Hazardous Location Valves [27 Series] 2/2, 3/2, 4/2 Functions

Product Overview

The ROSS Controls 27 Series Hazardous Location Valves are inline poppet directional control valves engineered specifically for use in classified hazardous areas where the ignition of flammable gases, vapors, flammable liquids, combustible dust, or easily ignitable fibers represents a genuine operational risk. Available in 2/2, 3/2, and 4/2 valve functions with port sizes from 1/4" to 2-1/2" and flow capacities up to Cv (81,000 Nl/min), these valves combine the proven reliability of the ROSS 27 Series poppet platform with CSA/FM approved explosion-proof coils, ATEX-certified coils, and intrinsically safe coil options to meet international hazardous area classification requirements.

The explosion-proof coil housing is designed and certified to contain any spark, arc, or thermal event originating within the solenoid coil or its housing. Should an internal electrical fault occur, the robust enclosure prevents ignition of surrounding flammable atmospheres by physically containing the potential ignition source. This approach, verified by CSA and FM approval, qualifies the valves for use in Class I, Division 1 locations where ignitable gas or vapor concentrations can exist under normal operating conditions. ATEX-certified coils extend this protection to European Zone 1 and Zone 2 classified locations. Intrinsically safe coil options limit electrical and thermal energy to levels inherently incapable of causing ignition under any failure mode.

Mechanically, the 27 Series hazardous location valves retain the full performance characteristics of the standard 27 Series platform. Perpendicular poppet face seals deliver near-zero leakage and positive shutoff without the sliding contact wear inherent in spool valve designs. The differential piston actuator generates overwhelming shifting forces, ensuring positive actuation from idle even after extended shutdown periods or in contaminated air environments. The rotating pilot feature allows coil orientation to be adjusted after installation, simplifying conduit routing and field service access in tight equipment enclosures.

For design engineers specifying pneumatic controls in oil and gas, petrochemical, pharmaceutical, mining, grain handling, and paint spray booth applications, the 27 Series Hazardous Location valves provide the combination of high-flow poppet performance, broad port size range, and multi-certification hazardous area approval that eliminates the need to source separate valve bodies for different international site standards.

Key Engineering Features

• Explosion-Proof Coil Certification (CSA/FM) - CSA and FM approved explosion-proof coil housing certified for Class I, Division 1, Groups A, B, C, D; Class II, Division 1, Groups E, F, G; Class III. The coil enclosure is designed to contain any internal spark or arc, preventing ignition of the surrounding flammable atmosphere.
• ATEX-Certified Coil Option - ATEX-certified coils meeting II 2 G Ex mb IIC T5 rated for European Zone 1 and Zone 2 hazardous area classifications. Provides compliance with ATEX Directive 2014/34/EU for European installations without requiring a separate valve body.
• Intrinsically Safe Coil Option - Intrinsically safe coils rated for Class I, II, III, Division 1, Groups A through G, T5 temperature class. Energy-limited design prevents spark generation under both normal and fault conditions, providing the highest level of hazardous location protection.
• Poppet Construction for High Dirt Tolerance - Perpendicular poppet face seals create high-velocity airflow across seating surfaces on each cycle, generating a continuous self-cleaning action. This construction delivers near-zero internal leakage and positive shutoff while maintaining performance in contaminated compressed air systems common in mining, chemical, and food processing facilities.
• Positive Sealing with No Sliding Action - Unlike spool valves that rely on precision sliding tolerances susceptible to contamination-induced wear and leakage, the poppet sealing mechanism lifts directly off a fixed seat. This eliminates the sliding friction mechanism that causes progressive leakage, seal groove wear, and eventual valve failure in high-cycle industrial applications.
• Rotating Pilot for Orientation Flexibility - The solenoid pilot assembly can be rotated after installation to any of four positions, allowing conduit entry direction to be optimized for the specific installation layout without modifying or replacing the valve body. This feature significantly reduces conduit routing complexity in hazardous area enclosures where space is constrained.
• Wide Port Size Range - Nine body sizes cover port configurations from 1/4" through 2-1/2" in both NPT and G (BSPP) thread forms, delivering flow capacities up to Cv for 3/2 functions. This range accommodates everything from small cylinder controls to large-volume air supply and exhaust in a single certified product family.
• NPT and G Thread Options - Standard models use NPT threads. G (BSPP) thread variants are available by adding the 'D' prefix to the model number (e.g., D2773B5002W), allowing the same certified valve platform to be used in both North American and international installations without separate certifications.
• Non-Locking Manual Override - Standard on all solenoid pilot controlled models. Allows manual actuation during commissioning, system verification, and troubleshooting without requiring electrical power. The non-locking design returns the valve to the solenoid-controlled state when released, preventing inadvertent position lock-in.
• Differential Piston Actuator Design - Generates overwhelming shifting forces relative to the spring return load, ensuring positive, no-hesitation actuation on every cycle including after extended idle periods. This design margin is critical in hazardous location installations where cycle verification before production restart must be reliable.
• Self-Compensating Seal System - Internal guidance geometry automatically adjusts poppet stroke as seals experience wear over time, maintaining consistent response characteristics and leak-free sealing over millions of operating cycles without recalibration or adjustment.

