SOP for DOP Testing of HEPA Filters - Filter Integrity Testing : Pharmaguideline -->

Editable Pharmaceutical Documents in MS-Word Format


SOP for DOP Testing of HEPA Filters - Filter Integrity Testing

Standard operating procedure to test the integrity of HEPA filters installed in HVAC air handling system by HEPA filter integrity testing using PAO aerosols.


To lay down the procedure for DOP testing (Integrity Testing) of HEPA filter.


This SOP shall be is applicable for HVAC system, Laminar Air Flow stations and air handlers of process equipment.




Head of Department


5.1 DOP test of HEPA filters to be performed by an outside agency and the head engineering should ensure that this SOP is followed by outside agency.
5.2 The measurement to be done by using a calibrated photometer having traceability to national standards.
5.3 Feed the DOP aerosol at the fresh air inlet of AHU.
5.4 Connect one end of DOP measuring probe to the upstream port of photometer.
5.5 Turn the knob provided on photometer at the upstream position.
5.6 Hold the detector of DOP measuring probe before HEPA filter or at the port provided in the plenum.
5.7 Press a key for 100% concentration.
5.8 Photometer will scan the DOP for 100% concentration.
5.9 Connect the DOP Measuring probe to a downstream port of Photometer.
5.10 Turn the knob provided on photometer at a downstream position.
5.11 Do the scanning after HEPA filter at a distance of 25 mm from the filter face or at the port provided on the plenum. Wherever access of filter is not possible to take three samples to check the repeatability.
5.12 The Filter and its installation should not show leakages greater than 0.01 % concentration.
5.13 If the downstream leakage exceeds 0.01 %, the installation to be rectified for any leakages near flanges using silicon sealant.
5.14 Again scan the filter and the installation with DOP.
5.15 If the downstream leakage exceeds 0.01 %, the filter shall be sent for testing.
5.16 After rectification of the leakages if the leakage does not fall within 0.01%, replace the HEPA filter with new and repeat the DOP tests as per the steps 5.1 to 5.10.
5.17 The DOP test for the HEPA filters of HVAC system and process equipment shall be performed once in a year and HEPA filters of the LAF shall be performed once in a six months.
5.18 The DOP testing shall be carried out as per DOP testing schedule.
Update: DOP is now replaced by PAO (Poly Alpha Olefin)
Related: HVAC System Validation Tests


6.1 SOP: Standard Operating Procedure
6.2 DOP: Di Octyl Pthalate
6.3 HEPA: High Efficiency Particulate Filter
6.4 HVAC: Heating Ventilation Air Conditioning
Get ready to use editable documents in MS-Word FormatView List

Ankur Choudhary is India's first professional pharmaceutical blogger, author and founder of, a widely-read pharmaceutical blog since 2008. Sign-up for the free email updates for your daily dose of pharmaceutical tips.
.moc.enilediugamrahp@ofni :liamENeed Help: Ask Question

1 comment: Post Yours! Read Comment Policy ▼

  1. DOP can be done using following chemicals
    Poly Alfa Olyfin
    Di-Octyle Sebacate
    Parafin Oil

    with Upstream concentration 22.2 mg/m3


Please don't spam. Comments having links would not be published.

Online Courses

Popular Categories

QA SOPs QC SOPs Micro SOPs HVAC Production SOPs Stores SOPs Checklists Maintenance SOPs HPLC Sterile GLP Validation Protocols Water System GDP Regulatory Maintenance Calibration Warning Letters Education B.Pharmacy
Online Courses

Follow Pharmaguideline



Editable Pharmaceutical Documents in MS-Word Format. Ready to use SOPs, Protocols, Master Plans, Manuals and more...




Pharmaceutical Updates

✔ Worldwide Regulatory Updates
✔ Pharmaceutical News Updates
✔ Interview Questions and Answers
✔ All Guidelines in One Place


Recent Posts