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Occupant Load - Do You or Don't You?

Discussion in 'Commercial Building Codes' started by nealderidder, Apr 29, 2019.

  1. nealderidder

    nealderidder Bronze Member

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    I've done this both ways and had it approved both ways. Do you or don't you include circulation (hallways, corridors, stairs) and spaces like bathrooms? These are spaces that are occupied non-simultaneously, meaning an occupant in a corridor is either coming from or going to another space, he's not camped out in the corridor (unless his desk was moved there and maybe he should take a hint!).

    Just curious what your experience is with including or excluding these spaces from an overall occupant load.

    Thanks,
    Neal
     
  2. steveray

    steveray Sawhorse

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    In gross you do, in net, you don't have to...

    FLOOR AREA, GROSS. The floor area within the inside
    perimeter of the exterior walls of the building under consideration,
    exclusive of vent shafts and courts, without deduction
    for corridors, stairways, ramps, closets, the thickness of interior
    walls, columns or other features
    . The floor area of a
    building, or portion thereof, not provided with surrounding
    exterior walls shall be the usable area under the horizontal
    projection of the roof or floor above. The gross floor area
    shall not include shafts with no openings or interior courts.

    FLOOR AREA, NET. The actual occupied area not including
    unoccupied accessory areas
    such as corridors, stairways,
    ramps, toilet rooms, mechanical rooms and closets.
     
    IJHumberson likes this.
  3. RLGA

    RLGA Sawhorse

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    Here's how I approach it:
    • If the story includes spaces that have occupant loads based on gross and net areas, then I include the restrooms, corridors, etc. within the floor area for the main gross area function since they support that function as well as the other functions. If a restroom, corridor, etc. only support a net area space, then I don't include those accessory areas. For example, if a story is mostly offices, but has conference rooms, then I would include the restrooms and corridors within the gross business area function. Another example, if a story half classrooms with a hallway and restrooms, and the other half is a school administration area with its own corridors and restrooms (but has access to the classroom half), then I would include the corridors and restrooms associated with the administration area within the gross business area of the administration offices, but not include the corridors and restrooms associated within the net area of the classroom half of the story.
    • If a story has predominately net area functions with some minor gross area functions (e.g., small storage rooms, a small office or two, etc.), then I do not include the corridors and restrooms, but each gross area function is based on the gross area that function occupies including walls and columns.
     
    IJHumberson, Joe Engel and Rick18071 like this.
  4. nealderidder

    nealderidder Bronze Member

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    I see what you're saying Ron and I'm wondering how receptive a B.O. would be to that approach...

    While we're on the subject. Has anyone had success having large assembly rooms counted as "business areas" for egress sizing when they are non-simultaneous uses? I'm thinking of a large training room in an office building used by employees (those people captured in the 100/SF gross calculation). I get that the room itself must provide exits based on 15/SF but I'm having trouble accepting that my exiting from that floor must be sized for the employees in the training room plus the employees in the office area (they're the same people).

    I'm wondering just how often a B.O. actually allows "the actual number of occupants for whom each occupied space, floor or building is designed, although less that those determined by calculation, shall be permitted to be used in the determination of the design occupant load"

    I'm thinking of a particular case where a floor designed to accommodate 126 people winds up with an occupant load of 781 because of large training rooms and break areas. Other than the occasional handful of visitors, the assembly spaces are only used by the employees. There will be no public concerts going on in the break room while the offices are fully occupied (or any other time).
     
  5. RLGA

    RLGA Sawhorse

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    If the training room is used by employees only from the same story, I could see how that might be acceptable. However, if the training room is used by employees from other locations or on other stories, then no, that would not be acceptable.
     
    JPohling and Ty J. like this.
  6. Rick18071

    Rick18071 Sawhorse

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    Why can't a training room be "B"?

    SECTION 304
    BUSINESS GROUP B
    304.1 Business Group B. Business Group B occupancy
    includes, among others, the use of a building or structure, or a
    portion thereof, for office, professional or service-type transactions,
    including storage of records and accounts. Business
    occupancies shall include, but not be limited to, the following:
    Airport traffic control towers
    Ambulatory care facilities
    Animal hospitals, kennels and pounds
    Banks
    Barber and beauty shops
    Car wash
    Civic administration
    Clinic, outpatient
    Dry cleaning and laundries: pick-up and delivery stations
    and self-service
    Educational occupancies for students above the 12th grade
    Electronic data processing
    Food processing establishments and commercial kitchens
    not associated with restaurants, cafeterias and similar
    dining facilities not more than 2,500 square feet (232 m2)
    in area.
    Laboratories: testing and research
    Motor vehicle showrooms
    Post offices
    Print shops
    Professional services (architects, attorneys, dentists,
    physicians, engineers, etc.)
    Radio and television stations
    Telephone exchanges
    Training and skill development not in a school or
    academic program (this shall include, but not be limited
    to, tutoring centers, martial arts studios, gymnastics and
    similar uses regardless of the ages served, and where not
    classified as a Group A occupancy).
     
