# COMAR Title 26 — Department of the Environment

## Subtitle 10 — Oil Pollution Control and Storage Tank Management

### Chapter 03 — UST Systems: Design, Construction, Installation, Registration, and Inspection

#### Regulation .06 Piping Installation.

*COMAR 26.10.03.06*

A. An owner and an operator of a UST system shall comply with the installation requirements of this regulation.

B. Install piping in accordance with the requirements of this regulation.

C. Place underground piping on a 6-inch bedding of appropriate backfill material as described in Regulation .04 of this chapter.

D. Maintain the following clearances when installing piping:

  (1) Twice the nominal diameter of the pipe but at least 4 inches between all piping;

  (2) At least 6 inches between piping and electrical conduits related to the UST system;

  (3) At least 6 inches between piping and excavation zone sidewalls; and

  (4) At least 18 inches between piping and the surface of the ground.

E. Unless otherwise approved by the Department, ensure piping rises 1/8 of an inch for each lateral foot from the UST to the piping endpoint.

F. Follow the manufacturer specifications and installation requirements when installing piping.

G. In accordance with manufacturer specifications, use a UL listed flexible connector to connect piping as follows:

  (1) Except for a direct fill line, to connect a pipe carrying a regulated substance to a UST at the end of a piping run; and

  (2) To connect a pipe carrying a regulated substance to a dispenser system.

H. Unless otherwise approved by the Department, an owner and an operator of a UST system may not use a flexible connector to connect piping carrying petroleum vapor or a regulated substance at any other point in the piping system not listed in §G of this regulation.

I. Place a UL listed shear valve on pressurized product piping dispensing motor fuel, and properly anchor the shear valve at the dispenser.

J. Install appurtenances such as water or air piping in a separate piping trench;

K. Ensure vent lines above the ground surface are:

  (1) Constructed with at least schedule 40 steel;

  (2) Protected from traffic;

  (3) Properly anchored; and

  (4) Protected from weather and debris.

L. Ensure the vents of a UST system storing a flammable or combustible liquid meet the following conditions:

  (1) If the UST system stores a flammable liquid, the vents terminate 12 feet above the ground surface and 2 feet above an attached building; and

  (2) If the UST system stores a combustible liquid, the vents terminate at least 3 feet above the ground surface.