Seal Material Temperature Resistance Guide

Temperature: The Critical Factor in Seal Selection

Temperature is one of the most important factors in seal material selection. Operating a seal beyond its temperature limits leads to rapid degradation, premature failure, and potential equipment damage. This guide provides comprehensive temperature data for all common seal materials.

Temperature Resistance Chart

Understanding Temperature Ratings

Continuous Operating Temperature

This is the maximum temperature at which the seal material can operate continuously without significant degradation. The seal will maintain its physical properties and sealing function within this range.

Short-Term / Peak Temperature

This is the maximum temperature the seal can withstand for brief periods (typically minutes to hours). Prolonged exposure at this temperature will cause accelerated aging and reduced service life.

Low-Temperature Limit

Below this temperature, the seal material becomes rigid and loses its ability to conform to surface irregularities. The seal may crack or fail to maintain a seal at temperatures below this limit.

Material Selection by Application Temperature

Ambient to +80°C

Most standard elastomers work well in this range. NBR is the default choice for oil-based applications, EPDM for water-based applications. Polyurethane provides excellent wear resistance in this temperature range.

+80°C to +150°C

NBR reaches its upper limit in this range. Consider HNBR, EPDM, or FKM depending on the media. HNBR is an excellent upgrade from NBR when higher temperature resistance is needed without changing to FKM.

+150°C to +200°C

FKM and silicone are the primary choices in this range. FKM for oil and chemical applications, silicone for dry heat and food-grade applications. PTFE seals also perform well but require different groove designs.

+200°C to +260°C

PTFE is the standard choice for this temperature range. FFKM (perfluoroelastomer) provides elastomeric sealing at these extreme temperatures but at very high cost.

Above +260°C

Only PTFE and FFKM can operate at these temperatures. For temperatures above 300°C, metallic seals or specialized ceramic-based seals may be required.

Below -40°C

Silicone (VMQ) and fluorosilicone (FVMQ) provide the best low-temperature flexibility. PTFE also maintains its properties at cryogenic temperatures. Standard NBR and FKM are not suitable for extreme cold.

Heat Generation in Dynamic Seals

In dynamic applications, friction between the seal and the moving surface generates heat at the sealing interface. This heat can raise the local temperature significantly above the ambient or fluid temperature. Factors that increase heat generation include:

• Higher shaft speed or reciprocating frequency
• Higher seal interference (compression)
• Higher fluid viscosity
• Poor lubrication conditions

When selecting seal materials for dynamic applications, always account for the additional heat generated by friction. A general rule is to add 15-30°C to the fluid temperature for the expected seal lip temperature in rotary applications.