Non Metallic Gaskets

Overview

Non-metallic gaskets are sealing elements manufactured from composite sheet materials and soft sealing compounds. They are primarily used in low pressure and moderate temperature applications where flexibility, chemical resistance, and ease of sealing are required.

Design & Construction

• Manufactured from composite or soft non-metallic materials
• Designed for flat-face (FF) and raised-face (RF) flange connections
• Provide excellent conformability to flange surface imperfections
• Available as full-face or flat-ring gasket types

Types of Non-Metallic Gaskets

• Full-face gaskets (for flat-face flanges)
• Flat-ring gaskets (for raised-face flanges)
• Compressed fiber gaskets
• PTFE and reinforced PTFE (RPTFE) gaskets
• Flexible graphite gaskets

Materials

• Aramid fiber
• Glass fiber
• Elastomers
• PTFE (Teflon®) and RPTFE
• Flexible graphite
• Compressed non-asbestos fiber (NAF)
• Compressed asbestos fiber (CAF), where permitted

Standards

• ASME B16.21 – Non-metallic flat gaskets for pipe flanges

Performance Characteristics

• Suitable for low to medium pressure applications
• Good chemical resistance depending on material selection
• Excellent sealing at low bolt loads
• High flexibility and adaptability to flange surfaces

Applications

• Water and wastewater systems
• Low-pressure steam lines
• Chemical processing with corrosive media
• HVAC and utility piping systems
• Oil, gas, and general industrial services

Advantages

• Easy installation and replacement
• Excellent sealing with lower bolt loads
• Wide range of material options for chemical compatibility
• Cost-effective solution for standard service conditions

Notes

• Material selection should consider pressure, temperature, and process media
• Not recommended for very high pressure or extreme temperature applications
• PTFE and RPTFE gaskets are preferred for highly corrosive environments