IBC 2000 Table 307.7 (Dust Collection/Area Class)

[moondoggy]

We have a room in our building that houses two silos used to store soybeans. In addition, there are bucket elevators used to move the material to the processing area located in another room. All of the equipment and silos have dust collection pickups on them which convey any dust to outdoor located baghouses. Our engineer did not rate the area, but the local building inspection authority is maintaining that this area should have been rated an H2.

Our engineer calculated dust generation to be below 12 lbs, which in accordance with the 1996 IBC was considered exempt from the H2 rating. Anything below 125 lbs. (in the 1996 edition) was considered to be exempt. However, in the IBC 2000, we are told that dust had been removed from Table 307.7 and therefore no further exemptions for the quantity of dust are allowed. But our engineer maintains that the remaining category of flammable solids still would apply for dust in Table 307.7 and therefore the exemption should still be allowed.

We are deadlocked on both sides. Meanwhile our building cannot receive its CO and our client is screaming that they cannot get into production. Our facility is 100% built with this one issue holding up the Building CO.

Can anyone lend some insight into this issue and how to go about defending our engineers position. We need to move this along quickly and feel that some additional insight as to the intention behind eliminating the dust category from the 2000 IBC would help move this along.

 

[henri2]

In the second paragraph you write "Our engineer calculated dust generation to be below 12 lbs, which in accordance with the 1996 IBC ". Do you mean the 1996 BOCA NBC?

I do not have BOCA's NBC but have copies of the 1997 UBC, IBC 2000, and IBC 2003.

UBC-97 Table 3-D does not have an item termed "combustible dust" and this table is similar to Table 307.7(1) of the IBC (00 and 03). However, the UBC does consider combustible dust for H-2 classification purposes as does the IBC.

In Sec 307.1.1 of the UBC, under sub-heading Division 2, it states " Occupancies where combustible dust is manufactured, used or generated in such a manner that concentrations and conditions create a fire or explosion potential: occupancices with a quantity of material in the building in excess of those listed in Table 3-D, which present a moderate explosion hazard...etc".

In your case, it seems that the combustible dust will have to be classified in accordance with one of the items listed in Table 307.7(1)....consistent with your engineer's views. ..and if they do not exceed the amounts, then the area may be classified as F-1. See IBC Sec 306.2

You should consider hiring a code consultant who has expertise in occupancy classifications and IBC/IFC and go to the board of appeals to make your case.

 

[moondoggy]

Thank you henri,

You stated taht "UBC-97 Table 3-D does not have an item termed "combustible dust" and this table is similar to Table 307.7(1) of the IBC (00 and 03)." Yes, the 2000 IBC had the dust category removed; would it be acceptable to say that the 'dust' is now covered in the 'Flammable Solid' Category of Table 307.1 (1)? You inferred this in your next to last paragraph when you said, "...it seems that the combustible dust will have to be classified in accordance with one of the items listed in Table 307.7(1)...."

Furthermore, Section 307.2 of the 2000 IBC states: “The following words and terms shall, for the purposes of this section and as used elsewhere in this code, have the meanings shown herein." It defines combustible dusts as a solid, see below:

"COMBUSTIBLE DUSTS. Finely divided solid material that is 420 microns or less in diameter and which,..." If this was the intent of removing the term 'combustible dust' to have it considered in the 'Flammable Solid' category, then my exemption should still hold true.

I do not have IBC Sec 306.2, what does it say?

 

[moondoggy]

In review of the IBC 2000 Table 307.7(1) and the various Use Groups, another question came to mind. Since the category of "Combustible Dust" was removed from this table, was it the intent to remove any exemption for this category or was it to be considered under a different category such as the "Flammable Solids"??? See previous post on how definitions.

Does anyone have any insight into this question? I raise this question because while the IBC made a deliberate removal of the Combustible Dust category, it kept it under the H2 Use Group, while Flammable Solids is under the H3 use Group. Keeping it under the H2 Use Group listing tells me that the intent is to not allow "any" exemption regardless of the quantity of Combustible Dust,i.e., 0.1 lb, etc. which would be absurd. Anyway I wanted to supplement my previous response with this new insight.

 

[henri2]

Check the ICC bulletin boards...a lot of code officials post there.

http://www.iccsafe.org/cgi-bin/ultimatebb.cgi

FYI, IBC Sec 306.2 is on page 27 of the 2000 edition of the code.