Purging & Pressurization Systems
Cost-Effective Alternative to Explosion-Proof Enclosures
Hoffman purging and pressurization systems allow standard general-purpose enclosures to be used safely in Class I and Class II Division 1 and 2 hazardous locations. By maintaining positive pressure with clean instrument air, these systems reduce the hazardous area classification inside the enclosure, eliminating the need for expensive explosion-proof equipment.
Why Choose Purge & Pressurization?
Cost Savings
Use standard enclosures instead of expensive explosion-proof equipment
Larger Panels
No size limitations of traditional explosion-proof enclosures
Easy Maintenance
Standard components are easier to service and replace
Standard Equipment
Use off-the-shelf electrical components inside
Understanding Purge Types (NFPA 496)
Type Y Purge
Division 1 to Division 2
Reduces the classification within an enclosure from Division 1 to Division 2. The enclosure must still be located in a Division 1 or Division 2 area, but the internal classification is reduced to Division 2.
- Requires initial purge cycle before energizing
- Continuous positive pressure must be maintained
- Alarm on loss of pressure (equipment continues to operate)
- Division 2 rated components required inside
Type Z Purge
Division 2 to Unclassified
Reduces the classification within an enclosure from Division 2 to unclassified (safe area). Allows use of standard general-purpose electrical equipment inside the enclosure.
- Initial purge cycle before energizing
- Continuous positive pressure maintained
- Alarm on loss of pressure
- General-purpose components can be used inside
Available Purge Systems
Small-Volume Type Y/Z System (Class I)
Catalog #: A1001YZUMC1
For enclosures up to 2 cubic feet in Class I hazardous locations with flammable gases and vapors.
| Type Y: | Class I, Div 1 Groups A-D → Div 2 |
|---|---|
| Type Z: | Class I, Div 2 Groups A-D → Unclassified |
Small-Volume Type Y/Z System (Class II)
Catalog #: A1001YZUMC2
For enclosures up to 10 cubic feet in Class II hazardous locations with combustible dusts.
| Type Y: | Class II, Div 1 Groups F-G → Div 2 |
|---|---|
| Type Z: | Class II, Div 2 Groups F-G → Unclassified |
Large-Volume Continuous Flow System
Catalog #: A3003YZHM (and variants)
For larger enclosures and control panels requiring continuous airflow. Suitable for multi-section lineups and large floor-standing enclosures.
- Continuous flow purge operation
- Handles large enclosure volumes
- External flow monitoring
- Multiple inlet/outlet configurations
Purge System Accessories
Complete your purge installation with these essential accessories and replacement components.
- Pressure relief valves (EPV-1-SA)
- Replacement gauges and regulators
- Air supply fittings
- Mounting hardware kits
How Purge & Pressurization Works
Technical Specifications
Materials of Construction
- Mounting Plate: Type 316L Stainless Steel
- Regulator Body: Zinc with enamel finish
- Pressure Gauge: Aluminum with enamel finish
- Regulator Handle: Polycarbonate
- Fasteners: Aluminum or stainless steel
Requirements
- Air Supply: Clean, dry instrument air
- Inlet Pressure: Up to 5 PSI standard (higher with EPV)
- Enclosure Type: NEMA 4, 4X, or 12 minimum
- Enclosure Material: Metal, fiberglass, or polycarbonate
Important Installation Notes
- Division 1 areas must be surrounded by Division 2 areas for proper installation
- Class II, Group E (metal dust) areas must always be rated as Division 1
- Pressure vent (EPV-1-SA) required when inlet pressure exceeds 5 PSI
- Includes tamper-proof regulator with gauge (TR-10G) per NFPA requirements
Ready to Reduce Your Hazardous Location Costs?
Contact us to discuss purge & pressurization solutions for your application.
Browse All Purge Systems Call (262) 252-1600