Field Cases

LNG-service piping — welded branch leak

Field Reality

LNG-service pipework cycling rapidly between a warm state of roughly 10–50 °C and a reported cryogenic phase near −173 °C. The leak was reported at a branch-to-header weld — the point where two different thermal responses meet. Frost stood on the operating pipework during the cryogenic phase, which is how the condition announced itself.

Cropped LNG-service pipework with localised frosting, identifying surroundings removed.
Frost around the operating pipework during the reported cryogenic phase.
Edited Field image marking the reported leak location at a welded branch connection.
The reported leak location at the branch-to-header weld. This is an edited Field image; the marking was added to identify the position.

Key verified Field facts

Medium
LNG operator-reported service
Temperature
Warm state approximately 10–50 °C, cryogenic phase reported near −173 °C operator-reported; describes this Case and its transitions, not a continuous-service rating
Asset
LNG-service pipework with welded branch connections operator-reported
Geometry
Branch-to-header welded connection observed in the Field record
Field condition
Reported leak at a welded branch, under rapid warm-to-cryogenic cycling; localised frosting visible during the cryogenic phase observed in the Field record
Dominant hazard / constraint
Repeated differential thermal movement at a welded geometry an engineering consideration for this Case; the record does not establish root cause

Resulting ISB

Case-specific ISBs were constructed around the welded branch connections and given a fibre-reinforced external protection layer. The completed bodies were observed in place during the reported cryogenic operating phase.

Frost around the constructed ISB during the reported cryogenic operating phase.
The completed body during the reported cryogenic phase. Frosting records this Case condition — it is not a temperature measurement and not a rating.
Fibre-reinforced external protection around two completed field bodies.
Fibre-reinforced external protection applied for this particular Field configuration.

Case boundary

This Case records one unique Field Reality. It is not a construction instruction and not a template. A Solution developed for one Field must not be copied into another Field without new DendroSeal Understanding.