Dynamic pass box validation

Rahul Kashyap

System Description:
The purpose of Dynamic Pass Box is to provide ISO class 5 (class100) air flow in the work
Performance Qualification Plan:
Following test parameter shall be performed during performance qualification
Sr. No.
Test Parameter
Velocity and air changes
Integrity test for HEPA filter
Non-viable particulate count
Recovery test
Viable count (microbial monitoring)
Air flow pattern
Performance Qualification Procedure:
Air Velocity:
  • Hot wire anemometer or Vane type anemometer is used with proper calibration certificates.
  • Start the respective DPB at least 15 minutes before conducting test.
  • Ensure that all the doors of respective room are properly closed.
  • Check the velocities at 6” below or away from the filter face using anemometer record the same.
  • Ensure that no object is present below the anemometer while taking the reading, except the built-in equipment.
  • Take each reading at least for 15 second.
  • Check the air velocity at each filter for at least five Spot As per figure-1 mentioned below.
  • Calculate the average velocity for each filter.
  • Acceptance criteria: Average velocity should be 90 ft. /min. ± 20%.
HEPA Filter Integrity test:
  • The filter integrity test shall be performed by qualified and trained person only.
  • Measuring and testing instrument being used shall be calibrated with reference to NPL/NABL traceable reference standard.
  • Filter integrity testing shall be performed after operational velocities have been verified and adjusted where necessary.
  • Poly alpha olefin (PAO) shall be used for the generation of particles/ fumes. MSDS of the same shall be provided by the external agency.
  • Position the aerosol generator such that aerosol is produced into the upstream of the subjected HEPA filter.
  • Provide compressed air to the fume generator at pressure of 1.5-2 kg/cm2.
  • The concentration of the aerosol challenge upstream of the filter should be between 20 mg/m³ and 80 mg/m³.
  • A concentration lower than 20 mg/m³ can reduce the sensitivity of leak detection. A concentration greater than 80 mg/m³ can give rise to excessive filter fouling over the extended test period.
  • Scan the upstream concentration and set photometer 100%.
  • Scanning should 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, including its joints at the distance of approximately 3 cm from the downstream filter face or the frame structure.
  • The probe traverse scan rate when using 3 cm x 3 cm square probe should not exceed 5 cm/s with a rectangular probe, the maximum area scan rate should not exceed 15cm²/s.
  • While scanning, any indication of leak equal to or greater than the limit which characterizes a designated leak should be cause for holding the probe at the leak location. The location of the leak should be identified by the position of the probe that sustains the maximum reading on the photometer.
  •  Measurement of the aerosol upstream of the filters should be repeated at reasonable time intervals between and after scanning for leaks, to confirm the stability of the challenge aerosol concentration.

Acceptance Criteria: The penetration of the HEPA filter should not be more than rated efficiency of the filter i.e. 0.01%. (ISO 14644 & WHO TRS 961)
Particle count:
  • The particle count test shall be performed by qualified and trained person only.
  • Measuring instrument being used shall be calibrated with reference to NPL/NABL traceable reference standard.
  • Ensure that the sampling locations are evenly distributed throughout the area of the clean room.
  • The volume sampled at each location shall be at least 2 litres, with a minimum sampling time at each location of 1 minute. The sampling probe shall be positioned at working level and air flow probe shall be directed vertically upward.
  • Where only one sampling location is determined, minimum of location shall be considered.
  • Sampling location shall be identified as per given table.

Equation A.1: N = 27 [A/1000]
Acceptance Criteria: All the clean rooms should comply as per the designed class at rest as per ISO 14644 & WHO TRS 961
Recovery Test:
  • The recovery test shall be performed by qualified and trained person only.
  • Measuring instrument being used shall be calibrated with reference to NPL/NABL traceable reference standard.
  • Locate the particle counter in the highest particle count location identified in particle count test.
  • Switch “off” DPB of the room under test and adjacent rooms.
  • Start particle counter and take sample till particle count reaches beyond the acceptance criteria.
  • Evaluate the hold time that subjected area will remains with clean room class.
  • When the particle counts level reaches more than the specified class limit, switch “ON” the DPB of the room and adjacent rooms immediately. Switch on the particle counter.
  • Record the particle count each minute until the cleanliness level in the room is restored to the original condition & recorded the recovery time.

