How do you prevent boiler explosion?

All boilers are made to a pressure specification and in most countries any pressure vessel over a certain size is required to be periodically inspected and pressure tested to ensure it is fit for purpose. In addition to being in sound condition, the boiler is also expected to have some form of pressure relief valve. This is of sufficient size to vent off excess pressure before it gets to an explosive situation. It is obviously important that the pressure of this device is set to a lower level than the ultimate pressure specification of the boiler. Even quite small boilers, like those in coffee makers need to be inspected.

Some boilers are 'gas fired' such as home heating boilers. These have a device called a thermocouple that detects the flame and is linked to the gas valve. If the flame goes out, or the burner does not ignite when gas is released in the boiler, it will shut the gas off. Typically gas fired boilers have a number of devices that will shut off the gas in the event that something doesn't work. This means that if the gas supply pipe is in sound condition, the boiler itself cannot leak gas and cause an explosion.