Composition and Applications

Durlon 8500 is a compressed non-asbestos sheet material featuring synthetic fibres and an elastomeric binder. This blend of reinforcements yields mechanical and sealing behaviour distinct from PTFE, flexible graphite, or purely aramid-based gasket materials. Manufacturer-specified application guidelines do not constitute a universal rating for all process media. Assembly parameters, normal operating temperatures, and thermal cycling must be evaluated before implementing any material substitution.

Differentiating Maximum Ratings from Continuous Service

Durlon product documentation explicitly distinguishes between catalogue maximum temperatures and lower continuous operating limits. The same rigorous caution applies to published maximum pressure ratings. These parameters must be evaluated concurrently alongside the flange design and bolting system. Stress relaxation, recovery, and gasket sheet thickness directly dictate the assembly's ability to maintain residual bolt load and seal integrity over time.

Evaluating Comparable Material Grades

Aramid/NBR or aramid-inorganic/NBR sheets can serve as an initial shortlist, but formulations and qualification testing vary significantly between manufacturers. Published mechanical properties, chemical compatibility limitations, and mandatory industry certifications must be thoroughly reviewed. Any proposed replacement must be formally validated for actual service conditions, even when sheet dimensions and colour appear identical.

To compare common material constructions: KLINGER KLINGERSIL C-4400 and Garlock BLUE-GARD 3000. While these grades share a general aramid/NBR polymer class, their proprietary formulations, third-party approvals, and pressure-temperature (P x T) envelopes remain distinct to each product.