  7. RLGA

    RLGA Sawhorse

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    It can be, as long as the occupant load does exceed 49. Once the occupant load hits 50, then it becomes a Group A.
     
    my250r11 likes this.
  8. Rick18071

    Rick18071 Sawhorse

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    Don't agree. It does not say that in section 304 under training and skill development and there is nothing about training rooms under any group A use.
     
  9. RLGA

    RLGA Sawhorse

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    But it also says “this shall include, but not be limited to,...and where not classified as a Group A occupancy.
     
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  10. JPohling

    JPohling Sawhorse

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    Absolutely a training room over 49 occupants is an A occupancy
     
  11. nealderidder

    nealderidder Bronze Member

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    I had the meeting with the B.O. They were comfortable with our approach of looking at the Training Room and Break Room as "accessory" to the main occupancy and non-simultaneous uses. We'll have to egress every space as if fully occupied but do not have to include occupant loads in these accessory spaces when determining overall egress width from the floor. Our issue was that the existing stairs (this is a big TI) couldn't handle the required egress width if all spaces were fully occupied and the Training Room and Break Room were considered assembly.
     
  12. Tim Mailloux

    Tim Mailloux Registered User

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    The ICC would disagree with this approach and I have a formal ICC code interpretation backing this up. Occupant loads are determined by the function of the space or room, and have nothing to do with the occupancy group. A small conference room (in an office building room) under 750sf is technically part of the B occupancy, but the occupant load of that conference room is still 1 person per 15sf of floor space. There is also nothing in the code regarding non-simultaneous use, this whole concept needs to go away.

    As an example my office has several larger conference rooms that 95% of the time are only used by employees already accounted for in the gross business occupant load calculation (non-simultaneous use). But at least once a month we host an outside industry work shop of 40 plus people in our office during normal business hours. Do we not need to make sure those people can safely egress our office building? The code commentary also goes onto to say that the calculated occupants loads represent the worst case occupant load scenario which will be much higher than normal day to day use.
     
  13. mtlogcabin

    mtlogcabin Sawhorse

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    It is how you determine the OL of the room that my get you over 49 people.
    If it is a classroom setting I use 20 PSF OL out of the table for classroom.
    If it is martial arts/gymnastics I use the 50 PSF OL out of the table for exercise room.
    If there are computer work stations set up in the room I count the work stations to determine the OL

    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.
    FYI
    The OL numbers change in the 2018 for "B" uses. It can be anywhere from 50 to 150 people per square foot depending on the use. The BO is charged with approving the numbers submitted.
     
  14. Rick18071

    Rick18071 Sawhorse

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    Training and skill development not in a school or
    academic program is under B but not listed under A.

    Would make more sense it would E rather than A.
     
  15. Tim Mailloux

    Tim Mailloux Registered User

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    That should only be allowed if those computer workstations were fixed (aka bolted to the floor), or the number or workstations was greater than the calculated occupant load.
     
  16. mtlogcabin

    mtlogcabin Sawhorse

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    Let me clarify
    If it is a training room that consist of individual computer work stations that the employees are training on that is how
    I determine the OL fixed or not.
    Now if it is a room the employees bring in their laptops to train on then no the laptops are not part of the furniture and fixtures that remain in the room
     
  17. steveray

    steveray Sawhorse

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    What level alteration is it? You may not need to even address egress.....

    805.1 Scope. The requirements of this section shall be limited
    to work areas that include exits or corridors shared by more
    than one tenant within the work area in which Level 2 alterations
    are being performed,
    and where specified they shall
    apply throughout the floor on which the work areas are
    located or otherwise beyond the work area.

    Too many designers do not go to the IEBC to work their way out of a problem IMO...
     
  18. JPohling

    JPohling Sawhorse

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    In my jurisdiction the occupant load for a training room is 1/20sf but the training room furniture needs to be fixed
     
  19. Sifu

    Sifu Gold Member

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    I also have a technical opinion from ICC that says the same thing.
     
  20. Rick18071

    Rick18071 Sawhorse

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    I want to understand how this is determined. Please where does this say that? Would it be A-1,2, 3, 4 or 5?
     

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