AC 022 - Egress: How to calculate occupant loads (Part 2 of 2) - Gross vs. Net. Sq. Ft.

[@zmims1884]

This is great. I've been working in the architecture field for a few years now and STILL didn't fully understand how this was calculated. Thank you!

[@archicorner]

You're very welcome!

[@labangoat]

Wow, the illustration sketch technique of the videos helps my ADHD brain tremendously. Thank you !!!!!

[@archicorner]

Glad you liked the videos!

[@MLD.Ltd.]

I love your explanation of Gross and Net that’s makes it easy to understand and memorize!

[@archicorner]

Thank you. Good to know it was easy to follow, that is the goal. :)

[@ErionQ]

Excellent stuff! I think your next video should be a quick, run down on the permitting process, since you have the videos just a run down of the bullet points, occupancy type and load, building types, fire separation, means of egress, and system integration! Thanks for all the videos you do! We watch them in the office all the time !

[@ChuckHickl]

Your delivery is so on-point, current (not an old gray haired dude like myself relaying the info) and engaging (modern graphics instead of the static PowerPoint snoozers). As a plans reviewer, It is so difficult to get our customers to understand occupancy calcs in general and the differnces in Gross and Net in particular. These videos are going to go a long way in helping us relay this information. Great job and new sub here.

[@archicorner]

I am thankful that you took the time to write this message. It makes my day when I receive positive messages from others in similar fields like you. It validates that all the effort that goes onto these videos is appreciated. THANK YOU.

[@MKangelo23]

first off thank you for the videos. Ive been practicign for 30 years and still will come back to your videos for certain projects.Great job with your narration and illustrations! Each jurisditction can treat occupant load calc different but one point I have tried to argue in the past is that in assembly spaces, you should be able to deduct casework like kitchen counters and appliaces as the net. Agree?

[@archicorner]

That is something I have discussed in the past with others. "net" area does say that it only includes "occupied area" but does not list millwork in it. I have seen and heard the argument that you cannot "occupy" the area where millwork is installed. You are not the only one with that idea. Thank you for leaving a comment. Perhaps a future code cycle may include that, for now, I have found it to be a bit of a hard sell.

[@alexglasenapp7668]

Thank you for the very clear and detailed video!

[@archicorner]

Glad you enjoyed it!

[@forrestcorral]

This was a great explaination! Thank you!!

[@archicorner]

You are welcome!

[@joro8604]

Thanks for the additional info.

[@archicorner]

You are welcome

[@travay6328]

Thank you archi corner I love your videos thank you very much

[@archicorner]

Glad you like them!

[@arqmiryam]

Thank you, all your videos are awsome!, can you do one including usable, rentable area? ❤

[@archicorner]

Great suggestion!

[@goharnazaryan7106]

Yes please!!

[@user-xo2pn5fp7b]

@@archicorner yes pleaseeeee

[@BrianWilson-it1ls]

I'm a fairly new fire inspector and have been tasked with determining the OL for a portion of our city council chambers. The room is a large room that is divided in half by a 3ft high wall. City council members have their desks and chairs on one side of the 3ft wall while the other side of the 3ft wall contains chairs for members of the public to sit and view the meetings. They want to know how many members of the public are permitted in that portion. The "public" half a perfect square floor plan with rows of chairs side by side. Am I correct in thinking that I just measure the SF of that half of the area and use "chairs only" and "standing room" factors to get the OLs for seated and standing? Thanks

[@MLD.Ltd.]

Thanks for posting this!!! I was going to ask online then found this while I’m benging your videos haha

[@archicorner]

Sweet! Glad it helped.

[@franksoto8101]

Awesome videos! What about the seating (pews-like fixed) in the general seating area? do you not use the 18" or 24" per person?

[@archicorner]

check out IBC 1004.6. fixed seating without dividing arms are usually calculated at 1 person per 18 inches. Booths are usually calculated at 1 person per 24 inches.

[@JulianMAguilar]

Thank you sir

[@balvantjhaveri9068]

Please provide a video showing how having a Sprinkler System and a Fire Alarm System in the project affect various Occupancies.

[@archicorner]

Hmmm.... good subject... pondering ideas...

