Gas Services, Installation and Safety
Gas fundamentals and safety
Gas work is licensed, high-consequence work. Understand the properties of natural gas and LPG - relative density, calorific value, odourant, and flammable range - and why LPG, being heavier than air, pools in low points and pits. Know the combustion requirements: adequate air for combustion and ventilation, correct flueing, and the danger of carbon monoxide from incomplete combustion. Never rely on smell alone; use detection and leak-testing methods.
Installation requirements
Know the sequence: verify appliance ratings and gas type, size pipe for pressure drop and load, install with correct clearances and support, pressure test, purge, commission, and document. Understand regulators, isolation valves, and the requirement for accessible isolation at each appliance. Flue terminals must clear openings, and appliances need the ventilation specified. Cylinders require restraint, clearance from ignition sources, and correct storage orientation. Conversion between natural gas and LPG requires injector or regulator changes - never assume compatibility.
Testing and commissioning
Pressure testing uses a specified test pressure and duration with no allowable drop; a drop indicates leakage or thermal effects. Purging removes air before ignition. Commissioning checks operating pressure, flame appearance, and safety devices. Defects must be reported and the appliance isolated if unsafe.
Traps and a worked rule
Traps: confusing gas type ratings; forgetting that LPG pools low; testing with the wrong gauge range; and treating a small pressure drop as acceptable. Rule of thumb: if an appliance is unsafe, isolate and tag it, inform the customer, and do not return it to service until rectified. Always confirm the gas type and appliance rating before connecting.