Important Recommendations - Pall SUPRAdisc Instructions

STEAM STERILIZATION OF PALL
®
SUPRADISC™ MODULES (USD2299)
Important Notice
Refer to safety instructions before use. Safety
instructions in this language are available from Pall.

1. IMPORTANT RECOMMENDATIONS

This section includes important procedures and
guidelines; it should be reviewed carefully be-
fore implementing steam sterilization protocols.
This publication describes important aspects
of the procedures to be adopted when steam
sterilizing Pall filter assemblies. It cannot take
account of particular features of individual systems.
Should you find difficulty in applying these rec-
ommendations or have any questions concerning
steam sterilization in general, please contact
your nearest Pall office.
Please note that Pall SUPRAdisc filters are not
supplied sterile and validation of any steriliza-
tion procedure is the responsibility of the user.
1.1 Installation
The filter assembly should be installed in such
a manner that condensate from the steam supply
cannot accumulate in the housing and that the
open end of the assembled filter module is ori-
entated downwards. It is preferable that the
pipework downstream of the filter assembly is
kept as short as possible. Critical pipe lengths
are shown in the procedure diagrams.
1.2 Control of Steam Sterilization
Steam used for sterilization must be saturat-
ed and free from condensation. Superheated
steam must not be used. Introduction of steam
into the system should be in such a way as
to prevent 'air traps' forming. Air pockets can
inhibit steam flow and produce regions where
inadequate sterilizing conditions are achieved.
This requires special attention where steam is
introduced from more than one position. Ad-
equate means condensate drainage should
be employed to ensure that steam is free from
condensate.
Condensate will wet hydrophilic filter assem-
blies, increase differential and reduce steam
flow.
It is important to consider:
(a) Steam supply
(b) System to be steamed (adequate drains etc)
(c) Pipe orientation
(d) Pipe insulation
Steam and air pressure should be regulated
carefully to avoid over-pressurization and dam-
age to modules. Accurate and calibrated pres-
sure gauges are important. Pressure differential
should be kept to a minimum, but it should not
exceed 300 mbar (4.3 psi) in flow direction. At
the completion of steam sterilization air should
be introduced to replace the steam; compen-
sation for steam collapse is important to pre-
vent a vacuum forming, which may cause filter
damage, leakage via pressure seals, or vessel
collapse. Pressure in the reverse flow direction
must be avoided.
1.3 Direction of Steam Flow
Depth filter modules are intended to be steam
sterilized in situ by steam flow in the normal flow
direction (out to in)
1.5 Steam for Sterilization
The steam should be free of particulate matter
such as rust and pipe scale as these will be re-
moved by the filter to be sterilized and shorten
its life. Pall porous stainless steel filters are suit-
able for the filtration of steam and appropriate
assemblies may be obtained from Pall.
1.5 Flushing
It is strongly recommended that the process filter
assembly and associated downstream equip-
ment is flushed after steam sterilization and be-
fore filtration to remove any residue originating
from the steam and trace amounts of filter ex-
tractables remaining after sterilization. Flushing
of the filter modules should be carried out in the
normal direction with a minimum flush volume
of 50 L/m filter area is recommended. (For
2
SUPRAdisc HP modules 100 L/m ) The flow
2
rate should be equivalent to 1.5 times the process
flow rate.
2. IN SITU STEAM STERILIZATION
PROCEDURES
Pressure Gauges
Pressure gauges which can be read with accuracy
over the range of 0 - 3 bar (0 - 43.5 psi) must be
installed to monitor steam pressure and differen-
tial pressure across the filter assembly during
the sterilization cycle.
Steam Sterilization Conditions (see also figure 1)
To ensure effective sterilization, steam tempera-
ture (measured at position T) in the assembly
should be held at a minimum of 121 °C (250 °F)
(1.1 barg (15.9 psi) saturated steam) for the min-
imum time validated by the user as necessary
to achieve system sterilization. The maximum
temperature must not exceed 125 °C (257 °F) at
a pressure of 1.32 bar (19.1 psi)
Procedure
1. Ensure that all valves are closed.
2. Fully open drain valve C.
3. Fully open condensate drain valve I, open
