ISO 14644 Key ChangesA quick overview to new ISO 14644-1: 2015

Apostolos Antoniou

ISO 14644-1 Major Changes

• ISO Classification Table• Minimum Required Number of Sample Locations• UCL 95 %• Equipment Calibration• Ultra and Micro Descriptors• Sequential Sampling

New ISO 14644-1:2015 Table Classification

ISO Class number (N)

Maximum allowable concentrations (particles/m3) for particles equal to and greater than the considered sizes, shown belowa

0,1 µm 0,2 µm 0,3 µm 0,5 µm 1 µm 5 µm

1 10b d d d d e

2 100 24b 10b d d e

3 1 000 237 102 35b d e

4 10 000 2 370 1 020 352 83b e

5 100 000 23 700 10 200 3 520 832 d,e,f

6 1 000 000 237 000 102 000 35 200 8 320 293

7 c c c 352 000 83 200 2 930

8 c c c 3 520 000 832 000 29 300

9gc c c 35 200 000 8 320 000 293 000

New ISO 14644-1:2015 Table Classification - What is changing?

ISO Class number (N)

Maximum allowable concentrations (particles/m3) for particles equal to and greater than the considered sizes, shown belowa

0,1 µm 0,2 µm 0,3 µm 0,5 µm 1 µm 5 µm

1 10b d d d d e

2 100 24b 10b d d e

3 1 000 237 102 35b d e

4 10 000 2 370 1 020 352 83b e

5 100 000 23 700 10 200 3 520 832 d,e,f

6 1 000 000 237 000 102 000 35 200 8 320 293

7 c c c 352 000 83 200 2 930

8 c c c 3 520 000 832 000 29 300

9gc c c 35 200 000 8 320 000 293 000

New ISO 14644-1:2015 Table Classification - What is changing?

• ISO Class 1: 0.2 μm limit of 2 pt/m3 removed• ISO Class 2: 0.5 μm limit of 4 pt/m3 removed• ISO Class 3: 1.0 μm limit of 8 pt/m3 removed• ISO Class 5: 5.0 μm limit of 29 pt/m3 removed• Limits for ISO Class 9 are now applicable only at “in operation”

state

Minimum Required Number of Sample LocationsISO 14644-1:1999

• From Equation ()

ISO 14644-1:2015

• From Table A.1• Equally Divided Areas• No Random Selection

Minimum Required Number of Sample Locations• The table lists the different cleanroom areas up to 1000

and defines from this the number of sampling locationsthat are required within this cleanroom area

• If the cleanroom is greater than 1000 then we use Formula A.1

Area of cleanroom (m2) less than or equal to Minimum number of sample locations to be tested (NL)

2 1

4 2

6 3

8 4

10 5

24 6

28 7

32 8

36 9

52 10

56 11

64 12

68 13

72 14

76 15

104 16

108 17

116 18

148 19

156 20

192 21

232 22

276 23

352 24

436 25

636 26

1 000 27

> 1 000 See Formula (A.1)

UCL 95 %

ISO 14644-1:1999

• If the number of sampling locations was between 1 and 10, standard deviation and UCL 95 % was calculated and it is this figure that must be within specification for the specific class of cleanroom

ISO 14644-1:2015

• Completely removed standard deviation and UCL 95 %

• The cleanroom has met its classification requirements if the average particle concentrations at each sample location are within specification.

Equipment Calibration

ISO 14644-1:1999

• “…The instrument shall have a valid calibration certificate; the frequency and method of calibration should be based on current accepted practice…”

ISO 14644-1:2015

• “…The particle counter shall have a valid calibration certificate: the frequency and method of calibration should be based upon current accepted practice as specified in ISO 21501-4…”

• Impact -> Review calibration certificates to ensure that it can conforms to ISO 21501-4 requirement.

Ultra and Micro (u,M) Descriptors

ISO 14644-1:1999

• Smaller than 0.1 microns defined as u, larger than 0.5 microns defined as M.

ISO 14644-1:2015

• Smaller than 0.1 micron particles will no longer exist in ISO 14644-1. This issue will address in ISO 14644-12

• Impact -> Classification can be done for smaller particles (<0,1μm) and larger particles using M descriptor

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