🌿 Classification of air cleanliness in cleanrooms, clean zones and separative devices by number concentration of airborne particles — ISO Classes 1–9 (Table 1) for threshold sizes from 0.1 to 5 µm, measurement with a light scattering airborne particle counter (LSAPC), occupancy state (as-built, at-rest, operational), designation of the class, compliance criterion for each sampling location, number of locations according to Table A.1 and a statistical model with at least 95 % confidence that at least 90 % of the area meets the limit; M descriptor for macroparticles > 5 µm; PN-EN ISO 14644-1:2016-03

Environment PN-EN ISO 14644-1

Overview

WHAT THE STANDARD COVERS. We read the text of the standard in the iTeh sample of ISO 14644-1:2015 (second edition, English text) — PN-EN ISO 14644-1:2016-03 adopts EN ISO 14644-1:2015 and ISO 14644-1:2015 as identical (PKN search): contents, foreword, introduction and Clauses 1–5 in full — the sample ends on page 7, before the annexes. We do not read Annexes A (reference method of classification, normative), B (examples of calculations), C (counting and sizing of macroparticles), D (sequential sampling), E (intermediate classes and thresholds) or F (instruments); we know their titles and role from the contents and the text of the clauses.

ACCORDING TO THE TEXT OF ISO 14644-1:2015. The standard was prepared by ISO/TC 209 “Cleanrooms and associated controlled environments”. The second edition replaces the first (ISO 14644-1:1999). Introduction: contamination control protects product or process e.g. in aerospace, microelectronics, pharmaceuticals, medical devices, healthcare and food; the title was changed; the nine ISO classes are retained with minor revisions; Table 1 for integer classes, Table E.1 for intermediate ones; the macroparticle concept is retained, nano-scale particles are to have a separate standard; the most significant change — a consistent statistical approach to the selection and number of sampling locations and to data evaluation: a hypergeometric model allows each location to be treated independently, with at least 95 % confidence that at least 90 % of the area meets the concentration limit of the target class; the assumption of a normal distribution and the 95 % UCL used in the 1999 edition were abandoned; the minimum number of locations is given in Table A.1, and the area is divided into a grid of equal sections with a location in each, chosen representatively (layout, equipment, airflow); part of the content on testing and instruments was taken over from ISO 14644-3:2005; the edition addresses the ≥ 5 µm limits for ISO Class 5 in the sterile products annexes of EU, PIC/S and WHO GMP by adapting the macroparticle concept; monitoring was moved to ISO 14644-2:2015; other attributes (e.g. chemical cleanliness) do not suffice alone for classification. Scope (1): classification of air cleanliness in cleanrooms, clean zones and separative devices (ISO 14644-7); only cumulative distributions for thresholds from 0.1 to 5 µm; the basis is the light scattering airborne particle counter (LSAPC); particles < 0.1 µm — a separate standard; macroparticles > 5 µm — M descriptor (Annex C); the standard does not characterize the physical, chemical, radiological, viable or other nature of particles. References (2): ISO 14644-2:2015, ISO 14644-7. Definitions (3): cleanroom, clean zone, installation, classification (level expressed as an ISO Class — maximum allowable particle concentration per unit volume), particle, particle size (equivalent diameter — for optical counters the optical diameter), particle concentration (number per unit volume), size distribution (cumulative), macroparticle (> 5 µm), M descriptor (does not define ISO Classes, may be quoted alone or with a class), unidirectional and non-unidirectional airflow, states: as-built (installation complete, without equipment, materials and personnel), at-rest (equipment installed and operating, without personnel), operational (with the specified number of personnel), resolution, maximum permissible measurement error, LSAPC (specified in ISO 21501-4:2007), macroparticle counter, time-of-flight apparatus (aerodynamic diameter). Classification (4): in one or more states; one or more thresholds within ≥ 0.1 to ≥ 5 µm; class number N, maximum concentrations from Table 1 (cumulative values, they are criteria, not the actual distribution) — e.g. Class 5: 100 000 (≥ 0.1 µm), 23 700, 10 200, 3 520 (≥ 0.5 µm), 832 (≥ 1 µm) particles/m³; Class 7: 352 000 (≥ 0.5 µm), 83 200, 2 930 (≥ 5 µm); Class 8: 3 520 000, 832 000, 29 300; Class 9 only in the operational state; for very low concentrations classification is inappropriate, for Class 5 the 5 µm size can only be expressed by the M descriptor together with another size; with several sizes each larger one at least 1.5 times the previous; designation example: “ISO Class 4; at rest; 0.2 µm, 0.5 µm”. Compliance (5): verified by testing and documentation; at-rest or operational classification is repeated periodically based on risk assessment, typically annually — with continuous monitoring the intervals may be extended; monitoring — according to ISO 14644-2:2015; the reference method is in Annex A, other methods with at least comparable performance — if agreed; instruments with valid calibration; at each location the concentration in a single sample volume (or the average of several) must not exceed the limit; all sizes are measured by the same method; test report: organization and date, “ISO 14644-1:2015”, location and coordinates of the points, designation criteria (class, state, sizes), details of the method and deviations, instrument and its calibration certificate, results for all locations, macroparticles if quantified.

