Marine Stores Guide (MSG) and IMPA Codes: How to Specify Goods Without Ambiguity
In ship supply, unclear item descriptions create delays, wrong deliveries, price disputes and unnecessary back-and-forth between buyers, suppliers and vessel teams. A request such as “cleaning brush,” “safety gloves” or “pump gasket” may look simple, but without a standard reference it can mean different products to different suppliers.
This is why the Marine Stores Guide (MSG), IMPA codes, ISSA references and structured item descriptions are important in marine procurement. They help buyers specify goods clearly, reduce RFQ ambiguity and improve quotation accuracy.
For buyers, vessel storekeepers and junior procurement staff, learning how to use IMPA and MSG references is one of the fastest ways to improve purchasing quality. A clear specification helps suppliers quote the correct product, helps procurement teams compare offers fairly and helps vessels receive what they actually requested.
AVS Global Ship Supply & Catering supports ship managers, vessel operators and procurement teams with global ship supply, provisions, technical stores, bonded stores and coordinated vessel supply solutions across international ports.
For marine procurement and vessel supply requests, use Quick Quote.
What the Marine Stores Guide Is
The Marine Stores Guide, often called MSG, is a widely used reference catalogue for marine stores and ship supply items. It helps buyers, suppliers and vessel teams identify products through standardized item references and descriptions.
In practice, the MSG is used to reduce uncertainty in purchasing. Instead of relying only on a free-text item description, buyers can refer to a structured catalogue item and code. This helps suppliers understand the exact product category, item type and expected specification.
The Marine Stores Guide is especially useful for:
- Deck stores
- Engine stores
- Cabin stores
- Safety items
- Tools and consumables
- Cleaning items
- Electrical materials
- Galley and hotel items
- General ship supply items
The guide is not a replacement for technical judgment. A code helps identify an item, but buyers should still include size, material, maker preference, standard, certificate requirement, quantity, unit of measure and delivery conditions where relevant.
For a broader overview of IMPA, see What Is IMPA?.
Why MSG Matters in RFQs
A good RFQ must be clear enough for suppliers to quote without guessing. MSG and IMPA code references help with this because they give both sides a shared starting point.
A clear RFQ may include:
- IMPA code
- Item name
- Full description
- Size or dimensions
- Material
- Unit of measure
- Quantity
- Brand or maker preference if required
- Certificate requirement
- Substitution rules
- Delivery port and deadline
When these details are missing, suppliers may quote different products under the same item description. This makes price comparison unreliable.
IMPA Code Structure: Section, Sub-Section and Item
An IMPA code is a standardized product reference used in marine purchasing and ship supply. It allows buyers and suppliers to identify common vessel supply items more consistently.
An IMPA code generally connects to a structured catalogue hierarchy. The code helps identify the relevant section, sub-section and item. This structure makes product search, RFQ preparation and supplier comparison easier.
How Buyers Use IMPA Codes
Marine buyers commonly use IMPA codes to:
- Search for the correct product reference
- Build RFQs
- Standardize vessel requisitions
- Compare supplier quotations
- Reduce wrong-item delivery
- Support ERP or procurement system item mapping
- Improve purchase order clarity
- Communicate with ship suppliers internationally
For example, if a vessel requests a general product description without a code, procurement may need several clarification rounds. If the vessel includes the correct IMPA code and technical details, the supplier can quote faster and more accurately.
IMPA Codes Are Helpful, But Not Always Enough
An IMPA code alone may not fully define every requirement. Some items still require additional details.
For example:
- Gloves may require material, size and standard.
- Ropes may require diameter, length, construction and breaking strength.
- Chemicals may require Safety Data Sheet and product compatibility.
- Electrical parts may require voltage, model and maker reference.
- Tools may require size, grade or certification.
- Technical spares may require part number and serial number.
The best practice is to use the IMPA code as a structured reference, then add the operational details needed to avoid ambiguity.
ISSA Code System and When It's Preferred
The ISSA Ship Stores Catalogue is another reference used in the ship supply industry. ISSA is the International Shipsuppliers & Services Association, and its catalogue is used by many suppliers and procurement teams to identify ship stores and supply categories.
In some markets or supplier networks, ISSA references may be preferred or used alongside IMPA codes. The choice often depends on supplier practice, company procurement systems, regional habits and the type of goods requested.
IMPA vs ISSA in Practical Procurement
In daily marine procurement, buyers may see both IMPA and ISSA references. The most important point is not which one appears first, but whether the item is specified clearly.
A practical RFQ can include:
- IMPA code where available
- ISSA code where available
- Item description
- Maker or brand preference
- Technical specification
- Quantity and unit
- Delivery requirement
- Certificate requirement
- Photos or drawings if needed
If a supplier works more comfortably with ISSA references, the buyer can still keep internal IMPA mapping for reporting and item standardization.
