Pressure measurement in marine and offshore environments is a critical discipline defined by extreme operational demands. Onboard vessels and platforms, from the engine room's propulsion systems to the deck's hydraulic cranes, gauges must provide unwavering accuracy amidst constant vibration, corrosive salt spray, and wide temperature swings. Key applications include monitoring lube oil and cooling water pressure, managing ballast water treatment systems, controlling high-pressure cargo pumps, and ensuring process safety on FPSO topsides. The selection of instrumentation is not merely about pressure range; it is a rigorous exercise in material science, mechanical resilience, and certified compliance. Failure is not an option when personnel safety and multi-million dollar assets are at stake, demanding gauges engineered specifically for survival and reliability at sea. Manogauge instruments are designed and certified to meet these stringent requirements, ensuring operational integrity from the shipyard to the open ocean.
Compliance in the marine industry is non-negotiable. Manogauge pressure gauges are manufactured in accordance with core international standards including EN 837-1 and ASME B40.100 for performance and safety, under an ISO 9001 certified quality system. For material integrity, our instruments meet the stringent demands of NACE MR0175 / ISO 15156 for sour service in offshore applications. External durability is verified through accelerated salt spray corrosion testing per ASTM B117 for a minimum of 720 hours. Mechanical resilience is confirmed via vibration testing to IEC 60068-2-6. Critically, for shipboard installation, our relevant product series carry type approvals from major class societies including DNV, ABS, Lloyd's Register, BV, and CCS, ensuring full compliance with maritime regulations.
| Typical pressure range | 0–16 bar (Ballast), 0–60 bar (Engine Systems), 0–400 bar (Hydraulics) |
| Recommended wetted material | 316L SS minimum; Duplex SS 2205 / Super Duplex 2507 for direct seawater; Monel 400 for H2S service |
| Accuracy class | ±1.6% Class 1.6 (EN 837-1) for general use; ±1.0% Class 1.0 for critical process control |
| Filling | Glycerin (ambient -20 to +65°C); Silicone oil (ambient -40 to +65°C) |
| Connection | G1/2 BSP or 1/2 NPT standard; bottom or back mount |
| IP rating | IP67 minimum for exposed deck locations; IP65 for machinery spaces |
| Safety pattern | S1 (solid front, blow-out back) standard; S3 (laminated safety glass) for high-pressure gas |
The key difference is resistance to chloride pitting and crevice corrosion. While 316L stainless steel is suitable for atmospheric salt spray, Duplex SS 2205 has a significantly higher Pitting Resistance Equivalence Number (PREN). This makes Duplex far more resistant to localized corrosion when in prolonged or direct contact with seawater, especially in warmer climates. For critical applications like ballast water or fire mains, specifying Duplex for wetted parts dramatically increases service life and reliability over standard 316L.
A class society type approval signifies that the gauge's design, materials, and manufacturing process have been rigorously audited and tested against standards specifically for marine environments. This includes enhanced vibration tests, electromagnetic compatibility (EMC) testing, and performance validation under humidity and temperature cycles that exceed standard industrial tests. It is an independent verification of fitness-for-purpose and is often a mandatory requirement for installation in a vessel's critical systems (e.g., propulsion, steering, bilge) to ensure the safety and insurability of the asset.
Glycerin is the standard, cost-effective choice for vibration dampening in moderate climates, typically effective from -20°C to +65°C. You must specify silicone oil for any application where the gauge will be exposed to ambient temperatures below -20°C. This is common on vessels operating in Arctic or other cold-weather routes. Below this temperature, glycerin becomes too viscous or freezes, which will impede pointer movement and cause inaccurate readings. Silicone maintains its low viscosity down to -40°C, ensuring the gauge functions correctly.
NACE MR0175 / ISO 15156 is a standard that specifies material requirements for metallic components exposed to hydrogen sulfide (H2S), or 'sour service,' common in oil and gas production. For a pressure gauge, compliance means all wetted parts—the Bourdon tube and process connection—are made from an alloy (like Monel 400 or specific duplex steels) that resists sulfide stress cracking (SSC). SSC is a form of catastrophic brittle failure caused by H2S, so NACE compliance is a critical safety requirement to prevent loss of containment on offshore platforms and FPSOs.
ASTM B117 is an accelerated corrosion test and does not directly correlate to a specific number of years in service. However, it serves as a crucial quality benchmark. A gauge case and bezel that can withstand 720 hours of continuous, intense salt fog without significant rusting demonstrates a highly durable coating and base material. This high rating provides strong confidence that the gauge's external components will resist atmospheric corrosion from sea spray and maintain their integrity and readability for many years in a real-world marine environment, far outlasting gauges with lower or untested ratings.