Jul 2017
Gas Transmission
Induction Heating
Jul 2017
Mar 2019
National Grid Gas Transmission
Kirsty McDermott, .box.GT.innovation@nationalgrid.com
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Network Innovation Allowance
GT - Safety and emergency
Gas Transmission Networks
Gas flame heating with oxy-propane is the most commonly used methods of applying preheat during in-service welding. Propane by itself does not give a hot enough flame for heating of high pressure gas pipelines, but can be used on low pressure pipelines/pipework. Gas flame heating is relatively cheap in terms of equipment needed, and it is versatile for site use.The disadvantages are:
  • The welder has to stop working whilst heat is being applied.& bull; There are increased safety considerations due to the naked flame being used in close proximity to other personnel (i.e. welders and inspectors).
  • Possible overheating may occur which leads to the integrity of the pipe will be comprised and the pipe must be replaced.
  • Replacing an overheated pipe can cost in the region of £500,000.

To evaluate induction heating techniques to assess the suitability to improve welding process within National Grid.

To maintain preheat using induction heating for in-service hot tap welding and include it into business as usual.