Description of Operation

The following case study involves a company with operations in chemical manufacturing. The unit of focus was a furnace that was 22 feet across, 12 burners long and 60 feet high.

Hazard Identification

The hazard identified with this particular chemical manufacturing operation involved heat stress for employees completing heavy work on the furnace.  Weather conditions involving 100° F temperatures for completing this type of work were not optimal. Problems with the furnace first began in late April of 2007.  Unsupported bricks inside the furnace were in need of maintenance because they were falling apart and collecting on the furnace floor.  If no action was taken, complete failure of the furnace would result. Furnace failure would lead to an inevitable shutdown. The operation involved high air temperatures, extreme heat sources, high humidity, direct physical contact with hot objects, and strenuous physical activities, which had a high potential for inducing heat stress in employees engaged in the work.  The goal was to complete the repair job flawlessly and on time.

Hazard Intervention

The company identified the heat stress hazard as a physical hazard to employees.  The abatement plan was developed by the Joint Safe Operations Committee (JSOC).  The abatement approaches involved changes in the PPE, administrative controls, and engineering controls, although the latter was the more effective level of control.  The method used to repair the furnace involved fixed equipment engineering, where the repair would take place from the outside.  A slot 16 feet wide and 6 inches long was cut on the outside of the furnace to hold the bricks in place.  Then a steel shelf (expanded metal plate) was inserted on the top edge of the furnace.  Finally, ceramic fiber refractory was injected to fill in the hole. The furnace was under negative pressure.  The team also conducted a “what if” analysis to anticipate all the hazards.  Once the analysis was complete the team recognized that setting up a hot zone and cool-down tent was important for maintaining a safe environment.

Impacts of the Intervention

There were many positive health, business, and risk management results due to the implementation of the hazard abatement intervention.  Employees were protected from exposure to heat stress, as heat stress management was used to control potential health risks.  This included development of a work-rest schedule where 25% of time was spent working and 75% of the time employees were resting.  There was also a very positive impact on employee morale.

The business process was improved since there was no shutdown of the process, which would have caused an $8-10 million loss.  If the unit had been shutdown other units would have to be shutdown as well.  A total shutdown for 10 days would cost approximately $15 million. The knock-off effect (2:1) was included in the estimation. If the wall inside the furnace had failed, a shutdown of 10 days would have occurred.

Many positive benefits resulted from the intervention.  There was no impact on production rates during the repair process.  The amount of time spent on planning was significantly shortened.  Risk management was greatly improved because the intervention provided many opportunities for heat stress reduction throughout other areas within the plant.

Financial Metrics

The lost production parameter is the most important parameter. Additional process staff costs were minimal with approximately 12 hours of additional work required. The total cost for mechanical repair would be $150,000 if a shutdown occurred for 7 days.

Lessons Learned