Refractory Inspection . . . . who needs it!
Is refractory inspection really necessary? Here's an installation contractor's view.
It's always a good idea to have an inspection program for any equipment and machinery. Most equipment manuals, even bicycle owner's manuals, recommend inspecting equipment before operation. Check tires for wear and proper inflation, test the brakes, etc., etc. Likewise, it's required for pilots to inspect the aircraft before take off. No one asks them why.
It's much the same with refractory linings. If you want to operate equipment safely, it makes sense to inspect before operating and on a regular basis thereafter. If the refractory lining is not viewable during operation, then it's a good idea to monitor steel shell temperature where possible. An above normal temperature on the equipment steel can be an indication that there is a problem with the underlying refractory lining.
If spotted early, a lining weakness can usually be treated easily and affordably. If ignored, it can deteriorate further and cause premature equipment shutdown, or worse, catastrophic failure.
If yours is a simple installation, like a firebrick floor or heater wall, then you can probably rely on visual inspection alone, looking for signs of lining deterioration such as cracks, spalls, loose sections, eroded areas, etc. But if a refractory failure could cause major problems, regardless of the configuration, it's wise to do a complete evaluation on a regular basis.
But who is best qualified to do a refractory inspection? The unit operator, engineer, maintenance contractor or a professional inspector? Ultimately, the owner is responsible for it. The task can be delegated to any responsible person, as long as they know the basics. If the equipment is small, then the owner can probably handle things on their own, without outside help. But as the size of the equipment grows, so do the demands of inspection. During hurried oil refinery and power plant shutdowns, refractory evaluation and record keeping can evolve into a full time job for several people on day and night shifts.
Some maintenance contractor's are capable of inspecting, we often do, but owner's generally prefer an "independent" third party. On large complex projects, like Fluid Catalytic Cracker (FCC) or "Cat Cracker" turnarounds, it's customary for the owner to hire professional inspectors. (FCC's break down crude oil using catalyst and high temperature, and are considered the heart of an oil refinery). A professional inspector will check:
The surest way to check a suspect lining is to collect a sample and have it evaluated by a certified lab. There are many certified labs, independent and refractory manufacturer run, that can perform a detailed evaluation of a refractory sample. It's scientific. it's cheap (an average set of tests is around $100), and it's objective. Labs can check sample strength, resistance to erosion, and insulating value, among other physical properties. They can also do chemical analysis if contamination is suspected. And it's all done using standards set by the American Society for Testing Materials (ASTM).
Equipment breakdown can make the cost of refractory inspection seem like pocket change. So isn't hiring a professional inspector like buying cheap insurance. Maybe and maybe not. There's no doubt, a thorough inspection by a seasoned professional can pay off and give you a sense of confidence, not to mention scientific record, about the quality of your lining. But like ice cream and cake, you can get too much of a good thing. Over inspection can be costly. A good hearted but over zealous inspector can condemn a satisfactory lining, suggest needless work, and extend your shutdown. (If you ever suspect you're in this situation, past experience, photos and records can be your most valuable evaluating tools)
Since shutdown extensions are taboo, refinery owners also hire professional inspectors to witness refractory materials being made, qualify installation crews and monitor each step of a refractory installation. Money spent to help prevent shutdown extending rework, on-line failures and premature shutdown.
The basic elements of a good inspection program should include:
One of the best things you can do is to sit down with everyone involved and talk about the inspection before hand. Get everyone focused on the same goal - upkeep of a high quality refractory lining. What procedures do you want followed? What should the inspector do if a deficiency is suspected?
Whether you do the inspection yourself or hire someone to do it, an inspection program with an emphasis on common sense and objectivity can save you big bucks.
Kraemer Gunite, Inc.
PO Box 305
Pitman, New Jersey 08071
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