I'll probably feel stupid about this but has anyone calculated the service for a commercial laundry before. My main question is if there are any demand factors that can be used. It's all gas washers and dryers. I've been through the code book but can't seem to find anything. Any help would be appreciated. TIA....
Commercial laundry calculation
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petersonra
Senior Member
- Location
- Northern illinois
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- engineer
It seems to me that there is a very good chance that every machine might well be in use simultaneously now and then, so I am not sure I would want to put in a demand factor.
That's all I've been able to find too and I agree that it's very likely that all the machines will be going at once. I'm just checking myself because my competition is bidding a service half the size. I'm not going to down size just because he is and I can't see where he's getting his numbers. Thanks for the responses so far.... 
kwired
Electron manager
- Location
- NE Nebraska
That's all I've been able to find too and I agree that it's very likely that all the machines will be going at once. I'm just checking myself because my competition is bidding a service half the size. I'm not going to down size just because he is and I can't see where he's getting his numbers. Thanks for the responses so far....
If all you have is motors and no dryer heating elements it takes quite a few machines to need more than a 200 amp single phase service, unless there is other significant load from something else. You are looking at maybe 8-10 amps per appliance at 120 volts or 4-5 at 240.
kwired
Electron manager
- Location
- NE Nebraska
where did you get those numbers from? 1200 for a washer seems reasonable, but for a dryer that has gas heat source, 1600 seems like an awful lot. That is 2 hp+ when all you should need is 1/3 or 1/2 hp max just to turn the drum.
I have a set of mechanical drawings that indicate 1hp on the dryers and only lists 4hp on the biggest washer (80lbs) the rest being a mixture of 75lb - 50lb units. These are not house hold units and I'm trying to fault to the side of too much is better than not enough. I think you're right though. Maybe I'm to heavy on the dryers, maybe too light on the washers? It's all 120/240 1ph.
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petersonra
Senior Member
- Location
- Northern illinois
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- engineer
No offense, but you are asking us to agree with your estimate without any idea of what the real loads are. Why don't you just show us your actual calculations. I have a feeling that you may not have done any formal calculations here based on some of your previous posts.
You really need to run the numbers based on the actual loads of each machine and the other loads that you have to account for.
kwired
Electron manager
- Location
- NE Nebraska
1200 watts mentioned earlier and 4 hp seems to be pretty conflicting values for same machine.
Motor operated machine is best to be figured in VA and not watts or HP.
Art 220 does use VA for most all calculations. Anything in there that may use watts is a load where watts and VA are going to be the same value.
jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
Seems to be a tad unproportional, but then I have never did a laundry facility.
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- Placerville, CA, USA
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- Retired PV System Designer
Commercial dryers (front loading stacked 2 high along the wall) hold more clothes than commercial washers, so it is actually quite reasonable.
You also may need to separate colors for washing but not for drying. Etc.
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