Technical Specifications

General Specifications

Temperature Ratings

The 27 Series Hazardous Location valves are rated for standard industrial temperatures. The ambient and media temperature limits are driven by solenoid coil thermal ratings. Pressure-controlled (air pilot) variants are not subject to coil limits and tolerate the full media temperature range.

Important: For media temperatures below 40 F (4 C), compressed air must be free of water vapor to prevent ice formation inside the valve. Dry the compressed air supply to a dew point below the minimum operating temperature before commissioning.

Electrical Data (Solenoid Pilot Valves)

Explosion-proof CSA/FM coils and ATEX coils carry different power ratings due to the distinct enclosure construction requirements of each certification. Intrinsically safe coils have the lowest power consumption. All coil types are rated for continuous duty.

Electrical Connection Options

Flow Performance Data

Flow performance data for representative Solenoid Pilot Controlled 3/2 NC and 2/2 NC configurations. Cv values for larger body sizes are identical between hazardous location and standard 27 Series models because the valve body is unchanged; only the coil/pilot assembly differs. Response time formula applies across all functions and body sizes.

Response Time Formula: Response Time (ms) = M + (F x V), where M is the minimum response constant (ms), F is the fill or exhaust factor (ms/cubic inch), and V is the downstream volume in cubic inches to be filled to 90% of supply pressure or exhausted to 10% of supply pressure. M and F values for each body size and function are published in the ROSS 27 Series catalog.

Certifications & Compliance

Typical Applications & Industries

Oil and Gas Production and Refining

• Wellhead pneumatic actuator controls and emergency shutdown (ESD) systems in Class I, Division 1 locations where hydrocarbon vapors can be present at ambient conditions. The explosion-proof coil provides the required containment for Division 1 service.
• Pipeline valve actuator controls at compressor stations, metering skids, and pipeline isolation points where fugitive hydrocarbon vapor creates persistent classified atmosphere conditions.
• Offshore platform pneumatic controls exposed to salt-spray and flammable gas atmospheres. The Buna-N seals and aluminum body provide corrosion resistance appropriate for marine industrial environments.
• Refinery process unit actuator circuits for control valves in distillation, cracking, and treating units operating in Division 1 classified areas.
• Tank farm loading rack automation where hydrocarbon vapor concentration during filling operations creates Class I, Division 1 conditions.

Chemical and Petrochemical Manufacturing

• Reactor vessel actuated valve controls and emergency dump systems in chemical manufacturing areas classified Class I, Division 1 due to volatile organic compound (VOC) process streams.
• Solvent storage and transfer automation in pharmaceutical and specialty chemical facilities where ketone, ester, and aromatic solvent vapors create ongoing explosion hazards requiring CSA/FM certified pneumatic controls.
• Dust-ignition-proof applications in powder handling facilities such as pigment manufacturing, plastic compounding, and mineral processing where Class II combustible dust atmospheres are present.
• Polymerization process controls where static-sensitive monomer atmospheres and reactive chemical environments require intrinsically safe coil configurations with energy-limited electrical circuits.

