A comparison of controlled negative pressure and aerosol quantitative respirator fit test systems by using fixed leaks

Details

• Personal Author:
  Crutchfield CD ; Ert MD ; Murphy RW
• Description:
  An automated negative pressure system for quantitative respirator fit testing was evaluated. The system consisted of a pressure transducer, a mass flow controller, pulse dampener and pressure relief valve connected to a vacuum pump, digital voltmeter, and computerized data acquisition system. It was tested with a 1 liter canister configured to simulate a sealed respirator using a reference pressure of -1.50 centimeters of water. A series of fixed leaks were introduced into the system by four hypodermic needles having inside diameters of 0.025 to 0.084 centimeters (cm) and lengths 2.5 or 4.5cm. This produced leak rates of 3 to 108 milliliters (ml) per minute. Predicted equivalent fit factors were computed by dividing leak rates measured in the canister into a previously derived mean inspiratory flow rate of 431ml per second. The results were compared with those obtained by a standard computerized aerosol fit test system that used the same hypodermic needles inserted through a septum mounted on a Y-fitting leading into a cartridge respirator and corn-oil as the test aerosol. Fit factors obtained by the negative pressure system and aerosol system ranged from 274 to 9901 and 348 to 15165, respectively. Regression analysis revealed that the negative pressure and aerosol fit factors were highly correlated, correlation coefficient 0.997. The fit factors were also correlated with the cross sectional areas of the needles, correlated coefficient 0.995. The authors conclude that equivalent fit factors obtained with the automated negative pressure test system are highly correlated with those obtained by an automated aerosol fit test system. [Description provided by NIOSH]
• Subjects:
  Air Movements Laboratories Occupational Health Personal Protective Equipment Respiratory Protective Devices Safety
• Keywords:
  Air-flow Laboratory-techniques Laboratory-testing NIOSH-Grant NIOSH-Publication Pressure-testing Respirators Respiratory-protective-equipment Simulation-methods Statistical-analysis
• ISSN:
  0002-8894
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Arizona ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  249-251
• Volume:
  52
• Issue:
  6
• NIOSHTIC Number:
  nn:00201428
• Citation:
  Am Ind Hyg Assoc J 1991 Jun; 52(6):249-251
• Contact Point Address:
  Pharmacology and Toxicology University of Arizona 1435 N. Fremont Ave Tucson, AZ 85721
• Federal Fiscal Year:
  1991
• NORA Priority Area:
  Respirator Research
• Performing Organization:
  University of Arizona, Tucson, Arizona
• Peer Reviewed:
  True
• Start Date:
  19870801
• Source Full Name:
  American Industrial Hygiene Association Journal
• End Date:
  19900731
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:ba055c061ca61e0e5f56fa12f8f428d609901ffc77f84d1e19469cd00aa6ba36dc477c8365a584de5814dbd768daa91de594122f2dbd5ab0e508bfa7e3bda7da
• Download URL:
  https://stacks.cdc.gov/view/cdc/203985/cdc_203985_DS1.pdf
• File Type:
  [PDF - 454.19 KB ]