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Monday, May 24, 2021 

Monitoring equipment company Rivertrace points out that oil discharges that are illegal under MARPOL regulations are still possible if calibration of the oil content monitor (OCM) has been neglected.

Legal action can be avoided by regular inspection and recalibration of the equipment installed on the ship in accordance with manufacturers requirements. The IMO guidelines are set out in MARPOL 73/78 Annex 1, under MEPC. 107(49) and amended by MEPC. 285(70). The guidelines recommend governments to apply them when checking the accuracy of 15ppm bilge alarms. Some governments (as flag states) have taken this course by including them in national regulation and others have tacitly accepted them by instructing their own surveyors and ROs to apply them when issuing IOPP Certificates at scheduled renewal dates.

Paragraph 4.2.11 in MEPC.107(49), as amended, reads: "The validity of calibration certificates should be checked at IOPP annual/intermediate/renewal surveys. The accuracy of 15 ppm bilge alarms is to be checked by calibration and testing of the equipment conducted by a manufacturer or persons authorized by the manufacturer and should be done at intervals not exceeding five years after its commissioning, or within the term specified in the manufacturer’s instructions, whichever is shorter. Alternatively the unit may be replaced by a calibrated 15 ppm bilge alarm. The calibration certificate for the 15 ppm bilge alarm, certifying the date of the last calibration check, should be retained on board for inspection purposes."

MARPOL compliance is enforced by the individual flag states of which many take the Guidelines as the only acceptable method.

OCMs and bilge alarms are produced by relatively few manufacturers and makers of separators generally turn to one of these to supply the monitoring and alarm functions of their equipment. Rivertrace supplies the Smart Bilge OCM for many of the leading separator manufacturers. The Smart Bilge OCM can simultaneously detect all three oil types (HFO, Diesel and emulsions) using Rivertrace's 'Smart Cell' Detector Array Technology. Smart Bilge comes as standard with a manual cell cleaning device, allowing easy routine maintenance, and thus avoiding the problem of malfunction caused by optical cell fouling. Optional pneumatic autoclean and flow switches can be added to reduce maintenance or increase compliance. To meet special requirements such as those applying in the Great Lakes and some classification societies ‘Clean’ notations, the Smart Bilge can be factory calibrated to 5ppm.

Replacement calibrated measuring cells can be purchased for easy change over on board the vessel, as well as calibration check kits which enable the crew to demonstrate the monitor is within factory calibration to PSC Surveyors. Ships that are registered on the Rivertrace Connected Portal will also receive automatic reminders before calibration expiry dates are due.

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