Updates from the ADCI-OSHA Delta P Task Force

updates from the adci osha delta p task force
JOSEPH SOHM/SHUTTERSTOCK.COM

Stemming the Tide of Power-Generating Fatalities in the U.S. was one of the feature articles in the last edition of Underwater. The article outlined the mission of the Task Force, which is to:

  • Educate clients/end-users on who should perform underwater work on their facilities;
  • Propose operational recommendations on best industry practices for performing underwater inspections, maintenance and repairs;
  • Propose what actions (surveys and revisions if needed) should be taken by operators to ensure that blueprints of the facilities accurately note all intakes and outfalls.

The article also stated who comprised the Task Force and some of the deliverables that have come from the Task Force, as of early November. The summary of issues for diving contactors and for facility operators was also covered in the article.

Since that time, the Task Force has finalized the Differential Pressure Dive Procedure Checklist. This check list, which is tailored for the diving contractors, looks at planning, execution, conduct of the dive, and post-dive assessment. The planning portion of the check list focuses on:

  • Understand the scope of work;
  • Review plans, blueprints, photos, surveys, as-builts with the appropriate competent people to understand the layout and geometry of the structure;
  • With plant representatives locate and document all Delta P hazards (this must include pumps that run intermittently, such as fire pumps);
  • Prioritize the Delta P hazards based on proximity to the work area;
  • Calculate the capture zone of known hazards;
  • Write a dive plan based on scope of work and JHA (dive plan must include an emergency action plan to include Delta P and umbilical management plan);
  • Identify known landmarks and understand the configuration of the work area;
  • Emergency procedures for the recovery of an injured/unconscious diver;
  • Conduct a dry dive/dry training (to include all emergency procedures.)

The execution (after mobilization and done daily) portion of the checklist focuses on:

  • Brief dive team on the scope of work;
  • With plant representative(s) develop a mitigation plan for each Delta P hazard:
    • Notify all plant personnel of the exact date and time ranges of diving operations
    • Conduct the work when the maximum number of delta p sources can be shut down
    • Lockout/Tagout (and verification)
    • Post warning signs
    • Install stop-logs
    • Install physical barriers
    • Limit diver and standby divers’ umbilical length
    • Use scanning sonar to locate possible delta p hazards and monitor diver’s movement
    • Use ROV (when possible)
    • Observe downstream for water flow
  • Brief the dive plan to the dive team, plant personnel, operators and any other stakeholders;

Ensure domain awareness (all dive team members must understand how the plant systems work and where Delta P hazards are located);

  • Provide safe entry and exit for divers to include a means of retrieving and injured/unconscious diver;
  • Test communication between the dive station, plant operation and EMS;
  • Set up and test umbilical management plan to limit the length of the diver and standby divers’ umbilicals;
  • Prepare physical barriers to be installed.

The conduct the dive portion focuses on:

  • Pre-dive briefing with the dive team and plant representatives;
  • Deployment of the scanning sonar;
  • Minimum entry flow check (2FPS);
  • Deploying the diver down a ladder or stage in a controlled manner (the diver must exercise domain awareness and report all water movement at the water entry point to the supervisor);
  • Test for Delta P (tell-tale);
  • Continuously hand-tend all divers;
  • Avoid slack with the diver’s umbilical (restrain diver’s umbilical to limit movement);
  • Diver will continuously communicate all movements with topside and be tracked using scanning sonar;
  • Install physical barriers;
  • Report the work-site water flow to the supervisor (immediately report any change);
  • Begin work only after the work area is deemed safe by the diver and diving supervisor;
  • Add new risks (if necessary, change the dive plan).

The post-dive portion will focus on:

  • Check on diver’s post-dive condition;
  • Assessment of the dive:
    • Supervisor’s debrief
    • Dive members remarks
    • Control of hazards
    • Identify safety violations
    • Post-dive equipment check

It should be noted that this contractor checklist will be in a table format and will include examples, definitions of terms, and links for reference documents. The checklist will be an evergreen document and will be included in the future guidelines for power-generating facility operations subsection in the International Consensus Standards for Commercial Diving and Underwater Operations. A companion checklist will also be developed for facility operators, which is slated for release in March of 2022.

Again, I want to thank the task force members for their hard work on the development of the Differential Pressure Dive Procedure Checklist.