External hot water cylinder not properly earthquake restrained

Causes

Restraining straps loose

Cylinder was never properly restrained

Restraining straps and fixings rusty

Listed under: Exterior, water heating, hot water cylinders, earthquakes, walls, durability, corrosion, rust, fixings and hardware

Cause

Restraining straps loose

Repair

  • external hot water cylinders should have 25 x 1mm stainless steel straps around the top and bottom of the cylinder securely fixed to framing with a tension device to keep the straps in place. Cylinders over 200 litres require a third strap in the centre (see drawing)

  • where existing straps have become loose, they should be tightened if possible. Check fixings at the same time, and ensure the base of the tank is secured against sliding

  • if there are no tensioning devices, or they no longer function, new devices (and strapping if required) should be used

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Cause

Cylinder was never properly restrained

Repair

  • ensure the base is blocked to stop it from sliding in an earthquake, then install restraining straps to stop the cylinder tipping over. Stainless steel straps 25 x 1mm around the top and bottom of the cylinder must be securely fixed to framing. Cylinders over 200 litres require a third strap in the centre. Restraint kits including straps, screws and tensioning devices are available from hardware stores. (Ensure you buy a kit with stainless steel straps and not the galvanised steel straps that are for indoor use.)

  • a heat pump water heating unit should be restrained to the outside of an external wall with suitable anti-vibration mounts to limit noise transmission into the house when the unit starts and stops

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Cause

Restraining straps and fixings rusty

Repair

  • replace rusty items with new stainless steel straps and fixings as described in the repair above. Ensure base is blocked to stop it from sliding

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