1. (a) Piping must be equipped and monitored as follows:

   1. (B) Mechanical release detection equipment used to continuously monitor under-dispenser containment, including an impact shear valve, which fails to function properly at any time, cannot be repaired and must be replaced with continuous electronic release detection equipment to meet the requirements of this subdivision.
   2. (C) On or after July 1, 2026, at facilities that are not routinely staffed, underground storage tank systems with pressurized piping that are not emergency tank systems must have a continuous interstitial release detection system that shuts off the flow of hazardous substance through the piping when it detects a release from the piping or the release detection system malfunctions.

   3. (2) Line leak detectors must be installed on buried pressurized piping and must be capable of detecting a three gallons per hour release rate at 10 pounds per square inch within one hour with a probability of detection of at least 95 percent and a probability of false alarm no greater than five percent and must restrict or shut off the flow of hazardous substance through the piping when it detects a release.

      1. (A) Piping connected to an emergency tank system may use a line leak detector as described in paragraph (2), which activates an audible and visual alarm in lieu of shutting off or restricting flow through the piping when a release from the piping is detected or the line leak detector or release detection system malfunctions.
      2. (B) A continuous vacuum, pressure, or hydrostatic interstitial release detection system that shuts off the flow of hazardous substance through the piping when a release from the piping is detected or the release detection system malfunctions satisfies the line leak detector requirement.
      3. (C) Piping connected to an emergency tank system may use a vacuum, pressure, or hydrostatic interstitial release detection system as described in subparagraph (B), which activates an audible and visual alarm in lieu of shutting off flow through the piping when a release from the piping is detected or the release detection system malfunctions.
   4. (3) Tightness testing must be conducted on buried pressurized piping connected to Type 1 and Type 2 underground storage tanks at least once every 12 months using a release detection method or equipment capable of detecting a release equivalent to 0.1 gallon per hour at 150 percent of the normal piping system operating pressure, with at least a 95 percent probability of detection and not more than a five percent probability of false alarm.

   5. (4) Continuous release detection systems as described in paragraph (1) satisfy the tightness testing requirement of paragraph (3) if both the following conditions are met:

      1. (A) The release detection system shuts down the pressure pump or stops the flow of hazardous substance at the dispenser when a release is detected in the under-dispenser containment; and
      2. (B) The release detection system for all buried pressurized hazardous substance piping other than that contained in the under-dispenser containment is fail safe and shuts down the pressure pump when a release from the piping is detected.

   (1)(A) Except as provided in section 2651(g), piping secondary containment must be equipped with a continuous interstitial release detection system that either activates an audible and visual alarm, or stops the flow of hazardous substance at the dispenser when a release from the piping is detected.

2. (b) Piping connected to Type 3 underground storage tanks must be monitored by a continuous vacuum, pressure, or hydrostatic interstitial release detection system in accordance with subdivisions (d) and (e) of section 25290.1 of the Health and Safety Code.

3. (c) Piping monitored by continuous vacuum, pressure, or hydrostatic interstitial monitoring must:

   1. (1) Be configured to facilitate testing required pursuant to section 2663(a); and
   2. (2) Be configured so that continuity can be confirmed for each zone to the extent practical as approved by the Unified Program Agency during testing required pursuant to sections 2642(f) and 2663(a).

Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Sections 25281, 25281.5, 25290.1, 25290.2, 25291 and 25404, Health and Safety Code; and 40 CFR Sections 280.40-280.42 and 280.44.

History

1. Amendment filed 8-9-91 as an emergency; operative 8-9-91. Text remains in effect uninterrupted pursuant to Health and Safety Code section 25299.7 (Register 92, No. 14).

2. Editorial correction of printing errors in History 1 (Register 92, No. 43).

3. Amendment filed 4-5-94; operative 5-5-94 (Register 94, No. 14).

4. Amendment of subsections (c), (c)(9), (d) and (f) and amendment of Note filed 10-13-2016; operative 1-1-2017 (Register 2016, No. 42).

5. Repealer and new section heading and section filed 10-28-2025; operative 1-1-2026 (Register 2025, No. 44).