IsoJoint, Monolithic Isolating Joint by APS

True monolithic isolating joint which effectively stops short circuits and stray currents from damaging pipelines and equipment.


IsoJoint is a true monolithic isolating joint. The most up-to-date, patented joint on the market, IsoJoint does not depend on the use of isolating sleeves and washers for bolts nor isolating gaskets or O-rings between flanges. Why? These isolating gasket kits require a critical, even surface to provide regular and variable crushing and must be maintained over the life of the insulator. External pressure, causing an uneven load on the flange area, can result in loss of isolating properties as well as the transported fluid.

IsoJoint employs one or more, preassembled pressure seals and the isolating rings. Unlike isolating gasket kits, IsoJoint does not depend on installer's actual fitting of the joint's isolating gasket, sleeves and washers and the possible loss or damage to any one of the number of these materials which would result in complete breakdown of the isolated flange. One lost or damaged part will render these flanges useless. The monobloc design of the IsoJoint allows the joint to be welded into place as one piece, virtually eliminating any field problems. Unless a meticulous on-site assembly and over-wrapping is undertaken in the installation of the isolating gasket kits, gradual penetration of moisture will erode the electrical resistance. This problem, along with the others listed above, make inspection and maintenance necessary. Contrary to this inconvenience, IsoJoint's technique and design of the pressure seals, coupled with the closure weld, guarantees that the specified mechanical and electrical properties will always be maintained allowing for direct burial and requiring no maintenance.

At first glance, flange gasket kits seem to be the economical route to take to the isolating problem, but when coupled with the expense of components, labor and maintenance, IsoJoint has proven itself to be the productive solution. The IsoJoint provides for current control by separating pipework into distinct zones as part of a cathodic protection system and effectively eliminating long-line currents. This assures increased plant and equipment life by reducing or eliminating corrosion damage. Effective control can be realized by placing IsoJoints at pipeline entry points to processing plants or gas compressor stations, where a branch is connected to the mainline, where two pipelines of different material connect to where well coated pipe meets a poorly coated system. Optimum cathodic protection can be achieved for each section of pipeline—maximizing savings and minimizing costs.

IsoJoints are manufactured in accordance with the highest technical standards which guarantee mechanical requirements (torque, traction, bending, etc.) are met for the specific needs of a plant. Full Technical details should be supplied.

  • Specific hydraulic internal pressures are maintained.
  • Isolating requirements are met and surpassed in regard to the electrical characteristics of the product carried in the pipeline.
  • IsoJoints are designed according to ASME VIII, Division I
  • All testing is done in-house. Hydrostatic and electrical are standard. Ultrasonic, X-ray and dye penetrant testing can be done if requested. Testing voltage 3,000 v-50 Hz. Electrical resistance -5 Mohm minimum. Test Pressure: 1.5 time working pressure. Working temperature up to 160 degrees F. Customers may require special test values.
  • All coatings are applied in-house. Standard joints are coated internally and externally with epoxy-resin coatings. Different standards as per customer's requirements.

Monolithic isolating joints, 1/2" to 100" diameter, ANSI 150# to 2500#, Gr. B to X70.
U.S. Patented • Manufactured to ISO9008