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California CPC 2016 Occupant Load Calculation

Discussion in 'Plumbing Codes' started by Steven J Schloeder, Jun 23, 2018.

  1. Steven J Schloeder

    Steven J Schloeder Registered User

    Jun 22, 2018
    Likes Received:
    Please verify or correct my understanding here:

    CPC 2016 calculates occupant loads differently from CBC 2016

    CPC 2016 uses Table A under section 422.0; CBC 2016 uses Table 1004.1.2.

    These two tables have different load factors, which assumes a very different number of people occupying the space (e.g., Assembly A-3 non fixed seating is only 30 SF per person in CPC vs 7 SF per person in CBC -- this is a vast difference, which calls for some explanation).

    CPC 2016 states:

    422.1 Fixture Count
    Plumbing fixtures shall be provided for the type of building occupancy and in the minimum number shown in Table 422.1. [OSHPD 1, 2, 3 & 4] and Table 4-2 The total occupant load and occupancy classification shall be determined in accordance with Occupant Load Factor Table A and the California Building Code. Occupancy classification not shown in Table 422.1 shall be considered separately by the Authority Having Jurisdiction.

    Does this mean that the occupant load is determined by Occupant Load Factor A in CPC; and the occupancy classification is determined by California Building Code? This is the only way I can think to reconcile the difference, since both have load factor calculations, though the language is ambiguous.

    Also, CPC 2016 states

    The minimum number of fixtures shall be calculated at 50 percent male and 50 percent female based on the total occupant load. Where information submitted indicates a difference in distribution of the sexes such information shall be used in order to determine the number of fixtures for each sex. Once the occupancy load and occupancy are determined, Table 422.1 shall be applied to determine the minimum number of plumbing fixtures required. Where applying the fixture ratios in Table 422.1 results in fractional numbers, such numbers shall be rounded to the next whole number. For multiple occupancies, fractional numbers shall be first summed and then rounded to the next whole number.

    Comparing CBC Table 1004.1.2. and CPC Table A, the egress and room occupancy calcs under CBC are quite more restrictive (as noted above), and the fixture counts under CPC are quite more reduced.

    So on the code check sheet for the permit set, we need to consider two entirely different occupant loads (the number of people who are assumed to be in the building), and then further reduce the CPC by 1/2 to arrive at fixture counts for male vs females.

    Is that accurate?

    Thanks for your help in clearing this up for me.


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