When ISSA References May Be Useful
ISSA references may be useful when:
- The supplier uses ISSA catalogue structures.
- The buyer is working with an ISSA-listed or ISSA-oriented ship supplier.
- The requested product is easier to identify through ISSA references.
- The procurement system supports both IMPA and ISSA mapping.
- A vessel sends an item list with mixed catalogue references.
A flexible procurement team can work with both systems while keeping internal item descriptions consistent.
For more context on ship supplier associations, see ShipServ.
Mapping Vessel Item Lists to IMPA Codes
Vessel requisitions often arrive with mixed descriptions. Some items include IMPA codes, some include maker references, some include crew-written descriptions and some include only photos or rough wording.
Mapping these requests to IMPA codes helps standardize procurement.
Typical Vessel Item List Problems
Common issues include:
- Generic descriptions
- Missing dimensions
- Wrong unit of measure
- Old item names
- Local terminology
- Missing part numbers
- Duplicate item lines
- Unclear material requirements
- Brand names used as generic terms
- Photos without product data
These problems slow down RFQ preparation and create supplier confusion.
Practical Mapping Process
A buyer can map vessel item lists to IMPA codes through a simple process:
- Review the vessel description.
- Check whether an IMPA code is already listed.
- Search the item in the Marine Stores Guide or IMPA code search tool.
- Match the item category and description.
- Add size, material, standard and quantity.
- Ask the vessel for clarification if the item remains unclear.
- Add photos, drawings or maker references where needed.
- Confirm whether substitutes are allowed.
- Update the procurement system item master.
This process helps reduce future ambiguity because the same item can be ordered again with a cleaner reference.
Item Master Discipline
For ship managers, mapping is not only a one-time task. Procurement teams should maintain item master discipline.
A clean item master should include:
- Internal item name
- IMPA code
- ISSA code if used
- Standard description
- Preferred unit of measure
- Category
- Certificate requirement
- Approved substitutes
- Common supplier references
- Notes for vessel or buyer
This creates more consistent purchasing across vessels and ports.
Using IMPA Codes in RFQs and POs
IMPA codes are most useful when they are included in both RFQs and purchase orders. The RFQ helps suppliers quote correctly. The PO confirms exactly what was ordered.
How to Use IMPA Codes in RFQs
A strong RFQ line should include more than a code.
Example RFQ structure:
- IMPA code
- Item description
- Quantity
- Unit of measure
- Size or specification
- Brand or maker if required
- Certificate requirement
- Delivery port
- Delivery deadline
- Substitute allowed or not allowed
This helps suppliers avoid assumptions and reduces the risk of quoting a similar but incorrect item.
How to Use IMPA Codes in POs
The purchase order should repeat the final agreed specification. If the supplier quoted an equivalent product, the PO should state whether the substitute is approved.
A clear PO may include:
- IMPA code
- Final item description
- Supplier item reference
- Approved substitute note
- Quantity and unit
- Unit price and total price
- Delivery location
- Required documents
- Packing or labeling instruction
- Contact details for delivery coordination
The goal is to make the PO clear enough that warehouse, logistics, agent and vessel teams all understand what should be delivered.
Using Codes in ERP Systems
Many ERP or procurement platforms can store catalogue codes in item master data. This allows buyers to search, compare, report and reorder more easily.
Useful ERP fields may include:
- IMPA code
- ISSA code
- Internal item code
- Item category
- Standard description
- Preferred supplier
- UOM
- Certificate requirement
- Last purchase price
- Approved substitutes
- Vessel-specific notes
If the ERP does not have a dedicated IMPA field, the code can still be stored in a reference, catalogue or description field depending on the system design.
Common Ambiguity Issues and Fixes
Even when IMPA codes are used, ambiguity can still occur. The solution is to combine codes with practical item details.
Issue 1: Generic Item Description
Problem:
A vessel requests “gloves” or “brush.”
Fix:
Add IMPA code, material, size, usage, standard and quantity. For gloves, specify whether they are chemical-resistant, heat-resistant, cut-resistant or general work gloves.
Issue 2: Wrong or Missing Unit of Measure
Problem:
The buyer requests “1” without specifying whether it means piece, box, pair, roll, drum or set.
Fix:
Always confirm UOM. This is especially important for ropes, tapes, gloves, chemicals, fasteners and consumables.
Issue 3: Similar Items With Different Technical Use
Problem:
Two products look similar but are used for different applications.
Fix:
Add application, operating condition, material and certificate requirement. For technical products, confirm maker reference or part number.
Issue 4: Brand Name Used as Generic Description
Problem:
The vessel writes a brand name, but the buyer does not know whether equivalent products are acceptable.
