There are numerous gas detection products on the market that might appear similar, but closer inspection of sensing physics, hazardous area certifications, environmental resilience, and communication protocols reveals fundamental performance differences.
Individual industrial plants have unique layouts, micro-climates, and gas release dynamics. System selection depends on site hazard classification, detector elevation, sensing technology, PLC/SCADA integration, and long-term calibration access.
Select your industrial operating environment below. Our system instantly matches your facility's specific gas hazards with certified fixed transmitters, optical flame detectors, portable monitors, and sensing physics.
Continuous 4-gas monitoring, dual CO/H2S sensor, triple visual/audio/vibration alarms
NDIR offers 100% immunity to catalytic poisons (silicones & high H₂S) with zero oxygen requirement for hydrocarbon flammables. Micro-electrochemical sensor provides rapid H₂S detection (T90 < 15s).
Heavy vapors (Propane, H₂S) at 30 cm above floor level. Lighter gases (Methane, H₂) within 30-45 cm of ceiling.
4-20mA Loop + Modbus RTU RS-485 to DCS / Plant Safety PLC
Dual-stage alarm relay outputs for automated deluge valve triggering and plant emergency trip (ESD).
Ultra-lightweight clip-on badge, field replaceable sensor and battery, zero contamination in cleanroom environments
PID UV lamp ionizes organic molecules with ionization potential below 10.6eV (Benzene, Toluene, Alcohols). Lead-free O₂ cell prevents nitrogen asphyxiation during reactor purging.
Solvent vapors are heavier than air (density > 1.5); install sampling points 30-50 cm from floor near centrifuge extractors.
4-20mA Output + Modbus RS-485 into Building Automation System (BAS)
Interlocked with cleanroom HVAC fresh air damper actuation and emergency solvent drainage cutoff.
Low-temperature battery conditioning, piercing 90dB audible alert audible through ear protection
Heated optics and sensor head eliminate condensation and ice formation on sensor pores. Dual-beam NDIR eliminates moisture cross-interference in cold rooms.
Pure ammonia vapor is lighter than air (density 0.59) — mount high near ceiling and evaporator headers. CO₂ is heavy (1.52) — mount near floor.
Dual Alarm Relays (Low 25 PPM / High 50 PPM) + Modbus RS-485
Low alarm activates emergency ventilation fans; High alarm trips ammonia liquid supply solenoids and sounds plant horn.
Sampling type pump with 37 gas combinations including VOCs and aggressive reactive gases
Utilizes specialized noble-metal electrodes (gold/platinum) engineered to resist corrosive degradation from continuous chlorine and sulfur dioxide exposure.
Chlorine is 2.5 times heavier than air — detectors must be positioned 15-30 cm above floor level around tonner manifolds.
4-20mA with Isolated HART + Dual Fail-Safe Relays
Immediate automatic activation of caustic wet gas scrubbers upon detection of 0.5 PPM chlorine threshold.
Multi-hazard personal detection with integrated automated man-down motion distress alarm
Hydrogen-compensated filter prevents high hydrogen concentrations in blast furnace gas from producing false CO alarms. Solid state/thermal conductivity sensor monitors H₂ cooling leaks.
CO has density 0.97 (nearly equal to air); mount at human breathing height (1.5 - 1.8 meters) in walkways and valve stations.
Networked via DT Xtreme HMI Control System + SCADA Fiber Loop
Direct relay interlock to gas flare ignition systems and plantwide evacuation hooters.
Non-dispersive infrared (NDIR) fast CO2 personal monitoring with USB charging
NDIR optics calibrated specifically for ethanol hydrocarbons. Unaffected by oxygen levels, high wash-down humidity, or cleaning chemical vapor poisoning.
Ethanol vapor is 1.6x heavier than air — mount fixed detectors 30-40 cm above finished floor level around pump manifolds.
4-20mA Output + Modbus RS-485 to Distillation PLC
Activates tank farm deluge cooling and trips ethanol pump motors on 20% LEL alarm.
Motorized pump for confined space paint flash-off tunnel and oven duct sampling
Fast PID response (< 3 sec) for volatile paint thinners (Xylene, Ethylbenzene). Catalytic bead engineered to resist silicone overspray vapors common in assembly plants.
Solvent vapors low (30 cm above floor); Hydrogen from EV charging at ceiling peak.
4-20mA Signals + Direct Voltage-Free Dry Contact Relays
Interlocked directly with robotic paint spray arm shutdown and high-volume fresh air purge fans.
Zero-power direct-reading tubes for rapid on-the-spot HVAC duct and air quality verification
Designed for 5+ years continuous unattended operation with minimal zero drift, ensuring false alarms do not cause unwarranted commercial disruptions.
CO at human breathing zone (1.5 m); LPG gas at 30 cm from floor; PNG/Natural gas at 30 cm from ceiling.
Daisy-Chained Modbus RTU RS-485 to Building Management System (BMS)
2-stage ventilation fan sequencing: Stage 1 (25 PPM CO) runs VFD jet fans at 50% speed; Stage 2 (50 PPM CO) runs fans at 100% speed.
Before beginning to consider gas detection equipment, a risk assessment needs to be conducted. If gas hazards are identified, gas detection is applicable as a risk reduction method.
Depending on processes and gases being detected, remote or off-site alarm notification plus event data logging/reporting may be required for health and safety records.
