The Dresser Style 39 Insulating Coupling provides both a mechanical pipe joint and complete electrical isolation in a single, field-proven assembly. It follows the same basic design and dimensions as the Style 38 coupling — with one critical addition: a full-boot plastic tubular insulator inside the middle ring that electrically separates pipe ends at the joint. One side of the coupling is fully isolated from the pipe; the other retains an armored gasket that bonds to the pipe and can share cathodic protection currents. The result is a coupling that handles both mechanical joining and corrosion protection simultaneously.

Style 39 couplings are specified on lines requiring cathodic protection, and wherever dissimilar metals are joined — conditions where uncontrolled galvanic current causes accelerated corrosion. They are widely used across gas distribution, oil transmission, and industrial pipeline applications. Insulating features can be supplied on both ends when the application demands complete end-to-end isolation.

Key Features

• Combines mechanical coupling and electrical isolation in one unit — no separate insulating flange kit required
• Full-boot plastic insulator inside the middle ring ensures complete pipe-end separation
• Armored gasket on the conductive end allows cathodic protection current sharing
• Dimensionally identical to Style 38 — same bolt patterns, laying lengths, and OD ranges for easy specification
• Available with insulating features on both ends for complete bilateral isolation
• Fusion-bonded grey epoxy exterior coating for corrosion resistance in buried and exposed service
• Sizes 3/4" through 24" nominal; working pressures from 150 to 750 PSI depending on size

Materials of Construction

Sizes & Specifications — Steel Pipe

* Gaskets include Armored Gaskets on conductive end. Larger sizes and special configurations available — contact us for pricing and lead time.