ISO 16232 Component Cleanliness Code (CCC) Explained

When a quality engineer receives a particle analysis report, it is not just about how many particles were found, but rather it is about communicating this information in a standardized, comparable, and actionable way. The Component Cleanliness Code (CCC) is an optional coding of the particle size distribution based on ISO 16232, which is described in Chapter 9.9.4 of VDA 19.1.

What is the CCC (Component Cleanliness Code)?

The CCC is a compact alphanumeric string that encodes the full result of a cleanliness analysis into a single, standardized format. Instead of exchanging raw data tables, engineers, suppliers, and OEMs use the CCC as a common language for cleanliness requirements and comparisons.

Important: The CCC does not distinguish between material classes!

A CCC string tells you, at a glance:

• Which normalization basis was used (wetted area of the test object, wetted volume, or per part)
• Which size classes of particles were found
• The concentration class code (a logarithmic index) for each size class

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The 13 Size Classes (B–N)

For the CCC coding, the particle size distribution and the size classes B to N are used.

Class	Size Range (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

Note: Class A (< 5 µm) is defined in the standard but is excluded from standard CCC reporting because particles of this size cannot be reliably detected and measured using optical microscopy methods.

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The Concentration Class Code (00–20)

The number following a size class letter is not the absolute particle count, but rather it is a concentration class code (also known as cleanliness class), a logarithmic index that encodes a defined range of particle counts.

To express a massive range of contamination levels with just two digits, the class limits increase progressively. The exact values should always be taken directly from the VDA table:

Concentration Class	Max. Particle Count (Upper Limit per 1,000 cm²)
00	0 (none detected)
01	1
02	2
03	4
04	8
05	16
06	32
07	64
08	130
09	250
10	500
11	1,000
12	2,000
13	4,000
14	8,000
15	16,000
16	32,000
17	64,000
18	130,000
19	250,000
20	> 1,000,000

Important: This table applies to area-normalized results (per 1,000 cm² wetted area of the test object). Volume-normalized (per 100 cm³) and per-part results use equivalent tables with different absolute values.

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Structure of a CCC String

A complete CCC string has the following basic structure:

• The first step is the Normalization Basis: The letter before the parentheses defines the normalization basis:
  • A = Area (per 1,000 cm² wetted area of the test object)
  • V = Volume (per 100 cm³ wetted volume of the test object)
  • N = Per Part (1 part or absolute count per individual component)
• The second step is the Size Class + Concentration Class: Inside the parentheses, each detected size class is listed with its concentration class code, separated by slashes. For size classes with zero detected particles, 00 can be used. Size classes that are not to be reported or for which no analysis result is available can be omitted from the CCC.

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Practical Example: Fuel Injector Analysis

A fuel injector is extracted using pressure rinsing according to VDA 19.1. The extraction liquid is filtered, and the membrane filters are scanned by an automated microscope. After normalizing to 1,000 cm² wetted area of the test object (Basis A), the following particle counts are measured:

Size Class	Particle Count (per 1,000 cm²)	Corresponding Interval	Concentration Class
B (5–15 µm)	1,540	> 1,000 to 2,000	12
C (15–25 µm)	310	> 250 to 500	10
D (25–50 µm)	75	> 64 to 130	8
E (50–100 µm)	12	> 8 to 16	5
F (100–150 µm)	0	0	00
G (150–200 µm)	0	0	00

Resulting CCC:

How to Read: The analysis was normalized to 1,000 cm² wetted area of the test object. In size class B, up to 2,000 particles were found (Class 12). Class C has up to 500 particles (Class 10), Class D up to 130 particles (Class 8), and Class E up to 16 particles (Class 5). From Class F onwards, no particles were detected (FG00).

→ Try it now: Open the CCC Decoder – decode any CCC code instantly and see the full size class table.

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Shorthand Notation and Special Case Basis ‘N’

VDA 19.1 specifies three important rules for applying the CCC:

1. Shorthand Notation: If adjacent size classes have the same concentration class, their letters can be combined. For example, if classes F and G both have 0 particles, you write FG00. This also applies to other classes, such as CD16 or LM0.
2. Special Case Basis N (per component): If the basis N is used, the use of concentration classes (00–20) is not permitted. Instead, the exact particle counts are included directly unencoded. For example: N(B1540/C310/D75/E12/FG0).
3. Combined size classes: If several size classes are combined, they are also shown in the CCC code: Example A(B-D20/E-M10/N00)

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Why the CCC Matters

• Supplier Comparison: Comparing CCC results instantly shows which supplier delivers cleaner components – without having to analyze long data tables.
• Cleanliness Requirements: Cleanliness requirements can be specified in the CCC format, for example. A component meets the specification if the concentration classes of the measured value do not exceed the defined limits.

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Automated CCC Calculation with PartikelART

Manually converting particle counts into concentration class codes is time-consuming and prone to careless errors. The PartikelART LensApp automates the entire process:

1. PartikelART Lens enables an analysis with the LightBox and can create your CCC code for compatible components within 60 seconds.
2. PartikelART Case has an automated conversion of CCC codes into cleanliness specifications or CCC into reports as an import. Digitized reports including the CCC string, particle images, and macroscopic findings are immediately ready for your QM audit.

Learn more:

• VDA 19.1 & ISO 16232 Guide
• Particle Analysis with PartikelART
• Technical Cleanliness Solutions