VALIDATION OF HVAC SYSTEMS S.R. Parthasarathy

VALIDATION OF HVAC SYSTEMS Validation test is carried out at Rest and also under dynamic conditions Validation of a clean room involves the following: Air flow velocity, air changes calculation Uni directional flow Airborne particle count HEPA  Filter installation leak test Total viable count (settle plate and air sampling)

VALIDATION OF HVAC SYSTEMS AIR FLOW VELOCITY AIM This test is performed to determine the average airflow velocity and the velocity uniformity within a laminar flow work zone.  APPARATUS Hot wire or Vane type anemometer which within ± 3%  of scale reading over the velocity of interest. The anemometer should be in a state of calibration and should have traceability certificate.

VALIDATION OF HVAC SYSTEMS AIR FLOW VELOCITY PROCEDURE Divide the work zone entrance plane into grids of equal area. The area of the individual grids  should not  be greater than 4 sq ft  Measure and record the velocity of each grid point under  an air producing area Take measurement for a minimum of 5 seconds  using the average during that period as the measurement.

VALIDATION OF HVAC SYSTEMS AIR FLOW VELOCITY PROCEDURE Get  average velocity and thereby calculate the air changes  per hour  in the  rooms.  Report the average air flow velocity  in fpm or mps. Under laminar, calculate the air flow uniformly range equal to  the average airflow velocity ± 20% Calculate  and Identify  all readings which are outside  this  airflow uniformity  range and calculate  the percentage  of readings which are within the airflow uniformity range.

VALIDATION OF HVAC SYSTEMS AIR FLOW VELOCITY ACCEPTANCE The  max. and mini average velocity should be agreed to between buyer and seller. The minimum percentage of airflow reading within the  ± 20%  is acceptable  limit. S.No Class Min. Changes 1 100,000 (ISO 8) 20 2 10,000 (ISO 7) 40 to 45 3 100 (ISO 5) Up to 80

VALIDATION OF HVAC SYSTEMS HEPA  FILTER INSTALLATION LEAK TEST AT REST  FACILITY At rest facility room which is complete and has the production equipment installed and operating, but has no personnel or material movement within the facility. HEPA A throw-away extended-media  dry type filter in a rigid frame having a minimum particle  collection efficiency of 99.97% for 0.3 micrometer  with PAO (Poly Alpha olefins) 

VALIDATION OF HVAC SYSTEMS HEPA  FILTER INSTALLATION LEAK TEST PROBING  OR SCANNING  A method for disclosing leaks in filters and in which the probe nozzle of an aerosol photometer is held approx.  1”  from the filter face and moved at a rate  of not more than 10ft/min.  across the test area AEROSOL GENERATOR An aerosol generated by blowing air through the PAO  When generated with a Laskking type nozzle the approximate  light scattering mean droplet size  distribution is 40% less than 1 micrometers 50% less than 0.7 micrometer and 10%  less than 0.4 micrometers 

VALIDATION OF HVAC SYSTEMS HEPA  FILTER INSTALLATION LEAK TEST OPTICAL PARTICLE COUNTER A Light scattering instrument with display or recording means to count and size discrete particles in air AEROSOL PHOTOMETER A light scattering mass conc. Indicator Instruments of this type with a threshold sensitivity of at least  102 mg per liter for 0.3 micrometer diameter DOP particles.

VALIDATION OF HVAC SYSTEMS HEPA  FILTER INSTALLATION LEAK TEST CLEAN ROOM A room in which the air supply, air distribution filtration supply, materials of constructions and operating procedures  are regulated  to control airborne particle concentrations to meet the appropriate cleanliness levels as defined by ISO requirements . CALIBRATED EQUIPMENT Test equipment which has been calibrated in accordance with the equipment manufacturer, recommendations and or accepted industry practices.

VALIDATION OF HVAC SYSTEMS HEPA FILTER  INTEGRITY TEST   (DOP TEST) This test is performed to confirm that the HEPA filter system is properly installed by verifying the absence of bypass leakage in the installation and that the HEPA  filters are free of defects and pinhole leaks.  It is particularly important for LAF units   and mixed airflow clean room where a ISO 8,7,6,5 cleanliness specification is imposed. 

VALIDATION OF HVAC SYSTEMS HEPA FILTER  INTEGRITY TEST   (DOP TEST) The test is made by introducing an aerosol challenge upstream of HEPA  filters and scanning immediately downstream of the HEPA  filters and support frame. This procedure  detects small pinholes or other damage in the filter medium and frame seal by-pass leaks in the filter frame and gasket seal and leaks in the filter bank framework.

