Fenceline Benzene Monitoring

Alternatives to EPA Method 325A/B

Open Path Compliance for 40 CFR 63.658, BAAQMD Rule 12-15, and SCAQMD Rule 1180

The Cerex UV Sentry offers an alternative method for regulatory compliant refinery fence-line benzene monitoring. In addition to compliance with 40 CFR Part 60 and 63, The UV Sentry is a turn key solution for monitoring BTEX under BAAQMD Rule 12-15 and SCAQMD Rule 1180. Our standard open path UVDOAS technology results in several unique advantages when compared to other single-gas and multi-gas monitoring technology. As a component within a larger monitoring plan or as a stand-alone solution for fenceline monitoring compliance, the UV Sentry offers cost-effective, high performance operation. Learn more… Combining the UV Sentry with the Cerex AirSentry FTIR results in a comprehensive and high performance solution for Rule 12-15 and 1180 compliance.

Operational Features of the UV Sentry

  • Species specific monitoring – No False Positives or inflated measurements
  • Part per Trillion detection limits for Benzene
  • Multi-gas: Monitor Toluene, Xylenes, SO2, NO2 etc… in addition to benzene
  • Measurements are absolute
  • Continuous, time resolved monitoring with data output rates as low as 15 seconds
  • Legally defensible data is independent of calibration and is always saved
  • Real time measurements may be verified at any time in the future
  • Turn-key integration with SAFER One RT Software for real time emergency management
  • Field proven, USEPA Tested
  • 40 CFR 63.658 Ready
  • BAAQMD Rule 12-15 Ready
  • SCAQMD Rule 1180 Ready


UV Sentry Brochure
PDF (1.3MB)
USEPA, BAAQMD and SCAQMD Refinery Compliance Solutions
PDF (1.4MB)

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Traceable Quality Assurance

EPA considers traceable quality assurance audits as paramount for open path fence-line analyzers. Cerex provides three methods of insitu QA testing for the UV Sentry. All methods produce traceable audit data using primary standard calibration gas under operational conditions, at the installed path length. When it comes to confidence in operation and defensible data, the proof is in the QA audit.

  • Internal Linear Sample Cell
    The UV Sentry may be equipped with a permanently installed internal cell for calibration gas.
  • External Half-Meter Linear QA Cell
    As an option, a half-meter linear QA cell may be placed in the beam path for QA audit. The long path of external cell allows low concentrations of toxics to be used for QA audit, resulting in reduced hazard when using toxic calibration gases.
  • Slide-On Linear QA Cell
    A great solution to avoid storing high concentration toxics onsite, the slide on QA cell may be filled offsite and transported to the facility for QA audit.