the structure.



Stephen Haines, P.E.
Haines Fire & Risk Consulting

http://www.hainesfire-risk.com