ISO14644 – Are you up to date with cleanroom standards?

ISO14644 Cleanroom

What Is ISO14644?


ISO14644 is the international standard used to design, construct, validate and operate a cleanroom. For those new to cleanrooms, look at our basic concept of a cleanroom animation.


The standard was first published in 1999, and replaced the former US Federal Standard 209E in 2001. After a consultation period and amendments, Parts 1 and 2 were updated and revised in December 2015.


What Are the Key Changes to ISO14644?


ISO 14644-1:2015 specifies the classification of air cleanliness in terms of concentration of airborne particles in cleanrooms and clean controlled environments.

The main improvement is in the particle sampling methods. The previous methods were dependent upon an ad-hoc approach in ascertaining the number and location of sampling points. Improved sampling methods in the revised ISO 14644-1 document along with the enhanced guidance for particle counter calibration and performance provides improved confidence to cleanroom users that their cleanroom is delivering the preferred level of quality-controlled environment.


What Are the Implications for EU GMP Cleanroom Operators?


It will impact on every GMP Pharmaceuticals cleanroom user.

  • The fundamental changes in the ISO14644-1:2015 document impacting on the GMP community are:
  • Change to the method for calculating number of sample locations for classification/re-qualification
  • Elimination of the 95% Upper Confidence Limit (UCL) calculation
  • Reference to ISO 21501-4 in the normative* Annex A where the requirements for air particle counters are de ned (*normative = must comply with this section)
  • Removal of the maximum allowable concentration of airborne particles/m³ ≥ 5 microns for ISO Class 5 from the Cleanliness Classes table (ISO Class 5 at 5microns is equivalent to GMP Grade B at rest)


The Key Changes Can Be Summarized As:


  • Title of the ISO14644-1 is changed from “Classification of air cleanliness” to “Classification of air cleanliness by particle concentration”.
  • The number of sampling points in the area is no longer calculated as the square root of the surface area formula but it is now taken from a given table A1. (See Appendix A)
  • Formula to calculate the particle concentration (Cn) in respective classification number is no longer used and the value is taken directly from the table.
  • Particles of 5 μm in ISO 5 class have been removed from the limit value table.
  • UCL calculation is not required. There is no need to perform an observation of all measuring points in the room. Each single measuring point is considered individually and must meet the limit value.
  • The length of tubing used in particle counter should be less than 1 metre.
  • The classification number, the air sample volumes, measuring time as well as the cancellation criterion is not changed and remains as same to the version ISO14644-1:1999.


ISO/GMP Cleanroom Hand Held Particle Counter:



Well designed, compact and easy to configure hand held particle counter. Complete with full validation certificate and carry case.

Complies fully with the latest revision of ISO14644. suitable for ISO and GMP cleanrooms.  The Airy Technology P311 stores 8,000 sample records that can be viewed on  the unit or on a computer via USB cable. The P311 complies with ISO 21501-4 and includes a one year warranty. With excellent quality and reliable performance, the Airy Technology P311 is the best priced handheld particle counter in the market.

For more information on particle counters


For more information on ISO standards check out our Cleanroom Guide.

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