Can a designer provide a larger occupant load?

[Yankee Chronicler]

1004.5.1​

The occupant load permitted in any building, or portion thereof, is permitted to be increased from that number established for the occupancies in Table 1004.5, provided that all other requirements of the code are met based on such modified number and the occupant load does not exceed one occupant per 7 square feet (0.65 m2) of occupiable floor space. Where required by the building official, an approved aisle, seating or fixed equipment diagram substantiating any increase in occupant load shall be submitted. Where required by the building official, such diagram shall be posted.

Correct.

And NONE of that changes the use group or occupancy classification of the space or spaces in question.

 

[Henchalwoog]

You are still confusing occupant load calculation with use/occupancy classification.

I think my example was not the best...I understand the occupant load factors - in this instance they are applying a more concentrated occupant load factor to achieve a higher number of occupants to classify it as an "A" occupancy. Keep in mind that in my particular instance the designer is trying to provide accessory occupancies to a main occupancies and using the higher occupant load to add them to the main occupancy so that they do not exceed the 10% cap thus allowing them to have more accessory spaces than with the main occupancy alone...I would not have an issue if they have a 800 sq ft conference room and listed it at 7 sq ft per occupant - that is assembly to assembly...I would question if there was a 2000 sq ft fitness room and they listed it as 15 sq ft per occupant to achieve an assembly occupancy.

 

[Yankee Chronicler]

I think my example was not the best...I understand the occupant load factors - in this instance they are applying a more concentrated occupant load factor to achieve a higher number of occupants to classify it as an "A" occupancy. Keep in mind that in my particular instance the designer is trying to provide accessory occupancies to a main occupancies and using the higher occupant load to add them to the main occupancy so that they do not exceed the 10% cap thus allowing them to have more accessory spaces than with the main occupancy alone..

I understand that's what the designer is trying to do. And that's not how it works. The occupancy classification is determined based on how the space is used, NOT by how many people are in it. A conference room in an office suite is classified as a Business use, but the occupant load is calculated at 1:15 (or maybe 1:7) without changing the conference room to an Assembly occupancy. Same for the waiting room in a doctor's office.

I would not have an issue if they have a 800 sq ft conference room and listed it at 7 sq ft per occupant - that is assembly to assembly...I would question if there was a 2000 sq ft fitness room and they listed it as 15 sq ft per occupant to achieve an assembly occupancy.

But a fitness center IS an Assembly use: It's an A-3.

A better example might be something like a hotel ballroom, which may be rented out and configured for a number of different types of layout, from a trade show to a high school reunion to a lecture series (or the annual ICC code hearings). Depending on how it's being used, it could be classified as an A-2 (Banquet hall) or it could be classified as an A-3 (Lecture hall). I would expect to see it classified as both (mixed use, non-separated), and the number and capacity of exits calculated based on the largest anticipated occupant load. But ... what is that? As a banquet hall, it would be based on tables and chairs, so one person per 15 square feet. As a lecture hall, it could be just rows of chairs so it would use a factor of one person per 7 square feet.

But maybe the hotel anticipates hosting receptions where people just stand and mill around. Standing assembly is one person per 5 square feet. So maybe the venue uses that, comes up with a number, and the manager says "Our other properties see more than that when they host receptions." Back when I started as an architect, the occupant load factor for standing assembly was one person per 3 square feet, so maybe they choose to use that and they arrive at a significantly higher occupant load. As long as they provide sufficient numbers, capacity, and distribution of means of egress, they can do that under IBC 1004.5.1.

That has NOTHING to do with the use and occupancy classification. It is what it is, and invoking 1004.5.1 to seek approval for a larger occupant load does NOT change the use and occupancy classification.

 

[Joe.B]

 

[Yankee Chronicler]

There's a reason why use and occupancy classification are found in Chapter 3, but we don't get to calculating occupant load until Chapter 10.



Table 1004.5 bases the occupant load calculation on the "Function of [the] Space," not on the use and occupancy classification of the building or portion of the building. What the designer is trying to do can't be done. Whether they understand that and are being unethical, or they're just stupid -- I have no idea. Back to my post about never attributing to malice that which can be adequately explained by stupidity.

 

[Henchalwoog]

I understand that's what the designer is trying to do. And that's not how it works. The occupancy classification is determined based on how the space is used, NOT by how many people are in it. A conference room in an office suite is classified as a Business use, but the occupant load is calculated at 1:15 (or maybe 1:7) without changing the conference room to an Assembly occupancy. Same for the waiting room in a doctor's office.



