MARPOL Annex I Reg.13: Standard Discharge Connection

The whole regulatory edifice of MARPOL Annex I for machinery spaces rests on one assumption: when a ship cannot discharge oily residue legally at sea, it can land that residue ashore instead. Regulation 13 is the regulation that makes the landing physically possible. It does nothing more than specify a flange. But without that flange, every shore reception facility would face a different bolt pattern, a different face diameter, and a different gasket size on every ship that came alongside, and the “deliver ashore” half of the Annex I scheme would collapse into a tangle of adapters and improvised couplings.

Regulation 13 is titled “Standard discharge connection.” It sits in Chapter 3 (Requirements for machinery spaces of all ships), Part A (Construction) of the revised Annex I. The text is short, and the heart of it is a table of dimensions. This article reproduces that table, verifies every figure against the regulation as implemented in US federal law, and explains why each number is where it is and what happens on inspection when one of them is wrong.

What Regulation 13 requires

The operative sentence is plain. To enable pipes of reception facilities to be connected with the ship’s discharge pipeline for residues from machinery bilges and from oil residue (sludge) tanks, both lines shall be fitted with a standard discharge connection in accordance with a fixed table of dimensions. That is the entire functional requirement: the ship’s discharge line and the reception facility’s receiving line both terminate in the same flange, so they bolt together without an adapter.

The connection applies to two distinct waste streams that machinery spaces produce. The first is oily bilge water: the water that collects in the bottom of the engine room from leaks, drains, condensation, and washing, carrying an oil content that must be processed by oil filtering (15 ppm separator) equipment before any overboard discharge, with the discharge itself governed by the discharge criteria of Regulation 15. The second is oil residue (sludge): the thicker, unpumpable-by-separator residue from purifier sludge, settling-tank drainings, and waste oil, held in the dedicated oil residue (sludge) tanks of Regulation 12. Sludge can’t be cleaned to 15 ppm and discharged at sea; it goes ashore or to an incinerator. Regulation 13 gives both streams a common shoreside exit.

The regulation says the line “shall” be fitted, not “may.” It’s a construction requirement, so it bites at the building yard and stays a survey item for the life of the ship. A ship that lands oily residue through a non-standard coupling has not met Regulation 13, even if the residue reaches the facility, because the standardization itself is the point.

The flange dimensions

Every figure below is taken from the standard table of flange dimensions as it appears in the revised Annex I and is reproduced verbatim in the US implementing regulation at 33 CFR 155.430, which transcribes the MARPOL flange without alteration. The dimensions have not changed since the revised Annex entered force on 1 January 2007.

Beyond the table, the regulation adds three qualifiers that matter as much as the numbers. The flange is designed to accept pipes up to a maximum internal diameter of 125 mm. It shall be of steel or other equivalent material having a flat face. And, together with a gasket of oil-proof material, it shall be suitable for a service pressure of 6 kg/cm2. That pressure is roughly 600 kPa, or about 6 bar, which is the figure a surveyor will quote when asked the rated pressure of the connection.

Read the table as a physical object and the logic of each number falls out. The 215 mm outside diameter sets the size of the steel disc. The 183 mm bolt circle is where the six fasteners sit, inside the rim. The slots, rather than plain holes, are cut open to the edge of the flange so the mating flange can be dropped onto the bolts and slid into place without threading each bolt through a closed hole, which is what you want when you’re aligning a heavy shore hose by hand on a moving deck. Six bolts of 20 mm spread the clamping load around the 600 kPa face. The 20 mm thickness gives the disc the stiffness to hold that load without dishing. And the 125 mm maximum pipe bore caps the flow path the connection is built to pass, so the flange is never asked to seal a pipe larger than its face can clamp.

The inner diameter is the one entry with no fixed number. It’s set “according to pipe outside diameter” because the ship’s own discharge pipe may be any size up to the 125 mm internal-diameter limit, and the flange bore simply matches whatever pipe it’s welded or bolted to. Everything that has to mate with the shore side, the outside diameter, the bolt circle, the slot pattern, the face, is fixed; the bore that faces inboard is left to the ship’s piping.

The material clause carries more weight than it looks. “Steel or other equivalent material having a flat face” rules out a raised-face or ring-joint flange, both common in process piping, because the mating shore flange is flat-faced and the two faces have to sit full against the gasket. A raised face on one side would leave a gap the gasket couldn’t bridge. “Steel or other equivalent” lets a builder use a corrosion-resistant alloy where the residue or the environment warrants it, but the equivalence is in the mechanical performance: whatever the material, the flange has to hold 600 kPa with the gasket and stay flat under the six-bolt clamping load. The flat face is not a detail; it’s what makes any two compliant flanges seal against each other regardless of who built them.

