# CCC cleanliness code and particle size classes

> How to read a technical cleanliness test result to VDA 19.1 and ISO 16232: particle size classes B–N, the CCC cleanliness code, contaminant mass and the largest particle.

Adres: https://p4cinternational.com/en/knowledge-base/ccc-cleanliness-code-particle-size-classes/

## CCC cleanliness code and particle size classes – how to read a test result

A technical cleanliness test report to VDA 19.1 and ISO 16232 gives the number of particles in size classes, the mass of contaminants, the largest particle and often the CCC cleanliness code. This article explains what these values mean and how to compare them with the cleanliness specification on the drawing or from your customer.

### Particle size classes

Light-optical analysis measures the longest dimension of every particle collected on the filter and assigns it to a size class marked with a letter. The lower limit belongs to the class, the upper limit to the next one.

Class Particle size [µm]

B 5–15

C 15–25

D 25–50

E 50–100

F 100–150

G 150–200

H 200–400

I 400–600

J 600–1000

K 1000–1500

L 1500–2000

M 2000–3000

N 3000 and above

A cleanliness specification usually defines how many particles in selected classes are permitted per part or per surface area, and how large the largest particle may be.

### Particle types

Besides size, the type of particle matters, because different particles pose different risks:

- **metallic shiny particles** – usually metal chips and filings; the most dangerous for hydraulics, bearings and electronics, so specifications often limit them separately,

- **non-metallic particles** – e.g. plastics, abrasion debris, sand and abrasive residues,

- **fibres** – long, thin particles, e.g. from fabrics and wipes; they are reported separately.

### CCC cleanliness code

The Component Cleanliness Code (CCC) records the result as a single string, e.g. **CCC = A(B13/C12/D11/E9/F7/G5/H3/I00)**. The letter before the brackets shows what the particle count refers to: **A** – 1000 cm² of component surface, **V** – 100 cm³ of volume, **N** – one component.

Inside the brackets, each pair is a size class and a contamination level. The higher the level, the more particles – each level stands for roughly twice as many particles as the previous one. Level 00 means that no particle was found in that class.

### Contaminant mass

Gravimetric analysis gives the mass of contaminants collected from the part, usually in milligrams per part or per 1000 cm² of surface. Mass and particle count tell different things, so specifications often require both values.

### What to check when comparing a result with the specification

- **extraction method** – pressure rinsing, ultrasonics, internal rinsing or agitation give different results, so the method and its parameters should match the specification or the agreed procedure,

- **declining test** – confirms that the chosen extraction removes practically all contaminants from the part: each further extraction yields fewer particles, and the last one no more than 10% of their total,

- **blank value** – contamination introduced by the test itself (liquid, equipment, environment) must be clearly lower than the contamination measured,

- **number of parts per sample** – small parts are tested several at a time so that the result is reliable,

- **largest particle** – a single particle larger than permitted is enough for the part to fail, even if the counts in the classes are low.

Unsure about a test report, or still defining a cleanliness specification? Our accredited laboratory (AB 1836) tests parts to VDA 19.1 and ISO 16232 and helps choose the right test method for the part.

### Related services

- [Technical cleanliness testing](https://p4cinternational.com/en/technical-cleanliness/technical-cleanliness-testing/)

- [VDA 19.1 and ISO 16232 cleanliness inspection](https://p4cinternational.com/en/technical-cleanliness/vda-19-1-iso-16232-cleanliness-inspection/)

- [Technical cleanliness laboratory equipment](https://p4cinternational.com/en/technical-cleanliness/technical-cleanliness-laboratory-equipment/)

- [Technical cleanliness training](https://p4cinternational.com/en/technical-cleanliness/technical-cleanliness-training/)

### Frequently asked questions

What does CCC = A(B13/C12/D11/…) mean?

It is the component cleanliness code according to ISO 16232 and VDA 19.1. The letter A means that the particle count refers to 1000 cm² of surface, and each pair in brackets gives a particle size class (e.g. B: 5–15 µm) and the contamination level in that class – the higher the level, the more particles.

Which particle size classes does VDA 19.1 define?

From B (5–15 µm) to N (3000 µm and above). The class is determined by the longest dimension of the particle measured in light-optical analysis.

What are metallic shiny particles?

Particles that reflect light like metal in light-optical analysis – usually chips and filings. They are the most dangerous for hydraulics, bearings and electronics, so specifications often limit them separately.