D'Brie
Apprentice Plumber
In the Seattle area, we install electric water heaters on foam pads.
We buy them from the supplier that supplies the water heaters.
Same here in Whatcom Co. Washington.
In the Seattle area, we install electric water heaters on foam pads.
We buy them from the supplier that supplies the water heaters.
Since concrete building foundations are sometimes poured over foam, perhaps foam of sufficient density can be regarded as structural?
"Foundations" are NOT poured over foam.
See Figures 7, 9 and 14 of this document:
http://www.toolbase.org/PDF/DesignGuides/revisedFPSFguide.pdf
In the Seattle area, we install electric water heaters on foam pads.
We buy them from the supplier that supplies the water heaters.
The feet have to extend to something structural, not resting on foam. If it's a flat-bottomed beast with mere dimpled sheet metal for feet it calls for building some. The last tank heater I owned was ca. 1982, had about 1.5-2" of clearance under it between some fairly substantial welded on feet, but I'm sure they're everything from dead-flat to fairly tall. I've seen a number of them with 2-3" structural rings beneath them for supporting the tank with some clearance,but I have no idea what/if there's a standard (I expect not.) Clearly it's easy to exceed 25psi many times over if it's a 3 metal feet or a stamped angle-iron ring holding up 600lbs. Looks like electric tanks often come with minimal clearance, whereas gas versions build in the necessary clearances for combusion air intake & burner heat issues:
I was advised that the Washington State Installation code now requires the foam pad on electric water heater installs.The whole point of the pad is to eliminate heat loss due to direct contact with the concrete floor. If the tank has feet that are more than just dimples in the sheet metal, a pad isn't necessary. Therefore, you wouldn't need to place a water heater with feet on a pad to begin with. That being said, if you try it the weight will sink the feet right through the pad. And if it's gas, it will melt the foam (seen it on an old style gas water heater).
This is awkward, but...
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