Why do outlet collectors only rarely fail, even when subjected to pressure-drops well above the design basis of the collector? The answer lies in the design approach which incorporates simplifying assumptions to accommodate a tractable and conservative approach. These conservatisms can be relaxed where necessary to give results much more in line with actual experience […]
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 […]
Review of rigging attachments to the equipment being lifted have prevented lift failures. When planning major crane lifts we are very careful about confirming the crane foundation, rigging stability/capacity, and crane capacity. Are we taking enough time to analyze the points of attachment for the rigging? Becht Engineering Heavy Lift Division says “NO”. Our experience […]
How hard can it be? I’ve heard from several (unnamed) analysts that because they have access to an FEA program and have successfully applied FEA in other fields, that FEA for pressure vessels should be a snap. What is it about FEA for pressure vessels that makes it unique? I was recently discussing with another […]
In the past ten years, there have been a few oil storage tank annular plate failures due to soil side corrosion and fatigue loading (filling and emptying) which has led to large spills. The corrosion tends to be localized in a groove fashion and the size of the flaw could vary from 3 feet to […]
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 […]
The ASME B&PV Section III Div.1 Code 2013 Edition is currently approved in 10CFR50.55(a). The 2013 edition, permits elastic FEA per NB-3200 in place of the stress equations of NB-3600, as follows: For pressure design – “NB-3611.2 Acceptability When Stresses Exceed Stress Limits. When the stresses as determined by the methods given in NB-3630 exceed […]
A recent review of equipment installed in a power plant found a piping strut that was visibly bent. Would the bend in the strut reduce its load bearing capacity as a compression member? The answer is YES! The load bearing capacity of a bent strut against buckling is reduced. The reduction in buckling capacity is […]
The NRC Inspection Manual Chapter 0326 refers to ASME III Appendix F as an acceptable method for the evaluation of “a degradation or nonconformance associated with piping or pipe supports …”. Appendix F provides five alternative methods for the qualification of pressure equipment, piping, and their supports. They are: (1) elastic analysis, (2) plastic analysis, (3) limit collapse analysis, […]