condensate drain valve J, open venting
valve G.
4. Adjust steam sterilization pressure P4 to
300 mbar (4.3 psi) above the saturated
steam pressure P2 necessary for steriliza-
tion of the filter. After condensate has been
expelled from I, partially close valve I.
5. Slowly open steam valve B to admit steam
to system. After condensate has been ex-
pelled from J, partially close valve J.
6. Partially close vent valve G when steam flow is
evident, ensuring that pressure at P2 remains
within 300 mbar (4.3 psi) of pressure at P1.
Partially open drain valve D to drain conden-
sate and partially open valve E.
7. Permit steam to flow through the system un-
til steam pressure is stabilized, and adjust
the regulated steam supply until the validat-
ed temperature is achieved at position T.
Monitor temperature at T for the necessary
sterilization time. Ensure that pressure at P2
remains within 300 mbar (4.3 psi) of pressure
at P1.
8. When sterilization time is complete, close
valve B. Valve D remains partially open, close
valve I completely.When P2 is pressureless,
then open valve G and drain valve J com-
pletely. Close valves D and E. When the gas
pressure has dropped at position T (tempe-
rature = 100 °C [212 °F]), open valve A and
lush the system with 150 L/m of ambient
2
temperature water for 10 minutes. After flush-
ing close valve G and drain valve J partially
and completely open valve D. Filter assembly
is now ready for use.
3. GENERAL GUIDELINES FOR STEAM
STERILIZATION OF FILTER ASSEMBLIES
Important:
It is the responsibility of the user to validate the
effectiveness and safety of procedures used
to steam sterilize process equipment and filter
assemblies. The following guidelines are in-
tended only to highlight some aspects of such
procedures which require special attention. For
further assistance or information, please contact
Pall Scientific and Laboratory Services.
3.1 Filter Sizing and Steam Supply
Filter modules should be sized appropriately for
product filtration, any gas or air flow and to permit
adequate steam flow to sterilize effectively the
downstream equipment. Failure to take account
of steam flow requirements may result in filter
damage, caused by high differential pressures
at elevated temperatures, and possible non-ste-
rility of downstream equipment.
3.2 Differential Pressure
During steam sterilization of downstream
equipment, differential pressure across the
filter assemblies must not exceed 300 mbar
(4.3 psi) in the forward direction. Reverse pres-
surization must be avoided in order to prevent
filter damage.
3.3 Monitoring of Temperature and pressure
It is important to monitor temperature and pres-
sure in downstream equipment to ensure that:
a) Validated sterilizing conditions have been
achieved
b) Excessive differential pressures are not ex-
perienced across filter assemblies
c) A sudden fall in pressure due to steam collapse
does not compromise downstream equipment
Caution:
Where vessels in the downstream systems are
unable to withstand negative pressure without
collapse, appropriate safety devices must be fitted.
Product and pressure surges must be avoided
to prevent damage and to allow optimal use of
the Pall SUPRAdisc modules.
3.4 Air Entrapment
It is important to ensure that valve sequences
do not lead to entrapment of air pockets in the
process equipment, as sterility may be com-
promised.
3.5 Condensate Drainage
Adequate means for condensate drainage
should be employed to ensure that steam is free
from condensate. Condensate in the modules
can wet the depth filter media, increase differential
pressures across the filters and reduce steam
flow. Provision should be made for drainage of
condensate from process equipment following
steam sterilization where such condensate is
undesirable for operational reasons.
4. Safety Instructions
(a) Steaming leads to a heating of the Filter hou-
sing and pipes. Touching these can cause
severe burns. Therefore, let the plant cool
down.
(b) Please make sure that the housing is in a
pressureless state before opening it. If
necessary, the housing can be depressurized.
(c) Steam will escape during the steaming
procedure. Avoid any contact.
5. Scientific and Laboratory Services
Pall provides a full laboratory and field technical
service to assist in the application and evaluation
of Pall filter products. If you have technical ques-
tions please do not hesitate to use this customer
service, available through your local sales office.