{"id":2362,"date":"2021-03-25T14:52:16","date_gmt":"2021-03-25T14:52:16","guid":{"rendered":"https:\/\/www.tcnloop.com\/?p=2362"},"modified":"2026-02-18T03:46:20","modified_gmt":"2026-02-18T03:46:20","slug":"how-confident-are-you-about-your-odmcs","status":"publish","type":"post","link":"https:\/\/www.tcnloop.com\/tcn\/how-confident-are-you-about-your-odmcs\/","title":{"rendered":"How confident are you about your ODMCS?"},"content":{"rendered":"\n

ODMCS<\/a> <\/strong>(oil discharge monitoring control system) or ODME is prime equipment under Marpol Annex 1 and is often need to monitor discharge of oily mixture from cargo tanks of oil tankers. ODME keeps a balance between \u201cdo not throw oil into the sea\u201d and \u201clessens operational costs\u201d to the ship owners. But the purpose of ODME is to eradicate water from the slops and not as much oil as is allowed.<\/p>\n\n\n\n

The Marpol requires the below-mentioned things for discharging oily Mixture.<\/p>\n\n\n\n

\u00b7\u00a0 \u00a0The tanker should not be in a special area<\/p>\n\n\n\n

\u00b7\u00a0 \u00a0The tanker should be Enroute<\/p>\n\n\n\n

\u00b7\u00a0 \u00a0The tanker must be more than 50 Nautical miles from the nearest land<\/p>\n\n\n\n

\u00b7\u00a0 \u00a0The immediate rate of discharge should not exceed 30 litres per Nautical mile.<\/p>\n\n\n\n

\u00b7\u00a0 \u00a0The total quantity of oil discharged should not exceed 1\/30000 of the total quantity of cargo of which the residues formed a part.<\/p>\n\n\n\n

\u00b7\u00a0 \u00a0 The tanker should possess an approved ODMCS and it should be operational.<\/p>\n\n\n\n

ODMCS is installed in such a way that it ensures compliance with requirements no 4 and 5. So, you should do the testing of ODMCS if you find,<\/p>\n\n\n\n

\u00b7\u00a0 \u00a0The ODMCS would stop if the \u201cinstantaneous rate of discharge\u201d exceeds 30 litres per nautical mile.<\/p>\n\n\n\n

\u00b7\u00a0 \u00a0 The ODMCS should stop when total oil discharged has reached the allowed limits as per point 5 above.<\/p>\n\n\n\n

Test for instantaneous rate of discharge,<\/strong><\/h2>\n\n\n\n

The formula for IRD is<\/p>\n\n\n\n

IRD (in litres\/Nautical mile) = Oil content(ppm) x Flow rate (m3\/hr) \/ Speed (Knots) x 1000<\/p>\n\n\n\n

This doesn\u2019t give in actual operation the oil content meter and flow meter will give a correct reading of oil content and sample flow respectively. That\u2019s why the oil majors require the annual calibration of oil content meter and flow meter by an external skilled company. Master and ship staff should ensure that such an annual test has been carried out and the certificate is available onboard.<\/p>\n\n\n\n

Test for total quality discharge<\/strong><\/h2>\n\n\n\n

If the vessel was carrying 45000 m3 of oil cargo and oily mixture are formed from washing or ballasting these tanks, the total oil that can be discharged through ODMCS is 45000\/30000 which is 1.5 m3 or 1500 Ltrs. This figure needs to be entered in the ODMCS before the actual run of ODMCS.<\/p>\n\n\n\n

Now how to test? The test is very simple, set a lower value and run the ODMCS in simulation mode with IRD say around 29 L\/NM. You would see the Total oil discharged reading go up. When you reach the set value of total oil discharged, the ODMCS should shut the discharge valve.<\/p>\n\n\n\n

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Brannstrom Cleantrack 1000 | Oil Discharge Monitor<\/a><\/h2>\n\n\n\n