Occupancy Classfication for pellet storage
Occupancy Classfication for pellet storage
(OP)
I am back reviewing the occupancy classification of a building that will store bulk wood pellets. Pellets will be loaded to trucks, but the main purpose of the building (and a great part of its area), is for storage.
I see as a first and obvious possibility of classification, Group S-1, which allows storage of combustible materials (examples in code are bamboos and rattan, lumber, books, furniture, grains).
But per code, to classify an area a storage, it should not be a hazardous occupancy, and here is where I found this unclear:
1. High hazard group H-3 applies to building containing materials that "readily support combustion" so, how do you interpret the concept of "readily". Books, rattan, lumber, etc are combustible as are the wood pellets. Even more, pellets are same material as lumber (other shape only) so am I right in saying that H-3 group should not apply to my case? I have no clarity in where to draw the line between combustible and readily combustible.
2. High hazard group H-2 applies to buildings containing materials that pose a deflagration hazard or hazard for accelerated burning, and includes "combustible dusts". Storing wood pellets will certainly "produce" some dust (as will storing grains and lumber) but the code accepts storing grains and lumber as S-1 occupancy. So, I understand that for the code, the single "presence" of dust is not enough to have an H-2 occupancy. Is it the correct interpretation of the code that the "material" been stored has to be dust in order to trigger this H-2 occupancy? If not, how can we discriminate between an S-1 occupancy with dust and and H-2 occupancy?
I'll appreciate very much any input on these questions.
I see as a first and obvious possibility of classification, Group S-1, which allows storage of combustible materials (examples in code are bamboos and rattan, lumber, books, furniture, grains).
But per code, to classify an area a storage, it should not be a hazardous occupancy, and here is where I found this unclear:
1. High hazard group H-3 applies to building containing materials that "readily support combustion" so, how do you interpret the concept of "readily". Books, rattan, lumber, etc are combustible as are the wood pellets. Even more, pellets are same material as lumber (other shape only) so am I right in saying that H-3 group should not apply to my case? I have no clarity in where to draw the line between combustible and readily combustible.
2. High hazard group H-2 applies to buildings containing materials that pose a deflagration hazard or hazard for accelerated burning, and includes "combustible dusts". Storing wood pellets will certainly "produce" some dust (as will storing grains and lumber) but the code accepts storing grains and lumber as S-1 occupancy. So, I understand that for the code, the single "presence" of dust is not enough to have an H-2 occupancy. Is it the correct interpretation of the code that the "material" been stored has to be dust in order to trigger this H-2 occupancy? If not, how can we discriminate between an S-1 occupancy with dust and and H-2 occupancy?
I'll appreciate very much any input on these questions.





RE: Occupancy Classfication for pellet storage
RE: Occupancy Classfication for pellet storage
As to wood producing combustible dusts, the literal interpretation is the mere presence of dust could require a Group H-2 occupancy. Fortunately, most code officials are reasonable because this is not the intent. The intent of the H-2 occupancy classification for combustible dusts is when the process presents a deflagration.
Criteria is available in NFPA 664 for empirically determining when a dust deflagration exists. Attached is an article I wrote on the subject a few years ago that explains the proper use of the NFPA standards.
RE: Occupancy Classfication for pellet storage
RE: Occupancy Classfication for pellet storage