32
Performing a System Integrity Test is recommended but not required. If the Membrane Cassette
Integrity Test passes, the integrity of the membranes and system is confirmed. However, if the
Membrane Cassette Integrity Test fails, then the System Integrity Test should be performed to
confirm that no external leaks contribute to the measured airflow.
The integrity test instrument should be placed at a level above the TFF system to prevent
gravity feed of liquid back into the instrument. (This is good manufacturing practice but not
absolutely necessary. The tubing arrangements of the Flowstar instrument protect the unit
against liquid ingress.)
Figure 22
System Setup for Determining Air Integrity
4.6.1
Drain the System (Feed/Retentate Flow Path)
Note: The feed/retentate flow path must be drained of liquid before performing the
system or membrane cassette integrity test.
The procedure for draining the feed retentate flow path will depend on the system
configuration. The objective is to remove most of the liquid. It is not necessary to
completely remove all liquid.
Procedure
The liquid can be removed by any combination of the following steps:
1. Opening the drain and vent ports on the system to allow liquid to drain out.
2. Draining or disconnecting the feed tank and then using the feed pump (positive
displacement) to pump air into the system to displace liquid out through the
retentate line.
3. Using an integrity test air source to pressurize with air to force liquid out through
feed/retentate line. Liquid can also be forced out through the membrane and
permeate line.
Retentate
Integrity
Inlet Valve
Integrity
Outlet Valve
Air
Source
Permeate
Feed
Tank
Drain
Feed
Pump
Pp
Rp
Fp
