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 has extensive experience and expertise in the field of Fitness-For-Service.  We have performed evaluations for all of the damage mechanisms covered in ASME FFS-1/API 579 for clients around the world.  We have performed Fitness-For-Service evaluations on piping, pressure vessels, heat exchangers and tanks.

Why do Clamped Connections With Metallic Seals Sometimes Leak?

cover-pipe-clamp
Clamp connections with metallic seals can offer superior joint integrity over traditional flanged connections but caution must be exercised regarding the service conditions, especially when cyclic thermal loading is present. This blog post highlights aspects of a clamp connection analysis performed by Becht Engineering. The client had observed significant loss of bolt preload at several clamp connections installed in a refinery process unit where the fluid temperature regularly fluctuated by 700 o F. The client attempted to counteract the bolt preload loss by re-torqueing any bolts that showed a torque reduction from the initially applied torque only to find that, after a period during which thermal cycles occurred, the preload was again reduced. A typical clamp arrangement is seen in Figure 1 (with parts labeled). After reviewing the installation and service conditions, it was hypothesized that the cause of the bolt preload loss could be the differential thermal growth of the...
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Do I Have to Replace My Bulged Pressure Vessel?

Figure1-Bulged_Shape_of_Vessel-cover Need to replace bulged pressure vessel?
There are a variety of conditions an in-service component (e.g. vessel, tank, piping) can be found in.  The purpose of Fitness-for-Service (FFS) is to evaluate the integrity of an in-service component given a certain degraded condition and rate it for future service considering potential for any additional degradation.  A degraded condition does not have to just be based on corrosion. Sometimes a component can experience a large deformation due to unexpected one-time loads resulting in stresses greater than yield.  When such a large deformation event occurs it is important to inspect the vessel to make sure no cracking occurred during the deformation event.  If it is found that the impacted area is defect-free then the next step is to determine if the component can operate in the deformed shape. One example of a non-corrosion related degraded condition is a bulged tank.  Figure 1 shows an example of a tank that bulged...
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Fitness-For-Service API 579-1/ASME FFS-1: Substantive Changes to the 2016 Edition

Fitness-For-Service API 579-1/ASME FFS-1: Substantive Changes to the 2016 Edition
Contributing Authors: Eileen Chant, Greg Epremian, Ranjan Nadarajah, Mark Stonehouse  Summarized herein are the substantial changes to API 579-1/ASME FFS-1, Fitness for Service , that were incorporated in the 2016 edition, as reviewed by Becht Fitness for Service experts. API 579-1/ASME FFS-1 is a Standard jointly published by API and ASME.  The purpose of the document is to provide a consensus of methods to quantitatively evaluate commonly observed damage to in-service pressure equipment.  Since it was first issued by API in 2000, this Fitness-For-Service standard has been used worldwide as a means of evaluating whether pressure equipment was fit for continued service, and in many cases, for how long.  This standard has been used to avoid costly and unnecessary unplanned outages, while maintaining safe and reliable equipment.  The Second Edition was released in 2007, followed by the most current release of the document in June of 2016.  In addition to the...
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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 tool....
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