Foam Pad Under Water Heater Gives Insulation

<i> Produced by the Energy Extension Service, a division of the Washington State Energy Office</i>

QUESTION: Our water heater was leaking so we bought a new one. An insulated pad was placed under the new tank. It is pink and seems to be a very high density type of Styrofoam. I noticed writing on one side saying it was combustible and to use with gypsum board. What is this pad and is it safe to use under the water heater?

Also, the water from the old heater leaked out onto the floors and loosened the floor tiles. Several became very brittle and cracked into small pieces. I believe they are called vinyl-asbestos tiles. What kind of health hazard does this pose for us and our children?

Lastly, why do water heaters use the same electric wire that comes from the breaker box while other 220 volt appliances (clothes dryer and range) use extra heavy wire coming out of the appliance?


ANSWER: Good list of questions. Let’s start with the first one. The insulated pad under your hot water tank is probably Dow pink Styrofoam. Dow pink Styrofoam is a high-density foam intended to have increased resistance to damage from compressive loads. It is much stronger than white Styrofoam (frequently referred to as bead board). Normally it is used to insulate walls. In that application, it needs to be sheathed by gypsum board to prevent possible fires.

Small quantities of Styrofoam will not sustain combustion under most conditions, however large surfaces will sometimes sustain fire. It is not likely that a small piece placed under your hot water tank could catch fire, nor be able to sustain one if it started. Placing a rigid foam pad under a hot water tank is a common practice and required under some government rebate programs.

The purpose of the insulation is to reduce heat loss from the tank into the living space, which will occur any time the tank is hotter than the surrounding space. Since the floor is denser than the air surrounding the tank, it will steal even more heat than the air, unless adequately insulated.

If you tried to put a sheet of gypsum board under the tank, you would be courting a mess. Gypsum board (Sheetrock) will turn into a crumbling mass if it gets wet. From your description, the installation is probably safe.

Second, we spoke with an asbestos abatement expert at the Department of Social and Health Services about your vinyl-asbestos tile. He said that you should just sweep it up and remove any whole tiles by prying them loose. Unless you saw or sand them or otherwise reduce them to dust, they are safe to handle.

Asbestos is dangerous when airborne and inhaled, but the pieces you describe are too large to either remain airborne or inhaled. Dispose of them by placing in a trash bag with a twist tie and put the trash bags containing the tiles in the trash. In this form they are not considered toxic waste.


Last, hot water tanks use a different type of wire than other 220 volt appliances because they are hard-wired into the home circuitry, while dryers and ranges are plugged into 220 volt outlets by pigtails. Hot water tanks are hard-wired because they are plumbed to the household water system.

So-called hard-wired appliances utilize solid, or single strand electric wiring. This wire is not intended to be flexed after it is installed. The differences in wiring are a function of resistance, insulation and flexibility. Different appliances use different amounts of electricity. Those that use a lot of electricity require large wires.

If an appliance that demands large amounts of current is wired using a wire gauge (wire size is rated in gauges) that is too small, the wire may overheat, a fuse could fail, a circuit breaker could be triggered, or a fire could start.

Soft-wired appliances such as stoves or dryers require multistrand wires because they are plugged into sockets and the cords are subject to movement when the appliances are plugged in and out, or are pulled away from the wall for cleaning, servicing, etc.

Tips for Dealing with Asbestos

* Older homes may have asbestos material on furnaces and heating ducts.

* If this material is intact, do not disturb it.

* If the material looks as if it is damaged or deteriorating, have it inspected and analyzed by a professional. Do not attempt to remove or repair this material yourself.

Tips for Buying Products That Contain Formaldehyde

* New furniture and carpets often emit formaldehyde and other volatile organic compounds (VOCs). The amount of emissions naturally decreases as these products age.

* Buy products carefully . . . compare the formaldehyde content of various products (some manufacturers have this information).

* Purchase carpet and major furniture items in the spring so you can allow increased ventilation in the home for the first six months.