Hard spots are a type of threat many operators are managing as part of their integrity management plan. Hard spots are areas on the pipeline that are more susceptible to cracking or could pose an integrity concern in combination with other threats. The United States gas transmission regulation, 49 CFR 192.3, defines a hard spot as “an area on steel pipe material with a minimum dimension greater than two inches (50.8 mm) in any direction and hardness greater than or equal to Rockwell 35 HRC (Brinell 327 HB or Vickers 345 HV10)”.