Secondary containment comes in several forms. In some instances, it may be the spill berm for a fuel tank, or even a tank itself to prevent leaks or discharges from reaching a drain and entering a water supply. Any industry involving storage of chemicals or hazardous waste must include a secondary containment system, be it a portable container, a large tank, a liner, double-wall piping, a STP pump, or a spill berm. No matter the medium, however, the system must always be effective, and testing determines just how well secondary containment holds a spill.
The quality of secondary containment should never decrease. A system, essentially, must always function as well as it did upon installation – assuming it works perfectly upon installation – and testing not only shows this but also the system’s ability to contain the leak until it’s cleaned up. So, how is its effectiveness determined? Hydro static or vacuum testing can be performed. The former is less involved and indicates if a system is effective or not, while the latter shows the rate at which the system leaks.
A period of 24 hours must be set aside for hydro static testing. For this procedure, the sump is filled with water, and its surface level marked with paint. Then, the system is left alone for 24 hours, and after this, the level of the water is measured of a ¼- to ½-inch drop.
Vacuum testing, on the other hand, takes less time but requires more action. Much like hydro static, vacuum testing involves filling the sump and marking the water level. Then, there’s a waiting period of five minutes for dispensers or 30 minutes for STP pumps. After this point, the rate at which the water dropped is measured at 0.05 gallons per hour.
SB 989 has required secondary containment testing since 2001, and when testing is needed, the owner or operator of the facility needs to contact a local agency of the procedure 48 hours before testing. After, the owner or operator has 30 days to submit a report. Testing is imperative if a new system is installed in order to establish baseline performance. Assuming the system works ideally upon installation, testing is required again six months later and every three years after that point. In the instance a system cannot be tested or does not pass inspection, it must be replaced with one that effectively contains all leaks and spills.