Dripleg size

The customary description of a drip leg is a blind (capped) vertical stub at the end of a vertical pipe run in the fuel gas supply. It traps water and sediment entrained in natural gas, and is placed as close to the burner as practicable.

At one time plumbing codes required a drip leg to be placed on the fuel supply of every appliance that burned natural gas, but this requirement has been relaxed or eliminated in some cases.

You should ask whatever agency maintains authority over safety in your industry whether your gas burners will require a drip leg. If this is for a residential or commercial installation, ask your local Building and Safety Department.

There are also drip legs installed in some air ducts where condensed moisture might accumulate. The Mechanical Code applicable in your area will contain at least a chapter on exhaust ducts and separators of various kinds.