TSI 8587A Laser Photometer

TSI 8587A Laser Photometer

In 1990, TSI began developing an advanced-technology light scattering photometer to replace ageing instruments incapable of measuring the high protection factors provided by newer gas mask designs. The result was the Laser Photometer Model 8587A, which is still in service for testing filter efficiency.

The  photometer owners asked TSI to develop a modern version of the Laser Photometer Model 8587 that retains data continuity with the original version. Without data continuity, vast amounts of legacy research would not be directly comparable to new research. The result was the Laser Photometer 8587A.

The Model 8587A can also be used in HEPA filter scanning systems to measure the penetration efficiencies of large, high-efficiency filter assemblies.


  • Same photometer engine as used by NIOSH
  • Filter-efficiency measurements to 99.999%
  • Penetration versus particle size to 0.001%
  • Fit factors to 100,000
  • Indicates low airflow conditions
  • Signal correlates with aerosol mass concentration
  • Stable 30mW laser light source
  • Internal valve switches between upstream and downstream samples
  • Automatic gain selection
  • Analog and digital output
  • Manual or remote control via RS-232 or USB
  • Critical orifice controls sample airflow
  • Plug-and-play compatibility with the original 8587 command language


  • Respirator certification testing (fit testing)
  • Efficiency testing of HEPA filter assemblies
  • Respirator design and development
  • Filter design and development
  • Aerosol laboratory research