VALIDATION OF HVAC SYSTEMS HEPA FILTER  INTEGRITY TEST   (DOP TEST) AIM To check leaks  above  0.01%  in The HEPA and installation  by DOP APPARATUS Aerosol generator, Air pressure, Photometer, scanning probe, DOP

VALIDATION OF HVAC SYSTEMS HEPA FILTER  INTEGRITY TEST   (DOP TEST) PROCEDURE This Test is performed by introducing the DOP or  specified  upstream of the HEPA  filters and searching the leaks by scanning the downstream side of the filters with the photometer probe. The design airflow velocity should be set prior to performing the filter installation leak test. Introduce the aerosol in the air supplied to the HEPA  filters in a manner which will produce  a uniform challenge conc. at each of the HEPA  filters being exposed  at the same time Where construction permits,  introduce the aerosol and measure the upstream concentration immediately upstream of the filter in question.

VALIDATION OF HVAC SYSTEMS HEPA FILTER  INTEGRITY TEST   (DOP TEST) PROCEDURE Set  the  aerosol generator air supply pressure at 20 psig  minimum.  Operate  one or more laskin nozzle and or generators as necessary to produce the upstream concentration required for the leak detection  10 mg per liter is recommended.   Photometer to be used. Measure the upstream aerosol challenge concentration,   using it a linear photometer scale.  10 mg per liter of air on the upstream cont,  is adjusted to read 100%.

VALIDATION OF HVAC SYSTEMS HEPA FILTER  INTEGRITY TEST   (DOP TEST) REPORTING  Block,  If the leakage is minor  by silicon sealant and re do the  procedure of DOP,  leak not more than 0.01% is  acceptable.

VALIDATION OF HVAC SYSTEMS AIRBORNE  PARTICLE COUNT AIM This test  is performed to determine that the  completed facility   AT REST  facility can achieve the air cleanliness level desired by the user.   This test is not intended for routine monitoring. APPARATUS Optical laser based particle counter  having a particle size  determination capability to detect particles of 0.3, 0.5, 1,  5  micrometers. 

VALIDATION OF HVAC SYSTEMS AIRBORNE  PARTICLE COUNT PROCEDURE Its  very important  that  one  looks minutely  towards  particle counter. The particle counter by which particle  count is carried out  must be of   1 CFM Verify that all aspects of the clean room system which contribute to its operational integrity  (air  handling, filtration systems, walls,  ceilings,  floors etc ) are complete and functioning nominally in accordance with the requirement of the type clean room and the operational mode  under test. 

VALIDATION OF HVAC SYSTEMS AIRBORNE  PARTICLE COUNT PROCEDURE Establish a test point  grid  pattern at the working level  or at the ground level  which satisfies user  requirement and compatible with the type of clean room and the operational mode being tested.  Determination of the number, location and grid size of sampling points  should be based on the specified  cleanliness level and number of critical locations in order to obtain the desired confidence level. 

VALIDATION OF HVAC SYSTEMS AIRBORNE  PARTICLE COUNT PROCEDURE Test point should not directly sample contamination released from operating equipment and or people.  i.e   the air should be sampled as it approaches  the work activity area.  This will generally be immediately above the work activity level or immediately upstream in laminar air flow rooms. The number of test points and their locations must satisfy the statistical requirement of the user. 

VALIDATION OF HVAC SYSTEMS AIRBORNE  PARTICLE COUNT REPORTING Record   the mean particle count at each grid  location  and  note all measurements exceeding the specified  air cleanliness level    S.No Class Max. particles of 0.5µ Max. particles of 5µ 1 ISO 8 100,000 700 2 ISO 7 10,000 70 3 ISO 5 300 of 0.3 µ and 100 of 0.5 µ Nil

VALIDATION OF HVAC SYSTEMS AIRBORNE  PARTICLE COUNT ACCEPTANCE To Classify  the complete clean room as meeting the specified air cleanliness level, particle counts shown  on the sample point plan should not exceed the specified level. Clean work zone areas  within the clean room may also be specified and classified by the maximum  allowable particle count.  In addition the room or work area may be classified differently  in the “At Rest” operating facility  modes.

VALIDATION OF HVAC SYSTEMS TOTAL VIABLE COUNT Settle plate method – Expose Agar plates Soya bean Casein digest Agar as well as Saboraud Dextrose Agar for a definite period– depends on the activities and the sensitivity of the products manufactured Settle plates measure exactly that phenomenon for which they are intended—the random settling of biologically active particles

VALIDATION OF HVAC SYSTEMS TOTAL VIABLE COUNT Another approach to sampling is to collect micro-organisms on a membrane filter in a filter cassette connected to a low-volume rechargeable pump. The whole assembly can be clipped to a belt and used to collect a personal sample over a normal working day. After sampling, small portions of washings from the filter and dilutions of the washings can then be spread out on a range of agar media, incubated and counts of viable micro-organisms made. An alternative to the filter sampler is the liquid impinger, in which particles in air drawn in through capillary jets impinge on and collect in liquid. Portions of the collection liquid and dilutions prepared from it are treated in the same way as those from filter samplers

Thank You