Dresser Gasket — Grade 42 BUNA-N Armored | Armored Nitrile Gasket for Dresser Couplings

Grade 42 Nitrile | Integral Brass Coil Armor | Oil, Hydrocarbon & Condensate Resistant | Electrical Continuity | Cathodic Protection | 212°F Maximum

Overview

The Dresser Grade 42 BUNA-N Armored Gasket is the most technically demanding specification in the standard Dresser gasket lineup — combining the oil and hydrocarbon chemical resistance of Grade 42 Nitrile rubber with the electrical continuity capability of the Armored gasket construction. It is specified whenever a pipeline requires both: (1) a gasket that will not swell, degrade, or lose sealing force when exposed to petroleum products, condensate, or aromatic hydrocarbons; and (2) a conductive joint path for cathodic protection or natural gas service electrical continuity requirements.

The construction is identical to the Grade 42 plain gasket in rubber compound and dimensional profile, with the integral brass coil helix permanently molded into the gasket tip. As the coupling followers are tightened, the armor bites into the pipe surface, establishing metal-to-metal contact at both pipe ends — providing the electrical continuity path required by cathodic protection systems and DOT-regulated gas service line standards. The surrounding Grade 42 Nitrile rubber seals the joint against hydrocarbon line content without swelling or degradation over time.

When Is Grade 42 Armored the Correct Specification?

Grade 42 Armored is specified when all three of the following conditions exist simultaneously: (1) the pipeline carries petroleum products, oil, condensate-bearing natural gas, or other hydrocarbons that would degrade Grade 27 BUNA-S rubber; (2) the coupling joint must remain electrically conductive for cathodic protection or DOT gas service compliance; and (3) the service temperature is within the 212°F limit of the Grade 42 compound. This combination is most commonly encountered in natural gas service lines with condensate, fuel oil and refined petroleum product pipelines, and multi-phase gas/liquid transmission lines where both chemical resistance and electrical continuity are simultaneously required.

Key Features

• BUNA-N (Nitrile) Base Compound — Oil and Hydrocarbon Resistant: Resists swelling, hardening, and sealing loss in petroleum oils, aliphatic hydrocarbons, natural gas condensate, gasoline, diesel, fuel oils, and aromatic solvents. Grade 27 SBR rubber is not appropriate for these services — Grade 42 is the minimum required.
• Integral Brass Coil Armor — Electrical Continuity: Brass coil helix permanently molded into the gasket tip bites into the pipe surface on both ends as the coupling is tightened. Provides cathodic protection current path and electrical continuity through the joint in conformance with DOT Part 192 and utility cathodic protection standards.
• Both Functions in One Gasket: Eliminates the need to choose between chemical resistance and electrical continuity. Grade 42 Armored delivers both simultaneously in a single, standard Dresser wedge-section profile gasket.
• Natural Gas Condensate Service Standard: Widely specified for natural gas service lines in wet-gas distribution systems where condensate accumulation at joints demands both oil resistance and cathodic continuity.
• Drop-In Replacement for Grade 27 Armored: Same wedge-section profile and dimensions as Grade 27 Armored. The only difference is rubber compound (Nitrile vs. SBR) and color code (Yellow vs. White). No coupling hardware changes required when upgrading from Grade 27 Armored to Grade 42 Armored for hydrocarbon service.
• DOT Part 192 Compatible: The combination of Nitrile compound and armored construction meets the requirements for gas service line couplings in DOT-regulated natural gas distribution systems carrying condensate-bearing gas.

Specifications

Armored Gasket Selection Summary

? VERIFY COMPOUND GRADE FOR REPLACEMENT: When replacing gaskets in an existing Dresser coupling on a hydrocarbon or condensate-bearing gas line, confirm the original gasket was Grade 42 before replacing with Grade 27. Installing Grade 27 in oil or hydrocarbon service will result in gasket swelling and eventual seal failure. Check the Yellow vs. White color code on the original gasket as a first-check indicator.

Questions? Contact us at sales@watermainsupply.com or call 281.664.8000.