Why the slots, not holes

The detail that catches people new to the connection is the word “slotted.” The six openings are not drilled holes; they are holes cut through to the flange periphery, open at the rim, 22 mm wide. The practical reason is alignment under load. A reception-facility hose is heavy and stiff, often handled by one or two people over the ship’s rail or down onto a barge. With closed bolt holes you’d have to line up all six holes simultaneously before any bolt could go in. With slots open to the edge, the operator drops the mating flange over bolts already started in the ship’s flange and slides it home radially, then tightens. The 22 mm slot width clears a 20 mm bolt with room to settle.

The slotting is also what visually distinguishes the Annex I oil connection from the international shore fire connection, which is a different standardized flange entirely (defined under SOLAS Chapter II-2, not MARPOL) used to take firewater from shore or from another ship when a ship’s own fire pumps fail. The two are easy to tell apart by size and bolt count. The SOLAS international shore connection is 178 mm outside diameter on a 132 mm bolt circle with four 19 mm holes and four 16 mm bolts; the Annex I oil connection is 215 mm outside diameter on a 183 mm bolt circle with six 22 mm slots and six 20 mm bolts. A deck officer who can read the flange pattern won’t confuse the two: the oil residue connection is the larger, six-slot disc for sludge and bilge water, while the fire connection is the smaller, four-hole disc. Mistaking one for the other would put firewater into the sludge tank or oily residue into the fire main, so the visual distinction earns its keep.

The numbers are not arbitrary. SOLAS and MARPOL deliberately picked non-overlapping bolt circles (132 mm for fire, 170 mm for sewage, 183 mm for oil) and different hole counts (four, four, six) so that the three ship-to-shore connections a vessel carries cannot be cross-mated by a tired crew at three in the morning. The fire connection’s four bolts on a 132 mm circle physically can’t span the oil connection’s 183 mm circle, and even where two connections share a bolt count, the bolt-circle diameter keeps them apart. This is standardization used in reverse: the dimensions are fixed not only so the right hoses fit, but so the wrong hoses don’t.

Regulation 12 and the “retain on board” alternative

Regulation 13 doesn’t stand alone. It’s the hardware half of a two-part scheme whose policy half lives in Regulation 12, the oil residue (sludge) tanks requirement. Regulation 12 obliges ships to carry tanks of adequate capacity to hold the oil residue that a separator can’t clean to dischargeable standard, and it requires a designated pump and piping for disposing of that residue. Regulation 12 then names two acceptable disposal routes: to a reception facility, or to an approved incinerator or other approved means. The route to the reception facility is the route that needs a flange, and the flange it needs is the one Regulation 13 specifies.

That’s why the two regulations are read together and have been amended together more than once. The amendments adopted by resolution MEPC.187(59), in force from 1 January 2011, rewrote the oil-residue definitions and the Regulation 12 sludge-tank requirements, touching Regulations 1, 12, 13, 17 and 38 as a set so the renamed “oil residue (sludge)” stream ran consistently through the tank rule, the discharge connection, the record book, and the reception-facility obligation. The further amendments in resolution MEPC.266(68), in force from 1 January 2017, refined Regulation 12.2 on the disposal piping and the prohibition on certain interconnections between the sludge system and the bilge system, so that the residue path to the Regulation 13 connection stayed segregated. IACS Recommendation No. 121 sets out how class societies apply the revised Regulation 12 and Regulation 13 uniformly, including the point that a dedicated pump is not strictly required and that screw-down non-return valves in lines leading to the Regulation 13 standard discharge connection can provide the segregation Regulation 12 demands. The detail to take away: Regulation 12 says retain and dispose, Regulation 13 says here is the connector that disposal uses, and the two are designed as one system.

The deeper significance is the alternative this system creates. Without a guaranteed way to land residue ashore, a ship that filled its sludge tanks at sea would face a choice between an illegal overboard discharge and a vessel that can’t sail. The standard discharge connection removes that choice by making the shoreside exit universal. Every port reception facility carries hoses ending in the Regulation 13 flange; every ship carries the matching flange; the residue moves from ship to shore through a connection neither party has to engineer on the day. The Oil Record Book Part I then records the disposal, with the quantity landed and the facility receipt, closing the audit loop that proves the residue went ashore rather than over the side.

