Logically it should not matter if your local code does or does not require one to be fitted – it is just plain commonsense and dam good practice to fit them on all LPG installations as well as run all pipework from the drip pipe to the appliance with a slight uphill grade.
I cannot ever see the situation where any Inspector would ever tell you to remove one from an installation but I can beleive at times that an inspector may ask what one is for!!!!!!!!!!!!!!!!!!!
Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians