Carbon steel Nelson curve methodology cannot be depended on to prevent HTHA equipment failures and cannot be reliably used to predict the occurrence of HTHA equipment damage. Revisions to recommended practices should be considered regarding the use of carbon steel in HTHA-susceptible service and the verification of actual operating conditions.
Given the difficulty of inspecting for HTHA because the damage might not be detected, inherently safer design is a better approach to prevent HTHA.
Process hazards analysis (PHA) and damage mechanism hazard reviews (DMHRs) need to carefully consider all assumptions, periodically if necessary, to ensure that hazard identification, safeguards and control of hazards to prevent equipment failure are effective.
Effective programs need to be in place to manage and provide oversight for hazardous nonroutine work.