P/V Breaker
2022-01-10
Inspection
- Is the P/V Breaker being inspected and maintained as per PMS?
- Are the outer and inner pipes free of rust / pitting corrosion?
- Is the anti-freeze liquid in normal level?
- Is there evidence that liquid level being checked prior cargo operations?
- Is the level gauge glass cleaned and free of damages?
- Is the scale plate values legible?
- Are the gauge cocks in good working condition?
- Is the atmosphere release valve in good working condition?
- Is the flame screen in good order?
- Has the P/V Breaker been set to a lower pressure that that of the secondary venting mean as well as within cargo tanks safe parameters?
- Are the pressure / vacuum settings (i.e. PRESS: +2100 mmWG // VAC: - 700 mmWG) and venting capacity (i.e 18750 m³/h) marked?
- Is the type of anti-freeze liquid with its lowest operating temperature (freezing point) being displayed?
- Is the last date of inspection marked?
- Are records related to liquid replacement being kept in PMS?
Maintenance
- Treat the inner and outer pipe surfaces by sand or short blasting preferably.
- Paint the surfaces according to maker's paint specifications.
- Renew the flame screen if it is rusted or wasted.
- Clean or replace the level gauge glass if necessary.
- Overhaul the gauge cocks.
- Overhaul the atmosphere release valve.
- Overhaul the drain valve.
- Replace the liquid if the level does not match with actual pressure indicated in IG main line.
- Use the proper solution of anti-freeze liquid and tap water as per maker's instructions (i.e. 25% and 75% respectively).
- Ensure that the specific gravity of the liquid is correct as indicated in maker's drawing (i.e. 1,042 MT/m³ at 20°C). Incorrect specific gravity causes wrong pressure settings.
- Refill the liquid. The level must be at "0" point of the scale plate when IG pressure is equal to atmospheric pressure. It indicates that the inner pipe level is equal to outer pipe level.
- Compare the liquid level with actual IG pressure indication. Adjust the liquid draining or adding accordingly if necessary.
- Add liquid in freezing conditions.
Common Poor Practices
- The liquid level was not aligned to the actual IG pressure.
- The flame screen found wasted.
- The P/V Breaker found with insufficient liquid.
- No records on the last liquid replacement.
References
IMO, TECHNICAL INFORMATION ON SYSTEMS AND OPERATION TO ASSIST DEVELOPMENT OF VOC MANAGEMENT PLANS. MEPC.1/Circ.680.Available: https://wwwcdn.imo.org/localresources/en/OurWork/Environment/Documents/Circ-680.pdf
IMO, International Convention for the Safety Of Life At Sea (SOLAS)
OCIMF, ICS & IAPH, International Safety Guide for Tankers and Terminals (ISGOTT)
OCIMF, SIRE 2.0