of filter cleaning.

Production Department: Coordinates equipment shutdown and area clearance prior to filter cleaning.

4. Accountability

The Head – Engineering Department is accountable for ensuring timely cleaning and preventive maintenance of HVAC filters in gel production zones.

5. Procedure

5.1 Preparation

1. Obtain approval for planned HVAC maintenance from Production and QA.
2. Ensure availability of PPE: gloves, goggles, face mask, and protective gown.
3. Shut down the HVAC system and electrically isolate the unit.
4. Display “Under Maintenance” signage at the respective HVAC control panel.

5.2 Cleaning of Pre-Filters and Fine Filters

1. Open the filter housing panel carefully.
2. Remove filters one by one and place them in a clean SS container for transfer.
3. Use compressed air (oil-free and filtered) in a laminar direction to clean visible dust and particles.
4. Wash with potable water followed by purified water if visibly soiled.
5. Dry using HEPA-filtered air blowers or in a controlled environment drying chamber.

5.3 Cleaning of HEPA Filters (Non-Washable)

1. Do not attempt to wash or dismantle HEPA filters unless validated.
2. Use dry HEPA vacuum cleaners to remove surface dust on the protective grill.
3. Inspect visually for damage or clogging; record pressure differentials.
4. If pressure exceeds validated range, initiate filter replacement per SOP.

5.4 Post-Cleaning Reinstallation

1. Reinstall cleaned filters ensuring correct orientation and proper sealing.
2. Wipe filter frame and housing with 70% IPA.
3. Start HVAC system and monitor differential pressure across filters.
4. Record all observations and measurements in the HVAC filter maintenance logbook.

5.5 Frequency

• Pre-filters: Every 15 days or as per differential pressure trends.
• Fine filters: Monthly or based on preventive maintenance schedule.
• HEPA filters: Semi-annually or when pressure limits are exceeded.

6. Abbreviations

• HVAC: Heating, Ventilation, and Air Conditioning
• HEPA: High-Efficiency Particulate Air
• PPE: Personal Protective Equipment
• IPA: Isopropyl Alcohol

7. Documents

1. HVAC Filter Maintenance Logbook – Annexure-1
2. HEPA Filter Inspection Checklist – Annexure-2
3. Differential Pressure Monitoring Log – Annexure-3

8. References

• WHO TRS 961 Annex 5: HVAC Systems for Pharmaceutical Facilities
• EU GMP Guidelines – Annex 1
• ISPE Baseline Guide: HVAC Systems

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation	Jr. Production Chemist	QA Executive	Head – Manufacturing
Department	Gel Manufacturing	Quality Assurance	Manufacturing

11. Annexures

Annexure-1: HVAC Filter Maintenance Logbook

Date	Filter Type	Location	Cleaning Status	Remarks	Done By

Annexure-2: HEPA Filter Inspection Checklist

Filter ID	Location	Visual Condition	DP (mmWC)	Status	Action Taken

Annexure-3: Differential Pressure Monitoring Log

Date	Filter Location	Pre-cleaning DP	Post-cleaning DP	Acceptable Range	Remarks

Revision History

Revision Date	Revision No.	Change Description	Reason	Approved By
12/03/2022	1.0	Initial release	New SOP	QA Head
09/06/2025	2.0	Added pressure log annexures and frequency clarification	Periodic update	QA Head