laundramat service calculations

[DaveBowden]

I'm in the process of doing a load calculation and riser diagram for a new laundramat going into an existing space. There will be 38 washers, 2 75# dryers and 18 double dryers. The dryers are gas with just a 13 amp load for the motors.
The general contractor gave me a set of prints from a similar laundramet in Orlando ( same number and type of appliances )
The load calculations on this set of prints shows the washer load with a demand factor of 75%. I can't find anything in my code book that allows me to calculate the load at less than the actual connected load. I realize that there will probably never be a time when all the machines are in use at once, but if I can't find a demand factor in the Code, I don't think I can apply one.
Any help out there?

 

[ramdiesel3500]

I think article 220.14 is where I would go to begin with!

 

[ramdiesel3500]

Oh, and no, I do not agree with the 75% demand factor. Code, or no code, I would not design this facility that way. I have seen every machine in a laundromat run at the same time for hours on end while people wait in line!!!

 

[jtester]

Dave

I've done a bunch of laundromats, and believe you need to add all at 100%. There is nothing that lets you diversify the dryers at all.

Jim T

 

[DaveBowden]

I'm glad to see people in agreement with me. This is the 5th laundry we've done for this builder and I'd hate to think I over designed the first 4.

 

[charlie b]

Whoever came up with those plans also came up with their own rules for demand factors. For a dwelling unit (which this is not, I certainly hope), there are demand factors for multiple dryers, and you can include the required washer (i.e., "laundry") outlet in the demand factor for general lights and plugs. But there is no similar rule for a commercial Laundromat.

 

[tshea]

I own a laundramat. I also designed it. Everything was calculated at 100%. I have been in it when all 20 washers and all 14 dryers were in operation. The dryers are gas. The actual service is 200Amp 1phase 120/240Volt. The space is 1300 sqft with 2x4 T8 troffers, 1 20Amp sign circuit, and 2 coin machines. I don't remeber what the total connected load is, but I can dig through the files.