IMPA Codes Explained for Ship Supply and Purchasing
An IMPA code is a six-digit number that identifies one specific marine store item. It is published in the IMPA Marine Stores Guide and used by vessels, purchasing departments and suppliers as a shared reference on requisitions, quotations and delivery notes.
If you handle ship supply orders, you read these codes every day. This page explains how they are built, what they cover, and where they stop being enough.
What an IMPA code is
IMPA stands for the International Marine Purchasing Association. The association publishes the Marine Stores Guide, usually shortened to MSG, which assigns a unique six-digit code to each item a vessel is likely to order.
The system has been in place for around forty years and the codes have stayed stable across editions. The eighth edition holds more than 50,000 codes, with over 6,000 added compared with the previous one. The digital version is refreshed every six months and can be imported into purchasing systems.
The purpose is narrow and practical. A vessel with a Filipino crew, a purchasing office in Hamburg and a supplier in Marseille need to agree on which item is being ordered. A written description leaves room for interpretation. A code does not.
How the six digits are built
The code reads as three pairs.
| Position | What it identifies |
|---|---|
| Digits 1 and 2 | The section, meaning the broad product family |
| Digits 3 and 4 | The sub-group inside that section |
| Digits 5 and 6 | The individual item and its variant |
Once you know the sections you order from most, you can tell which product family a code belongs to before reading the description. Purchasing teams who work with the same vessel types build that reflex quickly.
PREUVE À FOURNIR PAR LE CLIENT. Insérer ici un tableau des trois à cinq sections IMPA les plus fréquentes dans les commandes reçues par Shore to Sea, avec numéro et intitulé, plus une ligne sur le type de navire concerné.
What the Marine Stores Guide covers
The MSG spans the full range of what a vessel consumes and replaces. Deck and engine stores, cleaning materials, safety and protective equipment, galley and catering items, stationery, hardware, ropes and rigging, paint and painting equipment, medical supplies, electrical items.
Provisions sit slightly differently. Fresh food, frozen goods and dry stores are ordered against specifications, quantities and quality grades more than against a catalogue reference. In practice a single order often mixes both logics, coded technical items on one side and a provisions list on the other. Handling the two together in a single delivery window is the daily work of a ship chandler.
IMPA and ISSA side by side
ISSA, the International Ship Suppliers and Services Association, maintains a parallel coding system that does the same job. Some vessels and some purchasing departments quote ISSA references instead of IMPA ones.
Neither system replaces the other. IMPA is the more widely used reference for general stores across commercial shipping. ISSA remains in circulation and appears regularly in requisitions from certain operators. Most suppliers keep a cross-reference so that an order arriving in one system can be quoted in the other without going back to the vessel.
What a code does not tell you
This is where orders go wrong.
A code identifies an item. It does not carry the specification in full, and it does not carry the context of the order. Before quoting, four things still need checking.
- The unit. A code for a rope tells you the product. It does not tell you whether the vessel wants one metre, one coil or one drum.
- The specification. Sizes, grades, materials and certifications sit in the description, not in the number.
- The vessel requirement. Class approvals, flag state requirements and owner standards override the catalogue.
- The edition. A code from an older edition may point to an item that has since been split, renamed or superseded.
The safe method is to read the code and the written description together, then confirm anything ambiguous with the vessel before the quotation goes out. A code that is quoted without being checked against its catalogue entry is the most common cause of a wrong item arriving at the quay.
How codes are used on a real order
A requisition arrives with sixty lines, most of them coded, some described in free text. The supplier's job breaks down into four steps.
- Match. Each code is looked up in the current catalogue and compared with the written description. Any gap between the two is flagged.
- Source. Coded items are checked against available stock. What is not held is sourced, with a lead time attached to each line.
- Substitute. Where an exact match is not available in the delivery window, an equivalent is proposed with its own code and its specification, in writing. Substitutions are never made silently.
- Confirm. The quotation goes back with codes, descriptions, units, quantities and lead times, so the vessel can check line by line.
For technical items and spare parts, the sourcing step is the one that determines whether the order fits the call. That is also where the difference between a supplier with a coded catalogue and a supplier with real stock becomes visible. When the window is short, the sequence has to run in hours rather than days, which is the constraint behind express port delivery.
Frequently asked questions
What does IMPA stand for?
International Marine Purchasing Association. The association publishes the Marine Stores Guide, the catalogue in which the codes are defined.
How many digits does an IMPA code have?
Six. The first pair identifies the section, the second the sub-group, the third the individual item.
Where can I look up an IMPA code?
In the Marine Stores Guide, in print or digital form. A free online search of the catalogue is also available through ShipServ. Purchasing systems that hold an IMPA licence can import the digital catalogue directly.
Are IMPA codes mandatory?
No. They are an industry standard, not a regulation. They are used because they remove ambiguity, not because a rule requires them.
Can I send an order without codes?
Yes. Descriptions, specifications and part numbers work, and provisions orders are usually placed that way. Codes shorten the quoting cycle and reduce the number of clarification exchanges, which matters most when the delivery window is short.
What is the difference between IMPA and ISSA codes?
Both identify marine stores items with a standardised reference. IMPA is the more widely used across commercial shipping. ISSA is maintained by the International Ship Suppliers and Services Association and still appears in requisitions from some operators. Suppliers generally cross-reference the two.
Signature à insérer. Jérôme Delfieu, Sales Director, Shore to Sea.