I am looking for a way to detect wall thichness on transport pipe. We use 8" schedule 80 pipe to transport raw material to melt ito glass.

How about intelligent pigging? Or UT from external?

Tony,

Since glass is your end product, I infer that the materials transported are abrasive. You do not say whether the medium is compressed air, water or other fluid. With air as the medium, transport velocities will be very high, so one can expect higher wear rates, so I will assume you are using a liquid, e.g., water. Please advise if these assumptions are correct.

You do not say whether the pipe is straight or has bends, so I will assume the latter. You also do not state if there are ups and downs, so I will assume there are slopes, but that these are gradual and not sudden vertical lifts. Since I do not know if the pipe is overground or underground, I will assume it is overground, and that you have inspection access. You can see that what is obvious to you need not be so to somebody sitting 6000 miles away. Hence all these assumptions.

Wear is highest at bends or elbows, as you are well aware. So set up ultrasonic measurement points along the outer radius of bends or elbows, where it will be highest. Keep a database of these readings and measure trends in wall thickness readings. A more expensive way, but one that will also work is to measure wall thickness using radigraphs. If your pipe is underground, all this becomes a lot more difficult and expensive. It is likely that wear particles will travel with the raw materials to the glass Plant. At the water separation unit, a magnetic particle catcher may help you determine whether a lot of wear is taking place. Unfortunately, you do not know if it is localised or spread over. At least it will tell you how quickly you should act to measure thicknesses using UT ot X-Rays and provide a cost justification.

Josh, intelligent pigs can only work if the pipeline has been designed and built to take such pigs. They are also frightfully expensive and only justified in specific situations.

Vee made an excellent post. However with checking wall thickness and ensuring proper installation engineering also ensure the latest technology ergo metalurgy is best suited for your application. There are some really good new alloys suited for hi-abrasives.

Sam,

I assumed the pipe is already in place, from Tony's post. If redesign is an economic option, you are quite right in suggesting hard alloys. Even here, I suggest that rubber lined pipes would be a chaeper option.