Mining and Mineral Processing

• Underground coal mine pneumatic equipment controls in methane-classified atmospheres where ATEX or CSA/FM certification is mandatory for all electrical equipment including solenoid coils.
• Surface mining conveyor system controls in dusty environments classified Class II for combustible mineral dusts including coal dust, sulfur dust, and grain dust.
• Mineral processing mills handling explosive dust fractions from crushing and grinding operations where Class II, Division 1 classification applies to areas near dust collection and transfer points.

Food, Grain, and Agricultural Processing

• Grain elevator pneumatic conveying valve controls in Class II, Division 1 areas where grain dust creates explosion-hazard atmospheres. The large body sizes (2" and 2-1/2") accommodate the high-volume airflow requirements of pneumatic conveying systems.
• Flour milling equipment automation where fine flour dust suspended in air presents Class II explosion hazards requiring dust-ignition-proof certified coils.
• Alcohol distillation and fermentation facility valve controls in Class I, Division 1 locations classified for ethanol vapor hazard.
• Sugar refining and confectionery manufacturing where fine sugar dust in process areas constitutes a Class II combustible dust hazard requiring certified pneumatic components.

Paint, Coating, and Solvent Handling Operations

• Spray booth pneumatic controls for automated paint application equipment in Class I, Division 1 areas classified for flammable solvent vapor during continuous spray operations.
• Coating material pump and distribution valve actuation in paint mixing rooms where Class I, Division 1 or Division 2 classification applies based on ventilation design.
• Solvent-based adhesive and ink manufacturing process valve controls where aromatic and aliphatic solvent vapors create persistent flammable atmosphere classifications.

Pharmaceutical and Specialty Chemical Manufacturing

• Active pharmaceutical ingredient (API) synthesis reactor and vessel controls in solvent-classified areas where Class I, Division 1 conditions apply to reaction and extraction process zones.
• Tablet press dust collection and powder handling automation in Class II combustible pharmaceutical dust environments.
• Solvent-based coating and granulation processes in pharmaceutical manufacturing where explosion-proof or intrinsically safe coil specifications are required by facility electrical area classification.

Ordering and Model Number Configuration

The ROSS 27 Series Hazardous Location valves use the same base model number structure as the standard 27 Series, with coil certification designated by a suffix appended to the model number. The example below shows a 3/2 NC solenoid pilot controlled valve in 3/4" body size for 24 VDC service with an explosion-proof CSA/FM coil.

Voltage codes: H = 12 VDC, W = 24 VDC, Z = VAC/60 Hz, Y = VAC/60 Hz. Contact ROSS Controls for voltage requirements outside these options.

For G (BSPP) thread versions, add the prefix 'D' before the model number (e.g., D2773B5002W). G thread models are available for all body sizes and valve functions.

Coil certification suffix: no suffix = Explosion-Proof CSA/FM coil (standard); suffix -A = ATEX certified coil; suffix -N = Intrinsically Safe coil. Specify the required certification based on site electrical area classification and applicable standards.

The valve body, poppet assembly, seals, and all wetted components are identical between the standard 27 Series and the hazardous location 27 Series. Only the solenoid pilot assembly changes. This allows maintenance inventory to be shared between standard and hazardous location installations.

Pressure (pneumatic) controlled models do not require coil certification because they have no electrical components in the control interface. Specify actuation code '5' instead of '7' for pressure-controlled variants in applications where instrument air pilot signal is available.

Accessories

Exhaust Silencers

Aluminum exhaust silencers reduce compressed air exhaust noise at the valve exhaust port. Available for port sizes 1/4" through 2-1/2". Pressure rating 0 to 290 psig (0 to 20 bar). Silencers do not require separate hazardous location certification because they contain no electrical components.

Warning: Exhaust silencer flow capacity must equal or exceed the valve exhaust flow capacity. Undersized or contaminated silencers create back pressure on the exhaust port that reduces differential pressure across the poppet seat and can result in incomplete or erratic valve shifting.

