Labconco Precise Controlled Atmosphere and Basic Glove Boxes 5220131 - Manual (Page 26)

Chapter 3: Getting Started
Product Service 1-800-522-7658 22
Table 3-1
Classification of Glove Box Containment per ISO 10648-2
Class Hourly Leak Rate (T
f
) Usage Example
1 ≤ 5 x 10 -4 hr -1 Controlled atmosphere with high inert gas purity conditions
2 < 2.5 x 10 -3 hr -1 Controlled atmosphere under inert gas conditions or
permanently hazardous atmosphere
3 < 10 -2 hr -1 Permanently hazardous atmosphere
4 < 10 -1 hr -1 Atmosphere which could be hazardous
The required classification of leak tightness of each glove box must be
decided by the end user, their Safety Officer, and any oversight authorities.
Oxygen Method Leak Testing Summary (ISO 10648-2)
The method consists of measuring the increase in the oxygen concentration as
a function of time inside the glove box main chamber, previously purged with
an inert gas. The difference in the oxygen concentration between the end and
the beginning of the test, calculated on an hourly basis, gives the hourly leak
rate T
f
:
T
f
= 300 * (O
2f
–O
2i
) / (t * 10 6 ) where
O
2f
is the final oxygen concentration (ppm).
O
2i
is the initial oxygen concentration (ppm).
t is the duration of the test in minutes.
300 = 60 x 100/20 where 60 represents 60 minutes in an hour and 100/20
represents 20% oxygen in normal air.
Note: Use negative pressure of 1000 Pa (-4" water gauge) for acceptance test
and negative pressure of 250 Pa (-1" water gauge) for operational test.