Hot Tapping


Hot tapping is a method of employing an under pressure drilling machine to cut a hole in an operating pipeline or storage vessel which allows for a new branch connection from the existing pipe or vessel without any interruption to the flow.

Hot tapping is also the first procedure in line stopping, where a hole saw is used to make an opening the pipe, so a line plugging head can be inserted.
Hot Tapping


You may face the following problems during pipe alteration & addition works:
  • Insertion of a new branch in an operational pipeline
  • Insertion of branch that require to drain off large amount of fluid
  • Insertion or replacement of valve in an operational pipeline
  • Preparing the pipeline for line stopping


Step 1: A hot tapping fitting is welded/bolted onto the existing pipe or storage vessel, at the location where the new branch is to be connected.
Step 2: A opened gate valve is installed on the hot tap fitting.
Step 3: Pressure test is carried out by using water pump and pressure gauge.
Step 4: The hot tapping machine is then mounted.
Step 5: Hot Tap operation is performed through the open valve.
Step 6: When the hot tap operation is completed, move back the cutter and close the gate valve. Drain off the water between the gate valve and the machine via the drain valve.
Step 7: The hot tapping machine is dismounted. A piece of the cut-off from the pipeline (known as the "coupon") is retrieved as an indication of the cut-out size. The gate valve is permanently mounted and a new branch can be connected from this location.
The components required for a typical hot tapping operation include a hot tap fitting designed to contain system pressure, a valve used to control the new connection and a hot tapping machine. The basic operation procedure is as follows:
  • Install hot tap fitting and valve on existing pipeline.
  • Install hot tapping machine.
  • Perform hot tap through open valve and “coupon” is retrieved.
  • Retract cutting assembly.
  • Close hot tapping valve.
  • Remove hot tap machine to allow for connection to new pipe.
Hot Tap Valve installed
Hot Tap Valve installed
Installing Hot Tap machine & start cutting
Installing Hot Tap machine & start cutting
Hot Tap complete & coupon retrieved
Hot Tap complete & coupon retrieved
Connecting branch after Hot Tap
Connecting branch after Hot Tap


We provide hot tapping service with the following advantages :
  • One-Stop Service - Hot Tap accessories & service, insulation & piping works
  • Convenient - No need for massive draining of fluid
  • Hassle Free - Installation of valves, pressure & vacuum gauge, thermowell
  • Reliable - Many years of hot tapping experience
  • Cost Effective - Our hot tap services are price competitive


We are capable of providing hot tapping service for Tapping of various pipe material including carbon, galvanished and stainless steel, ductile and cast iron and metal pipe with concrete lining.
  • Pipeline up to 48" (1200mm) diameter
  • Operating pressure up to 2,000 psig
  • Operating temperature up to 300°C
  • Various pipe including oil, gas, water, steam or wastewater.
Technicians at Alstern Technologies are highly skilled and trained to operate and execute hot tapping operations. We have performed many such operations in various industries across the Asia Pacific region.




Our client
Our client
Our client

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Hong Kong Office

Alstern Technologies (HK) Ltd.
Address:Unit 2, 26/F, Global Gateway Tower,
63 Wing Hong Street, Cheung Sha Wan, Kowloon, H.K.
Tel:+852 2647 8163
Fax:+852 2647 4163