But a fitness center IS an Assembly use: It's an A-3.

A better example might be something like a hotel ballroom, which may be rented out and configured for a number of different types of layout, from a trade show to a high school reunion to a lecture series (or the annual ICC code hearings). Depending on how it's being used, it could be classified as an A-2 (Banquet hall) or it could be classified as an A-3 (Lecture hall). I would expect to see it classified as both (mixed use, non-separated), and the number and capacity of exits calculated based on the largest anticipated occupant load. But ... what is that? As a banquet hall, it would be based on tables and chairs, so one person per 15 square feet. As a lecture hall, it could be just rows of chairs so it would use a factor of one person per 7 square feet.

But maybe the hotel anticipates hosting receptions where people just stand and mill around. Standing assembly is one person per 5 square feet. So maybe the venue uses that, comes up with a number, and the manager says "Our other properties see more than that when they host receptions." Back when I started as an architect, the occupant load factor for standing assembly was one person per 3 square feet, so maybe they choose to use that and they arrive at a significantly higher occupant load. As long as they provide sufficient numbers, capacity, and distribution of means of egress, they can do that under IBC 1004.5.1.

That has NOTHING to do with the use and occupancy classification. It is what it is, and invoking 1004.5.1 to seek approval for a larger occupant load does NOT change the use and occupancy classification.

Well it COULD be certainly - but 2000 sq ft divided by 50 sq ft per person (exercise) would be less than 50 so I would classify it as "B"

 

[arwat23]

in this instance they are applying a more concentrated occupant load factor to achieve a higher number of occupants to classify it as an "A" occupancy.

That's not how that works. Like Yankee Chronicler said, OL means very little to the Classification.

You could flip it. An assembly space that's small or under 50 occupants doesn't have to be classified as A - it could be B or whatever it's accessory too. But I don't believe there's a mechanism for forcing an assembly classification on non-assembly spaces.

The designer either need to prove to you that their classifications make sense (not based on OL), or they need to find a section of code that supports an increased OL can force an assembly classification.

Edit: Is there a possibility that they genuinely believe those areas are classified as assembly and just blanket apply an assembly load factor? I had someone at a firm I worked at do that a few times.

 

[Joe.B]

2000 sq ft divided by 50 sq ft per person (exercise) would be less than 50 so I would classify it as "B"

An assembly space that's small or under 50 occupants

... can (shall?) be reclassified as a B.

303.1.1 Small buildings and tenant spaces. A building or
tenant space used for assembly purposes with an occupant
load of less than 50 persons shall be classified as a Group
B occupancy.

This is why I shared that "cart before the horse" meme. The information isn't wrong, it's the approach. Start with the appropriate classification per Chapter 3, then work from there. It's all about risk. The intended purpose is Assembly (higher risk) but the low occupant load allows the reclassification to a lower risk use.

SECTION 301
SCOPE
301.1 General. The provisions of this chapter shall control
the classification of all buildings and structures as to occupancy
and use. Different classifications of occupancy and use
represent varying levels of hazard and risk to building occupants
and adjacent properties.
SECTION 302
OCCUPANCY CLASSIFICATION
AND USE DESIGNATION
302.1 Occupancy classification. Occupancy classification is
the formal designation of the primary purpose of the building,
structure or portion thereof. Structures shall be classified into
one or more of the occupancy groups specified in this section
based on the nature of the hazards and risks to building occupants
generally associated with the intended purpose of the
building or structure. An area, room or space that is intended to
be occupied at different times for different purposes shall
comply with all applicable requirements associated with such
potential multipurpose. Structures containing multiple occupancy
groups shall comply with Section 508. Where a structure
is proposed for a purpose that is not specified in 'this section,
such structure shall be classified in the occupancy it most
nearly resembles based on the fire safety and relative hazard.
Occupied roofs shall be classified in the group that the occupancy
most nearly resembles, according to the fire safety and
relative hazard, and shall comply with Section 503.1.4.

 

[Yankee Chronicler]

Well it COULD be certainly - but 2000 sq ft divided by 50 sq ft per person (exercise) would be less than 50 so I would classify it as "B"

That's going in the opposite direction from the situation in the opening post. As Joe B. noted, there's a specific provision covering this.