National Fuel Gas Code (NFPA 54)

The National Fuel Gas Code, published jointly by the NFPA and the American Gas Association and carrying the dual designation ANSI Z223.1 — one document with two numbers, which is why the same clause is cited both ways in the literature. Its subject runs from the point of delivery to the appliance connection: piping materials and sizing, shutoffs and regulators, the air a burner needs, and the route the products of combustion take out of the building.

A jurisdiction adopting it will not also be enforcing the IFGC, so a clause number quoted from the wrong one of the two is unarguable in an inspection even where the requirement behind it is identical. Its venting chapter is the part least safe to reason about from first principles.

Vent sizing is a lookup against a table built from appliance input, vent height and connector rise, and a vent that is too large cools the flue gases below their dew point exactly as surely as one that is too small fails to draw. Where a listed appliance arrives with its own installation instructions, those instructions govern the installation and this document steps back — which is the boundary most often crossed by somebody applying a table to an appliance the table was never drawn for.

Obtained from National Fire Protection Association. What NFPA publishes

Published: 2024, 2021, 2018. A new edition every three years.