What is an IMPA number? A working guide for ship-stores teams

If you work in ship stores for more than a few weeks, you’ll see “IMPA code” on nearly every purchase order that crosses your desk. It’s treated as obvious shorthand, but it’s worth being precise about what it is, where it comes from, and — just as important — how inconsistently it actually shows up in real correspondence.

Where the code comes from

IMPA stands for the International Marine Purchasing Association. It maintains a marine stores guide — a standardized catalog of ship stores items, each with a numeric code, grouped by category: deck stores, engine stores, cabin stores, provisions, safety equipment, and more. The idea is straightforward: instead of describing “a 20-liter drum of hydraulic oil, grade X” in free text every time, a vessel or agent can reference a single code that both sides understand the same way, regardless of language or local naming conventions.

ISSA (International Ship Suppliers & Services Association) maintains a comparable catalog, and you’ll see ISSA codes used interchangeably with IMPA codes in some regions and by some suppliers. For a chandler, the practical distinction rarely matters day to day — what matters is that both are structured references to a known catalog, not a free-text description.

What it looks like on a real order

In theory, every line on a PO carries a clean IMPA code next to a quantity. In practice, that’s the exception more than the rule. A real order from an agent or a vessel might include:

• A correct IMPA code with a matching description
• A code with no description, or a description with no code
• A product name copied from a previous order, with the code long gone
• A photograph of a handwritten list, sent over WhatsApp

Whoever processes the order has to reconcile whatever version arrives against what the chandlery actually stocks — which is exactly the step that eats time when it’s done by hand, line by line, order after order.

Why this matters for how POs get processed

The gap between “how IMPA codes are supposed to work” and “how they actually show up in an inbox” is exactly the problem worth solving in software, not process discipline — you can’t train every agent worldwide to format orders consistently. What you can do is read the order as it actually arrives and extract the line items, whether or not a clean code is present. That’s the approach we cover in more detail in software for ship chandlers, which walks a purchase order through extraction end to end.

If your team is already deciding between a lighter, inbox-based approach and a full ERP rollout, it’s also worth reading how that trade-off plays out against a Dynamics-based system in our ShipCentric comparison.