Regulation 38 and the shore side of the connection

A flange on the ship is useless if the port has nothing to bolt onto it. That obligation falls on Regulation 38, reception facilities, which sits in Chapter 6 of Annex I and requires governments to ensure the provision of facilities at oil-loading terminals, repair ports, and other ports where ships have oily residues to discharge, adequate to meet the needs of the ships using them without causing undue delay. Regulation 38 is the demand side; Regulation 13 is the coupling that the demand side and the supply side meet at.

The pairing matters because each regulation would fail without the other. A perfectly standardized flange (Reg.13) leads nowhere if the port has no facility (Reg.38). An adequate facility (Reg.38) can’t receive residue if the ship’s pipe ends in a coupling the facility’s hose can’t grip (Reg.13). The system the MARPOL convention built for oil is a chain: tanks to hold the residue (Reg.12), a standard flange to land it (Reg.13), and a facility ashore to take it (Reg.38), with the record book (Reg.17) proving the chain was used. Break any link and the residue has nowhere lawful to go.

When a ship reports inadequate reception facilities, the standard discharge connection is also the evidence that the ship arrived ready to discharge. A surveyor or facility operator can see that the ship’s line is fitted with the compliant flange; if the residue still couldn’t be landed, the failure points to the facility, not the ship. That’s part of why the connection is standardized rather than left to bilateral agreement: it puts the burden of compatibility on a published table, not on a negotiation at the rail.

The blank flange and the reducer pieces

In service the standard discharge connection spends most of its life closed. When the line isn’t landing residue, the open flange face is sealed with a blank flange (a blind flange): a solid steel disc of the same 215 mm pattern, with the same six bolt slots, bolted on over a gasket so the pipe end can’t weep oily residue onto the deck or, worse, overboard. The blank, its gasket, and the six bolts are a standing item. Keep them with the connection, keep the gasket sound, keep the bolts free. A seized bolt or a perished gasket on the blank is exactly the kind of small neglect that turns into a deficiency at the next inspection.

Many ships also carry reducer or adapter pieces alongside the connection. The standard flange accepts pipes up to 125 mm internal diameter, but a given ship’s discharge line, or a given facility’s hose, may run smaller. A short reducer spool, standard flange on one face and the ship’s pipe size on the other, bridges the gap without compromising the standardized mating face. These spools live in the engine store with the blank flange and the spare gaskets, and a methodical chief engineer logs them so they don’t go missing between port calls. The principle holds throughout: whatever happens inboard of the face, the face that meets the shore stays the Regulation 13 pattern.

Physically, the connection usually lives at or near the engine-room discharge manifold, often grouped with the bilge and sludge pumping arrangement so that a single accessible point lands both the bilge holding tank and the sludge tank. On many ships it’s positioned for hose handling from the main deck, sometimes adjacent to or sharing a deck location with the bunkering and discharge manifold, so the crew works one familiar area for taking fuel aboard and for landing residue ashore. The grouping is practical rather than required: Regulation 13 fixes the flange, not where on the ship it sits, but yards put it where hoses can reach it.

Port State Control and the standard discharge connection

Port State Control officers check the standard discharge connection because it’s one of the few Annex I items that is fully visible, fully standardized, and quick to verify against a published table. The check is concrete: is the connection fitted, is it the correct 215 mm six-slot pattern, is the blank flange present with a sound gasket, are the bolts there and free, and does the arrangement match what the International Oil Pollution Prevention certificate supplement records for sludge and bilge disposal. A connection that’s missing, wrong-pattern, corroded into uselessness, or lacking its blank flange and bolts is a recordable deficiency.

The common findings are practical, not exotic. A blank flange that’s been removed and not refitted, so the open pipe end sits unsealed on deck. A gasket that’s perished or missing, so the blank doesn’t seal. Bolts seized or short, so the connection can’t be made up under the 600 kPa it’s rated for. A non-standard coupling fitted in place of the Regulation 13 flange, often a legacy of a repair or a conversion where someone fitted what was on the shelf. And the mismatch case, where the connection is present but the IOPP supplement, or the Oil Record Book, describes a disposal route that the hardware doesn’t support. Under the regional Paris MOU and Tokyo MOU inspection regimes, MARPOL Annex I deficiencies are among the categories that can escalate, so a flange item that looks trivial can sit inside a wider Annex I finding that draws a closer look at the whole machinery-space oil system.

