2013 CBC - Sec. 305.1.1 as applied to Table 1607.1

[PaulJi]

I've a multi-occupancy building w/ nonseparated occupancies, two stories. Primary occupancy is A-3.

Phase I Plans approved and first floor is occupied by church. Phase II was approved as future B-occupancy on second floor.

Client requested that a religious classroom for less than 100 occupants be added to the second floor.

Section 305.1.1 "Accessory to place of religious worship" allows the classroom to be classified as a Group A-3 occupancy.

Question: Would the uniformly distributed and concentrated floor live loads in Table 1607.1 for "27. Schools/Classrooms" of 40 psf and 1,000 lbs. apply or would the uniform distributed and concentrated floor live loads of "4. Assembly areas/Other assembly areas" of 100 psf apply?

 

[JBI]

For the religious classroom, the classroom load is appropriate. What does the B require?

 

[kilitact]

For the religious classroom, the classroom load is appropriate. What does the B require?

Agree (first time for everything,lol)

 

[PaulJi]

There was a change in the 2013 CBC from the 2010 CBC. Under the 2010 CBC Sec. 308.5 stating

"Places of worship during religious functions are not included." This essentially allowed the classrooms to be Group E ... and excluded them from being located on the level of exit discharge per Sec. 308.5.2 and from Sec. 308.5.2.1 Special provisions that set requirements for daycare facilities located above or below the first story. It was then a simple matter of using the category 27. Schools - classrooms with 40 psf. The max. floor area of Group E applied.

In 2013 CBC however this sentence about "places of worship" was deleted. The name of Sec. 442 was changed from Group E to "School Facilities for Kindergarten through 12 Grand and Group E Day Care." Sec. 305.1.1 made accessory to places of religious worship (less than 100 occupants) classified as Group A-3 occupancies.

Classifying a religious classroom as a Group A-3 occupancy means that the allowable floor area for 99 occupants is significantly less than the allowable floor area for 99 occupants classified as a Group E occupancy.

Table 1004.1.2 "Maximum Floor Area Allowances per Occupant" lists Assembly without fixed seats - Concentrated (chairs only-not fixed) as having an occupant load factor of 7 net sf. Educational - classroom area however has an occupant load factor of 20 net sf. Structurally the same weight (ie same number of occupants) is concentrated on a smaller floor area in an assembly than in a classroom. In fact it is approximately 2.86 times more concentrated in a Group A at 7 net sf.

My difficulty is that the 2013 CBC code is written in such a way that the occupant load of an A-3 occupancy forces a higher min. live load than the 2010 CBC code. The max. allowable are doesn't seem to make sense with using a live load 40 psf. A max. allowable of 100 sf (Assembly - other assembly areas) is closer to the expected loads that are more concentrated.

While I'd like to use School - classrooms at 40 psf I'm having a problem justifying it structurally unless I was able to increase the maximum allowable floor area to 20 net sf per occupant.

Personally I feel the Code failed to take this into account when it was re-written in the 2013 CBC.

To answer your question ... I haven't approached the Building Department yet for their interpretation.

 

[kilitact]

There was a change in the 2013 CBC from the 2010 CBC. Under the 2010 CBC Sec. 308.5 stating "Places of worship during religious functions are not included." This essentially allowed the classrooms to be Group E ... and excluded them from being located on the level of exit discharge per Sec. 308.5.2 and from Sec. 308.5.2.1 Special provisions that set requirements for daycare facilities located above or below the first story. It was then a simple matter of using the category 27. Schools - classrooms with 40 psf. The max. floor area of Group E applied.

In 2013 CBC however this sentence about "places of worship" was deleted. The name of Sec. 442 was changed from Group E to "School Facilities for Kindergarten through 12 Grand and Group E Day Care." Sec. 305.1.1 made accessory to places of religious worship (less than 100 occupants) classified as Group A-3 occupancies.

Classifying a religious classroom as a Group A-3 occupancy means that the allowable floor area for 99 occupants is significantly less than the allowable floor area for 99 occupants classified as a Group E occupancy.

Table 1004.1.2 "Maximum Floor Area Allowances per Occupant" lists Assembly without fixed seats - Concentrated (chairs only-not fixed) as having an occupant load factor of 7 net sf. Educational - classroom area however has an occupant load factor of 20 net sf. Structurally the same weight (ie same number of occupants) is concentrated on a smaller floor area in an assembly than in a classroom. In fact it is approximately 2.86 times more concentrated in a Group A at 7 net sf.

My difficulty is that the 2013 CBC code is written in such a way that the occupant load of an A-3 occupancy forces a higher min. live load than the 2010 CBC code. The max. allowable are doesn't seem to make sense with using a live load 40 psf. A max. allowable of 100 sf (Assembly - other assembly areas) is closer to the expected loads that are more concentrated.

While I'd like to use School - classrooms at 40 psf I'm having a problem justifying it structurally unless I was able to increase the maximum allowable floor area to 20 net sf per occupant.

Personally I feel the Code failed to take this into account when it was re-written in the 2013 CBC.

To answer your question ... I haven't approached the Building Department yet for their interpretation.

Why are you using the CBC when you location is shown has Oregon?

 

[JBI]

Most 'Sunday School' classrooms have tables and chairs, not chairs only...

 

[cda]

Most 'Sunday School' classrooms have tables and chairs, not chairs only...

And some have no chairs and no tables

 

[PaulJi]

Kilitact, My project is in California were I'm also licensed.

To answer my own question ... I confused "assembly occupancy" with "function of space" in Table 1004.1.2. My mistake.

There is a direct connection between Table 1004.1.2 and Table 1607.1. Structurally I don't have an issue with the floor live load.

My real issue however is how the Fire Marshal will interpret Section 442.4 "Special provisions". This section excludes kindergarden through second grade and day care facilities from the second floor unless certain conditions are met in Exceptions.