Fix:
Ask whether the brand is mandatory or whether an equivalent is acceptable. Add “no substitute” or “equivalent accepted subject to approval” in the RFQ.
Issue 5: No IMPA Code Exists
Problem:
Some specialized items, OEM spare parts or new product categories may not have a suitable IMPA code.
Fix:
Use the best available description and include maker, part number, drawing, photo, specification sheet or previous purchase reference. If useful, map the item to an internal code.
Issue 6: Old Codes or Outdated Descriptions
Problem:
Older vessel lists may include outdated catalogue references or descriptions.
Fix:
Validate the item against the latest available catalogue or supplier reference and update the item master after confirmation.
Issue 7: Missing Compliance Documents
Problem:
The item is correctly identified, but certificate, SDS or test report requirements are not stated.
Fix:
Add document requirements directly into the RFQ and PO. For chemicals, ask for Safety Data Sheet before delivery. For technical or safety-critical items, request certificates where needed.
How AVS Supports Clear Marine Procurement Specifications
AVS supports buyers, vessel storekeepers and procurement teams by helping clarify item requirements, coordinate with suppliers and organize ship supply requests across multiple categories.
AVS can support:
- IMPA-based RFQ preparation
- Vessel item clarification
- Provisions supply
- Technical stores
- Bonded stores
- Marine chemicals
- Multi-port supply coordination
- Supplier communication
- Delivery planning
- Documentation support
Clear specifications reduce delays and improve the chance of correct delivery. Whether the request includes IMPA codes, ISSA references, photos, vessel descriptions or previous purchase data, the key is to turn unclear requirements into a quotation-ready supply request.
For vessel supply requests, use Quick Quote.
Conclusion: Codes Reduce Ambiguity, but Details Complete the Specification
The Marine Stores Guide, IMPA codes and ISSA references are valuable tools for marine procurement. They help buyers and suppliers speak a common language and reduce uncertainty in RFQs and POs.
However, codes alone are not always enough. A strong specification includes the right code plus size, material, quantity, UOM, certificate requirement, maker preference and delivery instructions.
For buyers, vessel storekeepers and junior procurement staff, the best habit is simple: use catalogue codes where available, but never rely on the code alone when the item has technical, safety or compliance implications.
AVS Global Ship Supply & Catering supports marine procurement teams with global ship supply, provisions, technical stores, bonded stores, marine chemicals and coordinated vessel supply across international ports.
FAQ
What is the IMPA Marine Stores Guide?
The IMPA Marine Stores Guide is a marine purchasing reference catalogue used to identify and specify common ship supply items through standardized codes, categories and descriptions.
How is an IMPA code structured?
An IMPA code is linked to a catalogue hierarchy that helps identify the relevant product section, sub-section and item. This structure allows buyers and suppliers to search, compare and specify marine stores more consistently.
Is IMPA or ISSA more widely used?
Both IMPA and ISSA references are used in the ship supply market. IMPA codes are very common in marine procurement, while ISSA catalogue references may also be used depending on supplier practice, region and company systems.
Where can I search IMPA codes online?
IMPA codes can be searched through official or licensed MSG resources and online catalogue tools such as IMPA Code Search by ShipServ. Buyers should make sure they use reliable and up-to-date references.
Can I use IMPA codes in any ERP?
Most ERP or procurement systems can store IMPA codes if the item master has a field for catalogue code, reference code or item description. Some systems may need configuration or data licence integration.
What happens if no IMPA code exists for an item?
If no IMPA code exists, the buyer should use a clear technical description, maker reference, part number, drawing, photo, datasheet or previous purchase reference. The item can also be mapped to an internal code.
Are IMPA codes mandatory for ship supply?
IMPA codes are not universally mandatory, but they are widely used because they reduce ambiguity and make RFQs, POs and supplier quotations clearer.
How often is the Marine Stores Guide updated?
The Marine Stores Guide is updated periodically. Buyers using licensed data or online services should check current IMPA or MSG resources for the latest update information.
What is the role of ShipServ in IMPA usage?
ShipServ provides an online IMPA catalogue search experience that helps buyers and suppliers look up IMPA items and codes more easily. It supports clearer product identification in marine procurement.
Does AVS quote from IMPA codes?
AVS can work with IMPA codes, ISSA references, vessel item descriptions, photos and technical details when preparing ship supply quotations. Clear item data helps AVS respond faster and reduce ambiguity.
How does IMPA help reduce RFQ ambiguity?
IMPA codes give buyers and suppliers a shared catalogue reference. When combined with size, material, quantity, UOM and document requirements, they reduce wrong-item quotations and improve comparison between suppliers.
What is the cost of an IMPA Marine Stores Guide license?
The cost may vary depending on the product type, licence model, user needs and current IMPA/MSG pricing. Buyers should check the official Marine Stores Guide or IMPA channels for the latest licence information.