The connection is also a proxy. An officer who finds the standard discharge connection well maintained, blank flange on, gasket sound, bolts free, reducer spools logged in the store, reads it as a sign that the rest of the oily-residue management is run the same way. A neglected connection invites the opposite inference, and the inspection widens. That signaling value is part of why the connection earns disproportionate attention for a piece of hardware that’s just a flange & six bolts.

Two contrasting cases show how the same connection produces opposite outcomes. On a well-run ship, the officer finds the 215 mm six-slot flange in place at the manifold, the blank flange stowed on a labeled bracket beside it with two spare oil-proof gaskets, the six bolts free and a spare set in the store, & the IOPP supplement item 3.2 ticked for disposal both to a reception facility through the standard connection and to the incinerator. The Oil Record Book shows three sludge landings in the past year with facility receipts filed against each. The connection check takes two minutes & closes clean. On a poorly run ship, the flange is there but the blank is missing, the gasket groove is dry & scored, two of the six bolts are seized, the IOPP supplement names a disposal route the hardware can’t support, & the record book shows no landing in eight months despite a sludge generation rate that should have filled the tanks twice over. Now the connection check has opened a question about where the residue actually went, & the inspection runs much deeper into the Regulation 15 discharge control arrangements & the separator. The hardware is trivial; what it reveals is not.

The same idea in other MARPOL annexes

The standard discharge connection is a pattern MARPOL repeats wherever a ship has to land a waste stream ashore, but the dimensions differ by annex so the connections can’t be cross-mated by accident. The most direct parallel is the sewage connection in MARPOL Annex IV.

Annex IV Regulation 10, also titled “Standard discharge connection,” fixes the flange for discharging sewage from a ship’s holding or treatment system to a reception facility. Its dimensions are deliberately smaller and use a different bolt count, so a sewage hose can’t bolt onto an oil-residue line:

The six-versus-four bolt count is the safeguard. A four-bolt sewage hose physically can’t make up to a six-slot oil flange, and the bolt circles differ (183 mm against 170 mm), so the patterns won’t align even if someone tried. The Annex IV connection carries one extra provision the oil flange doesn’t: for ships of 5 m moulded depth or less, the inner diameter of the discharge connection may be 38 mm, a concession for small craft whose sewage lines are narrow. Both flanges share the same 6 kg/cm2 rated pressure and the same steel-flat-face-with-gasket construction, so the family resemblance is clear while the cross-connection is blocked by design.

MARPOL Annex VI, which governs air pollution from ships (sulphur oxides, nitrogen oxides, particulate matter, and the energy-efficiency regime), has no equivalent discharge flange. Annex VI controls gaseous emissions to the atmosphere, not liquid waste streams landed to a reception facility, so there’s no pipe-to-shore connection for it to standardize. The contrast is worth stating because the question “what’s the Annex VI standard discharge connection” comes up, and the answer is that there isn’t one: the standard discharge connection is a tool for liquid-residue annexes (oil under Annex I, sewage under Annex IV), not for the air annex. Garbage under Annex V is handled by transfer rather than a piped flange, so it too has no dimensioned discharge connection of this kind.

This article covers only the Annex I connection in detail. The sewage flange has its own dimensions, its own size concession, and its own inspection regime under Annex IV, and the full treatment belongs there rather than duplicated here. What’s worth carrying across is the design principle: MARPOL standardizes each ship-to-shore connection, then makes the standards mutually incompatible so the right hose only fits the right line.

How the connection fits the machinery-space oil system

Step back and the standard discharge connection is one terminal of a closed oil-handling system that Annex I builds into every ship’s machinery space. The bilge wells collect oily water; the bilge separator and its 15 ppm oil filtering equipment clean what can be cleaned for discharge under the Regulation 15 discharge criteria; the oil residue (sludge) tanks of Regulation 12 hold what can’t be cleaned; the designated sludge pump moves that residue; and the residue leaves the ship either to the incinerator or through the Regulation 13 standard discharge connection to a Regulation 38 reception facility. The connection is the gate at the shoreside end of that system.

The system is auditable end to end because of the connection. The quantity of residue generated is estimated against the ship’s fuel consumption and separator performance; the quantity held is read from the sludge tank gauges; the quantity landed is taken from the reception facility receipt and entered in the Oil Record Book Part I; and the connection through which it was landed is the standard one PSC can verify by eye. When those quantities reconcile, the inspection moves on. When they don’t, the standard discharge connection is the physical point where the paper trail meets the pipe, and the discrepancy gets investigated.

