AMSA has tightened oily water separator compliance.
Is your BilgMon 488 ready?

AMSA Marine Notice 2025/06 has raised the bar for oily water separator compliance. Approved equipment is only part of the picture - PSC officers now assess the complete installation. If your vessel operates a Brannstrom BilgMon 488, Insatech Marine can help you identify what needs to be reviewed, upgraded, or replaced to meet current requirements.

What the regulation requires

Under MARPOL Annex I Regulation 14, all oil filtering equipment installed on or after 1 January 2005 must meet Resolution MEPC.107(49). This applies to the complete oily water separator system - not just the alarm unit, but the sample line, fail-safe arrangement, valve configuration, and automatic stopping device, all working together within defined response times.

The key performance requirements are specific and non-negotiable. A truly representative effluent sample must reach the 15ppm bilge alarm with adequate pressure and flow at all times. The alarm must respond within 5 seconds of a change in the effluent sample. The automatic stopping device must activate within 20 seconds of discharge exceeding 15ppm. And if sample supply to the alarm is disrupted for any reason, the fail-safe arrangement must prevent overboard discharge automatically - without crew intervention.

What AMSA is finding during inspections

AMSA continues to identify non-compliant oily water separator systems during port state control inspections - including on vessels where the bilge alarm unit itself carries full type approval. The issues are consistently with the installation, not the unit: blocked sample lines, incorrectly positioned or unsealed valves, absent or non-functional fail-safe arrangements, and crew unfamiliar with correct operating procedures.

Marine Notice 2025/06 makes AMSA's inspection approach more detailed than its predecessor. PSC officers now assess sample line valve configuration, whether clean water flushing triggers the alarm and stopping device as required under MEPC.107(49) 4.2.10.2, and whether the crew can demonstrate the full system working correctly. Where deficiencies are found, vessel detention is likely until the installation meets requirements in full.

Why many BilgMon 488 installations need an upgrade

The Brannstrom BilgMon 488 is a well-established 15ppm bilge alarm approved to MEPC.107(49). However, a large number of BilgMon 488 installations were commissioned at a time when the practical interpretation of the standard was less stringent. Many were set up without a flow sensor in the sample line, without sealed valves, and without a verified fail-safe arrangement.

Without a flow sensor, there is no automatic mechanism to detect loss of sample flow and trigger the fail-safe. The installation relies entirely on valve positions and crew knowledge - both of which PSC officers will verify. If either falls short, the system is non-compliant, regardless of the unit's type approval.

Similarly, sample line valves not sealed in the correct operating position represent a compliance risk under MEPC.107(49) 4.2.10.1. An ageing unit with unverified response times may no longer meet the 5-second and 20-second limits. A stopping device not properly interfaced with the BilgMon 488 may fail to activate when required. Any one of these issues can result in a deficiency. Together, they describe an installation that has not kept pace with how MEPC.107(49) is now interpreted and enforced.

Unsure where your installation stands? We can help you find out.

What an upgrade typically involves

Depending on the current state of the installation, bringing a BilgMon 488 into full compliance with current AMSA requirements may involve one or more of the following:

• Replacing an ageing BilgMon 488 unit with a current model
• Adding a flow sensor to the sample line for automatic fail-safe detection
• Reviewing and correcting sample line routing and condition
• Sealing sample line valves in the correct operating position with appropriate signage
• Verifying the interface between the BilgMon 488 and the automatic stopping device
• Confirming alarm and system response times meet the required limits

For some vessels, a flow sensor and sealed valves are sufficient. For others, a full unit replacement is the most reliable path to compliance. Either way, the review should happen before the next port state control inspection - not after.

How Insatech Marine can help

Insatech Marine is an authorised worldwide distributor of the Brannstrom BilgMon 488. We supply new units, replacement parts, and flow sensor configurations to ship operators and technical teams globally. We can advise on what your specific installation requires to meet MEPC.107(49) as AMSA now interprets it - whether that means a targeted upgrade or a full unit replacement.

We work with ship operators, fleet managers, and technical superintendents across vessel types and trading routes. If you are uncertain whether your current BilgMon 488 installation will hold up under PSC scrutiny, contact us before your next port call.

Contact us to discuss your BilgMon 488 installation