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Minnesota Administrative Rules

4715.2150 CONNECTIONS NOT SUBJECT TO BACK PRESSURE.

Subpart 1.

Requirements.

Where a water connection is not subject to back pressure an atmospheric type vacuum breaker shall be installed on the discharge side of the last valve on the line serving the fixture or equipment. Where a valve is installed on the discharge side of a vacuum breaker, that vacuum breaker must be a pressure-type vacuum breaker assembly which complies with part 4715.2030. A list of some conditions requiring protective devices of this kind is given in subpart 2.

Subp. 2.

Cross-connections where protective devices are required and critical level (C-L) settings for backflow preventers.

Critical level (C-L) is defined as the level to which the backflow preventer (vacuum breaker) may be submerged before backflow will occur. Where the C-L is not shown on the preventer, the bottom of the device shall be taken as the C-L.

Fixture or Equipment Method of Installation
Aspirators and Ejectors C-L at least 6 inches above flood level of receptacle.
Dental units On models without built-in vacuum breakers C-L at least 6 inches above flood level rim of bowl.
Dishwashing machines C-L at least 6 inches above flood level of machine. Install on both hot and cold water supply lines.
Flushometer (Closet & Urinal) C-L at least 6 inches above top of fixture supplied.
Garbage can cleaning machine C-L at least 6 inches above flood level of machine. Install on both hot and cold water supply lines.
Hose outlets C-L at least 6 inches above highest point on hose line.
Laundry machines C-L at least 6 inches above flood level of machine. Install on both hot and cold water supply lines.
Lawn sprinklers C-L at least 12 inches above highest sprinkler or discharge outlet.
Steam tables C-L at least 6 inches above flood level.
Tank and vats C-L at least 6 inches above flood level rim or line.
Flush tanks Equip with approved ball cock. Where ball cocks touch tank water equip with vacuum breaker with C-L at least 1 inch above overflow outlets. Where ball cock does not touch tank water, install ball cock outlet at least 1 inch above overflow outlet or provide vacuum breaker as specified above.
Hose bibbs (Where aspirators or ejectors could be connected) C-L at least 6 inches above flood level of receptacle served.

Statutory Authority:

MS s 16B.62; 326.37 to 326.45; 326B.121; 326B.43 to 326B.49; 326B.52

History:

19 SR 590; L 2007 c 140 art 4 s 61; art 6 s 15; art 13 s 4; 36 SR 1479

Published Electronically:

November 13, 2012

700 State Office Building, 100 Rev. Dr. Martin Luther King Jr. Blvd., St. Paul, MN 55155 ♦ Phone: (651) 296-2868 ♦ TTY: 1-800-627-3529 ♦ Fax: (651) 296-0569