There’s no formula to compute for the connection itself, because it’s a fixed-dimension fitting, not a calculation. The numbers that surround it (sludge generation rates, tank capacity, discharge limits) belong to Regulation 12 & Regulation 15. The connection’s job is binary: it either mates with the shore hose and seals at 600 kPa, or it doesn’t. That binary nature is exactly why it’s a favorite inspection item: there’s no judgment call, only a flange that’s right or wrong against a published table.

The gasket and the pressure rating

The one consumable in the connection is the gasket, and the regulation is specific about it: the flange together with a gasket of oil-proof material has to be suitable for a service pressure of 6 kg/cm2, about 600 kPa. “Oil-proof” rules out a gasket that the residue would attack and soften; the gasket has to resist the oily, sometimes warm, sometimes chemically loaded residue it seals against without swelling, dissolving, or extruding under the bolt load. A perished or wrong-material gasket is the failure mode that turns a sound flange into a leaking one, which is why spare oil-proof gaskets sit in the engine store alongside the blank flange and the reducer spools.

The 600 kPa figure sets the working envelope. The ship’s sludge pump and the facility’s receiving system both operate below it, so the connection is never the weak point in a properly run transfer. But the rating also defines the test: a connection that can’t hold 600 kPa, because of a tired gasket, a warped face, or slack bolts, isn’t compliant even if it looks intact. The pressure number is the line between a connection that works and one that’s a flange-shaped ornament. Quoting “6 kilograms per square centimeter” or “about 6 bar” is the right answer when an examiner or a surveyor asks for the rated pressure of the standard discharge connection.

Where the regulation number came from

The “13” in Regulation 13 is a product of the 2004 revision. The original 1973 MARPOL Annex I, as modified by the 1978 Protocol, carried the standard discharge connection at Regulation 19. When the IMO Marine Environment Protection Committee adopted the comprehensively revised Annex I by resolution MEPC.117(52) on 15 October 2004, the whole annex was reorganized into chapters and the regulations were renumbered. The standard discharge connection moved from old Regulation 19 to new Regulation 13, and the revised annex entered force on 1 January 2007. The flange dimensions themselves carried over unchanged; only the number on the regulation moved.

This renumbering trips people up because older textbooks, older surveyor notes, and older ship’s documentation still cite “Regulation 19” for the standard discharge connection. A 2003 reference and a 2008 reference can describe the identical 215 mm flange under two different regulation numbers, and both are correct for their date. The safe practice is to cite the connection by its title, “standard discharge connection,” and the current number, Regulation 13, while recognizing that pre-2007 material calls it Regulation 19. The same revision renumbered the sludge-tank rule to Regulation 12 and kept reception facilities at Regulation 38, which is why those three numbers travel together in current practice.

Knowing the lineage matters for a surveyor reading an older ship’s file. A vessel built in 2005 may carry build documentation referencing the old numbering even though it’s surveyed today against the new. The connection on the ship is the same physical object; the paperwork around it spans the renumbering. When the IOPP supplement, the build drawings, and the survey report cite different regulation numbers for the same flange, the renumbering is usually the reason, not an error.

Landing residue ashore: the operation

The connection earns its keep at the moment of disposal, so it’s worth following the operation through. A ship that needs to land sludge or bilge water arranges a reception facility through the agent before or on arrival, often a road tanker, a barge, or a fixed shore line depending on the port. The crew rigs the ship’s discharge line to the standard discharge connection, removes the blank flange, and the facility’s operator presents a hose that ends in the matching Regulation 13 flange. The two flanges bolt together over an oil-proof gasket with the six 20 mm bolts, and because the slots are open to the rim, the facility hose is offered up and the bolts slid into the slots rather than threaded through closed holes.

With the connection made up, the ship’s designated sludge pump (the pump Regulation 12 requires for disposal) drives the residue through the 125 mm-or-smaller line, across the flange, and into the facility. The connection is rated for 600 kPa, so the pump’s discharge pressure stays within the flange and gasket’s working envelope. When the transfer finishes, the line is drained, the connection broken, the gasket inspected, and the blank flange refitted with its own gasket and bolts so the open end is sealed again before the ship sails. The whole sequence is mundane, which is the point: a standardized connection turns what could be a bespoke engineering problem into a routine deck and engine-room job.

