2017 (and 2020) NEC table 514.3(B)(1) has a category for Tank, Aboveground which says within 10' of shell, ends, or roof is classified as class I div 2. 2018 NFPA 30A table 8.3.2 has a category for Tank, aboveground, shop-fabricated, secondary containment tank used for the storage of Class I motor fuels which says within 18" of shell, ends, or roof of tank is class I div 2. Why does NEC not have this category? Typically if there is a conflict we go with the more stringent requirement, but it would really be great if we could just classify 18" from the tank to be class I div 2 instead of 10'. Any thoughts on this?
Aboveground Fuel Storage
- Thread starter depkel
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- Mission Viejo, CA
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- Professional Electrical Engineer
Reread 30A Table 8.3.2 carefully and compare its requirements for vents to those of NEC Table 514.3(B)(1).
My concern about the area around the shell, ends, and roof, not the vents.
- Location
- Mission Viejo, CA
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- Professional Electrical Engineer
In that case, review NEC Table 514.3(B)(1) carefully. The 10’ radius references vents. See NFPA 497, Fig. 5.10.4(a) as a somewhat stylized example. NFPA 30A is substantially the same.
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I did get confused about the whole "vent" thing. In all the other tables that line is under the shell, ends, and roof section, and I couldn't make sense of why it would be under "vents". I thought maybe it was supposed to be under shell, ends, and roof.
We do have a double-wall tank.
Thank you for your help, rbalex.
We do have a double-wall tank.
Thank you for your help, rbalex.
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
A double-wall tank with a vent still has the same requirements.
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