34
5. If the constant mass flow rate falls below the acceptance specification listed in
Table 12 (and is consistent with previous measurements), the membrane integrity
has passed. If the mass flow rate is above the recommended specification or
substantially above previous measurements, go to Section 4.6.5.
4.6.4
Troubleshooting System Integrity Failure
Procedure
1. If a manual-torque (MT) holder is used, check the torque. If an auto-torque (AT)
assembly is used, check to make sure the hydraulic pressure is at the correct
setting.
2. Check all sanitary clamp connections and fitting assemblies to assure they are
securely tightened.
3. Remove the cassettes and rinse with WFI water. Inspect the cassette gaskets and
the holder contact surfaces for imperfections. If the gaskets look worn or
deformed, install new gaskets. Reinstall the cassettes in the holder.
4. Repeat the System Integrity Test, Section 4.6.2.
4.6.5
Troubleshooting Membrane Integrity Failure
Procedure
1. If a manual-torque (MT) holder is used, check the torque. If an auto-torque (AT)
assembly is used, check to make sure the hydraulic pressure is set correctly.
2. Repeat the System Integrity Test.
3. Remove the cassettes and rinse with WFI. Inspect the cassette gaskets for
imperfections. If the gaskets look worn or deformed, install new gaskets. Reinstall
the cassettes in the holder.
4. Repeat the Membrane Cassette Integrity Test (Section 4.6.3). If the cassette still
fails an integrity test, contact your local Pall representative for assistance. If
multiple cassettes are installed and the air diffusion rate continues to exceed
specification limits, disassemble the stack of cassettes and test the integrity of
each cassette individually to determine if integrity failure is specific to a cassette.
Figure 23
Typical Mass Air Flow Example Plotted for System and Membrane Integrity Test
4.6.6
Integrity Testing Systems with Multiple Cassettes
True integrity can only be validated on individual cassettes. Hence, testing should first
be done on each cassette separately. Then the individual cassettes can be installed
in the holder and tested as a unit. For a stack of cassettes, the air diffusion rate is
additive and should approximate the sum of the individual cassettes.
Air Dif
fusion Rate (cc/min)
Time (minutes)
0
External Test
Membrane Test
Diffusion Rate
Cassette Limit Specification
External Test
As the system fills with air to the
targeted test pressure, the air flow
rate will decrease to zero (base line).
If it does not reach zero, the system
has an external leak. Check all
fittings and valves.
Internal Membrane Test
When the permeate valve is open,
the air flow rate will rise. Then the
flow rate will decrease to a steady
state, which is the true air diffusion
(forward flow) rate.