Hot Tap / Line Stop Fitting


WeldFit’s hot tap tees have been used successfully in thousands of hot tapping operations around the world. Consisting of a full-encirclement fitting and a weld-neck flange, our hot tap tees are designed and manufactured to ensure the integrity of the piping system. WeldFit’s full-encirclement fittings feature extruded outlets for branch sizes up to 48″ NPS and fabricated branches for larger sizes. There are several advantages to using extruded outlet fittings; including the ability to design reinforcement into the nozzle and the elimination of the weld between the header and the branch, which is difficult to radiographically inspect. Typically the mating flange is ASME Class 150, 300, or 600; although, other pressure classes and flange styles are available.


WeldFit’s standard hot tap tees are designed to meet the requirements of ASME B31.3 and B31.4/8 with a 0.72 design factor. The standard tee material is A234 Grade WPB or WPC with A105 flanges. Other tee and flange materials are available to match customer requirements and existing pipeline materials.

All of WeldFit’s hot tap tees are manufactured in accordance with our ISO 9001:2015 quality program and are compatible with major models of hot tapping equipment. In compliance with most pipeline design codes, all pressure containing welds are 100% radiographed.


  • Full branch or reduced branch fittings for use in hot tapping operations
  • Supplied with ASME Class 150, 300, 600, 900, 1500 flanges with raised face or RTJ grooves
  • Other flange classes available on request
  • Tee available with a butt weld outlet, ready to be welded to a valve or other fitting
  • Standard fittings meet the requirements of ASME B31.3 and ASME B31.4/B31.8 with a 0.72 design factor
  • Fittings with outlets through 48″ NPS utilize extruded outlets, which allows for 100% radiographic examination and eliminates the stress risers inherent in welded type tees
  • Compatible with all major models of hot tapping equipment
  • All pressure containing welds are 100% radiographed
  • Back-up strips available
  • Manufactured in compliance with WeldFit’s ISO 9001:2015 certified quality program


  • Run pipe size
  • Branch pipe size
  • Flange class
  • Design code and design factor, if applicable
  • Design pressure
  • Design temperature
  • Material grade
  • Backing strips required (Yes/No)
  • Any special requirements