Guide

The Complete Guide to NMQ Classification for Spare Parts

NMQ (Noun-Modifier-Qualifier) is the industry standard taxonomy for classifying industrial spare parts. It transforms inconsistent, free-text parts descriptions into a structured, searchable format that reduces duplicate purchases, speeds up part searches, and gives maintenance teams confidence that they are ordering the right part.

This guide explains how NMQ works, why it matters, and how it compares to other classification systems like UNSPSC and eCl@ss.

What is NMQ Classification?

NMQ stands for Noun-Modifier-Qualifier — a three-level hierarchy for describing any spare part or industrial material:

Noun

What is it? The primary part type.

VALVE

Modifier

What kind? The subtype.

BALL

Qualifier

Any further refinement.

FLOATING

A ball valve becomes VALVE > BALL > FLOATING. A circuit breaker becomes BREAKER > CIRCUIT. A hydraulic hose becomes HOSE > HYDRAULIC.

The system is deliberately simple. Maintenance technicians, procurement teams, and warehouse staff can all understand "VALVE BALL" without needing to decode a numeric classification code.

The NMQ Dictionary

Behind the classification sits a reference dictionary — a curated database of valid Noun-Modifier-Qualifier combinations, each with:

A plain English definition explaining exactly what the combination means
A short code for system use (e.g., VLV_BALL)
Usage statistics showing how commonly each combination appears across industry
Attributes — the engineering characteristics relevant to that part type (size, pressure rating, material, connection type, etc.)

1,828

Active classifications

926

Unique part types

20,500+

Defined attributes

Why NMQ Classification Matters

Duplicate parts cost money

Without consistent classification, the same part gets entered multiple times under different descriptions. Your ERP treats them as separate items — separate stock lines, reorder points, and safety stock.

Search actually works

NMQ ensures that searching for "VALVE BALL" returns every ball valve in the system — regardless of how the original data was entered. No more missed results or buried records.

Procurement gets smarter

When every part is classified, you can analyse spend by category. How much on bearings vs seals? Which valve types hold the highest inventory value? NMQ makes these questions answerable.

The same part, five different ways

Without NMQ — 5 separate records

BRG BALL 6205 (abbreviated)

Ball bearing 6205-2RS (mixed case)

BEARING,BALL,6205-2RS (comma-separated)

SKF 6205-2RS bearing (manufacturer first)

6205-2RS (part number only)

With NMQ — 1 classified record

Noun: BEARING

Modifier: BALL

Code: BRG_BALL

Description: BEARING BALL 6205-2RS

Manufacturer: SKF

All 5 records identified as duplicates and merged

How NMQ Classification Works — Real Examples

Real classifications from the NMQ dictionary, showing how the Noun-Modifier structure describes parts precisely. Each has an engineering definition — no ambiguity about what falls into each category.

Noun	Modifier	Code	Definition
VALVE	BALL	VLV_BALL	A non-lubricated valve designed to provide straight-through flow by controlling the rotation of a ported ball within a suitable ported seat
BEARING	BALL	BRG_BALL	An anti-friction bearing that permits free motion between moving and fixed parts by means of balls confined between outer and inner rings
GASKET	SPIRAL WOUND	GSKT_SPWD	A circular item constructed of spring-like metal strips, preformed into a vee shape, and laminated with a soft filler, designed to seal between two static surfaces
MOTOR	AC	MTR_AC	A machine that converts alternating current into rotary motion or torque to drive other equipment
FILTER	ELEMENT	FLTR_ELMNT	A replaceable inner device contained by the filter housing, designed to remove foreign matter and particles from a product
GAUGE	PRESSURE	GAUGE_PRES	An instrument designed to measure air, gas, fluid, and vapour pressure by means of a pressure-sensitive element
HOSE	HYDRAULIC	HOSE_HYD	A tubular hose for conveying fluids in a high-pressure hydraulic system
BREAKER	CIRCUIT	BRKR_CIRCUIT	An electrical device that opens a circuit automatically when a predetermined value is exceeded
VALVE	RELIEF	VLV_RELIEF	A valve designed to protect a system by the automatic release of excessive pressure at a predetermined setting
CABLE	ELECTRICAL	CBL_ELECTRICAL	Two or more insulated conductors contained in a common covering to provide an electrical connection between components

NMQ Attributes — The Detail Layer

Classification alone tells you what type of part it is. Attributes tell you which specific one.

The standard NMQ dictionary defines 20,500+ attributes across all part types. These are tagged as preferred (should always be captured), important (capture when available), or optional.

This attribute layer is what separates NMQ from simpler classification systems. You do not just know it is a ball valve — you know exactly which ball valve, specified in a consistent structure that works across your entire parts catalogue.

Example: VALVE > BALL attributes

Attribute	Type	Examples
Size	Numeric	2", 4", 6"
Pressure Rating	Numeric	150#, 300#, 600#
Body Material	Text	CARBON STEEL, STAINLESS STEEL 316
End Connection	Text	FLANGED, THREADED, SOCKET WELD
Bore Type	Text	FULL BORE, REDUCED BORE
Seat Material	Text	PTFE, RPTFE, METAL
Temperature Rating	Range	-29C to 200C

NMQ vs Other Classification Systems

NMQ vs UNSPSC

	NMQ	UNSPSC
Scope	Spare parts and industrial materials	All products and services, all industries
Parts depth	1,828 specific classifications + 20,500 attributes	Spare parts are one small branch of a massive tree
Readability	VALVE BALL	40141609
Attributes	Built-in engineering attributes per classification	No standard attribute schema
Best for	Maintenance, procurement, inventory management	High-level spend analysis, supplier catalogues

Bottom line: UNSPSC tells you "this is a valve." NMQ tells you "this is a ball valve, 4 inch, 300# rated, carbon steel body, flanged ends, full bore, with a PTFE seat."

