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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.
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

Five Keys to a Cost-Effective Repair/Modification Package for Tanks-Vessels-Piping

becht_nuclear_5_keys
: Process : Does the repair change the process chemistries, physics (fluid phase), and thermo-hydraulics (flow rates, pressures, temperatures)? Does the modification change the control room indications and the operating envelopes? Material : Are the selected metallic materials (base metal and welds) and non-metallic materials (gaskets, packings, etc.) compatible with the existing materials, with the environment, and with the service, for the design life of the repair? Is the material compliant with (a) the material specification (ASTM or ASME II), (b) the supplementary Code requirements, and (c) the supplementary plant-specific requirements? Will the material be procured from an approved supplier; does it require supplementary Quality Controls? ASME Code design : Does the modification alter the system layout? If yes, has the layout been checked for good practice and consistency with the process design (item 1 above)? Are the loads and load combinations well defined and categorized as Service Levels A,...
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12 Checks When Qualifying Piping Systems in Nuclear Applications

becht_nuclear_12_checks
The analysis and qualification of piping systems in nuclear power plants involves more than meeting Code stress limits. Generally, a piping system is qualified if the following criteria have been met. These various qualification criteria are typically specified in the plant FSAR, the plant design procedures, or the ASME Code. Pressure design in accordance with the design Code. This check will govern the schedule of pipes, the thickness of tubing, the schedule and pressure class of fittings, the reinforcement of openings and branch connections, the pressure rating of valves, the pressure class of flanges, and the pressure design of specialty fittings. ASME Code stress limits . This check will verify that the Code stress equations for the load combinations corresponding to Test, Design, and Service Levels A, B, C, and D loadings have been met. NRC Standard Review Plan (SRP) Section 3.6 stress limits for the postulation of high energy...
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Capacity Reduction of a Compression Member with an Initial Deformation

piping_support_3D
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 a function of the strut’s section properties and its initial deformation. We will see here how this can be quantified analytically (closed-form solution) and numerically (FEA solution). The equation for the maximum axial load capacity of a column, before it buckles, was first formulated by Leonhard Euler in 1757. F cr  = (π 2  E I)/(K L) 2 Where E = Young’s modulus of column material; I = cross-sectional moment of inertia of the column; L = unbraced length of column; and K is a factor that depends on the degree of fixity in the...
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Evaluation of Corroded Pipe in Accordance with ASME B&PV Code Section XI - A Comparison of the Three Code Cases

Evaluation of Corroded Pipe in Accordance with ASME B&PV Code Section XI -
A Comparison of the Three Code Cases
The evaluation of wall thinning corrosion in steel pipes is addressed in three ASME XI code cases: N-513, N-597, and N-806. I have no ambition here other than to summarize in a table the differences between these three code cases. A brief commentary follows the table. The brief commentary... Line A – While these are Section XI Code Cases applicable to ASME III Class 2 and 3, technically, nothing would prevent from applying these Code Cases for B31.1 piping. Line B – There is no technical basis for limiting N-513 to moderate energy lines, i.e. pressure at or below 275 psi and (“or”, depending on the plant vintage) temperature at or below 200oF, other than the understandable reluctance to operate with hot water flashing to steam through a pinhole leak. Line D – It can be confusing that N-513 includes fracture mechanics consideration because it attempts to address cracks (so-called...
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1284 Hits
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