• Zap-Lok™


    Zap-Lok Advantages

    Zap-Lok connections enable significant advantages in construction speed and overall cost when compared with other pipe joining methods. Our system replaces the variable performance, reliability and cost of welders and other skilled labor with a highly efficient, hydraulic Zap-Lok machine.


    Mechanical Interference Connection

    The Zap-Lok system relies on an engineered mechanical interference connection between a cold-expanded "bell-end" and an opposing, slightly larger "pin-end".

    The process derives its strength from the metal-to-metal friction generated as the two ends are hydraulically pressed together and highly compressive forces are transferred from the bell-end onto the pin-end - permanently holding it in place.


      End Preparation

      Every Zap-Lok joint is carefully prepared and inspected to ensure the highest connection integrity in the field. Our quality control procedures confirm that every heat of pipe meets both API dimensional tolerances and our own Zap-Lok specifications, thus reducing a large percentage of complications that commonly occur during construction.

      Pipe Specification & Logistics
      • Zap-Lok connections are ordered through a pipe distributor or mill as a specification for bare ERW, HFI or seamless line pipe.
      • Pipe is shipped from the distributor to one of our global facilities, or alternately pipe can be prepared on-site at the mill or Tuboscope coating plant.
      • The pipe ends are then prepared to Zap-Lok specifications.

      Zap-Lok and External Coatings

      When working in corrosive environments, extra care must be taken to prevent potential holidays from developing in the protective coating layer during traditional girth welding. 

      By eliminating the welding requirements of exposed bare steel and high-heat,  Zap-Lok connections allow for a continuous holiday-free coating layer, free from a heat-affected weld zone. 


        Zap-Lok and Internal Coatings 

        Zap-Lok connections improve coating integrity while simultaneously simplifying pipeline construction. By eliminating the heat of welding, Zap-Lok allows for the use of internal coatings without the risk of damage to the connection area.  Every length of pipe is manufactured to allow a 100% continuous coating layer by creating an overlapping, dual-layered coating section. 

        This process ensures a high margin-of-safety and can still be completed at rates over 1,000 ft. per hour in the field. 

        To learn more about Zap-Lok's Coating Advantages click here to navigate to our coatings page. 


        Technical Information

        During end-preparation, the bell-end is cold-formed resulting in an increased nominal yield stress of the steel. Since the pin-end has a larger outside diameter than the bell's ID, a mechanical interference fit is created. A slight groove is added and its nose tapered to allow the connection process to start more easily in the field.

        At the time of connection, the bell-end expands further into its elastic range and once completed that expansion recovers and applies significant compressive forces on the pin-end - these forces coupled with surface friction create the strength of the Zap-Lok connection. 

        Technical Reports & Documentation

        The interference fit of the Zap-Lok connection has been carefully engineered to harness the full strength of the steel in order to ensure a significant margin of safety during operation. 

          Hydrogen Sulphide Service

          Zap-Lok connections have been used in various H2S environments.  For more information please contact your local Zap-Lok representative. 

          High-Pressure Hydrostatic Performance 

          Unlike most other mechanical connections, Zap-Lok is not de-rated in terms of pressure bearing capacity. The design of the pipeline remains a function of the pipe diameter, wall thickness and intended operating pressure.  

          Tensile & Axial Performance 

          The tensile and axial strength of the Zap-Lok connection allows for versatile construction techniques such as long pull-sections, bore-sections and complex field bending. Many contractors have utilized pull-sections of several thousand feet in steep terrain conditions in areas such as Colorado, Montana, New Mexico and throughout the Rocky Mountains. 

          Since 2004, Zap-Lok has been certified and installed using the ‘S-lay’ configuration for offshore construction projects in the Gulf of Mexico, the Far East, and West Africa in water depths up to 220 ft.


          To simulate the various load combinations present in an offshore installation, Zap-Lok connections have undergone extensive independent destructive testing.

          Various FEA (Finite Element Analysis) and pipelay models such as OFF-PIPE, Orcaflex, and Ansys have been used to re-recreate the forces present for various pipe dimensions in underwater installations and verified with empirical data. Independent reports have concluded that the connection retains 100% integrity at 660 ft. water depths (test limit) and shows the potential to reach greater depths. 

          For more information please contact one of our regional sales representatives.



            • Achieves consistent construction rates of 800-1,000 ft./hr.
            • Reduces labor costs
            • Reduces man hours and equipment requirements giving significant time savings over traditional girth welding
            • Improves corrosion protection
            • Eliminates field joint coatings
            • Eliminates welding and X-Rays
            • Reduces Fire & Safety Hazards
            • No reduction in internal diameter
            • Produces "holiday-free" connections
            • 100% electrical continuity
            • Eliminates potential damage due to high-heat exposure
            • Perfectly suited for internally coated connections
            • No shrink sleeves or field-joint-coatings
            • Reduces handling and preparation-induced coating damage
            • Maintains a 100% continuous coating layer
            • Perfect for high-pressure CO2 & injection systems