Dormitory Load Calc help

Hi All,

I'm doing a load calculation to determine my service size for a 71000 SF dormitory. My building has three floors. Each floor has three pods. Each pod has: 20 Double Rooms,1 RA Room with Private Bathroom, 1 Single room with Private Bathroom,3 Shared Toilet Rooms, 1 750 SF Family Room, 1 Janitor Closet, 1 small electrical room, and 1 kitchen. Each pod is around 7,900 SF.

I'm having trouble finding a method in the NEC that applies to my situation. The only idea i had was to think of each pod as a dwelling unit, and use the demand factors in 220.84 to size my main service.

Any ideas, suggestions, guidance would be greatly appreciated.

Are you trying to find the minimum code-accepted circuit sizes, or make sure you have enough. You may consider having additional load for a buffer above the dwelling unit demand. College students can really torture electric loads with electronic equipment and cooking frozen foods 24/7, and leaving things on all day and all night. Look at putting each room on a separate circuit - especially the RA and single rooms. You can tout that as a design feature which will reduce total lifecyle costs with easier maintenance.

Take a look at other dorm designs and see what they've done.

Just use the NEC; figure out if it is in fact a NEC "dwelling unit" which changes some of your code requirements such as breaker type, required receptacles, etc but its pretty straight forward after that. Add receptacle (120V), lighting, and mechanical loads. Don't forget to accord for some future load which can be used as your "buffer". I would think your first step would be a va/sq calculation as you get more detailed information from the HVAC, etc and progress your design.

I haven't done any residential work so I can't really give you any good va/sq numbers for mechanical. The NEC has something you can use for lighting which is 3va/sq ... I think/ please verify. I would usually use ASHRAE for that since you are not allowed to use that amount anyway. if your project is in CA then you probably want to check out what title 24 requires. I've been using 3va/sq for 120V loads but it seem that you can very quickly lay out a typical and use that for your numbers.

Makes Sense?

All electric kitchen?

All electric everything?

12-16 va/sqft

don't for get the code would only give you minimally acceptable number and sizes of circuits. you may need to include a multiplying factor, considering there are more people per square feet and everyone one of them has 50 things to plug in ;-)

Unless there's cooking equipment, it would not be considered a dwelling unit.

cdcengineer said:

Unless there's cooking equipment, it would not be considered a dwelling unit.

Click to expand...

No cooking, and no laundry services I'm assuming here.

You are coorect the only area that could possibly be considered as a dewelling unit for service calcs would be the pod itself and that's only if there's a kitchen and that's probably a little sketchy.

I would have used Tables 220.11 and 220.13, but that's probably what you did since judging by the date of your question the design is most likely complete.