SOP for Performance Qualification of LAF, RLAF and Dynamic Pass Box

    1. Objective:
To lay down a procedure for performance qualification of LAF, RLAF and dynamic pass box.

  1. Scope:

This procedure is applicable for performance qualification of LAF, RLAF and dynamic pass box Installed in manufacturing, warehouse and quality control area.

  1. Responsibility:

Engineering and QA department

  1. Procedure:

4.1 Performance qualification shall be performed as per below frequency:

  • Filter leakage test (PAO test) – Six Monthly
  • Air velocity – Six Monthly
  • HEPA pressure difference – Six Monthly
  • Particle count – Six Monthly
  • Recovery Test – 2 yearly
  • Air Visualization Test – 2 yearly
  • Noise Test – Six Monthly
  • Illumination test – Six Monthly

4.2 Pre-requisites for performance qualification are:

  • Inform the concerned department in advance.
  • Respective equipment is properly cleaned.
  • The pre-filter of RLAF unit are cleaned and Magnehelic gauges are calibrated.
  • The instruments for performance qualification are in calibration state and Calibration certificates with traceability to national or international standards are available.

4.3 Filter Integrity test:
4.3.1 Filter leakage test is performed to confirm that the filter system is properly installed and that leaks have not developed during use.
4.3.2 The test shall be performed by introducing the aerosol challenge upstream of the filters and scanning immediately downstream of the filters and support frame.
4.3.3 The test shall be done at rest occupancy states.
4.3.4 Specifications of aerosol photometer: Poly Alpha Olefin (PAO). The concentration of the aerosol shall be 20 – 80 mg/m3. The mass median particle diameter of the aerosol particles shall be between 0.5 to 0.7 µm. The instrument used shall be linear aerosol photometer.
4.3.5 Average reading value for the aerosol shall be provided.
4.3.6 The aerosol concentration measurement shall be taken immediately upstream of the filters and it should not be more than ±15 % than the average measured value.
4.3.7 Probe shall be adequate size.
4.3.8 Probe shall be held in a distance of approximately 3 cm from the downstream filter face or the frame structure.
4.3.9 Scanning shall be performed over the entire downstream face of each filter, the perimeter of each filter, the seal between the filter frame and the grid structure.
4.3.10 Measurement of the aerosol upstream of the filters shall be repeated at reasonable time intervals between and after scanning leaks, to confirm the stability of the challenge aerosol concentration
4.3.11 Acceptance criteria: Leaks are considered to have occurred if the reading is greater than 0.01 % of the upstream challenge aerosol concentration.
4.4 Air Velocity Test:
4.4.1 The purpose of this test is to measure air flow velocity and uniformity and supply air flow rate in the GMP areas.
4.4.2 The supply air flow rate shall be measured downstream of final filters.
4.4.3 The uniformity of velocity shall be measured at approximately 150 mm to 300mm from the filter face.
4.4.4 The air flow velocity shall be measured with the help of vane type anemometer.
4.4.5 The measuring time at each position should be sufficient to ensure a repeatable reading.
4.4.6 Calculation of air flow supply      
Air velocity at each filter =  S  Air velocity at different locations of filter / Number of locations per filter
Measure the Air velocity at 5 different locations preferably at 4 corners and at the       centre of the filter.
4.4.7 Acceptance Criteria : 90 ± 20 feet per minute.
4.5 HEPA filter pressure difference test:
4.5.1 The purpose of this test is to verify the capability of complete installation to maintain specific pressure differentials across HEPA.
4.5.2 Check and record the pressure difference across HEPA
4.5.3 Acceptance criteria: – Between 8 mm – 15 mm of WG
4.6 Air borne particulate count:
4.6.1 Air borne particle counting is done to measure the airborne particle count concentrations of size 0.5 mm and 5 mm.
4.6.2 Check that following tests are passing before starting airborne particle count:

  • Airflow velocity
  • Installed filter leakage test
  • HEPA filter pressure difference test

4.6.3 Particle count shall be checked at 3 locations per filter for RLAF and LAF and 1 location per filter for Dynamic Pass Box at the height of the work activity. The particle counter shall be set to provided print with

  • Instrument details
  • Date and time
  • Measurement of particle count ranging from 0.3 µm to 25.0 µm.
  • 3 consecutive readings for 1 minutes shall be taken and
  • Average at each location

4.6.4 Acceptance criteria: (At rest)

ISO classification number Maximum concentration limit
(Particles / m3)
0.5  mm 5.0 mm
ISO class 5 3,520 29

4.7 Recovery Test:
4.7.1 Recovery test is done to find out recovery time of the LAF, RLAF after stoppage or break down.
4.7.2 Particle size used in this test shall be same as that used for the determination of cleanliness class.
4.7.3 Sampling Location of the room showing maximum count shall be selected for monitoring the recovery time.
4.7.4 A duplicate reading shall be taken at this location while the equipment is in ON condition. The counter is maintained in running mode. The equipment is then put off. The Particle count for each minute is taken until the clean room condition is disturbed .i.e. the particle count exceeds  clean room specification limits. The time period required to disturbed the cleanliness condition is noted. (This is HOLD Time)
4.7.5 The Equipment is restarted; the particle count is taken every minute from the start.
4.7.6 The time noted at which the particulate count regains the clean room specification.
4.8 Air Visualization pattern (air flow pattern test):
4.8.1 This test shall be done to demonstrate Laminar pattern of the air supplied. A recorded flow pattern shall be maintained as CD.
4.9 Noise and Illumination Test: This test shall be done to demonstrate Noise level and light illumination of the equipment.
4.9.1 Noise level shall be checked by using sound level meter. Check calibration status of the instrument before use. Noise level should not be more than 85 dB.
4.9.2 Light illumination shall be checked by using lux meter. Check calibration status of the instrument before use. Lux level should not be less than 150 lux.
4.10 After completion of the activity, raw data shall be evaluated by engineering and QA person. If the results are found to be within the specified limits, affix qualification status labels.

  1. Abbreviations:

SOP: Standard operating procedure
QA: Quality assurance
LAF: Laminar air flow
RLAF: Reverse laminar air flow
PAO: Poly alpha olefin
HVAC: Heating, ventilation and air conditioning
GMP: Good manufacturing practice
CD: Compact disk

  1. Annexures:

Annexure I   – Air Flow Test
Annexure II  – Filter Leakage Test
Annexure III – Non-viable particle Count
Annexure IV  – Recovery Test
Annexure V  – Pressure Differential, Noise and Illumination test
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