A recent gas incident has highlighted the need for gas fitters to be aware of the potential for over-pressurisation of a gas installation due to the failure of an older-style single-stage LP Gas installation regulator.
Failure of single-stage LP Gas regulators can lead to downstream piping, apparatus and appliances being exposed to dangerously high pressures.
Prior to 1999, most domestic and some commercial LP Gas installations were not fitted with over-pressure protection. Without over-pressure protection, the installation relies solely on the integrity of the single-stage installation regulator to ensure downstream apparatus and appliances are not exposed to high pressures.
Summary of the Incident
A gas fitter attended a property in response to a reported smell of gas within the kitchen and the area of the LP Gas cylinders. He checked the existing single-stage LP Gas regulator with leak detection spray and a leak was found.
On entering the kitchen of the residential premises, there was no smell of gas present, but he noted that one of the gas hotplate burner controls appeared to be in the “on” position.
As the gas fitter turned the burner control to the “off” position, there was a large fireball and explosion. Luckily, in this instance, no injuries were received and only property damage occurred.
The investigation identified that the single-stage LP Gas regulator was 33 years old and was supplying a downstream pressure of 210kPa to the hotplate, which is rated for a maximum gas pressure of 3kPa.
Since 1999, all installations have been fitted with over-pressure protection, which in the event of an installation regulator failure, will protect the downstream installation.
Commonly, the over-pressure protection on domestic and small commercial LP Gas installations is in the form of a twin-series regulator combination. This combination includes the installation regulator with the required over-pressure protection (see image below).
Without over-pressure protection, there is the potential for:
- gas leaks;
- damage to apparatus and appliances; or
- fires and explosions.
All of which constitute a hazard to persons and or property.
When working on existing LP gas installations, gas fitters should:
- Always check the age and condition of the installation regulator
- Recommend replacement if:
- there is no over-pressure protection;
- they are deemed to be in poor condition;
- the service life recommended by the manufacturer has been exceeded; or
- shows signs of excessive wear, such as on or near sea environments.
- Ensure any replacement includes over-pressure protection
- As a minimum, check the working pressure of the installation regulator.
Gas Suppliers should provide a copy of this information to customers via:
- the local branch; and
- delivery drivers, where an installation regulator, the same as or similar to that pictured below, is identified.
