Bubble Point Test For Cartridge Filter

1.           Purpose:-

This procedure is developed to test integrity of cartridge filter by Bubble Point Test Method.

2.           Scope:-

This procedure applies to perform bubble point test of Cartridge Filters.

3.           HSE Statement:-                               

3.1.      Follow the following instructions to perform subjected job in safe manners.
3.1.1.      Only trained and knowledgeable persons perform the subjected job.
3.1.2.      All work is performed in accordance with applicable regulatory requirements.
3.1.3.      Standard operating procedures are in place to perform the process.
3.1.4.      Report any job related injuries or illnesses, questions on health and safety, or any unsafe or unhealthy working conditions to their supervisor.
3.1.5.      Personal protective equipment necessary for safe use of the equipment,

4.           Responsibilities:-            

4.1.      Lab. Assistant is responsible to conduct assigned tasks in a safe manner and report to supervisor in case of any problem.
4.2.      Microbiologist is responsible to monitor the subjected process.
4.3.      Microbiologistis responsible to manage all activities include operator training, record keeping, proper use of personal protective equipment & other related tasks.

5.           Materials:-                       

Compressed air or nitrogen
SS Housing
Cartridge / Capsule Filter
Silicon pipe
Pressure gauge
Beaker / Flask

6.           Definition:-

6.1.   Bubble Point Test

A forward bubble point integrity test is a procedure which measures the pressure needed to be applied to the upstream side of a filter causing bulk or open pore flow through the largest pores of a wetted filter. This measurement is taken from the downstream side of the filter housing where a flexible piece of tubing has been attached and the other end submerged into a beaker of water. The bubble point is indicated by vigorous bubbling from the tubing. The accuracy of this test will rely on the operator’s ability to successful recognize this point.


6.2.   Cartridge Filter

Cartridge filters are defined as fabric or polymer-based filters designed primarily to remove particulate material from fluids.


1.           Description:-

Perform this test before use of a new filter and whenever required.
 Filter Brand                    Used For
Sarto Pure                   Liquids, gases / air
Sarto Flour                  Nitrogen & compressed air
Sarto Bran                   Liquids

1.1.   Installation of Filter:-            Remove the cartridge filter from the box.            Check whether the packing of the filter is intact.                                Cut open the plastic bag / wrapper at the bottom end of the cartridge – i.e. on the O – Ring.            Wet the O – Ring with the sterile WFI or solution to be filtered (70 % IPA in case of N2 / Air filter).            Insert the filter cartridge carefully by turning into the place while holding onto the base of the cartridge.            Lock the flanges carefully in the catches on the housing base.            When the cartridge is securely on the place, remove the plastic bag / wrapper and close the housing.
1.2.   Wetting of Filter            Open the vent valve.            Fill the filter cartridge housing with freshly prepared 70 % IPA solution for Sarto flour and use sterile water for Injection or solution to be filtered for wetting Sarto Bran and Sarto Pure Filters.            Ensure that all the air has been removed by keeping the vent valve slightly opened for 1st minute of flushing and then close it and rinse for 3 – 5 minutes (use 3 – 4 liter of wetting solution)            Drain the solution by opening the drain valve by applying compressed air / N2 at a max pressure of 0.5 Bar / 7 PSI.            When the housing is empty close all the valves, the filter has been wetted completely.

1.3.   Bubble Point Test            Close the inlet outlet as well as vent and drain valves of the filter housing.            Connect a flexible tube to the open downstream test valve.            Place the free end of the tube into a beaker / flask containing sterile liquid.            Slowly apply increasing pressure to the housing via the upstream inlet. The bubble point of the filter is achieved when a continuous flow of gas bubble appears in the liquid.            Record the bubble point test in.

1.4.   Pressure Limit

ΓΌ  Limit               :           2.0 – 3.0 Bar.
Note:   Ideally it should be achieved at ~ 2.5 Bar.

1.5.   Precautions

Keep the plastic bag / wrapper over the cartridge filter until the filter is securely installed.

  2.           Reference:-

2.1.      NA

3.           Distribution:-                  

Sr. #
Distributed to
Received (Current)
Returned (Obsolete)
Quality Control Department

Quality Assurance Department 

Quality Management Department

4.           Revision History:-                    

Date                                        Changes

N/ A