Cleanliness Standards
Lasair II Particle Counter Operations Manual
Page 8-7
BS-5295 Standard
The document, BS 5295 (1989), was used when designing the BS 5295 module,
and only the classes specified in the document’s tables have been implemented. The
Lasair II particle counter does not support intermediate class sizes or intermediate
particle sizes.
The BS 5295 standard specifies a particle counter with a sample flow rate of 0.4
Liters per second ±5% (24 Liters per minute). The Lasair II particle counter has a
flow rate of about 0.471 liters per second. It is common practice to use 1 CFM for
BS-5295 calculations. The standard also requires
samples of 27 Liters
. In BS-5295
mode, the min/max sample volume is 27.4 Liters (.0274 m
3
).
In BS-5295 mode, the statistics summary screen and statistics location summary
only show data for the smallest particle channel. Data for all relevant channels is
shown on the printed report.
Also, only the minimum number of sample locations may be used. That is, you may
not increase the minimum number of locations.
Use the following sources for more information about the BS-5296 standard:
B S I Standards
389 Chiswick High Road
London W44 AL
Tel: 0181 996 9000
Fax: 0180 996 7400
e-mail: info@bsi.org.uk
Table 8-4: BS 5295 Sample requirements
Maximum Particles Per M
3
Class
0.3
μ
0.5
μ
5.0
μ
10.0
μ
25.0
μ
Area
(M
2
)
Samples
C
100
35
0
10
20
D
1000
350
0
10
10
E
10000
3500
0
10
5
F
3500
0
25
5
G
100000
35000
200
0
25
5
H
35000
200
0
25
1
J
350000
2000
450
0
25
1
K
3500000
20000
4500
500
50
1
L
200000
45000
5000
50
1
M
450000
50000
50
1