Indicator Light Kits

Optional indicator light kits provide visual solenoid-energized confirmation for solenoid pilot controlled 27 Series valves. Note: Indicator light kits must themselves be rated for the hazardous location classification of the installation. Verify approval markings before installing in classified areas. Available for 24 VDC (model 862K87-W), 110-VAC (model 862K87-Z), and 220 VAC (model 862K87-Y).

Pressure Booster Adaptor

Mounts between the solenoid pilot and the valve body to allow operation at pilot pressures as low as 15 psig (1 bar). Useful in pneumatic circuits where supply pressure is too low to directly actuate the main valve poppet. The Pressure Booster Adaptor uses inlet supply pressure amplified by the adaptor piston to develop full shifting force from a low-pressure pilot signal.

Related Products & Accessories

• 27 Series Standard Temperature Classic Valves - Standard temperature inline poppet valves without hazardous location coil certification. Same valve body and poppet platform; specify when the installation area is unclassified and no explosion-proof certification is required. https://www.rosscontrols.com/en/series/230-standard-temperatures-classic-27-series
• 21 Series Hazardous Location Valves - Hazardous location valves in the smaller 21 Series platform (port sizes 1/4" to 1-1/2") with explosion-proof and ATEX coil options for low-temperature applications down to -4 F (-20 C). https://www.rosscontrols.com/en/series/2828-hazardous-location-valves-21-series
• NAMUR D20 Series Hazardous Location Valves - NAMUR interface valves with explosion-proof, ATEX, and intrinsically safe coil options for direct mounting to pneumatic actuators in classified hazardous areas. https://www.rosscontrols.com/en/series/3012-namur-valves-automatic-valve-d20-series
• L-O-X Lockout Valves - Pneumatic energy isolation lockout valves for OSHA lockout/tagout compliance. Install upstream of hazardous location valves to isolate pneumatic energy during maintenance. https://www.rosscontrols.com/en/series/1287-lockout-valves-15-series
• Exhaust Silencers - Aluminum threaded silencers for noise reduction at valve exhaust ports, rated to 290 psig for port sizes 1/4" through 2-1/2". https://www.rosscontrols.com/en/series/90-silencers

Frequently Asked Questions (FAQ)

Q: What is the difference between explosion-proof and intrinsically safe coil options for the 27 Series?

A: Explosion-proof coils use a heavy-duty, certified enclosure designed to contain any internal spark or arc within the coil housing, preventing ignition of surrounding flammable atmospheres. The enclosure is strong enough to withstand an internal explosion without allowing flame propagation. Intrinsically safe coils instead limit electrical energy within the circuit to levels incapable of causing ignition under any normal or fault condition. The choice between them depends on facility classification, existing control system architecture, and the relevant standard being applied. Explosion-proof is more common for Division 1 North American installations; intrinsically safe is often preferred where energy-limited circuits are already in use or where the control barrier simplifies system architecture.

Q: Which hazardous location classifications do the 27 Series explosion-proof coils cover?

A: CSA/FM explosion-proof coils are certified for Class I, Division 1, Groups A, B, C, D (flammable gases and vapors); Class II, Division 1, Groups E, F, G (combustible dusts); and Class III (easily ignitable fibers). They are also suitable for Class I, Division 2 non-incendive service. ATEX coils cover European Zone 1 and Zone 2 (gas/vapor) per II 2 G Ex mb IIC T5 classification.

Q: What is the operating pressure range for the 27 Series Hazardous Location valves?

A: For body sizes 3/8" through 1-1/2", the operating pressure range is 15 to 150 psig (1 to 10 bar). For the 2" body size, the minimum operating pressure increases to 30 psig (2 bar) due to the higher differential force required to shift the larger poppet assembly. Maximum pressure is 150 psig (10 bar) for all body sizes.

Q: What are the ambient and media temperature limits for the 27 Series Hazardous Location valves?

A: Solenoid pilot controlled models are rated for 40 to 140 F (4 to 60 C) ambient and 40 to 175 F (4 to 80 C) media temperature. The ambient limit is set by the solenoid coil thermal rating. For pressurized (pneumatic) controlled variants without solenoid coils, both ambient and media temperature limits extend to 175 F (C). For installations at the upper ambient limit, verify that the coil temperature class (T5) is compatible with the site hazardous area temperature classification requirement.

