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NFPA 1 and NFPA 45 Laboratory MAQ's

Question asked by tom.layton on Dec 31, 2019
Latest reply on Jan 3, 2020 by raymond.p.schmid

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-, the baseline maximum allowable quantity of hazardous chemicals per control area is required to be per NFPA 1 Table


In accord with NFPA 1 Table, 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 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.


  1.  If the entire floor is to be considered as 1 control area, does NFPA 45- 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?
  2.   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.