Minimum Dorm Room Size

[Frank Karp]

Is there anything in the 2015 IBC that sets a minimum square footage for a 2 person dorm room? (It seems NY code sets a 50 sf/person minimum, but our project is in RI.)

 

[cda]

Residential 200???

 

[cda]

DORMITORY. A space in a building where group sleeping accommodations are provided in one room, or in a series of closely associated rooms, for persons not members of the same family group, under joint occupancy and single management, as in college dormitories or fraternity houses.

 

[cda]

The I’s do not define Residential

 

[ADAguy]

maybe not but be wary of door latch side clearances, rooms may be "visited" by WC users.

 

[Inspector Gift]

Minimum habitable room size is 70 sq. ft. (7'x10') (IBC 1207.1 and 1207.3)

 

[ADAguy]

only room for Ikea bunkbeds and a freestanding closet & desks

 

[RLGA]

The 50 sq. ft. is based on gross floor area, so it includes all circulation, restrooms, etc. Table 1004.1.2 (2015 IBC) is not intended to establish a minimum area assigned to a person.

Times have changed and so has what we called "dormitories." If 2 to 4 students are assigned to a room as is the case in most older-style dorms and each floor or wing is provided with shared common area restrooms and showers, then the denser "Dormitories" occupant load factor would be appropriate. These would be considered "sleeping units" per building code parlance.

However, if your "dorm" is actually like an apartment (usually with private bathrooms, kitchen, laundry, and common living area) with one student per bedroom, then use the 200 sq. ft. per occupant load factor. This type of arrangement would be a "dwelling unit" per the building code."

 

[Inspector Gift]

Is there a toilet, sink, and shower (or bathtub) in the dorm room? and are there permanent provisions for cooking? If not, it is not a dwelling unit by our definition.

A DWELLING UNIT is a single unit providing complete, independent living facilities for one or more persons, including permanent provisions living, sleeping, eating, cooking and sanitation. (IBC 202)

 

[Frank Karp]

The 50 sq. ft. is based on gross floor area, so it includes all circulation, restrooms, etc. Table 1004.1.2 (2015 IBC) is not intended to establish a minimum area assigned to a person.

Times have changed and so has what we called "dormitories." If 2 to 4 students are assigned to a room as is the case in most older-style dorms and each floor or wing is provided with shared common area restrooms and showers, then the denser "Dormitories" occupant load factor would be appropriate. These would be considered "sleeping units" per building code parlance.

However, if your "dorm" is actually like an apartment (usually with private bathrooms, kitchen, laundry, and common living area) with one student per bedroom, then use the 200 sq. ft. per occupant load factor. This type of arrangement would be a "dwelling unit" per the building code."

These are "sleeping rooms", only beds, desks and a closet. So, per Table 1004.1.2, 2 occupants would translate to a minimum 100 sf room, correct?

 

[Frank Karp]

Is there a toilet, sink, and shower (or bathtub) in the dorm room? and are there permanent provisions for cooking? If not, it is not a dwelling unit by our definition.

A DWELLING UNIT is a single unit providing complete, independent living facilities for one or more persons, including permanent provisions living, sleeping, eating, cooking and sanitation. (IBC 202)

These are "sleeping rooms".

 

[RLGA]

These are "sleeping rooms", only beds, desks and a closet. So, per Table 1004.1.2, 2 occupants would translate to a minimum 100 sf room, correct?

Not really. The corridors, stairs, and restrooms are included in calculating the occupant load of a building since they are part of the gross floor area. The size of a room is not required to be based on the occupant load factor. You can make the size of the room whatever you want (as long as it complies with the minimum area of an occupiable space as previously mentioned).

 

[Inspector Gift]

These are "sleeping rooms", only beds, desks and a closet. So, per Table 1004.1.2, 2 occupants would translate to a minimum 100 sf room, correct?

Frank, based upon the information provided - that these are only sleeping/study rooms - then the minimum size for a habitable room is 70 sq ft. for a single occupant or more.

