Stored-Pressure Release During Maintenance (LOTO)

A worker prepares to open a pipe or vessel for maintenance. Electrical power is locked out, but pressure or trapped fluid is still bottled up behind a closed valve. Cracking the flange releases that stored energy suddenly.

OSHA 29 CFR 1910.147 requires that after isolation, all potentially hazardous stored or residual energy be relieved, restrained, and rendered safe (OSHA 1910.147); LOTO is perennially an OSHA Top-10 most-cited standard, showing how routinely energy control is done wrong .

1. Isolate all energy sources (not just electrical).
2. Bleed/vent the trapped section to zero pressure.
3. Verify at a gauge or telltale that pressure actually reads ~0.
4. Drain residual liquid.
5. Only then break containment.

The National Safety Council reported 48 deaths tied to hazardous-energy-control failures in 2023 (NSC via LegalClarity LOTO statistics, https://legalclarity.org/lockout-tagout-statistics-injuries-and-violations/); OSHA estimates the LOTO standard prevents…

Sudden blowdown at the flange — struck-by, chemical burn, engulfment; hazardous-energy injuries are typically catastrophic (amputations, crush, severe burns) with ~24 lost workdays on average (OSHA LOTO fact sheet via US Made Supply).