# COMAR Title 09 — Maryland Department of Labor

## Subtitle 12 — Division of Labor and Industry

### Chapter 01 — Board of Boiler Rules

#### Regulation .07 Gas-Fired Installations.

*COMAR 09.12.01.07*

A. A burner in a gas-fired installation shall be tested and certified by the American Gas Association.

B. A gas-fired boiler shall have a vent or flue that terminates at an acceptable location outside the building.

C. The size of the vent or flue shall be:

  (1) That recommended by the boiler manufacturer;

  (2) At least 4 inches in diameter or equivalent area; and

  (3) If the horizontal run exceeds 10 feet, at least 6 inches in diameter or equivalent area.