1. A. An owner and an operator of a UST system shall comply with the installation requirements of this regulation.
2. B. Install piping in accordance with the requirements of this regulation.
3. C. Place underground piping on a 6-inch bedding of appropriate backfill material as described in Regulation .04 of this chapter.

4. D. Maintain the following clearances when installing piping:

   1. (1) Twice the nominal diameter of the pipe but at least 4 inches between all piping;
   2. (2) At least 6 inches between piping and electrical conduits related to the UST system;
   3. (3) At least 6 inches between piping and excavation zone sidewalls; and
   4. (4) At least 18 inches between piping and the surface of the ground.
5. 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.
6. F. Follow the manufacturer specifications and installation requirements when installing piping.

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

   1. (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. (2) To connect a pipe carrying a regulated substance to a dispenser system.
8. 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.
9. I. Place a UL listed shear valve on pressurized product piping dispensing motor fuel, and properly anchor the shear valve at the dispenser.
10. J. Install appurtenances such as water or air piping in a separate piping trench;

11. K. Ensure vent lines above the ground surface are:

    1. (1) Constructed with at least schedule 40 steel;
    2. (2) Protected from traffic;
    3. (3) Properly anchored; and
    4. (4) Protected from weather and debris.

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

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

Authority: Environment Article, §§4-401, 4-402, 4-405, 4-407—4-411.2, 4-415.1, 4-417, 4-701 et seq., and 7-201 et seq., Annotated Code of Maryland

Effective date: February 4, 1991 (18:2 Md. R. 151)

Chapter revised effective November 4, 1996 (23:22 Md. R. 1498)

Regulation .01 amended effective January 12, 2009 (36:1 Md. R. 25)

Regulation .01B amended effective June 29, 1998 (25:13 Md. R. 997)

Regulation .02 amended as an emergency provision effective January 26, 2005 (32:4 Md. R. 406); emergency provision extended at 32:15 Md. R. 1315

Regulation .02 amended effective January 16, 2006 (33:1 Md. R. 38); January 12, 2009 (36:1 Md. R. 25)

Regulation .03A amended effective February 18, 2002 (29:3 Md. R. 224)

Regulation .03A amended as an emergency provision effective January 26, 2005 (32:4 Md. R. 406); emergency provision extended at 32:15 Md. R. 1315

Regulation .03A amended effective January 16, 2006 (33:1 Md. R. 38)

Regulation .03D adopted effective June 29, 1998 (25:13 Md. R. 997)

Regulation .04B amended effective January 16, 2006 (33:1 Md. R. 38)

Regulation .04H adopted effective February 18, 2002 (29:3 Md. R. 224)

Regulation .04I adopted effective January 12, 2009 (36:1 Md. R. 25)

Regulation .05A amended effective January 12, 2009 (36:1 Md. R. 25)

Regulation .07E amended effective February 18, 2002 (29:3 Md. R. 224)

Regulation .08 amended effective June 29, 1998 (25:13 Md. R. 997); February 18, 2002 (29:3 Md. R. 224); January 16, 2006 (33:1 Md. R. 38)

Regulation .09 amended effective January 16, 2006 (33:1 Md. R. 38)

Regulation .10 adopted effective January 16, 2006 (33:1 Md. R. 38)

Regulation .10 amended effective January 12, 2009 (36:1 Md. R. 25)

Regulations .01—.10 repealed and new Regulations .01—.10 adopted effective June 13, 2022 (49:12 Md. R. 642)