: Design must account for the continuous generation of hydrogen gas, which can be an explosion hazard if trapped.
(formerly NACE International). You can obtain the official document through these sources: AMPP Store The primary source for the active SP0391 standard. ANSI Webstore nace rp 0391 pdf
NACE RP0391 details how different materials behave in contact with concentrated acid: : Design must account for the continuous generation
Carbon steel is the most common material for concentrated HF storage and piping. The guide explains the phenomenon of nace rp 0391 pdf