8-449 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90449, an AS568-449 black Viton® (FKM) 90 Shore A Back-Up Ring built to an inside diameter of 9.975 in (253.37 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 10.525 in (267.34 mm). A back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

This material stands up to aggressive chemicals, many acids, and aromatic hydrocarbons. That behavior comes from the compound itself: Viton® (FKM) is valued for excellent resistance to compression set and permeation, outstanding high-temperature capability. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C). Exposure to hot water and steam or ketones and esters will shorten service life.

Common environments for this compound include aerospace, automotive fuel systems, and chemical processing.

Stocked as VBU90449 and sold individually. Nominal inside diameter is listed as 10 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation.