New at PipingDesign.com: 14 November 2000

Carmagen Engineering has added to their Newsletter Articles page at <a href="http://www.carmagen.com/newslet.html.">http://www.carmagen.com/newslet.html.</a> I've added the following links at PipingDesign.com:

<a href="http://www.PipingDesign.com/design.html">http://www.PipingDesign.com/design.html</a>

Piping Vibration
Carmagen Engineering

<<There's no question about it - excessive piping vibration can cause
real problems. Threaded connections can loosen. Flanges can start leaking. Pipes can be knocked off their supports. An in extreme cases, a pipe fatigue failure can occur. But when is vibration excessive? Vibration is obviously too much if it causes a failure, but hindsight is 20/20. What about having to decide if vibration that is occurring is too much to tolerate? What about having to decide if vibration could be a problem while a piping system is being designed? The entire subject of piping vibration cannot be discussed in this article, but I will highlight several items to consider.>>

Flexible Operations Doesn't Always Mean Piping Flexibility Carmagen Engineering

<<Several piping flexibility analyses were recently made for a large
East Coast refinery to help design a number of bypasses. The bypasses were being installed to provide additional operational flexibility. However this additional flexibility in operations doesn't necessarily increase the piping flexibility of the system. This means that piping flexibility stresses and heat exchanger nozzle stresses may exceed allowable values if the new bypass lines are not properly designed.>>

Control of Piping Loads Imposed on Load-Sensitive Equipment Carmagen Engineering

<<Properly designed piping systems keep stresses in the pipe wall itself
within established allowable limits, and ensure that end point reaction loads do not overload connected equipment nozzles. While avoiding excessive equipment nozzle loads is important in all cases, this is especially true for piping systems connected to pumps, compressors and steam turbines. Excessive piping loads in these cases can cause high machine vibration, shaft misalignment, and coupling failures. These problems result in increased maintenance costs, and can lead to equipment and plant shutdowns. This series of articles will discuss suggestions for the design and installation of such machinery piping systems which will reduce the likelihood of nozzle overloads.>>

Piping Design Considerations to Control Loads on Load-Sensitive Equipment, Part 1
Carmagen Engineering

<<This article discusses one important piping design consideration,
temperature. Future articles will discuss other design considerations. The piping system will have a design temperature associated with it, and this determines its stress and end point reaction loads. What's special about rotating equipment piping systems regarding temperature?>>

Piping Design Considerations to Control Loads on Load-Sensitive Equipment, Part 2
Carmagen Engineering

<<Piping must be designed and installed such that there is essentially
zero forces and moments applied to the machinery nozzles when the system is not operating and is at ambient temperature. In order to accomplish this, sufficient pipe supports must be installed near the machine to carry the weight load. In addition, close flange alignment tolerances must be specified in the system design specification and adhered to during piping installation. >>

<a href="http://www.PipingDesign.com/pressurevessels.html">http://www.PipingDesign.com/pressurevessels.html</a>

Addition of Shell Nozzles by Hot-Tapping in Atmospheric Storage Tanks Carmagen Engineering

<<Hot tapping has been a generally accepted method and, in some cases,
the only practical way of adding nozzles in an operating atmospheric storage tank (AST). API Standard 653, Tank Inspection, Repair, Alteration and Reconstruction, provides guidelines on making hot taps in ASTs. However, in our opinion, the requirements contained therein are unduly restrictive in some respects and prohibit hot tapping in certain situations where hot tapping has been done successfully in the past without incident. Hot tapping can be performed safely in situations prohibited by API-653 when appropriate consideration has been given to all relevant factors. >> Received on Tue Nov 14 17:03:00 2000