randynavarro Posted January 17, 2007 Report Posted January 17, 2007 In doing a bit of research lately for some other work, I could not find any specific requirement for a foam pad under an electric tank on a concrete floor. Looked through IRC and a few water heater mfg. webs sites. Is this a myth or was it ever required?
Inspectorjoe Posted January 17, 2007 Report Posted January 17, 2007 A foam pad? You mean like a structural foam? I'd think a soft foam would make for a pretty wobbly tank. What would be the purpose of it? I've never seen it.
Jim Katen Posted January 17, 2007 Report Posted January 17, 2007 Originally posted by randynavarro In doing a bit of research lately for some other work, I could not find any specific requirement for a foam pad under an electric tank on a concrete floor. Looked through IRC and a few water heater mfg. webs sites. Is this a myth or was it ever required? I've never heard of such a thing in the UPC or the IRC plumbing section and I didn't see it in the energy section. I suspect that it's one of those things that's sometimes speced in energy audits or something that's suggested by the public utilities as a way to save energy. - Jim Katen, Oregon
Terence McCann Posted January 17, 2007 Report Posted January 17, 2007 I guess you're talking about the type of a pad that goes under a condensing unit. Never heard of, or seen, this used with a electric water heater. Urban legend?
hausdok Posted January 17, 2007 Report Posted January 17, 2007 No, He's talking about a round styrofoam pad about 3 - 4 inches thick. I see them all the time, but I don't know whether they are specifically required by any law or regulation. My CodeCheck Plumbing does say: On the ground-3in. pedestal (concrete, etc) req'd.....(IRC 1305.1.4.1/UPC 510.6) OT - OF!!! M.
Les Posted January 17, 2007 Report Posted January 17, 2007 In our jurisdiction they would be prohibited. Only requirement here, Michigan Model Energy Code, is 5/8" blocking under electric storage tank water heaters; no contact with concrete floor. Wood floor contact allowed. Would fire codes apply?
Jim Katen Posted January 17, 2007 Report Posted January 17, 2007 Originally posted by hausdok No, He's talking about a round styrofoam pad about 3 - 4 inches thick. I see them all the time, but I don't know whether they are specifically required by any law or regulation. My CodeCheck Plumbing does say: On the ground-3in. pedestal (concrete, etc) req'd.....(IRC 1305.1.4.1/UPC 510.6) OT - OF!!! M. I believe that section is referring to water heaters placed on the ground -- for instance on the ground in a crawlspace. In that case, you're supposed to place a concrete pad, not just set the water heater on a sheet of plywood or a couple of 1x2s. I've seen the styrofoam pads too. My sense is that someone's trying to save energy, or perhaps avoid rust at the bottom of the tank if the slab is wet. It doesn't seem to be a requirement. - Jim Katen, Oregon
randynavarro Posted January 17, 2007 Author Report Posted January 17, 2007 Well, doesn't look like they've ever been required. Interesting. It does make sense however. An electric tank sitting on a concrete pad can rust faster. Also, I believe the concrete acts as a heat sink and can pull heat out of the tank, reducing its efficiency. In fact, one can purchase the foam pad at our local Lowes and Home Depot. Its 2" blue - about R10. Makes perfect sense to me and if I ever had an electric tank in the garage, I'd put a pad underneath it . . . wait, I do have a small electric holding tank for my radiant heat system and yes, its on a pad! As Mike mentioned, they're in place all over around here, thus reinforcing my carry-over belief from my construction days that they were required.
hausdok Posted January 17, 2007 Report Posted January 17, 2007 Hi Randy, I just took a look at the Seattle Residential Code in an effort to find anything that directly refers to these things. I found out that Chapter 20 of the IRC - Boilers and Water Heaters - hasn't even been adopted by the city. If memory serves, they're still on the UPC (1997, I believe) but I don't have time to poke around over there right now. If you want to, here's the link: http://www2.iccsafe.org/states/Seattle/index_main.htm Maybe you'll find something. ONE TEAM - ONE FIGHT!!! Mike
Jim Katen Posted January 17, 2007 Report Posted January 17, 2007 Originally posted by randynavarro . . . Makes perfect sense to me and if I ever had an electric tank in the garage, I'd put a pad underneath it . . . If you ever have an electric tank in the garage, you should elevate it so that its lower element is 18" off the floor, thereby obviating the need for the pad. - Jim Katen, Oregon
randynavarro Posted January 18, 2007 Author Report Posted January 18, 2007 Yup, good catch Jim. In my own case, my tank isn't energized. Basically, its just a small 30 gallon insulated holding tank for reserve hot water in the rare event there's a real high demand. There's still basement floors and lightweight concrete floors in mult-family stuff, though . . .
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