Flanged Isolation Joints
BARLOW

WHY ISOLATE A PIPELINE?

Pipeline isolation is used to electrically “split-up” pipelines into distinctive segments. This isolation of pipelines is essential to ensure that cathodic protection (impressed current) is applied and controlled, to prevent “long line” currents and to make the individual cathodic protection systems more effective and economic. Isolation also facilitates prevention of stray electric currents, decreasing corrosion. Isolation of pipelines can provide protection against earthing currents. Isolation of the pipeline can also be used where dissimilar metals are found together to help prevent the galvanic action between the metals. Importantly, isolation can also be used at custody transfer points in pipelines to ensure that two different pipelines, and their corrosion systems do not adversely affect one another.

WHY USE A BARLOW FLANGED ISOLATION JOINT?

The Barlow flanged isolation joint is a long-term, reliable, robust and cost-effective solution for pipeline isolation. The Barlow flanged isolation joints is assembled and tested in a clean factory setting. This allows for easy installation (weld into place). The advantage of Barlow isolation joints are multi-faceted including but not limited to:

1. Decreased project and life cycle costs
   • Decreased installation time and labor over gasket isolation kits
   • No maintenance after proper installation
   • Eliminates field assembly and related time and labor attributable to improper assembly of gasket isolation kits
   • No pipeline shutdown caused by failure, replacement or leakage of improper assembly of gasket isolation kits
2. Increases safety of pipeline and life duration of isolation joints in comparison to gasket isolation kits

DESIGN:

The Barlow flanged isolation joint is a highly engineered product, and is manufactured in a clean environment to provide a long term solution. The design has been perfected over 60 years to cultivate a superior product. Special features include:

• Extra thick dielectric sleeves (1/8” thick) machined to precise, close tolerance dimensions
• Flange bolt holes line reamed to provide perfect alignment and close tolerance fit to the dielectric sleeves
• Flange studs machined from alloy steel and heat treated to ASTM A-193-52T grade B-7, resulting in superior strength and greater resistance to stress induced elongation
• Coupling Nuts machined from alloy steel and heat treated to ASTM A-194 Class 2H
• Precision machined steel washers, flat, parallel, and counterbored, allowing for square alignment and clearance for dielectric sleeve
• Isolation gasket precision cut for ideal fit with small projection into stream to prevent bridging of the joint
• Flange gap sealed with epoxy resin to prevent contamination and electric shorting

Each joint is provided with a certificate of dielectric and electric testing. Other tests can be defined by user and witnessed by third party if required. Barlow Flanged isolation joints can be provided with testing data and material test reports (MTRs) upon request.