Answer
What is an In-Use Sample?
Under MARPOL Annex VI (Regulation 2 & Regulation 14) and Resolution MEPC.324(75), an In-Use Sample is defined as a representative sample of fuel oil currently in use on board a ship—meaning the fuel oil being drawn from the service system and supplied to operating combustion machinery (main engines, auxiliary engines, boilers, incinerators, or inert gas generators).
Where are Sample Points Located?
In accordance with IMO Guidelines (MEPC.1/Circ.864/Rev.1), designated "In-use" sampling points must be:
- Located downstream of the fuel oil service tank and as close to the inlet of the fuel oil combustion equipment as safely practical.
- Positioned in a low-pressure area of the fuel supply circuit (typically between the fuel oil service tank/booster unit and the high-pressure fuel injection pump inlet) to allow safe manual sampling.
- Clearly marked on piping diagrams, physically labelled on board for easy identification, and fitted with appropriate safety devices (such as shield covers to prevent fuel splash onto hot surfaces).
Feature | MARPOL Delivered Sample | Onboard Sample | In-Use Sample |
|---|---|---|---|
Statutory Ref. | MARPOL Annex VI, Reg 18.8.1 | MARPOL Annex VI, Reg 14.9 | MARPOL Annex VI, Reg 14.8 |
Definition | Sample of fuel oil delivered to the ship during bunkering. | Sample of fuel oil intended to be used or carried for use on board. | Sample of fuel oil currently in use in combustion machinery. |
Location Drawn | Bunker manifold via continuous drip sampler during bunkering. | Directly from storage, settling, or service tanks (or sounding pipes). | Designated sampling point downstream of service tank near engine inlet. |
Primary Purpose | Legal evidence of what supplier delivered to the vessel. | Verifies compliant fuel stored in tanks (e.g., checking carriage ban compliance). | Verifies compliance of actual fuel being burned at the moment of inspection (used by PSC). |
IMO Guideline | Resolution MEPC.182(59) | Resolution MEPC.1/Circ.889 | Resolution MEPC.1/Circ.864/Rev.1 |