What is intrinsically safe?

Intrinsically safe (IS) is a method of protecting equipment used in hazardous locations by limited electrical and thermal energy outputs to levels too low to ignite a flammable atmosphere. Devices certified as intrinsically safe must pass rigorous testing to verify they cannot produce sparks, arcs, or hot surfaces capable of igniting, even under specified fault conditions.

IS is one of the most practical protection methods for hazardous gas environments because it allows instruments to be installed directly inside the hazardous zone, often times without explosion proof enclosures or purge systems, while still allowing modern capabilities like electronic measurement, closed-loop control, and digital communication

Intrinsically safe instruments are most commonly used in applications where flammable gases or vapors may be present. Common examples include:

• Natural gas distribution and metering stations
• Hydrogen production, storage, and fuel systems
• Oil and gas well pads and processing plants
• Chemical processing and solvent handling
• Biogas, methane capture, and landfill gas systems
• Fuel transfer and vapor recovery systems
• Semiconductor and industrial gas delivery systems

In these environments, instrumentation must meet hazardous location requirements such as, ATEX, IECEx, and North American approvals.

Intrinsically safe instruments are designed to keep energy levels below ignition thresholds through engineering methods such as: 

• Limiting internal stored energy (capacitance / inductance)
• Restricting voltage and current under normal and fault conditions
• Controlling surface temperature to meet a temperature class
• Certifying the complete design against recognized standards and testing protocols

Many IS systems use an associated apparatus such as a Zener barrier or galvanic isolated, installed outside the hazardous location, to limit the power entering the hazardous area.

Hazardous locations are classified according to the type of explosive hazard (gas/vapor or dust) and the likelihood that an explosive atmosphere will be present. Alicat is not certified for hazardous dust locations. 

The table below summarizes this hazard classification system.

Important Note: Alicat intrinsically safe approvals are currently for gas/vapor hazards only. Alicat products are not certified for combustible dust hazardous areas (Zones 20/21/22 or Class II) 

These tables are simplified for educational purposes. Always consult applicable codes, local regulations, and the product marking/ certification documents for final installation compliance

See more information on CSA/ATEX certification for Class 1 Zone 2 or Class I Division 2 hazardous environments.

These devices are used in highly regulated hazardous environments where potentially explosives gases and dust can be or are constantly present.

If electronic, intrinsically safe devices are supplied energy through an electric barrier, which is an additional device that limits power. The barriers have additional failsafe electronics and limiters that are equally.

Alicat Scientific offers a dedicated product family of intrinsically safe flow and pressure instruments designed for hazardous gas environments, including Zone 0 / Class I applications

Alicat’s IS-Series instruments are certified through DEKRA and carry approvals aligned with ATEX (Europe), IECEx (international) and North American intrinsically safe requirements

IS-Series devices include:

• IS-Pro™ pressure controllers
• IS-Pro™ pressure meters
• IS-Max™ mass flow controllers
• IS-Max™ mass flow meters

Intrinsic safety requires correct selection of device approvals and markings, barrier/isolator configuration (when required), and installation practices. If you’re specifying a Zone 0 / hazardous gas application and want help selecting an IS-Series configuration, talk to an engineer for recommendations based on your installation and regional requirements.