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Becht Engineering Blog

In this section of the site contributing authors submit interesting articles relating to the various services, industries and research & development efforts of Becht Engineering.

Elastic Follow-up Can Result in Failures in Systems that Comply with Piping Code Rules

piping_results_elastic_followup1 Cracking In Reduced Diameter Region Caused By Elastic Follow-up
The analysis procedures in the Code essentially assume that the strain range in the system can be determined from an elastic analysis. That is, strains are proportional to elastically calculated stresses. The stress range is limited to less than two times the yield stress, in part to achieve this. However, in some systems, strain concentration or elastic follow-up occurs. A typical concern in refinery systems is hot walled sections in otherwise refractory lined piping systems, where thermal expansion loading has resulted in cracking in the hot walled section although it complied with the basic code acceptance criteria. As an example, consider a cantilevered pipe with a portion adjacent to the fixed end constructed with a reduced-diameter or -thickness pipe or lower-yield-strength material that has the free end laterally displaced. The elastic analysis assumes that strains will be distributed in the system in accordance with the elastic stiffnesses. However, consider what...
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The Becht Expert Witness – A Partner with Credibility

Becht_shaking_hands
In any legal case it is very important to establish a true partnership between the law firm and the expert witness. This partnership facilitates an effective, balanced team with both technical and legal knowledge. This will provide the client with the most cost-effective solution and best chance for a favorable outcome during trial or arbitration.  In some legal cases the expert is kept in a strict “need to know” position rather than being a partner. This situation can hinder the expert’s ability to evaluate the situation and add cost due to potential misunderstanding and rework.  This can also put the expert in an awkward position during deposition and trial since the legal teams have facts that may not have been disclosed to the expert. This does not mean the expert has to review all discovery materials but rather needs to have a complete overview or summary of all relevant issues...
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Securing the Right Expert to Support Your Lawsuit

lit-support-blog-image Becht Litigation Support
On March 25, 2016 I published a Blog titled “ Expert Witness, a Becht Engineering Service to Avoid ”. This Blog focused on a number of elements that can be used to assure projects do not result in litigation. These elements include: Developing a sound, complete scope of work Selecting a qualified contractor Using proven industry standards with specific addenda Putting a highly experienced management and technical team in the contractor’s office Implementing shop and field quality assurance programs Demanding timely reporting from the contractor However, we find that many times these elements are not implemented on major projects and there is a dispute over cost, schedule or performance resulting in litigation. There can also be cases involving equipment failures, underperformance of projects, patent infringement or injury where we are contacted after the litigation process is well under way. In these cases, it is critical the legal team engage the...
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Fluid Catalytic Cracking (FCC) Transfer Line Flexibility - Analysis and Design Considerations

fcc-3images-ppt
FCC’s are complex units - and the design of their transfer lines has some unique considerations.   While many of the lines are refractory lined to permit construction with carbon steel piping, some sections are hot walled, at temperatures well into the creep range, for the purpose of balancing thermal expansion or, in the case of piping between the final catalyst separations device and flue gas expanders, to prevent dislodged chunks of refractory from being drawn into and damaging the expander.  Below are some critical considerations: The stiffness of the piping and resultant loads on equipment are affected by the presence of internal refractory . The composite action of the steel pipe and refractory needs to be considered.  Note that this is not simply including the refractory as a monolithic element, since the refractory will have shrinkage cracks.  There is a paper by T Chadda on an approach that can...
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