OP,
You are confused. Customer's vessel with 2660psi at 700°F will have a higher hydrotest pressure. The heater Design pressure is 2500 psi at 700°F.
Where is the issue?
Hydrotest pressure of the vessel will be= 1.3 MAWP x LSR
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ASME Section III defines different service levels (A, B, C, D) that represent varying levels of loading and stress. Service level A (which is normal operating condition) occurs most frequently while level D occurs least frequently.
Consider a piping system designed for a specific operating...
No, it's not a stress range. By definition, Pm is derived from the average value across the thickness of the section from internal pressure and other mechanical loads, excludes secondary and peak stresses. Both Pm and Sy are to be determined at the average temperature of the cycle.
Stress distribution in a flat plate is more uniform than a cylindrical vessel. A major contributor shear stress in cylindrical vessel has also minor impact in flat plates.
The 1/4 thickness rule by the code is a conservative measure for flatheads and tube sheets for the reduced stress.
OP,
Piping Codes directs designer to follow ASCE Code for seismic design. The ASCE Code provide guidance for designing piping systems that can withstand seismic forces. These codes specify requirements for seismic forces, support systems, and other design elements.
Seismic support systems...
Tony,
I am curious about the 1600ft pipe itself and the 6 meters spaced horizontal supports:
1. The pipe will see an increased hydrostatic head from top to bottom (imagine static head) - naturally, the pipe wall thickness has to increase with the depth - similar to a storage tank shell thk.
2...
OP,
What best you can have other than a Proof Test? Ask for a copy of the proof test from the Supplier/Manufacturer when they qualified the fitting design. Note the acceptable size range that qualifies with a proof test (read B16.9 Para 9.4.1).
A production test is not required by B16.9...
I guess, OP has more issues with the flow range that goes outside the operating envelope of a constant speed drive pump than the back pressure control and he is finding a solution with a VFD to cover the wide flow range (specially on the lower side).
Keep it simple. The backpressure set point of 10 psi will not have enough energy to provide for the friction loss of 12 psi in the downstream piping. In this situation, there will be no flow at the receiving tank. To get the flow, either increase the set point or reduce the piping length. By...
It is all about stress. You need to convert the test pressure to stress. Use Barlow's equation. Make sure that stress does not exceed YS. Typically, companies keep it limited to 0.9YS at test temperature.
It's a bit of mind puzzling in the beginning. You need to learn the relationship between...
when you say, "upon review" and make a statement that it 'doesn't meet B31.4 code', you much have studied the stress report in detail. Don't you have the stress model or is your statement based on the report only?
Typically, the Code wants that the piping system should be taken as a whole when...
OP,
If the main line gas flow is unidirectional ( which I assume is yes, DIB is the best option). The first MOV XX3 is a welded valve, which is good for gas service. It has a better joint strength than a flanged valve, specially after the S-bend (U/G to A/G). The second manual valve is obviously...
The intent of the restriction orifice (RO) is to have a controlled flow to the atm tank. Put the RO downstream of the block valve.
Yes, the block valve will see a DP of 700 psig when you open it. Once, the flow starts, there will be pressure drop across the RO that will stabilize the line pressure.
Look at TGS4 response on 11 April. His is a first hand knowledge on what he did to an over-pressure event. It requires a FFS, not a theoretical stress analysis.
