What load factor do you use for Restrooms?

[Ryan Schultz]

What load factor do you use for Restrooms?

I have in the past, used a zero load factor for these--categorizing them as circulation.

My AHJ hasn't seem to have a problem with that.

 

[RLGA]

Depends on the main occupancy to which the restrooms are accessory.

If an assembly use, then only the net floor area is used and areas such as circulation and restrooms are not included. However, if the occupant load factor is based on gross floor area, then circulation, restrooms, etc. are included when determining occupant load.

Thus, if the restrooms are within an office building, then 100 gsf/occupant (150 gsf/occupant per 2018 IBC) is used. If it's a warehouse, then 500 gsf/occupant is used, and so on.

 

[Ryan Schultz]

Let's say the main occupancy of the building is a (Airport terminal - Baggage claim) which is at (20 gross/occupant). Do I then need to use a (20 gross/occupant) for the restroom areas that serve that Baggage claim?

Seems high.

 

[RLGA]

Airports can be a little tricky. Airport terminals are typically considered "covered mall buildings" and the occupant load of the "mall" portion would be determined per Section 402.8.2. If the restrooms are accessed from the "mall" circulation and not directly from the baggage claim area, then I would not include them as part of the gross area of the baggage claim area.

 

[Ryan Schultz]

lord have mercy on our souls.

 

[ADAguy]

You better have strong bladder control when waiting in baggage when all the planes land at the same time.
Consider if there is food service where liquor is served adjacent to baggage, what then when counting?
CPC table differs from occupancy when counting fixtures based on area use.

 

[mtlogcabin]

Got to love my small international airport with an arrival of about 1 every hour between 6 am and midnight with only 2 baggage carousals

 

[MarioTur]

As a licensed Architect since 1987, I have learned by experience that toilets, restrooms, spas, and showers are all counted in the gross area for occupant load calculations. However, they are not included in the net area, which focuses on usable space. This distinction is crucial for ensuring compliance with safety regulations and providing adequate facilities for occupants. Many AHJs do not comment on the plans because they are not as well-versed or trained to identify the crucial life safety considerations. "Less is more" does not apply in this situation; instead, be guided by exercising caution so that there will not be a question from an AHJ.

 

[mark handler]

Restrooms are generally not counted in the occupant load calculation itself, but rather in the calculation of the gross floor area, from which a net occupant load is determined. Different building codes use either gross or net calculations for the occupant load, but restrooms are considered accessory spaces that do not add to the net habitable area where the occupants are generally the same people in the main function of the space.

 

[arwat23]

Restrooms are generally not counted in the occupant load calculation itself, but rather in the calculation of the gross floor area, from which a net occupant load is determined. Different building codes use either gross or net calculations for the occupant load, but restrooms are considered accessory spaces that do not add to the net habitable area where the occupants are generally the same people in the main function of the space.

Gross load factors under IBC include restrooms by definition - there's no exclusion for that. Only in Net load factors do you not include restrooms.




This has been called out on more than a few of my early projects by multiple jurisdictions, all have referenced these definitions for their reasoning.

 

[Fred_F]

I usually use 50 sq ft per person for restrooms when calculating occupant load, unless it’s part of a larger assembly area. Zero load is fine if it’s accessory circulation and not meant for assembly.

 

[Yankee Chronicler]

I usually use 50 sq ft per person for restrooms when calculating occupant load, unless it’s part of a larger assembly area. Zero load is fine if it’s accessory circulation and not meant for assembly.

You're doing it wrong.

As has been explained above, if it's an occupancy that uses gross floor area (such as Group B), you just take the overall floor area and apply the occupancy factor to the entire floor plate. For occupancies that have the occupant load calculated on a net area basis, yiou only consider normally-occupied spaces, you don't include corridors, closets, or toilet rooms.

 

[arwat23]

As has been explained above, if it's an occupancy that uses gross floor area (such as Group B), you just take the overall floor area and apply the occupancy factor to the entire floor plate.

I disagree (or I'm reading this wrong). Occupancy classification and faction of space are two different things. Just because it's Group B doesn't mean everything is 150 gross. Conference and break rooms can be Group B but have a 15 net load factor. Storage rooms can be 300 gross.

I guess that leads me to another question. A restroom in an office suite is only accessed through a break room or a conference room. Do you include that restroom in the 150 gross for the business areas, or do you not include that because it serves and area with a "net" load factor?

 

[Joe.B]

For the sake of the conversation, when I open my code book, this is what I read. Is it the same for y'all, or is yours modified?

1004.2 Cumulative occupant loads. Where the path of
egress travel includes intervening rooms, areas or spaces,
cumulative occupant loads shall be determined in accordance
with this section.

1004.2.1 Intervening spaces or accessory areas. Where
occupants egress from one or more rooms, areas or spaces
through others, the design occupant load shall be the
combined occupant load of interconnected accessory or
intervening spaces. Design of egress path capacity shall be
based on the cumulative portion of occupant loads of all
rooms, areas or spaces to that point along the path of
egress travel.

1004.2.2 Adjacent levels for mezzanines. That portion of
the occupant load of a mezzanine with required egress
through a room, area or space on an adjacent level shall be
added to the occupant load of that room, area or space.

1004.2.3 Adjacent stories. Other than for the egress
components designed for convergence in accordance with
Section 1005.6, the occupant load from separate stories
shall not be added.

1004.3 Multiple function occupant load. Where an area
under consideration contains multiple functions having
different occupant load factors, the design occupant load for
such area shall be based on the floor area of each function
calculated independently.

1004.4 Multiple occupancies. Where a building contains
two or more occupancies, the means of egress requirements
shall apply to each portion of the building based on the occupancy
of that space. Where two or more occupancies utilize
portions of the same means of egress system, those egress
components shall meet the more stringent requirements of all
occupancies that are served.

 

[walker.t]

1004.2 Cumulative occupant loads.

That applies only to means of egress:

2021 IBC 1004.1 Design Occupant Load
In determining means of egress requirements, the number of occupants for whom means of egress facilities are provided shall be determined in accordance with this section.

Occupancy classification and faction of space are two different things.

It would be helpful if Table 1004.5 had a floor area allowance for restrooms.