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.
Becht Engineering staff are experts in piping, and include former chairman of various ASME piping committees, including ASME B31.3. Becht Engineering performs detailed design for complex piping systems including very high temperature and pressure systems such as piping for FCC flue gas expanders and high pressure LDPE systems, as well as design, a...nalysis, troubleshooting and fitness for service evaluation of piping. More

Loads on Buried Pipe: A 100-Year Old Empirical Formula Still Holds Water

Loads on Buried Pipe:  A 100-Year Old Empirical Formula Still Holds Water
The evaluation of the effects of surcharge loads on buried pipes can be addressed using the Iowa formula. This formula, over 100 years old, matches the results of state-of-the-art finite element analysis with pipe-soil interaction. In 1913, Iowa State University professors Marston and Anderson published the results of their experimental work on the resistance of concrete pipes to large surcharge loads ( Marston, A., and Anderson, A.O., The Theory of Loads on Pipes in Ditches, and Tests of Cement Clay Drain Tile and Sewer Pipe, Bulletin 31, Iowa Engineering Experiment Station, Iowa State University, Ames, Iowa, 1913). Their experimental work was triggered by the failures that were occurring in the agricultural fields as early tractors were driving over shallow-buried pipes. They developed a simple formula for the ovality of the pipe under surface loads, which has since been known as the Iowa formula.          In 1941 Spangler...
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Piping Settlement Screening Tool

Piping Settlement Screening Tool
Settlement of a pipe support foundation is usually not a big deal to assess. A local piping flexibility model will reveal if the settled support keeps the pipe bending stresses within the allowable codes and, if the bending stresses are unacceptable, modifying the support and monitor periodically for further settlement is normally a quite manageable task. However, if settlement is occurring site-wide at a large site due to errors in the pre-construction soil surveys, the problem quickly becomes unmanageable. A client recently approached Becht Engineering with a request to develop a screening tool. A tool that inspectors at such a site can easily use in the field to quickly screen pipe circuits subjected to support settlement. The stated objective was to determine which circuits are acceptable without further study based on conservative criteria requiring detailed follow-up, i.e. piping flexibility analysis. This blog supplies an overview of the bases for this...
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Dimensional Control - Post Fabrication Pipe Spool QC Surveys

Dimensional Control - Post Fabrication Pipe Spool QC Surveys
With the advancements in dimensional technology, obtaining accurate measurements at the worksite has become common practice for most owners and engineering companies. New and replacement piping is being designed from behind desks without the designer visiting the worksite. This means there is no need for string lines, tape measures, or auto levels to obtain measurements or the need for notes on drawings stating “field to verify”. Despite these advancements, when it comes to the install of piping, it is still like playing Russian roulette on whether the pipe spools will fit or not. Failure rates are reported between 17% - 38% on spools inspected with these results being in the 70% range if the acceptance criteria was held strictly to industry specification. Failure stats are based on: Cause of Rejection Typical Value Industry Specification Dimensional Error +/- 1/2” 1/8” Bolt Hole Rotation 1/8” 1/8” Flange Face Deviance 1/8” 1/32” Wrong...
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ASME B31.3 - Substantive Changes in the 2016 Edition

ASME B31.3 - Substantive Changes in the 2016 Edition
In addition to the many clarifications, updated references to codes and standards, updates to basic allowable stresses, and added listed materials, there are several substantive changes to the 2016 Edition of ASME B31.3, Process Piping, which is scheduled to be issued on January 4, 2017. These changes are: Severe Cyclic Conditions The definition for severe cyclic conditions was changed. Old Definition: conditions applying to specific piping components or joints in which SE computed in accordance with para. 319.4.4 exceeds 0.8 S A (as defined in para. 302.3.5), and the equivalent number of cycles ( N in para. 302.3.5) exceeds 7000; or other conditions that the designer determines will produce an equivalent effect. New Definition: conditions applying to specific piping components or joints for which the owner or the designer determines that construction to better resist fatigue loading is warranted The new definition is expected to lead to a more appropriate...
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Recent Comments
Don Frikken

It is not a Code requirement.

ASME B31.3 has no such requirement...it does not get into that much detail about documentation for radiographic examination. Perha... Read More
Wednesday, 21 March 2018 19:46
Don Frikken

Brother in law

For B31.3 piping, one welder can finish all of the passes for a weld.
Tuesday, 17 April 2018 19:14
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