A guide to intrinsic safety measurement instrumentation including explanations, applications and choice of products for installing in hazardous areas.
Intrinsically safe certification is a standard used to limit the amount of energy, heat or ignition sources entering a hazardous zone which may contain a potentially flammable or explosive atmosphere.
Typically a sensor installed in a hazardous area is connected to measurement instrumentation via a zener diode or galvanic (transformer) isolated barrier system located in a safe area.
The sensor is matched with the barrier system so that the barrier will prevent any voltage and current levels exceeding limits defined in the sensor intrinsic safety approval parameters.
Any electrical energy exceeding the barrier limits will be redirected to ground/earth in the case of the zener barrier or blocked in the case of the galvanic (transformer) isolated barrier.
Intrinsically safe certification is controlled and regulated by a government’s health and safety department in the country where the measurement instrumentation is to be installed and used. Commercial organisations are appointed to provide assessment and approval services to industry.
Browse intrinsically safe measurement instrumentation by product type for use in hazardous areas with an intrinsic safety barrier.
Hazardous Area Externally Fitted Hydrostatic Liquid Level Sensors - Ensure safe and accurate liquid level measurement in hazardous environments with our selection of externally mounted hydrostatic level sensors.
Hazardous Area Submersible Hydrostatic Liquid Level Sensors - Explore our range of intrinsically safe (IS) submersible hydrostatic level sensors, designed for accurate liquid level measurement in hazardous environments
Intrinsically Safe Pressure Switches - Intrinsically safe pressure switches, when used with approved zone barriers, provide reliable pressure monitoring and control in hazardous environments where explosive gases or dust may be present.
Intrinsically Safe DP Sensors - Intrinsically safe differential pressure sensors are essential for accurate pressure measurement in hazardous environments where explosive atmospheres may be present.
Intrinsically Safe Submersible Sensor and Instrument Probes - IP68/NEMA 6X sensors for immersing in tanks on sites where instrumentation must be certified for use in hazardous areas.
Landfill Site Intrinsically Safe Pressure Transmitters - Intrinsically safe pressure transmitters are essential for monitoring landfill gas pressure in hazardous environments.
Low Pressure Range Intrinsically Safe Pressure Transmitters - These intrinsically safe pressure transmitters are designed for precise measurement in hazardous areas where low pressure ranges are critical.
Hydraulic Testing Intrinsic Safety Approved Pressure Data Loggers - Intrinsically safe pressure data loggers are essential tools for testing and validating the performance of hydraulic systems in hazardous environments where explosive atmospheres may be present.
Underground Mining Intrinsically Safe Pressure Transmitters - Pressure transmitters which have been approved for use with intrinsically safe installations in underground mines.- Intrinsically Safe Liquid Level Sensors - Liquid level sensors with intrinsic safety approval for measuring the level of fluid contents where flammable gas or dust is present.
- Intrinsically Safe Pressure Data Loggers - Intrinsically safe (IS) pressure data loggers which can be used in potentially explosive environments such as oil refineries, offshore oil platforms and natural gas distribution.
Intrinsically Safe Pressure Gauges - Intrinsically safe pressure gauges which are Ex certified for use in areas where flammable or explosive substances are stored or processed.
Intrinsically Safe Pressure Transmitters - Choose an intrinsically safe pressure transmitters with a 4 to 20 milliamp output which is certified for use as part of an intrinsically safe installation.
Questions & Answers
USA version of ATEX II 2 G
What is ATEX II 2 G classification and what is the USA equivalent?
This refers to the ATEX Ex coding which is the European regulatory directive for using equipment in hazardous areas.
- II = Non-Mining
- 2 = Non-Mining: High Protection – Equipment must be safe during regular functioning and likely failures, required for Gas zone 1 and/or Dust zone 21
- G = Explosive Gas environment
Hazard area equipment is approved by FM Approvals (Factory Mutual) in the USA, and this chart shows a comparison between FM (top) and ATEX (bottom) markings, according to this chart the equivalent FM marking for ATEX II 2 G is:
- 2 = Division 1, Zone 1
- G = Class 1 (Gases, Vapours or Liquids)
Related Help Guides
Glossary of Measurement Signal technical terms
- 2 Wire
- 3 Wire
- 4 to 20 mA Current Loop Output Signal
- 4 Wire
- Amplified Voltage Output
- BFSG – Bonded Foil Strain Gauge
- Deadband
- FSO – Full Scale Output
- HART®
- mV/V – Millivolts per Volt Output Signal
- NC – Normally Closed
- NO – Normally Open
- Piezoresistive Strain Gauges
- Rangeable
- Ratiometric
- Span
- Span Offset
- Span Sensitivity
- Square Root Extraction
- Threshold
- Totalizer
- Transducer
- Transmitter
- TSL – Terminal Straight Line
- TSS – Thermal Span or Sensitivity Shift
- Turndown Ratio
- USB
- Vented Cable
- Wheatstone Bridge Strain Gauge
- Zero Offset
- Zero Tare
Help from Measurement Signal resources
- Supply voltage and load resistance considerations for pressure transmitters
- What can cause random variation in pressure transducer output
- What is the difference between zero offset and zero drift?
- Why use 4-20mA and 3-15 psi rather than 0-20mA & 0-15psi
