Labconco Precise CA 5220100 User Manual page 25

chambers. Figure 3-11 shows test results of the oxygen decay or oxygen level
increase as a function of time. Per ISO specifications, Class 1 controlled
atmosphere chambers have a specified hourly leak rate of less than 5 x 10
Table 3-1 listed at the end of Chapter 3.
140
120
100
80
60
40
20
0
0 10 20
The validation requirements and required testing instruments for all
applications shall be determined by the end user and Safety Officer. Other
validation test methods such as pressure leak decay tests may be conducted per
ISO 10648-2 standards. The pressure leak decay test may be performed, but
the pressure inside the glove box must be adjusted accurately for temperature
and barometric pressure.
These pressure leak decay tests are conducted under negative pressure of -
250 Pa (-1" water gauge) for operational use or -1000 Pa (-4" water gauge)
for the acceptance test; the pressure leak decay tests are usually performed
under stable barometric pressure and temperature conditions to minimize the
effect of these variables.
A 0.1°C fall in temperature results in an equivalent pressure change of -34
Pa or -0.14 inches of water gauge. A 0.01 inches of mercury rise in
barometric pressure results in an equivalent pressure change of -34 Pa or
-0.14 inches of water gauge.
Product Service 1-800-522-7658
Chapter 3: Getting Started
Precise CA Glove Box
Oxygen Decay Leak
ISO 10648-2 Test Method
30 40 50
Oxygen ppm
Figure 3-11
-4
per
Barometic Pressure:
28.66 inches of Hg
Main Chamber Temp.:
Pressure: -4 inches
Transfer Chambler
Pressure: 0 inches
Leak Rate Box 1.7 x
Class 1 Leak Rate <= 5
60 70 80
21
Oxygen Decay
77.6° F
Main Chamber
H O
2
inches Hg
-4
10
-4
x 10