Two people can describe the same item four different ways. A vessel writes “packing rope”, the purchaser writes “gland packing”, the supplier’s catalogue says “PTFE braided packing”, and the warehouse label says something else again. Every one of those is defensible, and none of them is precise enough to buy from with confidence.
That ambiguity is what product coding exists to remove. Used properly, an IMPA code turns a description into a reference both sides can check. Used carelessly, it creates a different problem: a confident-looking number attached to the wrong item.
What an IMPA code actually is
An IMPA code is a six-digit product reference from the IMPA Marine Stores Guide, published by the International Marine Purchasing Association. The Guide carries roughly 50,000 codes covering deck, engine, cabin, safety and provisions items, and it is now in its 8th edition. The six-digit format has been in consistent use for close to forty years, which is why it has become the default reference in marine purchasing.
The code’s value is that it survives translation. A chief engineer, a purchasing office and a supplier in three different countries can each read the same six digits and arrive at the same item, without depending on a shared vocabulary or a shared first language.
IMPA and ISSA are not the same system
This is the single most common misunderstanding we see on incoming requisitions. IMPA and ISSA are separate product reference systems, maintained by separate organisations, and their numbers are not interchangeable. An ISSA number is not an IMPA number with a different prefix, and mapping one to the other is not a find-and-replace exercise.
In practice this matters when a requisition mixes the two without labelling which is which. A six-digit figure quoted as “the code” is ambiguous unless the system is named. If your purchasing system holds both, say which one you are sending.
MARSEA catalogues stores to IMPA and ISSA item codes, so we can work from either — provided we know which one we have been given.
A code on its own is not a specification
A code identifies what the item is. It does not always carry the detail that determines whether the item is fit for your vessel. Before a line can be quoted reliably, it usually also needs:
- ■ Unit — piece, pack, set, metre or roll. The same code quoted per piece and per pack produces very different numbers.
- ■ Size or dimension — diameter, length, thread, capacity.
- ■ Material or grade — stainless versus galvanised, JIS versus DIN.
- ■ Approval or certification where the item is safety-related.
- ■ Brand constraint, where a maker’s part is genuinely required rather than preferred.
Five things that stall a quotation
These are the recurring reasons a requisition comes back with questions instead of prices:
- ■ An incomplete or mistyped number. Five digits, or a transposed pair. Always worth confirming all six.
- ■ The description does not match the code. When these disagree, the right move is to stop and ask — not to assume the code wins. Either could be the error.
- ■ The unit is missing or different. The most common cause of a quotation that looks wrong on price.
- ■ A stale internal mapping. A code saved against a part years ago and never revalidated against the current Guide.
- ■ A code with no specification behind it. Fine for a commodity item, risky for anything with a size, grade or approval.
What a well-formed requisition line looks like
A line that can be quoted without a round trip usually carries five things: the code and which system it belongs to, the description in words, the specification, the unit, and the quantity. For example:
IMPA 232101 — Gland packing, PTFE braided, 10 mm — 5 kg — Qty 2. Equivalent acceptable if branded item unavailable.
The last clause matters as much as the code. Telling a supplier in advance whether a substitution is acceptable is what prevents a vessel sailing without the item while someone waits for an answer.
How MARSEA handles coded requisitions
When a requisition reaches our desk, the code and the written description are checked against each other before anything is sourced. Where they disagree, we come back with the question rather than quoting the code and hoping. Where the exact specification is not available, the substitution is stated explicitly on the quotation, with the offered description alongside the requested one — so the decision stays with the vessel rather than being made quietly on its behalf.
Stores are catalogued to IMPA and ISSA item codes and handled under our ISO 9001:2015 quality system, so what arrives alongside can be checked line by line against what was ordered.
If you are preparing a requisition for a vessel calling at an Indian, Sri Lankan or U.A.E. port, send it with the port and ETA and our duty desk will confirm what can be sourced against the call.