Early contractor involvement critical to timely, quality pressure-part repairs

The portion of yesterday morning’s special workshop that focused on inspection of HRSGs for steam-drum nozzle cracks was an eye-opener (see previous article). Many attendees probably weren’t aware of how quickly and severely fast starts, rapid ramps, and spin cooling are beating up their boilers. But finding the cracks that pose safety hazards is only the first step.

Fixing the damaged components properly, or replacing them, may be the bigger challenge.

Bill Kitterman, VP/General Manager of Bremco Inc, which specializes in boiler repairs, was checking into the hotel soon after the HRSG Session let out and the editors asked him between phone calls how an owner/operator could be assured timely and quality pressure-part repairs.

“Being involved early regarding any pressure-part repairs is critical to the final outcome,” Kitterman advised. Important to this objective is the affected owner/operator having a relationship of trust with a qualified boiler repair contractor. If none exists, then the proper contractor must be found and that can take time you may not have. See CCJ article, How to select the right contractors to support your next outage, for more details.

A root cause analysis performed by an experienced third-party inspection company is particularly valuable for determining the actual scope of repair, Kitterman said. The last thing you want to do is just repair in-kind and repeat past mistakes. There may be a better way—one involving a design modification, for example—and that must be determined early and be based on engineering and metallurgical facts.

Most users are aware, he continued, that pressure-part repairs are governed by the ASME Boiler and Pressure Vessel Code and National Board of Boiler and Pressure Vessel Inspectors, as well as by certain local codes regarding quality assurance.

Design parameters and the materials test reports for your HRSGs are required by the repair contractor and its Authorized Inspector to formulate an acceptable repair plan. This activity must consider the metallurgy of the base metal, wall thickness, pre/post weld heat treatment, operating pressures/temperatures, specific methods of surface preparation, possible weather influences, nondestructive examination during the weld process and afterward, possible weld blend and other parameters governed by the Code, etc.

Personnel protection is particularly important, Kitterman noted, and it is repair-process dependent. For example, where preheat is required, repair personnel will likely require cooling vests; where P91 is being welded, a respirator is needed to protect against toxic hexavalent chrome.

Get answers to your questions on HRSG pressure-part repairs from Kitterman at Vendor Fair Booth 10 Tuesday evening; or email him at bkitterman@bremco.com.

Posted in 7F Users Group |

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