Performing a hazard-free, environmentally compliant outage
Walter M Higgins Generating Station
530-MW, gas-fired, 2 × 1 combined cycle located in Primm, Nev
Plant regional director: Steve Page
Key project participants: Kevin Newcomb, maintenance manager; Lloyd “Andy” Anderson, maintenance manager; Felix Fuentes, operations manager
During major maintenance outages, the sheer volume of heavy work and number of personnel in confined areas makes detailed planning and continuous monitoring all of work critical to ensuring no injuries and environmental incidents occur. Preplanning for any outage is crucial and safety and environmental compliance must be an integral part of outage preparation.Winter 2010 saw a large amount of work scheduled: two full generator rewinds, major valve work, HGP inspections, as well as numerous other maintenance activities. All of this work required a large number of personnel in a very crowded area.
Long before an outage begins, the team makes detailed site plans—including laydown areas for major pieces of equipment, location of construction trailers and restroom facilities, etc. Spill kits, safety supplies, firefighting equipment, evacuation routes, and assembly locations are also included. Contractor orientation includes a detailed description of all locations to ensure everyone onsite understands where needed supplies and facilities can be found.
Preplanning also identified several methods for reducing the likelihood of an injury occurring. Some of this work included relocating a cable tray to ensure easier access for elevated equipment, installation of pull routes for air hoses, extension cords, etc (which eliminates tripping hazards on walking surfaces), installation of additional outlets and welding stations, prestaging of spill kits, drums for used oil and oily debris (on containments), etc (Figs 66-69).
Several areas of the plant were also paved to provide better working surfaces and routes throughout the site.One person is dedicated to serve as a safety advisor on every shift during an outage. This trained expert has no other role to fulfill other than to serve as a safety observer, assist in permitting, and provide any expertise or equipment needed to ensure a safe workplace is maintained.
Through a collaborative working relationship, the safety advisor attends every shift safety meeting and maintains a running log of activities. The safety advisor’s presence alone ensures all contract labor has safety first and foremost in mind during any evolution.Daily environmental rounds are also completed by a designated employee. This task ensures no oil spills, necessary equipment is readily available, waste drums in satellite locations are maintained, and all chemicals used during the maintenance are properly labeled, contained, and disposed (Fig 70).
MSDSs for all substances to be brought on site are collected before the outage begins. These MSDSs are gathered and a book developed to ensure all employees and contractors have access to the needed information concerning all substances in the workplace.
Daily safety meetings begin every shift. These brief safety talks include relevant subject matter as well as a timely review of any incident which may have occurred the shift before. These incidents include accidents, injuries, near-misses, etc.
A collaborative working relationship with contractors, and preplanning and continual monitoring of safety and environmental compliance, help ensure a safe and efficient outage. Comprehensive outage safety procedures from the preplanning stages through major maintenance highlight the site’s attention to detail for personnel safety and environmental compliance.During the major maintenance outage in the winter of 2010, involving 309 contract employees, 14 near misses occurred and were properly documented. Two injuries occurred, neither of which resulted in lost time. Zero environmental incidents resulted from this work.
Natural-gas handling procedures
In light of several tragic and high-profile accidents involving handling of natural gas, our personnel began a concentrated effort to ensure a similar incident does not occur at the company’s facilities. Natural gas handling is a routine evolution at many powerplants: gas blows, flow checks, purging, and other O&M functions involve the handling of highly explosive natural gas and hydrogen.
Many employees take these evolutions for granted. Recent, large-scale accidents resulted in terrible loss of life, injuries, and equipment damage. Developing formal procedures and training of employees can eliminate the potential for more explosions.
O&M personnel developed formal gas handling policies. These procedures ensure a safety standdown before proceeding with any venting or purging operations. All affected personnel gather for a formal safety meeting before proceeding.
This meeting includes a review of the hazards associated with the gas involved, a review of the appropriate prints and P&IDs, and detailed discussion. To proceed, acknowledged understanding of each person’s role in the evolution and a Q&A session ensures everyone understanding.
All non-essential personnel are then removed from the affected area. Smoking and all hot work is secured throughout the plant, access to the plant is secured, and a walk down of the affected systems and adjacent areas takes place.Once these conditions are met, the CRO communicates this fact via the plant PA system. A checklist is followed to ensure no step is overlooked. The CRO then coordinates and gives the go ahead to proceed with the evolution. Upon completion of the gas venting or purging evolution the CRO announces the completion of the work and normal operations and work resume.
A formal natural gas and hydrogen handling policy, formal procedures, and employee training are critical to ensure no more disasters occur in our industry. Since implementation, no accidents related to gas handling have occurred at Higgins.