Water heaters in areas that may be subject to earth quakes and in a number of states are recommended to be strapped so that they will not shift about in an earthquake.
Leaks, water damage and fires
Shifting about of a water heater from an earthquake may cause the water heater to tip over or fall off of its stand or platform. If it moves too much, then broken or cracked water lines may leak, causing damage to the walls and floors.
It has been discovered that in earthquakes where a number of water heaters developed leaks or had broken water lines; that the water pressure in the area dropped significantly, because of these broken lines and that fire department had insufficient water pressure to fight some fires.
In addition to the loss of water pressure and the water damage issues, shifting of the water heaters may cause gas lines to rupture, creating fire concerns or if an electric water heater, then the conduit may be pulled apart, exposing live wires.
Basic Strapping Guidelines
(note that the requirements below are for Ca. and varies from jurisdiction to jurisdiction, other states may have different requirements; always read the Manufactures installation recommendations when installing your water heater)
You Need Two Straps & On Large Water Heaters 3 or 4 Straps
Water heaters up to 52 gallons generally require two straps.
Water heaters 53 gallons to 75 gallons may require three straps in certain building jurisdictions. Calling the local building department is a quick and easy way to determine their requirements.
Water heaters 76 gallons to 100 gallons may require three straps in certain building jurisdictions. Calling the local building department is a quick and easy way to determine their requirements.
Put in Bottom 1/3 and Top 1/3
When a water requires two straps; one of the requirements is that one be in the top 1/3 area of the water heater and the other be in the bottom 1/3 area of the water heater.
Strap not 4 inches above the gas valve.
The bottom strap on a water heater should be a minimum of 4 inches above the gas valve / controls. If the existing strapping is not 4 inches up, then it is rather easy to move the strap up.
Water Heater should “Resist Horizontal Displacement”.
Water heaters should be strapped so that in an earthquake they cannot shift about or move in any direction. The reason for this is that they weigh a lot (i.e. a 50 gallon water heater weighs 500 to 600 pounds), and if it can start moving around, it will pull the lags that hold the straps, right out of the wall.
Basically the strapping should be installed in such away that the water heater cannot start moving; therefore, a water heater should be strapped so it can not shift backwards, sideways, or wobble back and forth. Under some conditions, placing a block of wood between the water heater and the wall might prevent it from starting to move about.
Requirements vary State to State and Jurisdiction to Jurisdiction
States vary on their requirements for strapping of water heaters; for example it is a requirement in Ca. The Uniform Plumbing Code requires water heaters to be strapped on the upper one-third and lower one-third of the tank. The States Architects Office and many building jurisdictions want a third or fourth strap for water heaters up to 100 gallons. A quick call to your local building department, sometimes called the Department of Building and Safety can clarify if they want more than two straps on the water heater; i.e. a 75 gallon having 3 straps and a 100 gallon having 4 straps.
Should the straps be over or under a water heater blanket ?
There are some building jurisdictions that require the straps to be under a water heater blanket (if there is a water heater blanket). For those who feel this is important, a quick call to the local building jurisdiction will answer this question.
Who to consult? Plumbers and qualified handymen.
Home owners can generally strap their water heater themselves. Plumbers and qualified handymen can do this type of work quickly and inexpensively.