[@michellerichard5084]

How to you handle the occupant load for a facility where the overall occupant load factor is net? For example, a daycare use is 35net. If the only other spaces in your daycare building are mech/elect/I.T. rooms, small storage under 100sf, and toilet rooms, do you calculate the occupant load of the daycare spaces at 35net and exclude everything else? Or do you have to calculate and occupant load for the rest of excluded spaces in the building - 300sf for mech/elec/I.T./storage, and what for the toilet rooms?

[@genehudson6636]

Great videos. Thank you.

[@archicorner]

Thanks for watching!

[@stanleyoverby4179]

I always thought that gross area included the thickness of the walls. Is that not true?

[@abulsar]

Excellant content ! Are electrical rooms part of the net area? And what is the difference between net assignable and net area ? - Thanks

[@archicorner]

are you still referring to square footage as needed specifically for egress?

[@juheeporwal6032]

Hello, Thank you for helping us to understand these code concepts. Would you mind making one on Mezzanines?

[@archicorner]

I am not sure if you mean something specific. The occupant loads in a mezzanine are calculated the same way as any other spacE.

[@zaynabziaraty8534]

Thank you!!!

[@archicorner]

You're welcome!

[@PeggyShaw-e9i]

When calculating gross floor area for office, are the accessory assembly spaces (conference and break area) subtracted from the gross number or are they added? Example 3,000 sf office space, with 600 sf conference room. (3000/150 + 600/15)= 20+40 = 60 or (2400/150 + 600/15) = 16+40 = 55? Also, have you used areas of concentrated business use in one area of the floor and the normal 150 OLF in another area on the same floor? I have an "IT" department with heavy density and an executive/admin area splitting the floor.

[@archicorner]

Every area is calculated separately, and NOT normally doubled up. Using different occupant loads within a space is normal. A space may have one load for one area and a different load at another.

[@skf88]

Super helpful! Can a video be made clarifying egress convergence and how occupant load and egress requirements are calculated for each floor that is affected? So for example basement and second floor (and up) occupants all exiting through the ground floor when there are also occupants on the ground floor? Thanks!

[@archicorner]

Great suggestion. A quick summary of IBC requirements in this regard: If your egress is based on IBC; then the egress components that are shared between floors is generally limited to stairs. IBC Section 1005.3.1 is clear that "Where stairways serve more than one story, only the occupant load of EACH STORY considered INDIVIDUALLY shall be used in calculating the required capacity of the stairways serving that story." therefore, you normally don't have to worry about other floors when determining stairway with. Nevertheless, IBC section 1005.6 does give an exception where a floor below and floor above converge into an egress level.

[@trangelayo]

Thank you for explaining the difference between net and gross in a clear manner! In the last part of the video (when you mentioned why bother differentiating between the two), I had that pondering thought for the longest time. Now I pose to you if calculating net could be helpful in some instances to shed square footage, then why don't we calculate the net area for everything instead of gross? I don't see what calculating the gross area does.

[@archicorner]

I've pondered the same question. If you find the answer, please share! I haven't really looked into the why, but now my wheels are turning. Hmmm..... still thinking....

[@Calistogakid2u]

Occupant load is also needed to determine plumbing fixture counts.

[@archicorner]

👍🏽 correct

[@moawadashmawy]

thanks alot , you helped me a lot

[@archicorner]

Glad you liked the video.

[@guan5625]

For classroom or assembly with fixed sitting, net area calculation exclude the circulation area inside the room on a real project. But I did not see you exclude the circulation area in your court house scenario. Do you mind to expand on this to help me better understand?

[@doctyler5382]

Who is downvoting this? Why? Even if it doesn't have all the information you need, it might point you in the right direction?

[@archicorner]

😢 💔

[@doctyler5382]

@@archicorner Howdy bro' 🤗 Can't understand downvoting videos that are full of useful info? Trolls are everywhere 🙄

[@mohamedshabana6828]

Thank you so much, you are doing a such amazing work 🤓🙏

[@archicorner]

Thank you so much 😀

[@josephbradshaw7584]

Thanks for the videos. I'd recommend doing a video on common slopes for various site elements, because I've found lots of conflicting information on this topic and I'm not sure if they're all based on code or coming from somewhere else and it's really confusing.

