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Hazardous Gases

Avir Sensors' Technology

ChemSight™ Hazardous Gas Detection System

The ChemSight™ detector is an infrared (IR), line of sight, sensing system for point of entry, fixed security, fence line and perimeter protection that utilizes a simple, non-contact, spectral analysis of the atmosphere.   The use of optical line-of-sight detection and avoidance of direct contact with chemicals provides the following advantages unmatched by alternative, in-situ (or point) sensor technologies:

  • Continuous, uninterrupted (24/7, 365 days/year), monitoring
    Immediate response (1 sec followed by 15 sec confirmation measurement)
  • Long line monitoring (over 45m by a single detector) for the protection of large spaces, entry points, fence lines, perimeters of sporting events, etc.
  • Multi-chemical detection (most chemical warfare agents, most important toxic industrial chemicals, and common interferant)
  • Excellent background rejection capabilities (exhaust fumes, cleaning agents, fire extinguishing agents, water vapor, etc.)
  • Digital chemical library updateable via internet.
  • Long life, low maintenance (no contamination of sensing elements, filters, concentrators, etc.) and no consumables
  • Built in proprietary confidence tester for remotely testing the detector to confirm operation, sensitivity and response time.

Technology diagramChemSight Technology Overview (click for larger image)

The system IR illuminator emits a collimated beam.  Spectroscopic analysis of that beam is used to identify chemicals intercepting it anywhere along its path  and to determine their optical density (CL – the product of the concentration and the linear dimension of the chemical cloud).  The detector employs uncooled IR detectors.  Eliminating the need for cryogenic refrigeration reduces the cost of the detector and complexity while rendering it robust.  Chemicals are detected by comparing the detected signature with signatures stored in a digitally updatable chemical library.  The extensive library includes signatures of high and medium priority threat chemicals and non-toxic inteferants thereby providing excellent background rejection capabilities.

The proprietary processing software was developed by Avir Sensors to correct for non-linear effects associated with strong absorptions.  Therefore, the detector can provide detection at low levels of threat chemicals while the level of interferants is high.  It also includes a threat evaluation logic that determines the risk level associated with each of the detectable chemicals and provides alarms accordingly.


General Description: Software provides gas identification, concentration, time stamp, and other data in XML or flat file format for easy inclusion into industry standard software.
Diagnosis: Self-diagnosing for path obstructions, contaminants along IR path, and detector status.
Confidence Tester: Internal, software activated relay that confirms detector is operational and communication at user defined intervals (daily, weekly, etc.)

Chemicals Detected

Types: Wide range of toxic industrial chemicals and materials while providing strong interferent rejection. Look here for a detailed listing.


Technology Overview PDF

System Specifications

Sensor Type: Infrared Absorption
Detection Sensitivity: Varies by vapor; starting at 0.02ppm @ 45m
Well below IDLH in typical installation
Path Length: 45m
Response Time: 1 second
Identification Time: 1-30 seconds
Calibration: No calibration required
Warranty: One year
Consumables: None
Maintenance Requirements: Cleaning of windows depending on environments
Operation: Continuous

Mechanical Specifications

Housing Size:  
Detector: 7" x 7.5" x 22.5"
IR Lamp: 14" x 14" x 10.5"
Enclosure Material: Powder Coated Aluminum
Detector: 18 lbs (8.2kg)
IR Lamp (large): 10 lbs (4.5kg)
IR Lamp (small): 6.5 lbs (2.9kg)

Environmental Specifications

Operating Temp.: 32°F to +122°F
0°C to +50°C
Operating Humidity: 0 to 95% RH (Non-condensing)
Weather-proof Rating: IP66 Detector, IP53 Lamp
Certification: ISO 9001, UL, Safety, FCC, EMC & CE

Electrical Specifications

Operating Voltage: 120/240VAC, 50-60Hz
Power Consumption :
Detector: 40-60 watts max.
Lamp: 25-50 watts max.
The Avir Sensors' ChemSight™
Hazardous Gas Detection System
Avir TS400 Sensor A Department of Homeland Security
SAFETY Act Designated Technology