SPECTREX Quasar 950 Open Path – H2S

The Spectrex Quasar 950 Open Path H2S Detector is designed for long-range toxic gas detection in demanding industrial environments where hydrogen sulfide gas may be present. Using SafEye Quasar open path ultraviolet detection technology, the Quasar 950 monitors the line of sight between a transmitter and receiver to detect toxic gas clouds across path lengths of up to 200 ft. / 60 m, depending on the selected model.

Built for reliability in harsh operating conditions, the Quasar 950 offers high-speed response in under three seconds, heated optics to help reduce the effects of condensation, snow, and icing, and strong false alarm immunity against sunlight and challenging industrial surroundings. Its solar-blind UV technology is suited for facilities where flare stacks, arc welding, lightning, hydrocarbon flames, and other radiation sources may be present.

The Quasar 950 supports flexible integration with control systems through 0–20 mA output, optional HART communication, and RS-485 Modbus compatibility. It is also user-programmable for easier maintenance and asset management, with a 3 mA maintenance call and visual LED status indication for power, fault, and alarm conditions.

Westech Industrial supplies the Spectrex Quasar 950 Open Path H2S Detector in BC, Alberta, and Saskatchewan. Our team can assist with product selection, application review, service support, and custom fabrication for integrated gas detection panels, shelters, and site-specific safety system requirements.

SPECTREX Quasar 950 Open Path - H2S

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Description

Long-Range H2S Gas Detection

The Quasar 950 provides open path toxic gas detection across distances up to 200 ft. / 60 m, making it suitable for perimeter monitoring, process areas, and facilities where point detectors alone may not provide the preferred coverage.

Fast Response for Toxic Gas Hazards

With a response time of less than three seconds, the detector is designed to quickly identify toxic gas hazards and support prompt alarm or control system action.

UV Open Path Detection Technology

The Quasar 950 uses ultraviolet technology with a spectral response of 200–300 nm to detect toxic gas clouds along the monitored path.

High False Alarm Immunity

The detector is solar blind and designed for industrial environments, helping reduce unwanted alarms from sunlight, hydrocarbon flames, and other external infrared radiation sources.

Heated Optics for Harsh Weather

Integrated heated windows help eliminate condensation and icing on the optics, supporting operation in environments exposed to snow, ice, and moisture.

Flexible Communication and Output Options

Available outputs include 0–20 mA, optional HART communication for maintenance and asset management, and RS-485 Modbus-compatible communication for computer-controlled installations.

Simple Installation, Alignment, and Maintenance

The system is designed for straightforward installation and maintenance, with alignment tools, handheld diagnostic options, and programmable configuration through HART or RS-485 Modbus.

Rugged Stainless Steel Construction

The source, detector, and tilt mount are made with 316 stainless steel construction. Circuit boards are conformal coated and protected from mechanical vibration.

SIL2 Reliability

The Quasar 950 is approved to Safety Integrity Level SIL2 by TÜV and has a minimum MTBF of 100,000 hours.

Applications

The Spectrex Quasar 950 Open Path H2S Detector is suited for industrial facilities where toxic gas detection over an open path is required. The detector is especially useful where a clear line of sight can be maintained between the transmitter and receiver and where gas cloud detection is preferred across a wider monitored area.

Common applications include:

  • Offshore platforms and FPSOs
  • Petrochemical plants
  • Chemical processing facilities
  • Gas filling and distribution terminals
  • Gas transport and pipeline facilities
  • Metal refining operations
  • Food and beverage facilities requiring toxic gas monitoring

Documents

Spectrex_Safeye quasar 950_Spec sheet_AUG2024_Westech.pdf

SPECTREX_SafEye Quasar 950-960_Manual_May2026_Westech.pdf

Manufacturer info

Spectrex is a leader in Flame and Open Path Gas Detectors field. We are fully committed to enhance the safety of your employees, capital investments and to the environment.