Acceptance Criteria: Hold time shall be established. Recovery time should not be more than 15 minutes.
Air Flow Pattern:
  • The air flow pattern test shall be performed by trained and qualified person only.
  • Ensure area should be in rest condition and all equipment’s are covered before starting test.
  • Switch on the fogger. Wait till smoke comes out.
  • Place outlet of fogger near supply grill and ensure that smoke should be sufficient for visualization.
  • Record the Equipment name, Equipment identification number and differential pressure reading on measuring device (if applicable).
  • Record the air flow pattern and direction through video camera, gradually move fogger outlet from supply to return air grill and record the same.
  • Ensure recording should be sufficient to demonstrate the air flow direction and pattern.

Acceptance Criteria:
Smoke should flow through these critical areas in uniform and unidirectional pattern. If the smoke return or back flow due to turbulence, system cannot be accepted and must be rebalanced or readjusted.
Viable Air Microbial Count (Bio burden):
The test shall be undertaken to demonstrate that   the bio burden concentration is not exceeding by using Settle plate technique and air sampling technique. The test was undertaken only in the operational state as the main source of viable microbial load is the personnel working in the area.
Perform the Environmental monitoring by the following two methods:
Active Sampling     (By Air Sampler Method)
Passive Sampling   (By Settle Plate Method)
Frequency for environment monitoring by Air Sampler method is daily during performance qualification for continuously one weak.
Location for the air sampler and by settle plate method is as per Annexure-II
Active Sampling (By Air Sampler Method)
  • Prepare the pre-incubated Soyabean Casein Digest Agar plates and label the plates for details of “Sampling location, Date, Time and Duration of exposure, and exposed by.
  • Sterilize the Air sampler accessories in an autoclave at 121 Degree C+3 for 30 minutes and put the sterilize accessories, sterile gloves and mask in S.S container.
  • Wear the Sterilize gloves and mask and Place the autoclaved SS cone inside the Air Sampler and place the prepared plate in position (without lid).
  • Place the SS feeder cone circular clamp assembly in position. Select vertical or horizontal mounting position. At the end of the sampling period (1000 litres/8min) close the lid of the plates.
  • Transfer these plates to the Microbiology Lab and incubate plates in an inverted position at 20-25°C for 72 hours followed by 48 hours at.30-35°C
  • After completion of incubation period record the observations Annexure- I.
  • Acceptance Criteria: By Settle Plate Method for grade “A”, class 100 < 1 CFU/ 4hours.

Passive Sampling (By Settle Plate Method)
  • Prepare the pre-incubated Soyabean Casein Digest Agar plates label the plates for details of “Sampling location, Date, Time and Duration of exposure, and exposed by.           
  • Wrap the labelled plates in aluminium foil and put in a caped S.S. container with Sterilize gloves and mask.
  • Open the plates aseptically and expose the plates on SS Stand for four hours.
  • After four hours exposure, cover the lid of plate aseptically and wrap with aluminium foil and place in the SS container.            
  • Carry the plates to Microbiology lab for incubation at 20-25 Degree C for 72 hours followed by incubation at30-35 Degree C for 48 hours.
  • After incubation, take out the plates and count the colony forming units (cfu) with the help of colony counter.

Acceptance Criteria: By Air Sampler Method for Grade “A”, Class 100: <1 CFU/ m3.

Post a Comment

  1. This is excellent information which is shared by you. This information is meaningful and magnificent for us to increase our knowledge abouthvac cleaning services chicago . Keep sharing this kind of information. Thank you.

Post a Comment