Envirotank recommends the Hydroguard® Monitoring System for double-wall tanks because of its superior leak detection capability. By filling the cavity between the inner and outer tank walls with a non-toxic water based food dye, hydrostatic pressure is continuously applied to both the primary and secondary tank. This system is capable of detecting tank leaks in either the primary or secondary tank walls for all installed conditions.
The Hydroguard® Monitoring System, with a stand pipe, can also serve the dual function of a precision tank test.
The system has been independently tested and statistically validated to meet AS4897 criteria as a precision tank test. Using a stand pipe, the system has been shown to be capable of detecting leaks as small as 0.76 litres per hour with a 99.9% probability of detection and less than a 1.2% probability of a false alarm.
The Hydroguard® Monitoring System provides continuous leak detection while avoiding false alarms caused by changes in product temperature, product level or groundwater conditions.
The reservoir liquid level will be stable if both the inner and outer tanks are tight. The optional reservoir sensor will activate an alarm if the reservoir drains or overfills.
Hydroguard® fluid drains into the primary tank causing the reservoir liquid level to drop. No petroleum product escapes from the primary tank to contaminate the annular space.
Groundwater Below Tank Top
If the groundwater is below the tank top, the Hydroguard® fluid drains into the ground, causing the reservoir liquid level to drop.
Groundwater Over Tank Top
If the groundwater is over the tank top, the reservoir will fill up with groundwater.