As HVAC systems (Heating, Ventilation, and Air Conditioning) become increasingly critical across industrial, energy, and safety-critical environments, the demand for tough and reliable instrumentation continues to grow. And that includes within hazardous areas where standard HVAC units could be the source of an ignition as Paul Maddern explains.

Ex Switches and Transmitters in HVAC Systems in hazardous areas

HVAC systems used in industrial and energy infrastructure require precise and reliable instrumentation to maintain environmental control and ensure operational safety.

These switches and transmitters are essential for monitoring pressure, temperature, and flow within HVAC systems, particularly in safety-critical zones such as control rooms or accommodation modules for example. However, if standard devices were to be used in a potentially explosive atmosphere, the switch could be the source of an ignition and trigger an explosion.

For these hazardous area applications, flameproof or explosion proof switches and transmitters are therefore needed.

Designed and manufactured in the UK, the Pyropress range of robust and highly reliable Ex switches and transmitters meets the highest standards for hazardous area operation, with ATEX, IECEx and SIL2 rating.

Pyropress products are available in flameproof (Ex d) and intrinsically safe (Ex ia) configurations, ensuring compatibility with a wide range of hazardous environments including Zone 0, 1, 2, 20, 21 and 22.

SPOTLIGHT ON EX SWITCHES USED IN HVAC APPLICATIONS

For pressure control in hazardous areas:

• Perseus™ flameproof and intrinsically safe pressure switches are Ideal for OEMs building HVAC systems for hazardous areas

For temperature control in hazardous areas:

• Perseus™ flameproof and intrinsically safe temperature switches are available with rigid stem or capillary sensors and multiple switch configurations to suit a variety of HVAC applications

For level control in hazardous areas

• Argus™ intrinsically safe level switches are suitable for Zone 0, 1 and 2 hazardous areas and are perfect for applications such as water storage or cooling water for radiators

Ex Switches in HVAC Chiller Units

Pyropress switches used in HVAC systems can provide many different functions, such as essential pressure and temperature measurement to control the refrigeration cycle. In chiller units, these switches also activate condensate pumps, ensuring the system efficiently drains condensate to external outlets. Their compact designs and wide operating ranges make them ideal for both new installations and retrofit projects.

Pyropress switches are deployed in HVAC systems across a variety of sectors, including:

• Emergency Deluge Safety Showers: Small-scale HVAC systems maintain water temperatures between 15°C and 37°C to ensure operability in critical safety scenarios.
• Chemical and Refining Processes: Chilling operations in explosive atmospheres demand instrumentation that prioritises safety and reliability.
• Switchgear and IT Server Rooms: HVAC units typically operate outside the enclosures in hazardous zones.
• Analyzer shelters: Houses that safeguard critical equipment from adverse conditions in hazardous areas often feature HVAC systems that require ATEX rated switches and transmitters

Look for SIL2 switches and transmitters in hazardous areas

A Safety Integrity Level (SIL) is a measure of the reliability and performance of safety systems used to reduce risk in industrial processes. SIL levels are used to specify the necessary performance requirements for safety-related systems to ensure they function correctly when needed. There are four levels, with SIL2 commonly expected in the oil and gas industry.

SIL and ATEX address different aspects of safety while complementing each other. For example, ATEX ensures that equipment is safe to use in potentially explosive atmospheres by preventing ignition sources, while SIL ensures that safety systems are reliable and perform correctly to mitigate risks and prevent hazardous events.

In addition to their suitability in hazardous areas, and because of their reliability and SIL2 rating, Pyropress switches and transmitters are also ideal for challenging, long-life and critical applications. Nuclear is one example.

Case Study: Hinkley Point C

Pyropress has supplied SIL2 Titan™ flow and differential pressure switches for the HVAC system at Hinkley Point C Nuclear Power Station. These switches are engineered to detect ultra-low pressure changes, as low as 0.25 mBar, which are vital for maintaining airflow and system balance in critical infrastructure.

The Titan™ range features robust stainless steel housings and has a proven track record. Their deployment at Hinkley Point C highlights Pyropress’s commitment to precision, safety, and long-term reliability.

Pyropress Ltd is a UK manufacturer that is well-positioned to support the expanding HVAC market with a range of robust pressure, temperature, and level switches designed for performance in tough, critical and demanding environments, including Zoned hazardous areas.

About the author

Paul Maddern, Product Manager for Pyropress switches and transmitters, is a recognised expert in ATEX / IECEx certified and intrinsically safe instrumentation.

With decades of experience in hazardous area applications, Paul leads the development of reliable solutions for HVAC systems in applications ranging from nuclear, energy and a variety of industrial facilities, ensuring Pyropress products meet the highest standards of safety, precision, and durability.