Reference manual hosted for technician access. 1 pages.
Brand
IMO MEPC.107(49)
Equipment
15 ppm bilge separator + 15 ppm bilge alarm
Document type
Regulatory compliance guide
Revision
MEPC.107(49)
Issued
2026-07-05
Pages
1
Format
PDF (application/pdf)
IMO MEPC.107(49) compliance guide for the 15 ppm bilge separator (oily-water separator, OWS), the 15 ppm bilge alarm and the automatic three-way stopping valve required under MARPOL Annex I Regulation 14 on every ship of 400 GT and above. Lists what the resolution requires of the equipment (15 ppm effluent limit under all conditions, independent alarm actuation, three test-fluid families, rated-capacity envelope, manufacturer's identification plate), what has to be on board (type-approval certificate for both OWS and alarm, IOPP Supplement, Oil Record Book Part I, operating manual, monthly alarm test log) and the three most common port-state survey findings.
IMO Resolution MEPC.107(49) — Revised Guidelines and Specifications for Pollution Prevention Equipment for Machinery Space Bilges of Ships — is the current type-approval standard for the 15 ppm bilge separator (oily-water separator, OWS) and the 15 ppm bilge alarm required by MARPOL Annex I Regulation 14 on every ship of 400 gross tonnage and above. It replaced MEPC.60(33) on 1 January 2005 and every unit installed on a ship whose keel was laid on or after that date must be MEPC.107(49) approved.
What MEPC.107(49) requires of the equipment
15 ppm limit — the effluent from the OWS must not exceed 15 parts per million (mg/L) of oil under any operating condition (Reg. 14.7). No dilution is permitted.
15 ppm bilge alarm — an oil-content meter continuously monitors the effluent. When the reading exceeds 15 ppm, the alarm activates and the automatic three-way overboard stopping valve returns the flow to a holding tank or the bilge (Reg. 14.7 and MEPC.107(49) §3.5). The alarm and the stopping arrangement must be independent of the OWS operator.
Test-fluid families — Annex II of MEPC.107(49) prescribes three test fluids: Test Fluid A (light distillate, marine gas oil), Test Fluid B (heavy fuel oil emulsion) and Test Fluid C (bilge-water equivalent with detergents and solids). The unit is tested against all three plus a fresh-water challenge.
Rated capacity — the OWS carries a rated throughput (m³/h). The type-approval performance is only valid at or below this rate; oversizing wastes bilge capacity and undersizing lets emulsions through untreated.
Marking and identification — every unit carries a manufacturer's plate with type designation, MEPC.107(49) type-approval certificate number, rated capacity, serial number and year. This plate is what the port-state inspector reads.
What has to be on board
Type-approval certificate for the specific serial numbers of the OWS and the 15 ppm bilge alarm, issued by the flag administration or by a recognised organisation on its behalf.
IOPP certificate with the OWS make, model and rated capacity entered in Supplement Form A/B section 3.1.
Oil Record Book Part I — every discharge, transfer and internal recovery of bilge water logged with date, position, quantity and OWS operating hours (Reg. 17).
OWS operating manual specific to the model on board.
15 ppm alarm test log — record of the monthly alarm calibration test.
Common survey findings
The most frequent MEPC.107(49) non-conformity at survey is a missing or defaced manufacturer's plate on the 15 ppm bilge alarm — the alarm is often replaced during retrofit without transferring the plate, and the port-state inspector will not accept the OWS certificate as proof for the alarm. Second most common is a fouled or overdue coalescer / filter cartridge that allows the outlet to exceed 15 ppm on test; MEPC.107(49) §3.7 requires the coalescer to be changed at the interval specified by the maker (typically 6 to 12 months). Third is manual operation of the three-way valve, which MEPC.107(49) prohibits — the valve must be actuated automatically by the alarm signal only.