ASPE Hot water Demand for Fixtures

[kevinsherlock]

I have been in the engineering business for 30 years. Specifically, plumbing. In the ASPE Data Book (pick any year), the hot water demand for showers in Gymnasiums, Industrial Plants, Schools and YMCA's has been declared 225 GPH. When will this number be corrected? IPC limits the flow for showers to 2.5 GPM at 80 PSI. 2.5 x 60 = 150 GPH.
Where did 225 come from? Who uses this number in their water heater calculations?

 

[PEDARRIN2]

The numbers come from old information when showers were ~4gpm - which was not too long ago.

I use a much lower number which takes into account that you will not be running the shower for an entire hour and only a part of the water is hot.

But I do use the demand factor and the storage capacity factor that ASPE gives. They give pretty good numbers which accounts for diversity among the total number of fixtures and the facility needs.

 

[kevinsherlock]

I trim the load myself, just as you do. It makes plenty of sense to base it on an actual flow rate x an assumed duration. One problem which causes us to debate with high intelligence, low common sense, plan reviewers in a government like setting is they stipulate that our calc's must adhere to ASPE. When I indicate a shower at say, 40 GPH in lieu of 225, I find myself having to (once again) substantiate my decision. They usually accept it. But, time arguing is still time, which = money. I say, shame on ASPE for not addressing this factor a long time ago. I just received my 2005-06 Data book and it's still in there.

 

[PEDARRIN2]

You are in a "long" line waiting for ASPE to update some of their information.

They are waiting for somebody to give them money to do the research since they cannot seem to come up with the money on their own.

IMHO they need to fix Hunter's curve before they do anything else. That information dates back to the 50's if I am not mistaken.

 

[kevinsherlock]

Well, I will keep doing it how I've been doing it. One day, the ASPE experts will see that a person could actually drown under a 4 gpm shower head if they stayed in there for a solid hour. If it's one of my systems though, the last 50 minutes will be a very chilling experience.