Factory assembled, permanent and maintenance-free weld-in electrical isolation joint. Replaces flanged connections.

The ElectroStop® monolithic isolation joints are a leak-proof, maintenance-free and long lasting block against the flow of electric current in all piping systems. The ElectroStop® eliminates short circuits and field assembly. The ElectroStop® is coated internally and externally to prevent corrosion and is 100% hydrostatically, electrically and weld tested. All ElectroStop® monolithic isolation joints are manufactured under an ISO Quality Management System.


  • Eliminates short circuits
  • Eliminated field assembly
  • Eliminates maintenance
  • Is less expensive than competitive products
  • Is coated both internally and externally
  • Is 100% electrically tested
  • Is completely weld inspected
  • Is manufactured under an ISO Quality Management System
  • 100% butt weld construction


  • Available for NPS 10 – 48
  • Available up to ANSI 900# Class



  • 150# ANSI Pressure Rating = 285 psi
  • ElectroStop® Continuous Operating Pressure = 300 psi
  • Test Pressure = 450 psi
  • Working Temperature: Range = -20 °F to 212 °F (-28 °C to 100 °C)
  • Electrical Resistance (Dry Air) = 25 Mohms @ 1kv D.C.
  • Breakdown Voltage (Dry Air) = 5kv @ 60Hz for 1 minute

300-400# ANSI CLASS (PN OR DP 64)

  • 300# ANSI Pressure Rating = 740 psi
  • 400# ANSI Pressure Rating = 990 psi
  • ElectroStop® Continuous Operating Pressure = 1000 psi
  • Test Pressure = 1,500 psi
  • Working Temperature: Range = -20 °F to 212 °F (-28 °C to 100 °C)
  • Electrical Resistance (Dry Air) = 25 Mohms @ 1kv D.C.
  • Breakdown Voltage (Dry Air) = 5kv @ 60Hz for 1 minute

600# ANSI CLASS (PN OR DP 100)

  • 600# ANSI Pressure Rating = 1,480 psi
  • ElectroStop® Continuous Operating Pressure = 1,500 psi
  • Test Pressure = 2,225 psi
  • Working Temperature Range = -20 °F to 212 °F (-28 °C to 100 °C)
  • Electrical Resistance (Dry Air) = 25 Mohms @ 1kv D.C.
  • Breakdown Voltage (Dry Air) = 5kv @ 60Hz for 1 minute

Monolithic isolation joints shall be bolt less and completely factory assembled in accordance with the appropriate requirements of ASTM, API, DIN and BS codes. All welds shall be butt weld construction. The dielectric isolation material shall be a high temp thermosetting fiberglass epoxy material. Sealing shall be by dual static, self energized “O” ring seals housed in accurately machined grooves, fully protected from cavitation in full compliance with ASME design codes.  Each unit shall be tested for Electrical (@5kv, 25 Mohm), Hydrostatic (@ 1.5 x O.P.) and Weld (Ultrasonic/Magnetic Particle). The Monolithic Isolation Joint shall be the Electro-Stop® Isolation Joint as manufactured by GPT.

Note: All data supplied is for standard joints. Please contact factory for nominal diameters, pressures (up to 2500 ANSI), temperatures (up to 320 °F / 160 °C) and electrical characteristics not shown. The information is subject to change at the manufacturer’s discretion.


Eliminates Short Circuits

Bolts, sleeves and washers — the major source of short circuits in most isolation assemblies — are eliminated with the ElectroStop® monolithic isolation joint. Each joint is electrically tested during production to assure integrity, performance and isolating properties.

Eliminates Field Assembly

The ElectroStop® isolation joint is completely factory assembled and tested. There are no flanges, gaskets, nuts, bolts, sleeves or washers to handle and consequently no fluid leaks due to improper field assembly.

Coated Both Internally and Externally

A two-part bonded epoxy is sprayed to within 2” (50.8mm) of each weld end. Each joint is tested for coating thickness uniformity and for coating holidays.

100% Hydrostatically Tested

All ElectroStop® joints undergo hydrostatic pressure tests at 1.5 times their rated operating pressure in accordance with ASME B31.3 standards. Testing is normally conducted for 30 minutes on joints up to 6” and for 60 minutes on 8” to 24” joints, but can be longer upon customer request. A pneumatic test is held at 87 psi for 10 minutes.

Completely Weld Inspected

All ElectroStop® joints undergo a weld inspection with a combination of phased array ultrasonic testing (PAUT), visual testing (VT), and magnetic particle testing (MT) on all welds. In addition, radiography testing (RT) can be conducted upon request. All ElectroStop® joints are manufactured under an ISO 9001;2015 Quality Management System.