The purpose of flange isolation kits is to prevent the (electrolytic) corrosion of flanges and flanged joints that static currents present on a piping system may induce.
The gasket isolation kit consists of a special gasket, isolation sleeves for all the stud bolts and nuts, and special washers. These components are manufactured in special materials with proper chemical stability, low water absorption, and dielectric properties.
Even if flange isolation kits are inexpensive accessories, they may extend the service life of pipes and flanged joints. Insulation kits are available up to 24 inches, generally, but higher nominal sizes can be manufactured if needed.
Dielectric flange isolation kits are available for ASME B16.5, B.1647, API flanges of all sizes and classes, from 1/2 up to 80 inches.