10.60933/PRDR/NBJJEM YU, Samuel0000-0002-5615-9956(The Hong Kong Polytechnic University)HO, Marco Kin Pan(The Hong Kong Polytechnic University)LAI, Wallace Wai-lok0000-0002-0696-6741(The Hong Kong Polytechnic University)SHAM, Janet Fung Chu0000-0001-6424-5734(The Hong Kong Polytechnic University)HO, Chun Yiu(The Hong Kong and China Gas Company Limited) PolyU Research Data Repository 2025 This dataset presents a thermal imaging dataset from a buried ductile iron pipe that were in-pipe inspected by infrared thermography with convective heating by hot air to validate whether convective heating is a reliable way in detecting and characterising external corrosion of metallic underground utilities (manually milled flat bottom holes on the outer pipe wall representing corroded regions). A heat blower was set to 50 °C, and the hot air was blown into the pipe with a 400 mm diameter at a velocity of 0.8 m/s for approximately 140 seconds. The pipe is 1.5 m long with a wall thickness of 8 mm, with an initial temperature of 22.3 °C. 36 flat-bottom holes were milled on the outer pipe wall, spread in 6 circumferential rings and angular direction. Three types of milled shapes with three different lateral sizes of 75 mm, 50 mm, and 25 mm were designed with varying residual thickness ranging from 1.7 mm to 4.4 mm. A Tau2 infrared camera in tunnel-view (facing frontward) is used to record the thermal images at an 8.7 frames per second sampling rate. Finally, the dataset proposed consists of 1 sequence of 4446 images of 640 x 512 pixels. YU, Samuel(The Hong Kong Polytechnic University)LAI, Wallace Wai-lok(The Hong Kong Polytechnic University)