Steam Sterilization

Steam Sterilization Procedure
Steam sterilization is recommended at the time of new equipment installation and after installation of new filter cartridges. Steam sterilization safety procedures established in the facility must be strictly followed.


Start with all valves closed

  1. Turn on the steam and blow down condensate from the steam line through condensate drain valve (not shown in Figure 1)
  2. When all condensate has been drained partially close the condensate drain valve and fully open V7 (vent) and half open V6 (drain).
  3. Slowly open steam valve V3. When steam is flowing continuously from vent valve V7, open valve V8 and partially open valve V10. Leave V9 closed.
  4. When steam flows continuously from valve V10, partially close vent valve V7 to stabilize steam pressure so that pressure is 14.5 psig (1 barg) at G5 with no more than 3.0psid (0.2 barg) across the filter.
  5. Steam in this mode for the time specified in facility procedures.
  6. Preset the pressure (G3) of regulated air or nitrogen at 3.0 psig (0.2 barg) above the steam pressure (G2).
  7. Close valves V10, V8, V6 and vent valve V7.
  8. Immediately open valve V5.
  9. To start cooling, flush steam from the housing assembly by slowly opening vent valve V7 and drain valve V6.
  10. Slowly cool the housing assembly to ambient temperature.
  11. Close vent valve V7 and drain valve V6 after cooling.
  12. Close the air or nitrogen valve V5.

For two or three stage filter systems, follow these procedures. It may be necessary to steam sterilize each housing separately to assure that temperatures are maintained and pressure differential limits are not exceeded.
Use only dry saturated steam regulated at G2 to a maximum 19 psig (1.3 barg).
NOTE: During steaming, the differential pressure (G4 –G5) across the filter should not exceed 3.0psid (0.2 barg). The downstream pressure (G5) should not be less than 14.5 psig (1 barg) and the temperature should be at least 110 °C (230 °F) to achieve sterilization.
Rapid changes in differential pressure may damage filters.