These questions relate to design of a Class C laboratory space in a building classified as business occupancy, using flammable chemicals on the fifth floor above grade of a sprinklered building. The Authority Having Jurisdiction adopts the latest editions of NFPA codes. For this laboratory, in accord with 2018 NFPA 1-188.8.131.52.10.2, the baseline maximum allowable quantity of hazardous chemicals per control area is required to be per NFPA 1 Table 184.108.40.206.1.3.
In accord with NFPA 1 Table 220.127.116.11.1.3, a total of 1,000 scf of gas-state flammable gas would be allowed within a control area on Level 1. This is increased to 2,000 scf for this sprinklered building in accordance with Footnote d from the table. For this example it is assumed none of the footnotes other than d applies. NFPA 1 Table 18.104.22.168.1 reduces this 2,000 scf volume to 12.5% on Level 5, or 250 scf.
Our questions relate to applying 2019 NFPA 45 to the baseline quantity limits established above from NFPA 1. Only a small portion of the floor area is designated as a lab space and it is separated by a 1 hour fire wall from the adjacent occupancy in accordance with NFPA 45.
- If the entire floor is to be considered as 1 control area, does NFPA 45-22.214.171.124.2 apply a 25% reduction in the volume of flammable gas calculated above, such that the maximum allowed volume within the lab space on Level 5 of this building (treated as one control area) would be 187.5 scf, allowing the remainder of the 250 scf, or 62.5 scf, to be stored on level 5 outside of the lab space?
- If we were to segregate this laboratory unit from the remainder of Level 5, making the laboratory one control area, and the remainder of the floor a second control area, is the volume allowed in the laboratory area 187.5 scf, and the volume in the remainder of the floor (business occupancy, non-laboratory) 250 scf, totaling 437.5 scf for the 5th floor?
Thanks for your consideration.