Two workers received second degree burns when they
were sprayed with hot liquid and steam while removing
a flanged inspection port on a pressure vessel. The vessel
had been drained and was thought to be empty. However,
there was residual liquid and steam released when the
inspection port was opened.
Serious incidents can occur at industrial plants when inadequately
isolated or de-pressurized piping systems or vessels are opened up
for maintenance or cleaning. Hazards include chemicals, pressure,
heat and cold, and the potential for a flammable or toxic atmosphere.
Risks need to be mitigated for activities such as opening drained or
undrained pipelines or equipment by disconnecting flanges, opening
valves, breaking pipe joints, removing blanks or opening ports and
penetrating a line by mechanical or other means. Workers can be
seriously injured or killed if they fail to use correct first line break
Recommended Preventive Action
When opening any pipeline or vessel, always work defensively and
take all of the following precautions:
- Perform a Job Hazard Analysis (JHA) before breaking into any
hazardous substance pipeline or vessel. Those developing the
JHA must include a person who understands the process and the
- Test safety showers in the area and have additional running water
available at the break site.
- Barricade the area and maintain the barricade while the system
- Follow lockout procedure to achieve a zero energy state. Flush or
neutralize systems as required.
- Whenever conditions change from the original plan you must stop
and reassess. Ensure drain valves are not passing, and check for
heat, vibration and other evidence of live equipment.
- Plan to collect or control any residual liquid and know how to
dispose of it correctly and safely.
- Obtain and wear the appropriate personal protective equipment
(PPE) and ensure its condition is suitable for use.
- Work out of the line of fire. Use a spray screen if necessary. Break
the flange (if applicable) away from your body by slackening the
far side of the joint first.
- Beware of the sudden release of gases or liquids once the line is
- Clean up spillage immediately.
Subsection 9(2) of the OHS Act and sections 58 to 64, 239, 240 and
253 of General Regulation 91-191.