Industrial Touch Screen Monitors for Hazardous Environments: What to Look for

Hazardous environments where flammable gases, combustible dusts, or ignitable fibers exist require specialized equipment to prevent ignition sources that could trigger explosions or fires. Standard industrial touch monitors generate electrical arcs, produce heat, or create sparks during regular operation—characteristics that make them unsuitable for hazardous locations without proper safety measures in place. Displays designed specifically for hazardous areas incorporate explosion-proof enclosures, intrinsically safe designs, or purged/pressurized housing, preventing the ignition of surrounding atmospheres while maintaining the functionality operators require for process control and monitoring.

Facilities handling petroleum products, chemical processing plants, grain elevators, paint manufacturing operations, and pharmaceutical production commonly contain hazardous atmospheres requiring certified equipment. As Faytech provides industrial displays across numerous applications, understanding hazardous location classifications, applicable certification standards, and selection criteria helps facilities choose displays that meet both operational needs and critical safety requirements.

Understanding Hazardous Location Classifications

Regulatory frameworks classify hazardous locations based on the types of hazardous materials present and the likelihood of reaching ignitable concentrations.

North American Classification System (NEC/CEC)

The National Electrical Code (NEC) in the United States and the Canadian Electrical Code (CEC) define three hazardous location classes:

Class I Locations – Flammable Gases and Vapors

Class I environments contain or may contain sufficient concentrations of flammable gases or vapors to produce explosive mixtures. Examples include:

• Petroleum refineries and fuel storage facilities
• Natural gas processing plants
• Chemical manufacturing areas
• Paint spray booths and solvent handling areas

Class I divisions indicate the likelihood of hazardous atmosphere presence:

• Division 1: Hazardous concentrations exist continuously, intermittently, or periodically during normal operations
• Division 2: Hazardous concentrations exist only under abnormal conditions (equipment failure, container rupture)

Class I groups (A, B, C, D) categorize gases by ignition characteristics, with Group A (acetylene) being the most hazardous and Group D (gasoline, propane) being the least dangerous.

Class II Locations – Combustible Dusts

Class II environments contain combustible dusts in quantities sufficient to produce explosive mixtures. Common Class II locations include:

• Grain elevators and agricultural processing
• Coal handling facilities
• Woodworking and sawmill operations
• Metal powder processing areas

Division 1/2 classifications apply similarly to Class I, with groups (E, F, G) differentiating dust types.

Class III Locations – Ignitable Fibers

Class III locations contain easily ignitable fibers or flyings in quantities sufficient to produce ignitable mixtures. Textile mills, cotton processing facilities, and woodworking operations that use fibrous materials may be classified as Class III.

European ATEX Classification

European ATEX directives classify hazardous areas differently:

Zone Classification:

• Zone 0/20: Hazardous atmosphere present continuously (very rare)
• Zone 1/21: Hazardous atmosphere likely during regular operation
• Zone 2/22: Hazardous atmosphere unlikely, exists only during abnormal conditions

Zones 0, 1, 2 apply to gases/vapors; Zones 20, 21, 22 apply to dusts.

Equipment Protection Levels (EPL) indicate suitable zones, with EPL Ga/Da (Zone 0/20), EPL Gb/Db (Zone 1/21), and EPL Gc/Dc (Zone 2/22).

Certification Requirements for Hazardous Locations

Displays deployed in hazardous areas must carry appropriate certifications demonstrating compliance with safety standards.

UL/CSA Certification (North America)

Underwriters Laboratories (UL) and the Canadian Standards Association (CSA) certify equipment for use in North American hazardous locations. Look for:

• UL 1203: Explosion-proof equipment for Class I locations
• UL 1604: Electrical equipment for use in Class I and II, Division 2 locations
• UL 913: Intrinsically safe apparatus
• CSA C22.2 No. 25: Enclosures for electrical equipment in hazardous locations

Certification marks on displays indicate that the operation has been tested and approved for specific Class/Division/Group combinations.

ATEX/IECEx Certification (International)

European ATEX and international IECEx certifications indicate compliance with global hazardous area standards:

• ATEX Directive 2014/34/EU: Equipment for explosive atmospheres
• IECEx: International Electrotechnical Commission system for certification

These certifications specify suitable zones, equipment categories, and temperature classes, ensuring safe operation in defined hazardous environments.

Intrinsic Safety (IS) Certification

Intrinsically safe designs limit electrical energy to levels incapable of causing ignition even under fault conditions. IS displays require:

• Low voltage/current operation
• Energy-limiting components
• Isolation from non-IS equipment
• Associated apparatus (barriers) maintaining IS integrity

IS certification enables installation in Division 1/Zone 0 locations (the most hazardous), where explosion-proof housings would be impractical.

Protection Methods for Hazardous Areas

Different protection techniques prevent ignition depending on hazardous location classification and operational requirements.

Explosion-Proof Enclosures

Explosion-proof (XP) housings contain internal explosions, preventing flame propagation to the surrounding atmosphere. Heavy metal enclosures with flanged joints withstand internal pressure while cooling escaping gases below ignition temperature.

