Products & Services » Offshore » Subsea Pipelines & Structures » Pipeline Fittings
Pipe Insulating Joint

Electrically Isolates Pipeline Sections
The Pipeline Insulating Joint (PIJ) is a high-resistance fitting used to electrically isolate sections of a pipeline to improve the effectiveness of cathodic protection systems and to reduce ground-loop currents. Unlike insulating flanges or flange kits that are field assembled and tested, the PIJ is factory assembled, electrically tested at five different stages of manufacturing, and hydrostatically tested. The PIJ is provided with extension nipples that match the pipeline wall and grade and are long enough to eliminate any possibility of thermal damage to the PIJ during field welding.

The monolithic design of the PIJ results in a pipe fitting having high cyclic bending strength integrity. This aspect is particularly important for offshore pipeline riser applications where cyclic loading is common. The integrity of the PIJ is further enhanced by using dual high-temperature fluorocarbon (Viton) seals and insulation of high-pressure, glass-filled, structural epoxy laminate. The clean, monolithic profile will not trap moisture and reduces the possibility of crevice corrosion. This is an additional advantage of the monolithic design over conventional insulating flanges.

Pipeline Insulating Joint Graphic
Pipeline Insulating Joint

Pipeline Insulating Joint Photo
PIJs in standard pipe sizes from 4-inch through 12-inch are kept in inventory.

Oil States Houston maintains an inventory of Pipe Insulating Joints with 900 ANSI ratings in nominal sizes from 4-inch to 12-inch, with schedule 80 bores. Nominal sizes 4-inch through 8-inch are provided with API 5L grade B extension nipples, and sizes 10-inch and 12-inch are provided with API 5L-X52 extension nipples. Pipe Insulating Joints can be designed and manufactured for any pipeline size and pressure rating.

Design Specifications
Pipe Insulating Joints are designed in accordance with ASME Pressure Vessel Code, Section VIII, Division 1, unless another recognized code is specified. Each PIJ is designed to be at least as strong as a comparably rated pipeline when subjected to external loads.

The electrical resistance, leakage current, and breakdown voltage are functions of the insulating material, insulator thickness, and capacitance. The electrical resistance of the PIJ is at least 40 mega-ohms with 1000 VDC applied potential, and the maximum leakage current, with 2500 VAC (60 HZ) applied potential, is 5 mA. The dielectric strength (breakdown voltage) of the PIJ is designed to exceed 20,000 volts.

Ordering Information
Please provide the following information on any purchase order or request for quotation:
   • Nominal pipe size 
   • Pipe wall thickness or bore 
   • Pipe grade 
   • Design rating or pipeline pressure

To view the PIJ Brochure & Contacts click, on the corresponding link below:
PIJ Brochure
PIJ Contacts


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