Automatic Valves NAMUR Valves New Low Temperature Rating Announcement

Background on the Temperature Rating Change

Automatic Valves historically used a conservative approach to low temperature ratings for many legacy products. Rather than rating valves to their actual design capability, the company applied temperature limits based on the principle that water vapor in compressed air systems has the potential to form ice when operating below 40°F (4°C). This practical consideration guided the published temperature ratings, even though the valve hardware itself was fully capable of operating at much lower temperatures. With the updated announcement, Automatic Valves has modernized these ratings to reflect the actual mechanical and material capability of the valve design, while continuing to advise that air supply must be free of water vapor when operating below 40°F (4°C) to prevent ice formation.

No Design or Component Changes Required

An important aspect of this announcement is that no design modifications or component changes were made to the NAMUR Series valves. The improved low temperature rating is a reclassification based on the inherent capability of the existing valve design. This means that any currently installed Automatic Valves NAMUR valves are already capable of operating at the newly published lower temperatures. Customers with existing installations in cold environments can take immediate advantage of this updated rating without needing to replace or modify their valve equipment.

NAMUR Series Valve Product Overview

The Automatic Valves NAMUR Series encompasses a comprehensive range of pneumatic solenoid valves designed for direct mounting on quarter-turn and linear actuators according to the NAMUR (VDI/VDE 3845) interface standard. These valves are widely used in process control applications throughout the oil and gas, chemical, pharmaceutical, water treatment, and power generation industries. The NAMUR mounting interface provides a standardized, compact connection between the valve and the actuator, eliminating the need for external tubing and fittings and reducing potential leak points.

Weather-Proof NAMUR Valves

The Weather-Proof NAMUR valve configuration is designed for outdoor installations where the valve will be exposed to rain, humidity, dust, and temperature extremes, but where no hazardous atmosphere classification is required. These general-purpose valves provide robust, reliable actuator control in non-hazardous outdoor environments such as water treatment plants, power stations, and general manufacturing facilities. With the updated temperature rating of -29°C to 50°C (-20°F to 123°F), Weather-Proof NAMUR valves are now formally rated for use in the cold climates commonly found in northern regions of North America, Scandinavia, Russia, and other high-latitude locations.

Explosion-Proof NAMUR Valves

Explosion-Proof NAMUR valves feature CSA, FM Approved, and ATEX Approved solenoid coils housed in a robust explosion-proof enclosure. These valves are designed for installation in Class I, Division 1 hazardous classified locations where flammable gases or vapors may be present under normal operating conditions. The explosion-proof design contains any internal ignition within the enclosure, preventing it from reaching the surrounding hazardous atmosphere. The updated low temperature rating extends the formal operating envelope of these valves to -29°C (-20°F), which is particularly significant for oil and gas production and refining operations in cold climates where both hazardous atmosphere classifications and extreme cold temperatures are common.

Intrinsically Safe NAMUR Valves

Intrinsically Safe NAMUR valves use energy-limiting solenoid circuits that restrict electrical energy to levels below the minimum ignition energy of the surrounding hazardous atmosphere. These valves provide an alternative to explosion-proof designs and offer advantages in applications where live maintenance is required. Like the explosion-proof variants, Intrinsically Safe NAMUR valves carry CSA, FM, and ATEX approvals for hazardous locations. The -29°C (-20°F) low temperature rating allows these valves to be specified for cold-climate hazardous area applications with full confidence in their operational reliability.

Technical Specifications and Operating Conditions

The updated NAMUR Series valve specifications confirm the extended temperature range while maintaining all other performance parameters that have made these products a trusted choice in the industry. The complete standard specifications provide engineers with the detailed data needed for accurate system design and product selection.

Temperature and Pressure Ratings

The NAMUR Series valves now carry an ambient and media temperature rating of -29°C to 50°C (-20°F to 123°F). For temperatures below 40°F (4°C), air supply must be free of water vapor to prevent formation of ice within the valve passages. Operating pressure ranges are 0 to 10.3 bar (0 to 150 psig) for 3/2 valves, 2.4 to 10.3 bar (35 to 150 psig) for 5/2 valves, and 3.4 to 10.3 bar (50 to 150 psig) for 5/3 valves. External pilot supply pressure ranges from 2.4 to 10.3 bar (35 to 150 psig) for 3/2 and 5/2 valves and 3.4 to 10.3 bar (50 to 150 psig) for 5/3 valves.

Valve Construction and Materials

NAMUR Series valves feature spool-type construction with bar stock aluminum valve bodies and aluminum spools, providing excellent corrosion resistance and lightweight strength. Seals are constructed from Buna-N (nitrile rubber), which maintains its flexibility and sealing capability across the full rated temperature range, including the newly published low temperature limit of -29°C. Solenoid bodies are manufactured from Polyamid 66 (nylon), and all solenoids are rated for continuous duty operation. The valves accept filtered air as the flow media and use threaded NPT connections. A push-type, non-locking manual override is standard on all NAMUR valve models.