[@archicorner]

What slopes are you referring to? Are you referring to ramps, paths of travel, etc? Please provide more detail if you can. Thanks!

[@josephbradshaw7584]

@@archicorner roads, grass recreation areas, ground areas for drainage, paved parking, sewer lines, approach walks to buildings, landscaped slopes, mowed grass etc. I've come across these things as I've studies for the ARE exams, but some of these items may not be code related which is why I may be finding conflicting information from different sources. Some of the sources also aren't super descriptive and are kind of vague which doesn't help.

[@TheTm56857]

Awesome videos, keep it going,

[@archicorner]

Thanks, will do! thank you for taking the time to leave a comment!

[@cutefacelex]

how did you get the sq footage of the interior walls?

[@travay6328]

Can you please do a video on plans review or on how to become a plans reviewer?

[@aqb89989]

Thanks for the video! A doubt I have: If two rooms with different gross-calculated uses are adjacent to each other, do you use middle of wall as dividing line for GSF calculation? Also..how do you calculate the load factor on stairs and corridors that happen to be next to spaces with different uses?

[@archicorner]

That is a very good question. What you have mentioned sounds reasonable. You do not want to double count a space (counting the wall twice). Having one occupancy count half the wall (centerline) and another occupancy count the other half (also centerline), sounds like a reasonable approach.

[@heatherhenriques4141]

Great explanation, I have a question I'd love for you to explain. What is the difference between A and B in Construction Types? What is the difference between Type 1A and 1B for example...and so on? Thank you.

[@archicorner]

Good question! This question is partly answered in episode AC 004. Take a look at it and comment if that is still a question. Thanks!

[@sharononeill6477]

Hello Archicorner; Thank you for the video. How did you derive the area sq. ft. that you subtracted to get the net sq. footage. I do not see any dimensions on the walls, ramps or closets.

[@BobbyJ529]

its his drawing that he's using for demonstration purposes. The numbers can be whatever he wants to make his point. You wouldn't build from it.

[@archicorner]

Jackie R is correct. The purpose of the plan is to show the concept. It is not meant to have exact numbers. Hopefully the concept came across well. Sorry for the confusion.

[@BrianWilson-it1ls]

How do we determine OL for a classroom in an "E" occupancy? In 2018 IBC Table 1004.5, the OL factor for classrooms is 20net. Does that only speak to the floor area after closet and bathroom deductions are considered or do we also have to subtract the total SF of all of the desks as well? Thanks

[@archicorner]

Check out chapter 2 in the IBC, there it has definitions for "Floor Area, Gross" and "Floor Area, Net". And it will let you know what you can include and what you can exclude.

[@BrianWilson-it1ls]

@@archicorner didn't quite get that tidbit of info in my fire inspector class...Thanks a bunch!!

[@googleit1131]

I have a question: let's say you have a row of private offices. Since they are have the same function, and have a GROSS occupancy factor, would you calculate each space individually or as one space? The gross definition says you can't exclude interior wall thicknesses, but does that apply where there are walls separating a room? Would you instead calculate all the offices as one space or calculate them individually? If individually, do you figure out the square footage from the face of the wall or the center of the wall? I've seen it done both ways, so I want more opinions on this.

[@archicorner]

1) Regardless of whether you are calculating occupant loads on an office by office method or if you are calculating them as a group, net will have to account for the walls. 2) You are correct, It is common to see both approaches, it is left up to you as the designer to pick which one you like best. There is no correct answer so as long as the information is provided in a clear manner for the plan reviewer to confirm that an office or area meets the egress requirements (i.e. number of exits).

[@adrianbonnin5096]

I’m still confused about gross. Does this include balconies? Moreover, outdoor open ground floor space over a transfer slab? I say this because i believe gross does include this per ibc, but it feels strange to include outdoor area beyond an exit discharge. I see you referenced chapter 2 of ibc. However, the definition you referenced is for [bg] Area Building. Is there another location in definitions that i’m not seeing for gross? Because if not, you only referenced one portion of the definition if I’m not mistaken. It continues to state something weird “Areas of the building not provided with surrounding walls shall be included in the building area within the horizontal projection of the roof or the floor above.” This implies that if you stack balconies they are included in the gross, and if shafts run up to an enclosed AHU then the shafts would also be included, and that if your building has an overhang so would that apply? Is this correct? Please help!!

