A quick overview to new ISO 14644-1: 2015

1. ISO 14644 Key Changes
A quick overview to new
ISO 14644-1: 2015
Apostolos Antoniou

2. ISO 14644-1 Major Changes
• ISO Classification Table
• Minimum Required Number of Sample Locations
• UCL 95 %
• Equipment Calibration
• Ultra and Micro Descriptors
• Sequential Sampling

3. 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
9g c c c 35 200 000 8 320 000 293 000

4. 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
9g c c c 35 200 000 8 320 000 293 000

5. 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

6. Minimum Required Number of
Sample Locations
ISO 14644-1:1999
• From Equation 𝑁𝐿 = √𝐴 (𝑚2)
ISO 14644-1:2015
• From Table A.1
• Equally Divided Areas
• No Random Selection

7. Minimum Required Number of
Sample Locations
• The table lists the different cleanroom areas up to 1000 𝑚2
and defines from this the number of sampling locations
that are required within this cleanroom area
• If the cleanroom is greater than 1000 𝑚2
then we use
Formula A.1
𝑁𝐿 = 27 × (
𝐴
1000
)
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)

8. 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.

9. 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.

10. 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

11. THANK YOU!