SOP for Operation of DOP Tester

Objective To establish a standard procedure for operation of DOP tester.

Scope This SOP is applicable for the operation of Aerosol Photometer (Model: TDA-2GN) and the aerosol generator (Model: TDA-5B) of (Company Name).

Responsibility
=>> Maintenance Engineer shall be responsible to follow the procedure strictly.
=>> Supervisor shall be responsible to ensure that the SOP is followed properly.

Precautions Concerned personnel should be trained on the SOP.

Procedure
=>> Carry out the following steps for operation of the Aerosol Photometer:
=>> Connect the aerosol generator according to the following steps:
=>> Unscrew the liquid fill cap located on top of cabinet and fill reservoir untill gauge registers ¾ full with DOP.
=>> Connect any inert gas or compressed air in the port located on front of the cabinet.
=>> Connect the power line and turn power switch ON.
=>> Open the inert gas or compressed air supply and adjust the supply pressure at 50 psi.
=>> When the temperature controller reaches the desired operating point, the unit is ready to produce aerosol.
=>> Open the metering valve fully by turning it in the counterclockwise direction.
=>> Turn aerosol switch ON and adjust the aerosol concentration by rotating the metering valve in clockwise or counterclockwise direction.. Turn the valve in clockwise direction to decrease and in counterclockwise direction to increase the aerosol concentration.
=>> Connect the output line of the aerosol generator to the upstream side of the filter.
=>> Place the Aerosol Photometer firmly on a flat, stable surface.
=>> Turn the selector valve knob to the CLEAR position.
=>> Connect the scanning probe to the downstream port of the unit.
=>> Turn instrument ON by setting the power rocker switch in the lower right corner of the front panel to the ON (1) position. The % LEAKAGE bargraph scans 20 seconds and the display fully illuminates, showing 8.8.8.8.8. and a complete bargraph.
=>> Press the ENTER key and REF key subsequently. The % LEAKAGE display will briefly flash the manufacturer’s internal reference numerical value setting i.e,100 for DOP-P1.
=>> Press ENTER. The internal adjustment for the new value shall be completed within 15 seconds and then the red LED in the 0 function key will begin to flash.
=>> Press ENTER again in order to automatically zero the instrument. When zeroing is completed, the instrument will give an audible alarm beep. This will take approximately 5 seconds.
=>> A final beep shall be heard shortly and the machine gets ready for starting the DOP test.
=>> Connect the upstream sample line with the upstream port.
=>> Set the selector valve knob to the UPSTREAM position.
=>> Observe that the % LEAKAGE display immediately begins to show the concentration of the upstream challenge aerosol in % of the 100 % baseline.
=>> Observe the upstream concentration, it should be 20 – 80 µg/L (micro gram per litre)
=>> If the reading seems reasonable, normal testing at DOWNSTREAM position can be started. If further verification is required, carry out the following steps:
=>> Press REF function key. Observe that the REF LED illuminates, the 100 key LED goes out and the % LEAKAGE display bargraph begins to sweep left to right.
=>> After approximately 15 seconds, the % LEAKAGE display will illuminate giving the actual concentration of the upstream sample in micrograms per liter.
=>> If the reverification indicates that the concentration of the aerosol has changed significantly, check the UPSTREAM source thoroughly for damage and ensure proper performance.
=>> After ensuring that significant % of aerosol is present in the UPSTREAM position, the photometer should be set for scanning in the DOWNSTREAM position.
=>> Set the scanning probe at 1″ distance from the filter surface.
=>> Set the selector valve knob to the DOWNSTREAM position.
=>> Pass the end of the probe over the area of the filter being tested at a traverse rate of not more than 10′ per minute or 2″ per second.
=>> Read and record the data as displayed either on the pistol grip of the probe or on the photometer front panel. The reading is directly equivalent to the percentage of LEAKAGE.
=>> Leakage should not be more than 0.03% incase of H13 and 0.01% incase of H14.
=>> When testing is complete, close the metering valve of the aerosol generator by turning it in clockwise direction.
=>> To be certain that all aerosol is expelled from the unit, wait approximately 30 seconds after the metering valve has been closed.
=>> Turn the aerosol and power switches OFF.

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