Website: https://www.spectrex.net

SPECS

Product Type:
Open path toxic gas detector.
Product Series:
SafEye Quasar 950.
Detection Technology:
Ultraviolet open path detection.
Detected Gas:
Hydrogen sulfide (H2S); sulfur dioxide (SO2).
Detector / Source Models:
Detector model QRU; Source model QTU.
Detection Range by Model:
Quasar 951: 17–52 ft. / 5–16 m; Quasar 952: 46–132 ft. / 14–40 m; Quasar 953: 115–200 ft. / 35–60 m.
Response Time:
Less than 3 seconds.
Sensitivity Range:
0–500 ppm.m.
Spectral Response:
200–300 nm.
False Alarm Immunity:
Not influenced by solar radiation, hydrocarbon flames, and other external infrared radiation sources.
Gas Cloud Detection:
Detects gas clouds at very low concentrations, up to 95 percent obscuration.
Displacement / Misalignment Tolerance:
±1 degree.
Drift:
Up to ±5 percent of full scale.
Temperature Range:
-67 to +149 °F / -55 to +65 °C.
Humidity:
Up to 95 percent non-condensing; withstands up to 100 percent relative humidity for short periods.
Heated Optics:
Heated windows help eliminate condensation and icing on the window.
Power Supply:
24 Vdc nominal (18–32 Vdc).
Typical Power Consumption with Heated Optics:
Detector: 135 mA; Source: 150 mA.
Warm-Up Time:
60 seconds for transmitter and receiver.
Electrical Connection:
Two ¾-in. –14 NPT conduits or 2 x M25 x 1.5 mm ISO.
Electrical Input Protection:
According to MIL-STD-1275B.
Electromagnetic Compatibility:
EMI/RFI protected to EN50270.
0–20 mA Current Output:
Sink configuration with source option: maximum load of 500 ohm at 18–32 Vdc.
0–20 mA Output Signals:
Gas reading: 0–20 mA; Normal zero reading: 4 mA; Maintenance call: 3 mA; Misalignment: 2.5 mA; Obscuration / beam block: 2 mA; Zero calibration mode: 1 mA; Fault: 0 mA.
RS-485 Interface:
RS-485 Modbus-compatible communication link for computer-controlled installations.
HART Protocol:
Optional HART communication on the 0–20 mA analog current for maintenance and asset management.
Visual Status Indicator:
Three-colour LED; green for power on, amber for fault, red for alarm.
Enclosure:
Detector and source housings are 316 stainless steel with electro-polish finish; tilt mount is also 316 stainless steel.
Circuit Board Protection:
Conformal coated and protected from mechanical vibration.
Detector / Source Dimensions:
10.5 x 5.1 x 5.1 in. / 267 x 130 x 130 mm.
Tilt Mount Dimensions:
4.7 x 4.7 x 5.5 in. / 120 x 120 x 158 mm.
Detector / Source Weight:
11 lb. / 5 kg.
Tilt Mount Weight:
4.2 lb. / 2 kg.
Water and Dust Tight Rating:
IP66 and IP68 per EN60529; NEMA 250 6P.
Environmental Standards:
Meets MIL-STD-810C for humidity, salt and fog, vibration, mechanical shock, high temperature, and low temperature.
Reliability:
SIL2 per IEC61508 by TÜV; minimum MTBF of 100,000 hours.
Hazardous Area Approvals Listed:
ATEX, IECEx, UKCA, CSA C/US.
Additional Approval Note:
TR CU (EAC) and INMETRO approvals are pending.
Performance Approval:
ANSI/ISA-92.00.04-2014; UL 920004:2014.
Laser Classification:
Class 1 Laser Product per IEC 60825-1:2014 ed. 05.
Warranty:
Three years.
Accessories:
Tilt mount, wall mount, pole mounts, duct mount, air shield, protective cover, Quasar 950 H2S communication kit, H2S check filter, auxiliary harness, HART handheld diagnostic kit, USB / RS485 harness converter kit.

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PRODUCT FAQ's

What is the Spectrex Quasar 950 Open Path H2S Detector used for?
The Spectrex Quasar 950 Open Path H2S Detector is used to detect toxic hydrogen sulfide gas across an open line of sight between a transmitter and receiver. It is designed for industrial environments where wider-area gas cloud detection is required.
How far can the Quasar 950 detect H2S gas?
Depending on the selected model, the Quasar 950 can monitor path lengths from 17 ft. / 5 m up to 200 ft. / 60 m. The Quasar 951 covers short ranges, the Quasar 952 covers medium ranges, and the Quasar 953 covers longer distances.
How fast is the Quasar 950 response time?
The Quasar 950 has a response time of less than three seconds, supporting fast detection of toxic gas hazards.
Why use an open path H2S detector instead of only point gas detectors?
Open path gas detectors monitor across a defined line of sight, helping detect gas clouds that pass through the monitored path. This can be useful in facilities where gas dispersion, leak trajectory, wind direction, and site layout make wider-area detection important.
Can the Quasar 950 operate in cold or wet environments?
Yes. The Quasar 950 includes heated optics to help eliminate condensation and icing on the window. It is designed for operation in harsh environments, with an operating temperature range of -67 to +149 °F / -55 to +65 °C.
What outputs are available with the Quasar 950?
The Quasar 950 supports 0–20 mA output, optional HART communication, and RS-485 Modbus-compatible communication. These options help integrate the detector into a range of control, safety, and asset management systems.
Does the Quasar 950 provide maintenance indication?
Yes. The 0–20 mA output includes a 3 mA maintenance call signal, along with defined output levels for normal operation, misalignment, beam block, zero calibration, and fault conditions.
Does Westech Industrial provide service support for the Spectrex Quasar 950?
Yes. Westech Industrial can support customers with product selection, application review, service support, and coordination for toxic gas detection requirements. Our team can help ensure the selected detector model and path length fit the site conditions and safety objectives.
Can Westech Industrial integrate the Quasar 950 into a custom fabricated system?
Yes. Westech Industrial offers custom fabrication capabilities and can support integration of gas detection equipment into custom panels, shelters, or packaged safety systems depending on project requirements.
Where is the Spectrex Quasar 950 Open Path H2S Detector available from Westech Industrial?
The Spectrex Quasar 950 Open Path H2S Detector is available through Westech Industrial in British Columbia, Alberta, and Saskatchewan.