HEPA Filter Cleaning , Purpose:
HEPA Filter Cleaning , The purpose of this SOP is to define the cleaning and changing procedure of G4, F7, F9 and HEPA filters of HVAC system of XX Pharmaceuticals Ltd.
HEPA Filter Cleaning , Scope:
This Standard Operating Procedure applies to the G4, F7, F9 and HEPA filters of HVAC system installed at Sterile and Solid Block of XX Pharmaceuticals Ltd.
Definitions / Abbreviation:
[][]SOP: Standard Operating Procedure
[][]AHU: Air Handling Unit
[][]G4 Filter: G4 filters are used as pre filters inside the AHUs and in low return line of rooms of HVAC system. This is also known as coarse graded filter
[][]F7 and F9 Filter: F7 and F9 filters are used as intermediate filters inside the AHUs of HVAC system. These are factory fabricated and mounted with galvanized steel or plastic frames
[][]HEPA: High Efficiency Particulate Air
[][]DOP: Di – Octyl Phthalate
[][]PAO: Poly Alpha Olefin
Responsibilities:
[][]The roles and responsibilities are as follows:
Engineering (Validation) Department
[][]Preparing the SOP and revise it when necessary.
Engineering (Maintenance) Department
[][]To provide necessary support for performing cleaning/changing operation smoothly.
[][]To ensure that the operators are responsible to carry out the operation and fill up the logbooks.
Operators/Technician
[][]To clean/change the filters according to the SOP.
[][]To fill up the log sheets.
Manager, Engineering
[][]To ensure that the cleaning/changing of filters are done properly.
Manager, Quality Assurance
[][]To approve the SOP.
[][]To ensure overall implementation of this SOP.
Procedure:
Precautions:
[][]All operation work must be done safely in accordance with the requirements of the Plant Safety Statement and the safety notices around the plant. Specific attention must be paid to the following:
[][]Do not open the doors of AHU while the motor is running.
[][]Do not wash the filters beside the AHUs.
[][]Use personal protective equipment and clothing as necessary at the time of performing cleaning/changing work.
[][]Be careful about the hot water line.
System Description
[][]In HVAC system, the filtration of air is done in three stages to remove the particulates from the air. The stages are: primary, secondary and tertiary stages.
Primary stage:
[][]Coarse graded filters are used in primary stage. The grade of this filter is G4. This type of filter is washable. This is also used in the low return duct line of AHUs. This type of filters are used to remove the coarse particles.
Secondary stage:
[][]After primary stage filtration the air is filtered in secondary stage filter inside the AHUs. Normally, the secondary stage filters are of F7/F9 graded. The bag type F7 filter is washable but cartridge and flat type F7 and F9 filters are not washable. They have to be replaced after being blocked with particles.
Tertiary stage:
[][]The air is finally filtered by the HEPA filters in tertiary stage. In some cases, filtration is done by the HEPA filters after secondary stage inside the AHU followed by terminal HEPA filter. Otherwise, HEPA filter is used only in the terminal of supply duct. These filters are neither washable nor cleanable rather than these are replaced or changed in case they fail the filter integrity test commonly known as DOP/PAO test.
[][]Monitor the differential pressure in the magnehelic gauge across the filters of AHUs in the log sheet. If the differential pressure is beyond the set limit, then clean/change the filters.
Cleaning Procedure
[][]Cleaning of G4 and F7 (bag type) filters:
[][]Switch off the power of AHU and wait until the motor rotation is fully off.
[][]Open the door of the filter section and unmount the filter from its frame.
[][]Take the filter to the wash area at the roof top of both cephalosporin and general blocks.
[][]Wash the filter with water. Then, use any kind of non ionic cleaning agent to clean the filter.
[][]After cleaning the filters are dried.
[][]During cleaning a lot of dust may come out from the filters. So, use mask, goggles, hand gloves and other clothes to be safe from any harmful dust.
[][]After drying set the filters in the filter frame.
[][]The G4 filters of low return and inside the AHUs are cleaned once a week and every 15 days respectively for periodic maintenance. The F7 (bag type) filters are cleaned once a month.
[][]Fill up the log sheet (Annexure – I) after performing the activities.
Changing Procedure
[][]Changing of G4, F7, F9 filters:
[][]Both the G4 and F7 (bag type) filters are changed when filters cannot filter the air although it has been cleaned.
[][]Monitor the differential pressure across the filters. If the differential pressure across F7 (cartridge and flat type) and F9 filters is more than 500 Pa, the filters have to be changed. Both of these filters are changed once in a year for periodic maintenance.
[][]To change the filters follow the steps 1 to 2 of previous section.
[][]Take the filters to the dispose area.
[][]Destroy the filters in the dispose area abiding by the proper safety rules.
[][]Set a new filter.
[][]Fill up the log sheet (Annexure – II).
Changing the HEPA filters:
[][]The differential pressure across the HEPA filters (fitted inside the AHUs) is monitored. These filters are changed when the differential pressure exceeds 300 Pa.
[][]The integrity test (DOP/PAO) is performed at a defined interval for every HEPA filters. The filter is changed if it fails the test.
[][]To change the HEPA filters follow the previous steps
[][]After replacing the filter fill up the log sheet (Annexure – II).
Annexure:
Annexure – I: Log sheet for cleaning of G4 & F7 (bag type) filters.
Annexure – II: Log sheet for changing of G4, F7, F9 and HEPA filters.