Q: Can the pilot on the 27 Series Hazardous Location valve be rotated after installation?

A: Yes. The solenoid pilot assembly is designed to rotate to any of four positions (0, 90, 180, or 270 degrees) relative to the valve body, allowing the conduit entry direction to be oriented for the installed conduit routing without replacing the valve. This feature is particularly valuable in hazardous area installations where conduit routing is constrained by enclosure geometry or other equipment. Rotate the pilot before sealing conduit fittings.

Q: Are NPT and G (BSPP) thread options available in the same hazardous location certification?

A: Yes. G (BSPP) thread versions carry the same CSA/FM and ATEX certifications as NPT models. To order G thread versions, add the prefix 'D' to the model number (e.g., D2773B5002W for an NPT standard model becomes D2773B5002W with G threads). Both thread types use identical valve bodies and poppet assemblies.

Q: What filtration level does the compressed air supply need to meet?

A: The 27 Series requires filtered compressed air. A 40-micron inline filter is recommended upstream of the valve. If the upstream air supply is questionable in quality, finer filtration (5-micron) reduces the risk of particulate contamination on poppet seating surfaces. The self-cleaning poppet design provides significant tolerance for airborne contamination, but gross particulate ingestion will reduce valve service life in any pneumatic valve.

Q: Can the 27 Series Hazardous Location valve be field-converted from internal to external pilot supply?

A: Yes. Field conversion from internal to external pilot supply is accomplished by relocating the pipe plug between the external pilot port (X-1) and the internal pilot passage. No replacement parts are required. This conversion is useful when supply pressure varies below the minimum operating pressure, requiring a stable external pilot source. Document the conversion and update the valve model number designation in the installation records for traceability.

Q: Are spare parts and service kits available for the 27 Series Hazardous Location valves?

A: Yes. ROSS Controls offers valve body service kits containing all parts needed for complete valve body reconditioning, including poppets, spindle, gaskets, and seals. Separate gasket and seal kits are available for routine preventive maintenance. The solenoid pilot assembly and replacement solenoid coils are also available as individual service items. Because the valve body is identical between the standard and hazardous location 27 Series, body service kits are interchangeable.

Q: What does the T5 temperature classification on the ATEX coils mean?

A: The T5 temperature class indicates that the external surface temperature of the coil enclosure will not exceed 100 C (212 F) under any operating condition, including fault conditions. This maximum surface temperature is below the ignition temperature of the gas groups covered by the IIC classification (which includes hydrogen and acetylene, the most easily ignited gases). The T5 class must be equal to or lower than the ignition temperature class required by the site hazardous area assessment and documented in the area classification drawing.

Q: Can the 27 Series Hazardous Location valves be used in Group A (hydrogen) classified areas?

A: CSA/FM explosion-proof coils are approved for Class I, Division 1, Group A (hydrogen and equivalent), which is the most demanding North American gas group classification. ATEX coils certified to IIC Gas Group also cover hydrogen and acetylene. Verify that your specific model number carries the applicable Group A or IIC approval before installing in hydrogen-classified areas.

Q: What maintenance interval should be planned for the 27 Series in continuous-duty hazardous location service?

A: The 27 Series poppet construction does not require periodic lubrication of the valve body internals under normal service conditions. Maintenance planning should focus on (1) periodic air quality verification to confirm the upstream filtration system is functioning correctly, (2) inspection of the exhaust silencer for contamination-induced back pressure, and (3) visual inspection of conduit seals and coil housing integrity during routine plant inspections. Service kits should be on-hand as part of the maintenance stock. In continuous-duty high-cycle applications, budget for valve body kit replacement after multi-million cycle service intervals based on valve body condition.

Q: Are 3D CAD models available for the 27 Series Hazardous Location valves?

