Hot Tap Coupon Drop and Drag Test

Abstract This paper presents an experimental study to investigate the potential damage to the pipeline from large-diameter hot tap coupon drop during hot tap activities. To this end, a hot tap coupon drop and drag test is designed to simulate the hot tap coupon drop and travelling process, and is conducted in a shop with two NPS 36 pipe joints to examine the extent of damage from the hot tap coupon contacting with the internal pipe surface and travelling along the pipeline. After the drop test was completed, Magnetic Flux Leakage (MFL) tool pull test on one joint and Non-Destructive Examination (NDE) measurement test for both joints were performed. The experimental results substantiated safe operation of the carrier pipeline subsequent to hot tap coupon drop event and affirmed adequacy of using MFL in-line inspection (ILI) technology to monitor the carrier pipeline.