Suitable equipment is selected by asking questions about gases to be detected, location and environmental conditions, and ease of use for operators and service personnel.
The gases to be detected should be identified by risk assessment. It is also essential to identify the potential source of gas release to determine detector quantity and location based on vapor weight.
Temperature, humidity, pressure, production variations and seasonal changes all affect the type of equipment that should be selected (IP66/67 rating, heated optics, splash guards).
Wiring configuration, retrofit requirements, local displays, configuration needs and communication protocols such as analog 4-20mA signal, HART, Lonworks or Modbus RS485 may be required.
Routine maintenance is important. Different sensing technologies have different maintenance needs, so in-house resources or third-party maintenance budgets should be considered.
Our senior instrumentation engineers will review your P&ID schematics, hazardous area classifications, and recommend an optimal detector grid.
KNOWLEDGE BASE & REGULATORY COMPLIANCE
Practical compliance, sensor physics, DCS telemetry, and NABL calibration answers curated by Detection Technology senior instrumentation specialists.
Under the Indian Factories Act (Section 38 & Second Schedule), Directorate of Industrial Safety and Health (DISH) guidelines, OISD-179 standards for Petroleum and Natural Gas, and Central Electricity Authority (CEA) regulations, any facility handling hazardous, combustible, or toxic chemicals must install continuous gas and flame monitoring with automated failsafe trip interlocks. Instruments installed in hazardous areas must possess statutory PESO (CCOE) and IS/IEC 60079 certificates.
Zone 1 designates an area where an explosive gas atmosphere is likely to occur during normal operation (requiring flameproof Ex d IIC Gb or intrinsically safe Ex ia enclosures). Zone 2 designates an atmosphere where flammable mixtures are not likely to occur during normal operation, or will only persist for a short time (requiring Ex nA, Ex ec, or Ex d). Detection Technology fixed transmitters are engineered and certified for harsh Zone 1 and Zone 2 industrial environments.
Safety Integrity Level 2 (SIL-2, per IEC 61508 / IEC 61511) certifies that an instrument has a Probability of Failure on Demand (PFD) between 0.001 and 0.01 (99% to 99.9% reliability). In critical safety instrumented loops, SIL-2 certified detectors guarantee that toxic gas accumulation or hydrocarbon flame triggers automated trip valves and deluge systems without dangerous unrevealed hardware failure.
Catalytic pellistors detect both hydrocarbons and hydrogen through catalytic oxidation, but can be poisoned by airborne silicones, sulfur, and halogenated compounds. NDIR sensors use optical infrared absorption; they are 100% immune to chemical poisons, operate in zero-oxygen atmospheres, and last 5+ years without replacement, making them the industry standard for refineries, offshore platforms, and tank farms.
Sensor elevation must be engineered around vapor density relative to ambient air (Air = 1.0). Heavy gases (LPG: 1.5–2.0, H₂S: 1.19, Chlorine: 2.45, CO₂: 1.52) sink and must be mounted 30 cm to 60 cm above floor level. Lighter gases (Methane/Natural Gas: 0.55, Hydrogen: 0.07, Ammonia: 0.59) rise and must be installed within 30 cm of the ceiling or directly above potential release points.
Standard %LEL sensors only measure flammable gas concentrations in the percent range (1% LEL = 10,000 ppm), which is far too coarse for toxic solvent vapors. Photoionization Detectors (PID) use a 10.6 eV UV lamp to ionize volatile organic compounds (VOCs such as benzene, toluene, xylene, and chlorinated solvents) down to parts-per-billion (ppb) and ppm exposure limits.
Transmitters output standard 3-wire or 4-wire linear 4-20mA analog signals (sink/source) and multi-drop digital Modbus RTU RS-485. This allows seamless daisy-chaining or point-to-point wiring directly into any standard industrial DCS, SCADA, or PLC system.
Yes. Our transmitters feature onboard dual SPDT dry contact relays (Low Alarm / High Alarm / Fault). These relays can directly switch 230V AC or 24V DC visual strobes, 110 dB sirens, and magnetic motor starter coils for ventilation blowers independently of any PLC communication failure.
We specify 3-core or 4-core, 1.5 mm² or 2.5 mm² stranded copper conductors with overall aluminum foil shielding, tinned copper drain wire, and steel wire armor (FRLS / PVC sheath) to protect against electromagnetic interference (EMI) from variable frequency drives (VFDs) and high-voltage switchgear.
A bump test is a brief functional check using certified challenge gas to verify that the sensor responds and alarms trip within 15 seconds. A span calibration involves adjusting the instrument's electronic zero and gain multipliers using certified zero air (or pure N₂) and NIST/NABL traceable span gas to restore absolute measurement accuracy.
Electrochemical toxic and oxygen sensors should be calibrated every 3 to 6 months. Catalytic pellistors require calibration every 3 to 6 months. NDIR infrared optical sensors should be verified every 6 to 12 months. Facilities with high continuous chemical exposure or statutory DISH audits should maintain quarterly calibration schedules.
Yes. Detection Technology provides Pan-India on-site calibration services with portable certified gas cylinders, factory-trained service engineers, emergency breakdown response, and NABL-traceable calibration certificates accepted by factory inspectors and third-party safety auditors (TUV, DNV, Bureau Veritas).
Speak directly with our senior application engineers or schedule an on-site hazardous area walkthrough.
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