The transfer is then recorded. The quantity landed, the date, the port, and the reception-facility receipt number go into the Oil Record Book Part I under the relevant operation code, and the facility’s signed receipt is retained as the documentary proof. That receipt is what a Port State Control officer or a subsequent surveyor checks the record book against. The standard discharge connection is the physical event; the record book entry and the receipt are its paper shadow, and the two have to agree.

The bunkering and discharge manifold context

On most ships the standard discharge connection isn’t a lonely fitting tucked in a corner of the engine room. It’s part of the deck-level cluster where the ship transfers liquids to and from shore. The bunkering manifold, where fuel oil comes aboard, sits at the same general deck location on many vessels, and the engine-room residue discharge is often grouped nearby so the crew works one familiar transfer station for both taking fuel and landing residue. This grouping is operational convenience, not a regulatory requirement: Regulation 13 fixes the flange and says nothing about where on the ship it must live.

The proximity has a practical logic. Both bunkering and residue landing involve hoses handled from the main deck, both need a clear area for the shore connection, both want a drip tray or save-all under the connection to catch leaks, and both are oil transfers that the deck and engine departments crew together. Putting the residue connection near the bunker manifold means one well-lit, well-drained, accessible part of the deck serves both, and the crew that handles bunkers also handles the sludge hose with the same gear and the same procedures.

There’s a safety dimension too. A save-all or coaming around the connection contains a spill if a flange weeps or a hose fails, and scuppers in the area can be plugged during the transfer so any escape stays on deck rather than going overboard. These are operational measures the ship’s safety management system and the port’s regulations impose around the connection, not parts of Regulation 13 itself, but they’re where the standardized flange meets the practical business of moving oily liquids across a ship’s rail without polluting the harbor. The connection is the coupling; the manifold area is the workplace built around it.

Limitations

This article describes the standard discharge connection as defined in the revised MARPOL Annex I (resolution MEPC.117(52), in force 1 January 2007) as further amended through the oil-residue packages in force 1 January 2011 (resolution MEPC.187(59)) and 1 January 2017 (resolution MEPC.266(68)), which between them revised the Regulation 12 sludge-tank and disposal-piping requirements that Regulation 13 serves. MARPOL is amended on a rolling schedule, so a reader fitting out, surveying, or inspecting a ship should confirm the current consolidated Annex I text and the latest IACS unified interpretations rather than relying on a secondary summary. The dimension table reproduced here has not changed since 2007, but the surrounding Regulation 12 and Regulation 38 text has, and the relationships between them are the part most likely to be refined by future amendment.

The flange dimensions given are the MARPOL standard values, verified against the US federal implementation at 33 CFR 155.430, which transcribes the MARPOL table without alteration. National implementations are intended to mirror the MARPOL standard exactly, and a compliant connection should mate regardless of flag, but a builder or repairer should work from the flag administration’s adopted text and the classification society’s drawings for the specific ship, not from this article, when manufacturing or replacing the connection. Tolerances, material grades, and gasket specifications beyond “steel or equivalent, flat face, oil-proof gasket, 6 kg/cm2” are matters for the class rules and the relevant standards, not for the regulation, which deliberately fixes only the mating dimensions.

Port State Control practice varies by regime and by officer. The deficiency types described here are the common ones, drawn from the way the connection is inspected under the regional memoranda of understanding, but the categorization of any specific finding, and whether it escalates, is a matter for the inspecting authority under its own procedures. This article explains why the connection is inspected and what is commonly found; it is not a substitute for the inspection guidelines of the relevant MOU or flag administration. Nothing here is legal advice, and the operative requirement is always the regulation as adopted by the flag state and applied by the port state, not any summary of it.

See also

• MARPOL Annex I: the full structure of the oil annex, chapter by chapter
• MARPOL Convention: the parent instrument and its six annexes
• Regulation 12: oil residue (sludge) tanks: the tanks and disposal route the standard connection serves
• Regulation 38: reception facilities: the shore-side obligation the connection bolts onto
• Regulation 14: oil filtering (15 ppm) equipment: the bilge-water side of the machinery-space oil system
• Regulation 15: discharge control: the criteria for what may be discharged at sea rather than landed ashore
• Oil Record Book, Part I: where the disposal through the connection is logged
• Port State Control: how the connection is inspected and what deficiencies arise
• MARPOL Annex IV: the sewage annex, whose Regulation 10 defines the parallel sewage flange