NMQ vs eCl@ss

	NMQ	eCl@ss
Origin	MRO/maintenance industry	German standardisation body (international)
Structure	3 levels: Noun > Modifier > Qualifier	4 levels: Segment > Main Group > Group > Sub-Group
Coding	VLV_BALL	27-02-01-01
Language	English-first, readable without lookup	Numeric, requires reference table
Best for	Internal parts management, ERP data quality	Cross-company data exchange, European procurement
Cost	Included with data cleaning service	Licensed (membership required for full access)

Bottom line: eCl@ss is stronger for cross-company data exchange, especially in European supply chains. NMQ is more practical for internal parts management — your technicians can read "BEARING BALL" without consulting a code table. Many organisations use both.

NMQ vs NMA (Noun-Modifier-Attribute)

NMA is a similar methodology used by some consultancies. The main difference is structural:

NMQ

Uses three levels: Noun > Modifier > Qualifier, with attributes as a separate layer. Cleaner for ERP implementation.

NMA

Folds attributes into the classification name itself. Both achieve the same goal, but NMQ's separation maps better to ERP system fields.

Industries That Use NMQ Classification

NMQ is used across asset-intensive industries where spare parts management directly impacts operational reliability and cost.

Oil and Gas

Offshore platforms and refineries carry thousands of critical spare parts. NMQ enables standardisation across multiple sites, reducing duplicate inventory and ensuring safety-critical parts are correctly identified.

Mining

Remote mining operations cannot afford wrong parts. NMQ ensures consistent naming across sites that may have used different conventions for decades, especially after mergers and acquisitions.

Power Generation

Turbine components, switchgear, and instrumentation require precise classification. NMQ attributes capture the engineering detail needed to distinguish between similar but non-interchangeable parts.

Manufacturing

Production line spare parts need fast identification to minimise downtime. NMQ's readable naming convention means warehouse staff can find parts without decoding numeric classification systems.

Water and Utilities

Pump stations, treatment plants, and distribution networks share common part types across many sites. NMQ enables centralised parts management and bulk procurement.

How We Implement NMQ Classification

Our AI-powered classification process works against the full NMQ dictionary of 1,828 active classifications and 20,500+ attributes.

Data Audit

We analyse your existing parts data: description quality, completeness, existing classification coverage, and duplicate rate. You receive a governance maturity score (Level 1-5) and a detailed quality report before any cleaning begins.

Automated Matching

Each part description is matched against the NMQ dictionary using tiered matching:

HIGH CONFIDENCE

Noun + Modifier exact match

MEDIUM CONFIDENCE

Noun match, modifier inferred

LOW CONFIDENCE

Partial match — flagged for review

UNMATCHED

Flagged for specialist review

Attribute Extraction

For matched records, we extract engineering attributes from the description and populate the NMQ attribute fields: size, material, pressure rating, connection type, and other characteristics relevant to that part type.

Human Review

Low-confidence and unmatched records are reviewed by spare parts specialists. New NMQ entries are added to the dictionary when genuinely new part types are discovered.

Delivery

Classified data is delivered in your ERP's import format with NMQ noun, modifier, qualifier, customer code, and populated attribute fields ready to load.

Frequently Asked Questions

Common questions about NMQ classification

What is NMQ classification?

NMQ (Noun-Modifier-Qualifier) is a three-level taxonomy for classifying spare parts and industrial materials. The Noun identifies the primary part type (e.g., VALVE), the Modifier specifies the subtype (e.g., BALL), and the Qualifier provides further refinement. It creates a standardised, searchable structure for parts data across ERP and CMMS systems.

What is the difference between NMQ and UNSPSC?

UNSPSC is a broad commodity classification covering all products and services across all industries. NMQ is purpose-built for spare parts and industrial materials, with far more granular detail. UNSPSC might classify a ball valve under a general valve category, while NMQ classifies it as VALVE > BALL with specific engineering attributes like size, pressure rating, and material. NMQ is better for maintenance and procurement of industrial parts; UNSPSC is better for general spend analysis.

How many NMQ classifications exist?

The standard NMQ dictionary contains over 1,800 active Noun-Modifier combinations covering 926 unique part types (nouns) and 552 modifiers. Each combination can have dozens of defined attributes, totalling over 20,500 attribute definitions that describe the engineering characteristics of each part type.

How is NMQ different from eCl@ss?

eCl@ss is a comprehensive international product classification standard used widely in Europe. NMQ is specifically designed for MRO spare parts and focuses on the language maintenance teams actually use. eCl@ss uses a numeric code hierarchy; NMQ uses plain English nouns and modifiers that are readable without a reference manual. Both can coexist — many organisations use NMQ for day-to-day parts management and map to eCl@ss for procurement and external reporting.

Can NMQ be customised for specific industries?

Yes. The base NMQ dictionary covers parts common across all industries. Industry-specific extensions add nouns and modifiers relevant to sectors like oil and gas, mining, power generation, and manufacturing. Customer-specific entries can also be added for proprietary or unusual part types unique to a particular operation.

How long does it take to classify spare parts using NMQ?

With AI-assisted classification, a typical dataset of 10,000-50,000 spare parts records can be classified in days rather than the weeks or months required by manual approaches. The process uses pattern matching against the NMQ dictionary, with human review for ambiguous records. Initial classification rates of 70-85% are common, with the remainder flagged for specialist review.

What ERP systems support NMQ classification?

NMQ classification output can be loaded into any ERP or CMMS system including SAP, Oracle, Maximo, IFS, and Infor. The noun, modifier, and qualifier fields map to material group or classification fields in most systems. For SAP, NMQ typically maps to the material short text structure and can align with S/4HANA material classification.

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