Is topping off the manometer with interstitial fluid a normal maintenance procedure?

A: Frequently, No. Adding fluid frequently should not be necessary. However, monitored DoubleWall systems are subject to various and varying physical and environmental conditions as outlined below. When these conditions are present, periodic observation and maintenance may be required, which may include topping off the interstitial fluid. The majority of these false-alarms happen in the Fall and Spring during seasonal temperature shifts.
It is recommended that a maintenance program be established to support the integrity, cleanliness and function of a containment system at any fuel site in an effort to proactively protect the environment from contamination. Each and every alarm caused by a fluid level drop should be evaluated and monitored. Sumps where an alarm occurs more frequently than every 6 months between seasonal shifts should be considered suspect due to a leak. Testing procedures for Bravo DoubleWall sumps as outlined in each respective installation manual should be followed to attempt to pinpoint the cause of a potential loss of interstitial fluid. This testing should be conducted only by a Bravo Systems DoubleWall-Certified individual or company.
NOTE: Repairs on sumps with major damage that constitutes a containment breach of any material component below grade are not allowed unless Bravo Systems Technical Support has been contacted, the situation is evaluated and a Letter of Authorization is provided on company letterhead detailing the specific issues and remedy’s.
If there is a drop in the fluid level to the point where an alarm is generated, you have one or more of a few common issues.
A) You have a breach. Most commonly a leak is caused by a Flexible entry fitting. This could also be caused by impact damage to the interior or exterior sump wall. Impact damage or bruising on Bravo Systems sumps may be visually identified by a concentration or spider-web of white color in the fiberglass. This is true for Bravo sumps that are a natural color on the interior. Our sumps have been paint and gel-coat free since mid 2006.
B) You have air in the interstice, and it is either a) Expansion and contraction of the liquid, expansion and contraction of the air trapped in the liquid, air in the system expanding within the propylene glycol during hot weather causing the fluid to spill out of the manometer, causing an alarm when the temperature drops and the fluid level falls. Alarms that frequently occur at night time or early morning hours are usually attributed to a fall in brine level due to a temperature drop and may happen because the level was already low. Most alarms due to fluid level fluctuations occur at night, and the majority of these types of false-alarms happen in the Fall and Spring during seasonal temperature shifts. and/or b) A DoubleWall sump that was not filled with interstitial fluid per our mandatory Vacuum-Hydrostatic filling procedure is burping air from being “gravity-fed” the fluid. After gravity-feeding fluid into an interstice it can take weeks or months for air to gurgle out of a sump through either the primary or atmospheric manometers.
C) Localized environmental and/or weather conditions may cause the interstitial fluid to evaporate at a more noticeable rate than other areas. In this case, you should determine whether the liquid loss is recent or if it has been occurring over a long period of time.
D) There also exists an issue with some Tank Sumps where the lack of an atmospheric manometer to equalize sump interstice pressures exacerbates the chance of a false alarm and/or fluid spillage. To minimize these alarms, you can install our new low-profile atmospheric manometer for the B400 Series DoubleWall tank sumps. It’s part number is “ATM-400-LP” and can be easily installed into the test port opposite the manometer to assist in equalizing the sump interstice pressures.