By Tan Yean Chin
The Institution of Engineers, Malaysia (IEM) is concerned over the report of a water heater exploding in a condominium in Mont Kiara on Feb 9, 2017.
It was fortunate that no lives were lost in this incident. The water tank type water heater is different from the instant type, as there is heated water volume stored.
There are several reasons why explosions can happen in the water heater system, especially the gas heated type.
Water has dissolved minerals and sediment. When water is heated, the minerals can get deposited as scales on metal surfaces within the tank – as happens in a kettle. The sediments in water would settle at the bottom of the tank.
The scales and sediment build-up could lead to many problems, but most importantly it becomes a barrier between the heat source at the bottom of the water tank and the water being heated.
This barrier forces the tank to work harder to heat the water, which could affect the integrity of the tank floor. Regular draining of the tank will prevent sediment build-up.
Heated water tanks are equipped with a temperature and pressure relief valve. This safety equipment ensures that the tank does not get overly hot or over pressurised.
Over time, scaling or sediment can block and hamper the ability of the relief valve to operate properly. A failed relief valve could cause an explosion should there be a fault with the heater’s thermostat.
The maintenance of the relief valve will require the service of a qualified technician, who should be familiar with the particular water heater model.
The gas burners in water heaters are usually well engineered and have built-in safety features. Modern heaters have an electrical igniter to light the burner.
However, when the igniter does not light up the burner within the pre-requisite time or gas flow is poor, an explosion could occur when gas flows into the main burner. An explosion by gas could also happen when the ventilation pipe is obstructed and there is no sufficient air or the flue gas is not exhausted.
In Malaysia, we have stringent regulations on gas supply and larger industrial boilers. The gas supplying company’s responsibility and maintenance is usually up to the metering point. The gas pipes and the gas heating equipment that uses the gas is the home owner’s responsibility.
In short, the regulations on maintenance of these household water heater are lacking.
IEM would be willing to work with the authorities concern to draw up additional regulations or guidelines.
Tan Yean Chin is president of The Institution of Engineers, Malaysia (IEM).
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