NFPA-pressure at deflagration

[nuche1973]

When determining the maximum internal pressure of a dust collector: is it correct to assume that the hopper will be empty at deflagration? NFPA 68 doesn't clearly define this. Also, is it correct to assume that wether or not the hopper is full at deflagration is a product to product specification? Considering NFPA defines both the Lower Flammable and Upper Flammable Limits. I am working on the maximum pressure for corn starch and I am wondering if the internal pressure at the hopper includes fully loaded conditions or empty. Any thoughts would be greatly appreciated. Thanks.

 

[psafety]

Consider the volume as described in A.6.4.3 placement of the explosion panel determines L/D and if just the dirty air volume or the clean air volume is also used. I always assume an empty enclosure e.g maximum volume as the examples in 68 reflect.

Some vendors don't include the hopper, Annex A of NFPA clearly shows inclusion.

 

[nuche1973]

psafety:
thanks I appreciate it.

 

[psafety]

Don't a problem most of my work these days is related to explosion venting or migation.