STATUS (as of 03.10.2026). The PKN search engine (query “PN-EN ISO 14644-1”, 03.10.2026) lists PN-EN ISO 14644-1:2016-03 — English version, “Introduces: EN ISO 14644-1:2015 [IDT], ISO 14644-1:2015 [IDT]”, without a withdrawal note; PN-EN ISO 14644-1:2005 (Polish version) — “Withdrawn and replaced by PN-EN ISO 14644-1:2016-03”, and PN-EN ISO 14644-1:2002 — by the 2005 edition.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read 03.10.2026). The number 14644-1 appears in 3 records at 2 laboratories: AB 243 (2) and AB 752 (1). In the current PCA documents (read 03.10.2026; AB 243 issue no. 27 of 09.12.2025, AB 752 issue no. 26 of 08.07.2026) the number appears at the same 2 laboratories; in every document the number of page markers equals the number of PDF pages, without repetitions; a search of all PCA documents downloaded from BIP on 03.10.2026 found no laboratories outside the database copy. The form “PN-EN ISO 14644-1:2016-03” at both; at AB 243 together with PN-EN ISO 14644-3:2020-03 (4.2.10 and B.10 — cleanliness, 4.2.4 and B.4 — recovery time). None of these items is suspended. The “Laboratories” tab (query “PN-EN ISO 14644-1”) shows both laboratories — checked by a tab query on the labcoda.pl production server on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). AB 243: working environment — air: cleanliness and recovery time to initial cleanliness, particle counter, diameters 0.1; 0.2; 0.3; 0.5; 1.0; 5.0 µm, from 1 to 349 999 965 particles/m³. AB 752: working environment — air: cleanliness, particle counter, diameters 0.1; 0.3; 0.5; 1.0; 3.0; 5.0 µm, (1–9 999 999) particles/ft³ or (35–349 999 965) particles/m³.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. State: a class without the state (as-built, at-rest, operational) is not a complete designation (4.4) — the same room may have a different class at rest and in operation; Class 9 applies only to the operational state (Table 1). Sizes: thresholds must differ by at least 1.5 times, and 3.0 µm (AB 752) is not a Table 1 threshold — intermediate sizes are derived by the formula of Annex E (4.4, 5.3). 5 µm: for ISO Class 5 this size is not classified directly — only by the M descriptor together with another size (Table 1, footnotes). Criterion: each location is assessed separately — the average over the whole room is not the criterion of the 2015 edition; the number of locations is given by Table A.1 (introduction, 5.3). Units: Table 1 limits are in particles per m³, and a range in particles per ft³ needs conversion (4.3). Method: all sizes are measured by the same method, with an instrument with valid calibration (5.2, 5.3). Monitoring: ongoing monitoring belongs to ISO 14644-2, not to classification (5.1). Nature of particles: the class says nothing about viable or chemical particles (1).

WHAT WE DO NOT GIVE. We do not quote the reference method of Annex A (number of locations, sample volume, procedure), calculation examples, the M descriptor, sequential sampling, intermediate classes or instrument requirements — they lie outside the sample. We do not repeat here the test methods of PN-EN ISO 14644-3 described in a separate entry of the knowledge base; we do not summarize ISO 14644-2, ISO 14644-7 or ISO 21501-4. We do not map ISO classes to GMP grades.

Method principle

At selected locations of the cleanroom or clean zone a light scattering particle counter draws a defined volume of air and counts particles with a diameter equal to and greater than the chosen thresholds (from 0.1 to 5 µm). The concentration in particles per cubic metre at each location is compared with the ISO Class limit of Table 1 for each size. The room meets the class in the given state if no location exceeds the limit; the number of locations follows the statistical model of the standard.

Applications

• Classification of cleanrooms, clean zones and separative devices — ISO Classes 1–9 (1, 4)
• Demonstration of compliance with the required class in the as-built, at-rest and operational states (5)
• Pharmaceuticals, microelectronics, medical devices, healthcare, food industry, aerospace (introduction)
• Working environment — air: cleanliness and recovery time — 3 accreditation scope records of 2 laboratories in PCA

Key parameters

Standard

Standard number

PN-EN ISO 14644-1:2016-03

Title (PL)

Pomieszczenia czyste i związane z nimi środowiska kontrolowane — Część 1: Klasyfikacja czystości powietrza na podstawie stężenia cząstek

Title (EN)

Cleanrooms and associated controlled environments — Part 1: Classification of air cleanliness by particle concentration

Step-by-step procedure

1. Criteria

   ISO Class, state and particle sizes agreed with the customer (4, 5.1). PN-EN ISO 14644-1:2016-03 — 2005 edition withdrawn and replaced (PKN, 03.10.2026).

2. Sampling locations

   Number from Table A.1, grid of equal sections, representative locations (introduction; Annex A outside the sample).

3. Measurement

   LSAPC, the same method for all sizes (5.2, 5.3).

4. Evaluation

   Concentration or average at each location ≤ limit of Table 1 or E.1 (5.3).

5. Test report

   Location and coordinates of points, criteria, method, instrument and calibration certificate, results (5.4).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The part of the standard read contains no safety requirements; measurements follow the entry and working rules of the cleanroom concerned

Frequently asked questions