# IPC & fixture calculations



## JPohling (May 8, 2017)

I have a project in Texas that is under the IPC.  This is a small tenant improvement for a "B" occupancy professional business office  (stock broker)  3,652 SF.  We originally submitted fixture calculations based upon 1 occupant per 100SF of the gross suite area which resulted in 37 occupants.  This yields two single occupancy toilet rooms for this suite area.  

The plumbing plan reviewer is requiring that we match the occupant load that we have calculated for exiting.  There is a lobby and a conference room as a part of the suite.  We calculate these areas for exiting at 1/15 as an Assembly occupant load.  These areas are still considered B occupancy as the occupant loads are less than 50.  The issue is that this really increases our occupant load for the plumbing fixtures to 92 occupants and requires additional plumbing fixtures.

Is this how you all calculate plumbing fixtures under the IPC?  This is one area where California is less stringent.

Exiting occupant loads are essentially halved for plumbing fixture calcs under the CPC.

The part that is difficult for me to accept is if this was a proposed office building that did not have a tenant then the calculation would for sure be based upon 1/100 multiplied by the gross square footage of the space.  Our tenant would then come in and the TI would be completed and no additional toilet fixtures would be required.  

What are your thoughts?


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## mark handler (May 8, 2017)

International Plumbing Code 2015
403.1 Minimum Number of Fixtures 
Plumbing fixtures shall be provided in the minimum number as shown in Table 403.1, based on the actual use of the building or space. Uses not shown in Table 403.1 shall be considered individually by the code official. The *number of occupants shall be determined by the International Building Code.*

Yes, CA does have an alternate table.


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## JPohling (May 8, 2017)

Mark,  I guess I would question if I indeed have an "assembly" occupancy based upon table 403.1.  The actual use of the space is "B".  Even my areas where we use an assembly occupant load for exit calculations are actually considered to be B occupancies as they are less than 50.


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## steveray (May 8, 2017)

If that is what the AHJ requires, then that is what IS required....I would do it at the 1 per 100 personally for fixtures, I would make sure the exiting works at the higher number...But your "future" tenant in the hypothetical situation is not necessarily off the hook for more fixtures..


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## JPohling (May 8, 2017)

Exiting works at higher number.  Fixture counts are good at 1/100.  Fixture counts are not good at higher number used for exiting.  That is the problem.


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## mtlogcabin (May 8, 2017)

Unless the lobby functions similar to a bank with queue areas I would not calculate it as an assembly. As for the fixture count i would ask the AHJ to use the following exception.

 IBC 2012
1004.1.2 Areas without fixed seating.
The number of occupants shall be computed at the rate of one occupant per unit of area as prescribed in Table 1004.1.2. For areas without fixed seating, the occupant load shall not be less than that number determined by dividing the floor area under consideration by the occupant load factor assigned to the function of the space as set forth in Table 1004.1.2. Where an intended function is not listed in Table 1004.1.2, the building official shall establish a function based on a listed function that most nearly resembles the intended function.

Exception: Where approved by the building official, the actual number of occupants for whom each occupied space, floor or building is designed, although less than those determined by calculation, shall be permitted to be used in the determination of the design occupant load.


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## steveray (May 8, 2017)

To me, if I run a conference room at 15 per and I come out at less than 50, it stays B at 1 per 100...


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## skipharper (May 8, 2017)

Agree with 37 occupants and IPC table 403.1-business-is what you use-looks like 1 for each sex-accessible (maybe) and good to go! Plumbing fixtures have nothing to do with exit requirements.


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## Francis Vineyard (May 8, 2017)

Use of the IEBC provisions won't get you 92:

*SECTION 810
PLUMBING
810.1 Minimum fixtures. *Where the occupant load of the story is increased by more than 20 percent, plumbing fixtures for the story shall be provided in quantities specified in the _International Plumbing Code _based on the increased occupant load.

Note "where subject to the approval" in Virginia for example the Building Official does not have administrative authority to deny a code provision or exception that is permitted; is this the case in Texas too? 

Code Commentary:
*Business Facilities*
Consider a barber college where the code classifies the entire building as a Group B occupancy. The building has several large assembly rooms where the intent is to have training sessions for large groups of students. Clearly, these areas are used for assembly and, therefore, the use of the fixture ratios in Section 1, Row 4 of Table 2902.1 should be used.

The choice of an occupancy use for the purposes of determining plumbing fixtures does not affect the occupancy group chosen for egress purposes. In other words, using a previous example, the school gymnasium with stage space should be chosen to be “assembly use” for plumbing fixture requirements, but the entire building is still a Group B occupancy for the purposes of egress.

Note that Section 1004.1.2 has an exception, which allows the designer to present an “actual” occupancy load number to the code official for approval instead of the calculated load for the occupancy square footage. While this exception would allow a smaller occupancy load to be chosen for the purposes of determining the required number of plumbing fixtures, code officials must carefully consider and appropriately justify the reduction. The code official should consider the potential for the space to be loaded with more persons than stated by the designer, future use by different tenants of the same occupancy classification and the difficulty of enforcement of the maximum occupancy load based upon the limited number of fixtures provided.


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## JPohling (May 8, 2017)

Thank you for the responses.  I agree with many of you that the B occupancy should be used from Table 403.1 and the entire space calculated at 1/100.  The BO is working with us and has gotten us to where we need to be in terms of occupant load, but it is not the way one would expect.  They are having us calculate all areas except the one conference room at 1/100.  Conference room at 1/15.  But they are allowing us to remove all of the "hallway" square footage from the calculations.  I do not understand how this works with the code, but I will take it!


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## steveray (May 8, 2017)

That is so dumb as B and 1/100 you need to include hallways and shafts even....


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## JPohling (May 8, 2017)

yes I agree, but that's how they wanted it done...............


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