XP displays suitable for Division 1 locations weigh considerably more than standard displays due to their thick metal construction. Installation requires maintaining enclosure integrity, including proper conduit sealing, an appropriate cover gasket condition, and the correct enclosure rating for the specific gases present.

Purged and Pressurized Enclosures

Purge/pressurization systems maintain a positive internal pressure with an inert gas (such as nitrogen or clean air), preventing hazardous atmosphere infiltration. This approach enables the use of standard electronics within protective enclosures rated for dangerous areas.

Pressurization requires:

• Controlled gas supply with pressure monitoring
• Alarms indicating pressure loss
• Automatic equipment shutdown on pressure failure
• Periodic pressure integrity testing

While enabling the use of standard display components, purged systems add complexity through gas supply infrastructure and monitoring requirements.

Non-Incendive (Division 2) Construction

Division 2 locations (hazardous only under abnormal conditions) permit non-incendive equipment that won’t cause ignition during regular operation. These displays incorporate:

• Sealed electrical connection, preventing park exposure
• Component temperature limits below ignition temperatures
• Energy-limiting designs reduce spark intensity
• Current-limiting power supplies

Non-incendive displays offer lighter weight and lower cost than explosion-proof alternatives while meeting safety requirements for less hazardous locations.

Display Selection Criteria for Hazardous Environments

Beyond hazardous area certification, several factors affect display suitability for specific applications.

Visible Area and Resolution

Control rooms monitoring hazardous manufacturing locations require displays showing complex process graphics clearly. Determine:

• Viewing distance from operator positions
• Information density (number of data points displayed)
• Multi-window requirements showing multiple process areas

Balance screen size/resolution against weight restrictions imposed by explosion-proof housings, which require heavier construction.

Environmental Rating

Hazardous locations often present additional environmental challenges beyond explosion risk:

Temperature Extremes

Oil and gas operations in Arctic regions or desert environments expose workers to temperature extremes. Verify that the operating temperature ranges (-40°C to +85°C for extreme applications) match the installation environment.

Ingress Protection

IP-rated displays prevent dust or moisture infiltration that could compromise explosion-proof integrity. A minimum IP65 rating is typically necessary for outdoor or washdown areas in hazardous locations.

Vibration and Shock

Offshore installations, such as drilling platforms or vessels, are subject to continuous vibration. Ruggedized touchscreens with vibration-isolated components maintain functionality despite mechanical stress.

Touch Technology Considerations

Touch technology selection affects both usability and hazardous area approval:

Resistive Touch

Resistive screens operate through pressure, functioning with protective gloves that operators wear in chemical environments. However, resistive technology typically requires front surface flexibility, potentially complicating its use.

Capacitive Touch

Projected capacitive touch screens offer superior optical clarity, but function effectively through thick protection. Implementations support glove operation through sensitivity adjustments.

No-Touch Alternatives

Extremely hazardous environments may benefit from displays that do not require direct touch input, utilizing externally or intrinsically safe input devices (IS-rated keyboards, trackballs) that are isolated from the display electronics.

Temperature Class/T-Code

Hazardous area equipment carries temperature class ratings (T-codes) indicating maximum surface temperature. Ensure display T-code remains below the auto-ignition temperature of materials present:

• T1: 450°C (gasoline, propane)
• T2: 300°C (jet fuel, kerosene)
• T3: 200°C (aviation gasoline)
• T4: 135°C (acetaldehyde, ethylene oxide)
• T5: 100°C (carbon disulfide)
• T6: 85°C (certain solvents)

Lower T-codes offer broader compatibility but may require additional cooling, which can impact display design.

Installation and Maintenance Considerations

Proper installation and ongoing maintenance ensure hazardous area displays maintain certified safety levels.

Installation Requirements

• Use only approved conduit sealing fittings, preventing gas migration
• Maintain minimum conduit run lengths before sealing (per NEC Article 501)
• Verify all enclosure fasteners torqued per manufacturer specifications
• Label circuits with hazardous location classification
• Document installation per applicable codes for inspection

Maintenance and Inspection

Regular inspection verifies that displays maintain explosion-proof integrity:

• Inspect gaskets and seals for damage or deterioration
• Verify all enclosure fasteners remain tight
• Check conduit seals for integrity
• Clean external surfaces, removing combustible dust accumulation
• Test purge pressure systems per maintenance schedules
• Document inspection, maintaining compliance records

Never open explosion-proof enclosures when they are energized or when a hazardous atmosphere is present.

Ensuring Safety in Hazardous Environments

Selecting industrial touch screen monitors for hazardous locations requires understanding classification systems, certification requirements, and protection methods, ensuring safe operation while meeting operational needs. The combination of appropriate certifications, proper protection techniques, and correct installation procedures prevents ignition sources that could endanger personnel and facilities.

Facilities considering displays for hazardous areas benefit from consulting with both display suppliers knowledgeable about hazardous location requirements and certified electrical contractors experienced in hazardous area installations. This collaboration ensures that selected displays meet both technical specifications and critical safety standards, protecting people and assets in inherently dangerous environments.

Ready to specify displays for hazardous location applications? Contact Faytech North America to discuss hazardous area classifications, certification requirements, and display options that meet your specific safety and operational needs.