[@archicorner]

Does it include balconies? Yes. Does it include shafts? Yes. Can it include covered areas such as porches, carports or other exterior space intended to be used as the building's occupiable space? Yes.

[@eyobkinfe141]

Please do more

[@archicorner]

Trying, it takes a lot of time and effort to create these, but we are not giving up!!

[@danielmagharious7870]

An assembly without fixed seats (15 net) includes a 60 sqft accessory Storage room. Do you add the 1 occupant for the storage room (60/300 = 0.2 person) to the number of occupants you get from the previous calculations based on the net area?

[@archicorner]

Since the storage room exits into the assembly room then the occupants of the assembly room are the assembly room occupants + storage room occupants

[@danielmagharious7870]

@@archicorner Thanks for the prompt response. What if the nomenclature changes to 40 sqft of closets. Would that change anything?

[@magdastefan]

Can you do more videos on fire rating and separation ( Chapters 5,7,9)

[@archicorner]

Sorry for the late reply. If you have not already done so, you can check out episode 032. Also Episode 015. I hope you like them!

[@PakoWakoTako]

video idea - Calculating allowed floor area for separated occupancies.

[@archicorner]

Thanks for the idea!

[@mariaallgood1420]

I am getting confused-didn't they change the Business Occ load to 100 in the 2018 IBC?

[@archicorner]

That is a very good observation. You are correct, in the new code, office load is 1:150 sf. Good catch!

[@martymartinez9954]

At what occupant load do you need architect stamp plans?

[@archicorner]

Marty; That is a good question. An architect's stamp is not determined by the occupant load. Each state limits the type of building structures that an unlicensed person may design (if at all). SOME states allow for non-licensed persons to design a limited number of buildings, usually limited to farm buildings and/or some residential buildings. However, every state is different, so you may want to look at what your state allows and does not allow. Sorry there is no defined answer.

[@steffanmoran9580]

How do I calculate hospital egress width requirements?

[@archicorner]

The egress of all buildings are calculated using the same basic concepts. The difference is that some building occupancy groups have equipment that is needed to operate. Hospitals for example often have to use mobile beds to transport patients from one room to another. Therefore things like these have to be kept in mind when determining widths for corridors and other spaces. This of course is not a complete answer to your questions, but just a little bit more of information. Hope it makes sense.

[@ega0117]

Why don’t you do a session on dimensioning a floor plan

[@archicorner]

Currently we are trying to keep a focus on codes and technical explanations. Nevertheless, that's a great subject. We will keep it in mind. Thank you for taking the time to leave a comment.

[@maxviamonte998]

so... is it 12 0r 40 occupants?

[@archicorner]

Max; Thank you for leaving a comment. The idea the video is trying to convey is that he number of occupants depends greatly on what the space is being used for. The USE of the space dictates 1:What areas you need to include in the square footage and 2: what load factor to use to get the occupant load. In the example, of the video, it was noted that the space was used as a "COURTROOM" therefore the 12 occupants is incorrect because the 12 occupants incorrectly assume the space is used for "BUSINESS". 40 Occupants assumes the space is used as a "COURTROOM" which is correct.

[@gonedawning]

You video on accessible door clearances has errors. Please correct - it is a common error that affects accessibility and usability of the space and poses risk for architects. Thanks.

[@archicorner]

Thank you for watching the video and taking the time to write down your comment. We will look into this.

[@sthomas703]

Nice Video. However, the IBC doesn't calculate an "occupancy load", it calculates an "occupant load". Occupancy is the classification of the building based on risks and other hazards in a building. This is a pet peeve of mind. Sorry.

[@archicorner]

Steve; We truly appreciate comments like yours. We keep learning and we appreciate the correction. We will try to modify the label soon. There is little that can be done about videos that are already uploaded, but our sincere appreciation goes to you. We learn something everyday! No need to apologize :)