Lighthouse solair 3100, Operating Manual

Page: 44 / 188

Lighthouse S3100/S5100/Boulder Counter Operating Manual
4-8 248083389-1 Rev
ISO 14644-1
For this report, a sufficient sample volume of air must be sampled at
each sampling location. The sample volume must be sufficient enough
to detect a minimum of 20 particles if the particle concentration for the
largest considered particle size were at the class limit for the designated
ISO class.
The single sample volume Vs per location is determined by using the
following equation:
where,
Note:
When V
s
is very
large, the time required for
sampling can be
substantial. By using the
sequential sampling
procedure (see Annex F of
the ISO 14644-1:1999-05-
01 procedure), both the
required sample volume
and the time required to
obtain samples may be
reduced.
V
s
is the minimum single sample volume per location expressed in
liters.
C
n,m
is the class limit (number of particles per cubic meter) for the
largest considered particle size specified for the relevant class.
20
is the defined number of particles that could be counted if the
particle concentration were at the class limit.
Note:
The volume sampled at each location must be at least 2 liters.
The minimum sampling time at each location must be at least 1
minute.
A minimum of three single sample volumes must be taken at a location,
when only one sampling location is required.
Compute the overall mean of the averages, standard deviation and 95%
upper confidence limit from the average particle concentrations for all
locations, when the number of locations sampled is more than one and
less than ten.
Table 4-3 specifies the concentration limits for particular particle sizes
at a particular cleanliness class level. Limits not specified in the above
table, such as the blank areas and particle sizes not listed in the table,
are not supported by this standard.
V
s
=
20
C
n,m
X 1000