“Where a sediment trap is not incorporated as part of an appliance, a sediment trap shall be installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical at the time of the appliance installation. The sediment trap shall either be a fitting with a capped nipple in the bottom outlet or another device recognized as an effective sediment trap.
Illuminating appliances, gas ranges, clothes dryers, decorative appliances for installation in vented fireplaces, gas fireplaces, and outdoor cooking appliances shall not be required to be so equipped.”- National Fuel Gas Code 9.6.8
A sediment trap or “drip leg” is an important part of your fuel line system. This trap is designed to collect any particles/debris that may be in the fuel lines to prevent blockage or damage to the appliances gas components. This trap must have a drip leg of at least 3”.
Some smaller appliances such as dryers and fireplaces do not require these sentiment traps to be installed.