1.0 OBJECTIVE:To lay down procedure for DOP testing (Integrity Testing) of HEPA filter.
2.0 SCOPE:This SOP shall be is applicable for HVAC system, Laminar Air Flow stations and air handlers of process equipment.
5.0 PROCEDURE:5.1 DOP test 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 fresh air inlet of AHU.
5.4 Connect one end of DOP measuring probe to upstream port of photometer.
5.5 Turn the knob provided on photometer at 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 downstream port of Photometer.
5.10 Turn the knob provided on photometer at 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 plenum. Wherever access of filter is not possible 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.
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