 

[RLGA]

Frank, based upon the information provided - that these are only sleeping/study rooms - then the minimum size for a habitable room is 70 sq ft. for a single occupant or more.

The building code does not establish minimum assignable area for occupants. For example, business areas has an occupant load factor of 100 sq. ft. per occupant (2015 IBC and earlier). That does not mean a 1-person office is required to have a minimum of 100 sq. ft. Similarly, a dorm room with 2 students assigned does not mean you have to provide a 100 sq. ft. room. As a matter of fact, 50 sq. ft. per student is less than half the national average of 114 sq. ft. per student. The 50 sq. ft. per occupant (meaning a person inside the building and not just a resident) covers visitors, housekeeping (if they're so lucky), maintenance, etc.

So, as an example, assume a 9-room story with rooms accommodating 2 students each. At 114 sq. ft. per student, that would be about 2,052 sq. ft.--but wait, gross area includes all associated dorm living areas and not just the rooms. Therefore, you have to add in the corridor. If the rooms are 12-foot wide and the corridor is double-loaded, then it would be 60 ft. long. If the width is 5 ft., then the area is 300 sq. ft. Then you need to add the area of a restroom and showers at, let's say, 250 sq. ft. Thus, you have a gross floor area (including walls and everything mentioned) of about 2,700 sq. ft. (FYI, stairs would be included if it is a multi-story building).

At 50 sq. ft. per occupant, the occupant load of that story is 54--even though only 18 students live there. It's really hard to get that number of occupants unless one room is having a blow-out party. This load factor was more intended for the barracks-style dorms (imagine military barracks such as that shown in the scene of Full Metal Jacket ).

However, using the 200 sq. ft. residential load factor may not be enough. Per the example I provided, it would provide an occupant load of only 14. If you find that by using 50 sq. ft. per occupant provides an unusually high occupant load and 200 sq. ft. per occupant is too little, you could request an approval to use another occupant load factor that is more reasonable per the exception to Section 1004.1.2.

 

[Frank Karp]

The building code does not establish minimum assignable area for occupants. For example, business areas has an occupant load factor of 100 sq. ft. per occupant (2015 IBC and earlier). That does not mean a 1-person office is required to have a minimum of 100 sq. ft. Similarly, a dorm room with 2 students assigned does not mean you have to provide a 100 sq. ft. room. As a matter of fact, 50 sq. ft. per student is less than half the national average of 114 sq. ft. per student. The 50 sq. ft. per occupant (meaning a person inside the building and not just a resident) covers visitors, housekeeping (if they're so lucky), maintenance, etc.

So, as an example, assume a 9-room story with rooms accommodating 2 students each. At 114 sq. ft. per student, that would be about 2,052 sq. ft.--but wait, gross area includes all associated dorm living areas and not just the rooms. Therefore, you have to add in the corridor. If the rooms are 12-foot wide and the corridor is double-loaded, then it would be 60 ft. long. If the width is 5 ft., then the area is 300 sq. ft. Then you need to add the area of a restroom and showers at, let's say, 250 sq. ft. Thus, you have a gross floor area (including walls and everything mentioned) of about 2,700 sq. ft. (FYI, stairs would be included if it is a multi-story building).

At 50 sq. ft. per occupant, the occupant load of that story is 54--even though only 18 students live there. It's really hard to get that number of occupants unless one room is having a blow-out party. This load factor was more intended for the barracks-style dorms (imagine military barracks such as that shown in the scene of Full Metal Jacket ).

However, using the 200 sq. ft. residential load factor may not be enough. Per the example I provided, it would provide an occupant load of only 14. If you find that by using 50 sq. ft. per occupant provides an unusually high occupant load and 200 sq. ft. per occupant is too little, you could request an approval to use another occupant load factor that is more reasonable per the exception to Section 1004.1.2.

Yes, that all makes sense. Thanks. It's first time I've considered using the OLF to determine room size, and I see the drawbacks now.