Maintaining Proper Boiler Inspections Through Proper Relationships
District Representative Buckman Laboratories Inc.
Summary: The following article is a part of National Board Classic Series and it was published in the National Board BULLETIN. (3 printed pages)
In my previous article on water treatment of boilers, I mentioned I would discuss the relationship between the owner/operator, boiler inspector, and water "treater" (or water treatment consultant). Their relationship is a topic that is seldom discussed and rarely found in print. However, it is key to maintaining safe boilers and pressure vessels.
In simple terms, a boiler inspector is a professionally trained and commissioned technical specialist charged with the examination of boilers.
While every boiler should be professionally inspected annually, there is more than one type of inspection made by an inspector. Jurisdictions and insurance companies recommend that power boilers be inspected annually, both internally and externally, while not under pressure. An external inspection while the boiler is under pressure is suggested midway between the annual inspections.
An internal boiler inspection consists of all waterside areas of the vessel (steam, blow-off, and water connections), and fireside conditions, as well as dearators, superheaters, and economizers. While evidence of internal corrosion and scale, leaks, overheating, and flame impingement are noted and documented in the boiler inspector's report, the root cause may require additional resources. Both the owner/operator and the water treatment consultant are this resource, playing an active role at this inspection, and in any subsequent adjustments made tot he boiler management program.
The term "water treatment service," performed by a water treatment consultant, connotes a wide variety of meanings. The functions performed both onsite and offsite include: technical back-up, report writing, problem solving, knowledge transfer, and chemical feed equipment maintenance, to name a few. Operating conditions and complexity of the system will often determine the frequency and scope of the service. Cost of this value-added service can be incorporated into the price charged for the treatment chemicals, or determined by a separate consulting service contract agreement.
During the course of an operation year, the water treatment consultant provides the owner/operator with chemical recommendations (and often treatment chemicals), to achieve the goals of safe operation and minimized maintenance through sound water chemistry. The owner/operator's water treatment log and consulting service water treatment reports are integral parts of the units' operating performance.
At the time of the inspection, pertinent data (records) for the steam generating unit must be readily available to the inspector in order for the changes of any condition to be easily noted and their impact on system operations assessed.
Advances in data management through upgrades of both in-plant computer hardware and software provide statistical process control capabilities for large and small steam plants. Graphical presentation of monitored parameters can highlight periods of operations within set specifications, as well as those where problems have occurred.
In turn, the owner/operator follows the prescribed chemical treatment recommendations that often specify the addition of corrosion inhibitors, polymer dispersants, crystal modifiers and sealants, etc. Both water chemistry and boiler feed water chemistry limits are defined using parameters contained in the ASME Code, Section VIII.
In addition to providing the inspector with operational chemical data, the water treatment consultant should have the capability to perform deposit analyses and metallographic analyses as the need arises. Frequently, these services are available either directly as an in-house function or outsourced to a credible independent analytical library. Photographic documentation using high-quality detailed 35 mm photography, and/or VHS video recording with fiber optic capability, is highly recommended for inspection of inaccessible areas of the vessel.
Advanced notice of a pending internal boiler inspection should also be made to the water treatment consultant by the owner/operator. It is a good idea for the service representative to be informed of waterside conditions and the collection of any deposits.
A written report (including analytical data and photographic documentation) by the water treatment consultant should be presented to the owner/operator and the boiler inspector. In the water treatment consultant's report, conclusions should be drawn from the assimilation of operating logs, routine water treatment service reports, deposit, and metallographic analysis. Time-bounded correction action should be clearly outlined and discussed in a scheduled annual review in order to achieve desired improvement goals for the next internal inspection. As a courtesy, the water treatment consultant should make these corrective actions and conclusions available to the boiler inspector.
Upon conclusion of the inspection, verbal discussions among the boiler inspector, owner/operator, and water treatment consultant often compare and contrast the general condition observed with that of previous inspections. Operation problems that were encountered since the last inspection should be brought to the inspector's attention. The impact upon the observed conditions can be evaluated and preliminary conclusions can be made.
The boiler inspector's written report to the owner/operator will then serve as a useful, concise chronological document in which cause and effect problems can be highlighted and constructive action can be taken to avoid recurrence.
Editor's note: Some ASME Boiler and Pressure Vessel Code requirements may have changed because of advances in material technology and/or actual experience. The reader is cautioned to refer to the latest edition of the ASME Boiler and Pressure Vessel Code for current requirements.