Valve Functions and Configurations

The NAMUR Series is available in 3/2 Normally Closed, 5/2, and 5/3 configurations. The 5/3 variants are available in Closed Center, Open Center, and Power Center options to match specific actuator control requirements. All configurations are designed for electrical solenoid pilot-controlled actuation and feature direct mount NAMUR interface mounting according to the VDI/VDE 3845 standard with 5mm fasteners. These configurations cover virtually all common actuator control scenarios in process automation.

Product Credentials and Safety Certifications

In addition to the updated temperature ratings, Automatic Valves NAMUR Series valves carry an impressive array of product credentials and safety certifications that make them suitable for the most demanding applications worldwide.

The valves hold Functional Safety Approval from SGS-TUV Saar, certifying them per the IEC 61508:2001 standard for Safety Integrity Level (SIL) applications. In singular application with HFT = 0, the valves are certified up to SIL 2, and in redundant application with HFT of 1 or greater, they are certified up to SIL 3 with Performance Level e. This SIL certification is critical for safety-related applications in the process industries, including emergency shutdown systems and safety interlock functions.

Additional certifications include ATEX approval for use in explosive atmospheres per EU directives, Factory Mutual (FM) approval for hazardous location use in North America, CSA Certificate of Compliance for Canadian and US markets, and a Declaration of Conformity for European regulatory requirements. This comprehensive certification portfolio allows engineers to specify Automatic Valves NAMUR products for virtually any global installation with confidence that all applicable regulatory requirements are met.

Impact for Cold Climate Applications

The extended low temperature rating to -29°C (-20°F) has significant implications for industries operating in cold climates around the world. Oil and gas production in arctic and subarctic regions, mining operations in northern climates, LNG processing and storage facilities, and outdoor process installations in continental climates with severe winters all benefit from pneumatic valve products that are formally rated for extreme cold operation.

Previously, engineers specifying valves for cold climate applications may have needed to request special temperature testing data or rely on anecdotal field experience to justify the use of standard NAMUR valves below their published rating. With the updated temperature specification, Automatic Valves has eliminated this uncertainty by providing a formal, published rating that can be confidently referenced in engineering specifications, project documentation, and regulatory submissions.

Automatic Valves has also indicated that adjustments for the low temperature capability of other products not included in this initial announcement will be documented in future online and downloadable product catalog updates. Customers can expect additional announcements as the company continues to modernize temperature ratings across its product portfolio.

Download the Low Temperature Announcement

The complete product news announcement detailing the updated low temperature ratings for Automatic Valves NAMUR Series valves is available for download in PDF format from this page. The document includes the updated specifications table, product credential information, and valve configuration details.

Automatic Valves, part of the ROSS Controls global family, is exclusively focused on fluid power, delivering high-quality and cost-effective pneumatic solutions for the automation, transportation, process, and automotive industries. Since 1945, Automatic Valves has been serving customers with quality, timely, and expertly engineered solutions specialized to their pneumatic needs. For questions on low temperature applications not covered by published data, contact Automatic Valves Technical Service at www.automaticvalve.com.

Frequently Asked Questions

What is the new low temperature rating for Automatic Valves NAMUR Series valves?

The updated temperature rating for Automatic Valves NAMUR Series valves is -29°C to 50°C (-20°F to 123°F). This applies to Weather-Proof, Explosion-Proof, and Intrinsically Safe NAMUR valve configurations. The previous published ratings were more conservative, based on water vapor icing concerns rather than the actual mechanical capability of the valve design.

Do I need to replace existing valves to get the new low temperature rating?

No. The improved low temperature rating reflects the inherent design capability of existing Automatic Valves NAMUR products. No design or component changes were made. Any currently installed NAMUR Series valves from Automatic Valves are already capable of operating at the newly published lower temperatures without modification or replacement.

Are there any special requirements for operating valves below 40°F (4°C)?

Yes. When operating NAMUR Series valves at temperatures below 40°F (4°C), the compressed air supply must be free of water vapor to prevent the formation of ice within the valve passages and ports. Proper air preparation, including drying and filtration, is essential for reliable operation in cold environments. Automatic Valves recommends using appropriately rated air dryers and filters upstream of the valve installation.

Which NAMUR valve configurations are covered by this announcement?

The low temperature rating update covers the full NAMUR Series product range, including 3/2 Normally Closed, 5/2, and 5/3 (Closed Center, Open Center, and Power Center) configurations. All solenoid types are included: Weather-Proof, Explosion-Proof (CSA, FM Approved, ATEX Approved), and Intrinsically Safe solenoid options.

Will Automatic Valves extend low temperature ratings for other products?

Yes. Automatic Valves has stated that adjustments for the low temperature capability of other products not included in this initial NAMUR announcement will be documented in updated online and downloadable product catalogs. Future announcements are expected as the company continues to modernize temperature ratings across its broader product portfolio.