A: Yes. Downloadable CAD models are available for all 27 Series Hazardous Location valve variants through the ROSS Controls website at rosscontrols.com. Note that the dimensional envelope of the hazardous location models differs from the standard 27 Series due to the larger explosion-proof or ATEX coil housing. Always use the hazardous location-specific CAD model during machine design to ensure correct clearance and conduit routing allowances.

Installation & Maintenance Guidelines

• Mount the valve inline in any orientation. Vertical mounting with the pilot on top is preferred because it promotes condensate drainage away from the valve internals and provides optimal coil heat dissipation. Avoid mounting with the pilot facing downward in environments with significant airborne contamination or washdown exposure.
• Supply filtered compressed air at a minimum 40-micron filtration level. Contaminated or wet air accelerates poppet seat wear and can cause seal degradation. Install an air filter-regulator upstream of the valve, positioned as close to the valve as practical to minimize unfiltered line volume.
• Verify that supply pressure remains within the valve operating pressure range throughout the full system operating cycle, including pressure drops during high-demand periods. The minimum operating pressure is 15 psig (1 bar) for 3/8" through 1-1/2" body sizes and 30 psig (2 bar) for the 2" body size. Operation below these minimums results in incomplete valve shifting.
• For external pilot supply configurations, the pilot pressure must be equal to or greater than the inlet pressure at all times. Use a separate regulated pilot supply if inlet pressure varies significantly during the operating cycle.
• Install all electrical conduit and conduit fittings in accordance with the applicable hazardous location wiring standard for the site: NEC Article 501 (Class I locations) or NEC Article 502 (Class II locations) in North America; IEC 60079-14 for ATEX installations. Use explosion-proof rated conduit sealing fittings (EYS or equivalent) within 18 inches of each conduit entry into the explosion-proof coil housing.
• Verify conduit seal compound compatibility with the installed wire gauge and conduit size before sealing. The conduit seal prevents the propagation of flames and explosive gases through the conduit system from the hazardous area to unclassified areas or between explosion-proof enclosures.
• Before connecting electrical power, confirm that the solenoid voltage matches the available supply voltage. Applying incorrect voltage to the coil will cause immediate coil failure and may generate sufficient heat to compromise the explosion-proof enclosure integrity.
• Rotate the pilot assembly to the desired conduit entry orientation before sealing conduit fittings. The pilot can be oriented to four positions (90-degree increments) to align the conduit entry with the installed conduit routing. Confirm the pilot is fully seated and secured before energizing.
• Do not restrict the valve exhaust port with an undersized silencer or a blocked exhaust line. Restricted exhaust creates back pressure on the exhaust side of the poppet, reducing the net differential force available for valve actuation and potentially causing incomplete shifting or sluggish response.
• Air must be free of water vapor for media temperatures below 40 F (4 C). Install a refrigerated air dryer or desiccant dryer upstream of any valve operating in a low-temperature environment, and verify the system dew point is at least 10 F below the minimum expected media temperature.
• Use only petroleum-based lubricants with an aniline point between 180 F (C) and 220 F (C) and ISO 32 or lighter viscosity if lubricating upstream mechanisms on the same air supply. Oils with phosphate-type additives are incompatible with polyurethane valve components and will cause accelerated seal degradation.
• After installation and before initial production operation, perform a manual override test to confirm free valve shifting and proper cylinder or actuator response. The non-locking manual override button should shift the valve smoothly without sticking. If resistance is felt, check inlet pressure and verify that the pilot assembly is correctly seated.

Warranty & Global Support

ROSS Controls provides a one-year warranty on all products, covering defects in material and workmanship from the date of purchase.

Global technical support is available through ROSS Controls offices in the USA (headquarters in Ferndale, Michigan), Canada, Brazil, Germany, France, United Kingdom, India, China, and Japan.

For hazardous location applications requiring documentation of CSA/FM or ATEX certifications for facility safety records, request the applicable declaration of conformity and approval certificate copies from ROSS Controls at the time of product order.

Contact ROSS Controls USA at (800) 438-7677 or visit rosscontrols.com for product configuration assistance, hazardous location selection guidance, distributor locator, and technical support services.

Download Catalog: https://www.rosscontrols.com/en/documents/364