Aerospace Sourcing
Procurement tools

ISO 4406 code and beta ratio

Enter particle counts per millilitre from your particle counter or lab report. The code updates as you type.

ISO 4406 cleanliness code

Filter beta ratio

Codes follow the ISO 4406 scale, where each code step roughly doubles the allowed count. Check results against your copy of the standard and the limit in your specification. Background: hydraulic and fuel filters.

Result
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Code at 4 / 6 / 14 micrometres

CodeMore than (per mL)Up to and including
134080
1480160
15160320
16320640
176401,300
181,3002,500
192,5005,000
205,00010,000
2110,00020,000
Fluid components

Need filters, valves or clean fluid hardware?

Send the part numbers or the cleanliness requirement and a person replies within 1 business day.

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