INSPECTION OF FIRED BOILERS & FIRED HEATERS

Fired Boilers:

The requirements governing inspection of boilers can differ widely from one location to another since they are often regulated by jurisdictions. Under some jurisdictions, inspections must be made by state, municipal, or insurance company inspectors. Other jurisdictions may allow inspections by qualified owner/user inspectors. In either case, the inspector is usually commissioned by the regulatory authority and must submit reports of the inspection to the official responsible for enforcement of the boiler law. If the boiler is insured, inspection by the insurance company inspector also serves to satisfy his company that the boiler is in an insurable condition.

Normally, governmental and insurance company inspectors concern themselves only with the pressure parts of the boiler, the safety valves, level indicators, pressure gauges, and feedwater and steam piping between the boiler and the main stop valves, superheaters, and economizers. The plant inspector should also be concerned with related nonpressure parts, including the furnace, burners, flue-gas ducts, stacks, and steam-drum internals since these can affect equipment reliability and performance. When inspection by an outside agency is necessary, joint inspections by the outside inspector and the plant inspector can reduce the length of boiler outages and result in shared learning’s. The outside inspector is primarily interested in seeing that minimum legal safety requirements are met. The plant inspector should be interested not only in safety but also in conditions that affects reliability and efficiency. The outside inspector has an opportunity to examine many boilers that operate under widely varying conditions and often can offer valuable advice on the safe operation of boilers.

Fired Heaters:

The vulnerabilities inherent to fired process heaters serves to enforce the highest measures of integrity management. Fired heaters are frequently subjected to additional or unique degradation mechanisms due to the various chemical characteristics of process fluids. Alloys designed to counteract specific corrosion mechanisms often exhibit other sensitivities requiring specialized inspection techniques and operating controls. Inspectors should prepare by carefully reviewing the furnace history briefs and become familiar with the type of heater being inspected, corrosion control measures, critical reliability/process variables, past problems and furnace repair history.

Critical reliability and process variables associated with integrity operating windows are monitored for abnormal trends and exceedances. This data should be monitored and tracked as an integral component

of a fired heaters history. This data in conjunction with on-line visual and IR monitoring/mapping is invaluable in the determination excessive heat flux, sag/strain, localized, accelerated corrosion, coking, creep and metal dusting associated with the various metallurgies and chemistries presented by fired process heaters. This information is the inspector’s first line of defense in the creation of a fired heater integrity inspection plan and is mandatory for risk-based inspection compliance.