What is a cleanroom certification?

Aug 19, 2023

What is a cleanroom certification?

Cleanroom certification is when users have their cleanroom periodically tested by 3rd party to ensure they meet ISO cleanroom classification. For medical device and pharmaceutical companies this may be to stay compliant with their CGMP or FDA validation. For semiconductor, aerospace and other industries, the cleanroom is essential to manufacturing yield and product quality.

Cleanroom classification standards include particle counts and air changes per hour. Other parameters that are often tested as part of cleanroom certification include: room pressure, temperature, humidity, viable particles, light and sound.

Particle tests can be non-viable or viable (living). For cleanroom classification the tests are for non-viable particles. For ISO 14644-1 each cleanroom classification has a maximum number of particles of a certain size per cubic meter. These measurements are taken using a laser particle counter (Figure 1).

ISO 14644-1 Cleanroom Standards | Cleanroom ClassificationsClassMaximum  Particles/m³FED STD 209E equivalent
>0.1 um>0.2 um>0.3 um>0.5 um>1 um>5 um
ISO 1102

ISO 210024104

ISO 31,000237102358
Class 1
ISO 410,0002,3701,02035283
Class 10
ISO 5100,00023,70010,2003,520832 29Class 100
ISO 61,000,000237,000102,00035,2008,320293Class 1,000
ISO 7

352,00083,2002,930Class 10,000
ISO 8

3,520,000832,00029,300Class 100,000
ISO 9

35,200,0008,320,000293,000Room Air

ISO 14644-1 Cleanroom Standards | Cleanroom Classifications
Class	Maximum Particles/m³	FED STD 209E equivalent
>0.1 um	>0.2 um	>0.3 um	>0.5 um	>1 um	>5 um
ISO 1	10	2
ISO 2	100	24	10	4
ISO 3	1,000	237	102	35	8		Class 1
ISO 4	10,000	2,370	1,020	352	83		Class 10
ISO 5	100,000	23,700	10,200	3,520	832	29	Class 100
ISO 6	1,000,000	237,000	102,000	35,200	8,320	293	Class 1,000
ISO 7				352,000	83,200	2,930	Class 10,000
ISO 8				3,520,000	832,000	29,300	Class 100,000
ISO 9				35,200,000	8,320,000	293,000	Room Air

Figure 2. ISO-14644-1 cleanroom classes

There is also the US FED STD 209E cleanroom classes which measures particle per cubic foot but is very similar to the ISO-14644-1 classes.

US FED STD 209E Cleanroom Standards | Cleanroom ClassificationsClassMaximum  Particles/ft³ISO equivalent
>0.1 um>0.2 um>0.3 um>0.5 um>5 um
 135731
ISO3
 10350753010
ISO4
100


100
ISO5
1000


10007ISO6
10,000


10,00070ISO7
100,000


100,000700ISO8

US FED STD 209E Cleanroom Standards | Cleanroom Classifications
Class	Maximum Particles/ft³	ISO equivalent
>0.1 um	>0.2 um	>0.3 um	>0.5 um	>5 um
1	35	7	3	1		ISO3
10	350	75	30	10		ISO4
100				100		ISO5
1000				1000	7	ISO6
10,000				10,000	70	ISO7
100,000				100,000	700	ISO8

Figure 3. FED STD 209E cleanroom classification

Room air pressure testing is typically done with portable manometers. Most cleanrooms have permanent magnehelic gauges that display cleanroom pressure in inches of water or pascals.

What is a cleanroom certification? — Figure 4. Permanent cleanroom magnehelic gauge

Air flow testing: Another requirement for both ISO and FED STD cleanroom classification is HEPA filtered air changes per hour.

Design Requirements for Cleanroom ClassificationsCriteriaClass 10 ISO4Class 100 ISO5Class 1000 ISO6Class 10,000 ISO7Class 100,000 ISO8
Air changes per HR/Min500-600 / 8 to 10300 to 480 / 5 to 8180 / 360 /120 /0.33
Filter coverage %90 – 10060 – 7020 – 307 – 154  – 5
CFM per square foot85 – 9036 – 6518 – 329 – 164 – 8
Filter Efficiency99.9997% ULPAs99.997% HEPAs99.997% HEPAs99.997% HEPAs99.97% HEPAs

Design Requirements for Cleanroom Classifications
Criteria	Class 10 ISO4	Class 100 ISO5	Class 1000 ISO6	Class 10,000 ISO7	Class 100,000 ISO8
Air changes per HR/Min	500-600 / 8 to 10	300 to 480 / 5 to 8	180 / 3	60 /1	20 /0.33
Filter coverage %	90 – 100	60 – 70	20 – 30	7 – 15	4 – 5
CFM per square foot	85 – 90	36 – 65	18 – 32	9 – 16	4 – 8
Filter Efficiency	99.9997% ULPAs	99.997% HEPAs	99.997% HEPAs	99.997% HEPAs	99.97% HEPAs

Figure 5. Cleanroom Classification - Air changes per hour

The individual air flow rate from each HEPA fan filter unit can be measured with air flow capture hood or Velgrid system.

Viable testing is for live organisms. Typically, samples are collected using settling plates with some type of media. The plates are placed in the cleanroom at specific locations for 4 hours and then are then sent off to analytical labs for incubation and measurement.

Temperature testing is done with a NIST traceable digital thermometer. Humidity testing is done with NIST traceable humidity sensor.

Light testing is typically done with a light meter in grid pattern. The cleanroom test is lumens per square meter (LUX).

Sound testing is done with sound level meter in grid pattern. The cleanroom test is in decibels.

Frequency of cleanroom testing

Most companies do 3rd party cleanroom testing annually and do internal testing quarterly or monthly. How often depends on company manufacturing procedures, ISO-9001 procedures, customer requirements, or CGMP/FDA validation document.

Cleanroom certification is when a cleanroom is tested by 3rd party to ensure they meet cleanroom classification standards including particle counts and air changes per hour. Other parameters that are often tested include room pressure, temperature, humidity, viable particles, light and sound. The tests are required to meet FDA validation/CGMP requirements, ISO procedures or ensure manufacturing yield and product quality.