
This guide provides a comprehensive overview of intrinsically safe measurement instrumentation, crucial for ensuring safety in hazardous environments. It explains the core principles of intrinsic safety, focusing on limiting electrical and thermal energy to prevent ignition in potentially explosive atmospheres.
The guide details the key components of an intrinsically safe system, including sensors, barriers, and cabling, and how they interact to safeguard personnel and equipment. It also explores the importance of certification, regulatory compliance, and proper installation and maintenance practices. Finally, the guide illustrates the diverse applications of intrinsically safe measurement instrumentation across various industries, highlighting its significance in protecting against the risks of explosions and fires.
- Intrinsic safety prevents explosions by limiting energy in hazardous areas, unlike containment methods.
- Systems comprise a hazardous-area sensor, safe-area barrier, and connecting cables. The barrier restricts energy flow.
- Sensors must be certified for the specific hazardous area classification to prevent ignition.
- Compliance with regulations is mandatory; proper installation and maintenance are crucial.
- Intrinsically safe instrumentation is used across diverse industries with explosive atmospheres.
Browse intrinsically safe measurement instrumentation by product type for use in hazardous areas with an intrinsic safety barrier.
Intrinsically Safe Liquid Level Sensors - Explore intrinsically safe liquid level sensors designed for hazardous areas (ATEX/IECEx). Options for external tank mounting & submersible use with IP68 seals.
Intrinsically Safe Pressure Gauges - Specialized intrinsically safe pressure gauges designed for hazardous environments. Certified to ATEX and IECEx standards for safe operation in volatile gas and vapor atmospheres.
Intrinsically Safe Pressure Transmitters - Intrinsically safe pressure transmitters which are certified for use with zener barriers or galvanic isolators, as part of an hazardous area installation.
Underground Mining Intrinsically Safe Pressure Transmitters - Intrinsically safe pressure transmitters specifically certified for underground mining, engineered to prevent methane (firedamp) ignition. Robust, reliable, and compliant with stringent mining IS standards.
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.
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.
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.
The Essence of Intrinsic Safety
Intrinsically safe measurement instrumentation plays a crucial role in ensuring safety within hazardous environments. These environments, often found in industries like chemical processing, oil and gas, and mining, may contain potentially explosive atmospheres. The core principle of intrinsic safety is to limit the electrical and thermal energy within these hazardous areas, preventing ignition of flammable gases, vapors, or dust. This is achieved by carefully designing and certifying equipment to ensure that even under fault conditions, the energy released is insufficient to cause ignition. This approach differs from other protection methods, such as explosion-proof enclosures, by preventing the explosion from occurring in the first place.
The Role of Barriers and Sensors
A typical intrinsically safe measurement system consists of a sensor located within the hazardous area, connected via cables to a barrier device situated in a safe area. The barrier, which can be either a Zener diode barrier or a galvanic isolator, acts as a safeguard. It restricts the amount of electrical energy that can travel into the hazardous area, effectively limiting voltage and current to intrinsically safe levels. Zener barriers divert excess energy to ground, while galvanic isolators use transformers to provide isolation and limit energy transfer. The selection of the appropriate barrier type depends on the specific application requirements, including the type of sensor, the signal characteristics, and the safety requirements of the hazardous area.
Sensor Design and Certification
The sensor itself is a critical component. It must be designed and certified to operate safely within the designated hazardous zone. Certification bodies, accredited by relevant government agencies, rigorously test and assess the sensor’s design and performance to ensure compliance with stringent safety standards. This certification process involves evaluating the sensor’s electrical parameters, its operating temperature, and its construction to ensure that it cannot become a source of ignition. The sensor’s certification details, including its permissible energy levels and installation requirements, are essential for proper system design and installation.
Sensors must be certified for the specific hazardous area classification to prevent ignition. This certification process involves rigorous testing and assessment by independent bodies to ensure compliance with stringent safety standards. Manufacturers seeking to market their intrinsically safe products globally often obtain certifications from multiple national approval bodies to facilitate acceptance in different regions. Some of the most commonly sought-after certifications include:
- ATEX (Europe): Mandated by the European Union, ATEX certification covers equipment used in potentially explosive atmospheres.
- IECEx (International): A globally accepted scheme for certification of equipment for explosive atmospheres, providing a basis for mutual recognition between participating countries.
- UL (North America): Underwriters Laboratories (UL) offers certification and safety testing services for a wide range of products, including those used in hazardous locations.
- FM (North America): FM Approvals, part of FM Global, provides testing and certification services for industrial and commercial products, with a focus on loss prevention.
- CSA (North America): The Canadian Standards Association (CSA) offers certification and testing services for various products, including those used in hazardous environments.
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Cabling, Grounding, and Bonding Considerations
The cables connecting the sensor to the barrier are also carefully considered. They must be selected to minimize the risk of energy storage or transfer, and their installation must adhere to specific guidelines to prevent damage or degradation that could compromise safety. Furthermore, the entire system, including the sensor, barrier, and cabling, must be properly grounded and bonded to prevent the buildup of static electricity, which could also serve as an ignition source.
Regulatory Landscape and Compliance
Intrinsic safety standards and regulations vary by region. It’s crucial to consult the local regulations and guidelines to ensure that the measurement instrumentation is compliant. These regulations often specify the types of hazardous areas, the required protection levels, and the certification procedures for equipment used in those areas. Choosing certified equipment from reputable manufacturers is essential for ensuring compliance and maintaining safety. Regular inspection and maintenance of intrinsically safe systems are also critical to verify their continued integrity and proper operation. This includes checking cable connections, verifying barrier performance, and ensuring that the sensor remains within its certified parameters.
Diverse Applications of Intrinsic Safety
Use cases for intrinsically safe measurement instrumentation are diverse. In chemical plants, these systems are used to monitor process variables such as temperature, pressure, and flow in areas where flammable or explosive materials are present. In oil and gas exploration and production, intrinsically safe sensors and transmitters are essential for monitoring well conditions and pipeline integrity in hazardous offshore or onshore environments Mining operations rely on intrinsically safe instrumentation to detect gas levels and monitor equipment performance in underground areas where explosive atmospheres can accumulate.
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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
- Transforming a 2 wire Current Loop into a Voltage Output Signal
- 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