Occupancy Classfication for pellet storage 1

[garfio]

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.

 

[garfio]

I forgot to mention I am using IBC 2006

 

[stookeyfpe]

If you look at International Fire Code Section 2701.2.2, you will see that wood is neither a physical hazard or health hazard material. Because wood is not a hazardous material, you do not need to apply the requirements in Table 307.1(1) for maximum allowable quantities for hazardous materials.

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.

 

[garfio]

Thanks for the information: the article is excellent and addresses the exact same doubts that the code gave me. So, is it correct to say that my classification is not H-3 and can be S-1 unless the amount of dust (and other factors in the deflagration pentagon) is such that can constitute a risk of deflagration, in which case it would be and H-2 occupancy?

 

[stookeyfpe]

You're correct. If you don't have a deflagration hazard it is incorrect to assign the building a Group H-2 occupancy classification.