piping-systems-faq
Excessive flexibility increases material costs, increases pressure drops, increase vibration, and creates 2-phase flow occurrences.
Increase in the number of segments (nodes) reviewed though computer use and use of precise calculations.
Welds, fittings, branch connections , and other piping components where the possibility of fatigue failure could occur.
The Stress-Intensification Factor is the ratio of the maximum stress intensity compared to the nominal stress.
The maximum shear stress theory states that failure of a piping component occurs when the maximum shear stress exceeds the shear stress at the yield point in a tensile test.
The Maximum Principle Stress Theory and Maximum Shear Stress Theory
This theory states that yielding in a piping component occurs when the magnitude of any of the three mutually perpendicular principal stresses exceeds the yield strength of the material.
Failure by general yielding, yielding at sub-elevated temperature, brittle fractures, and fatigue.
Stress analysis ensures the safety of piping and piping components, safety of connected equipment and supporting structure, and that piping deflections are within limits.
A term applied to calculations, which address the static and dynamic loading, resulting from the effects of gravity, temperature changes, internal pressures, fluid flow, seismic activity, and any external loads.
It is a visual representation of the effects of various loading conditions on a piping system between stress and strain.
Vibration, thermal bowing, creep, thermal fatigue, and steam/water.
Excessive flexibility causes an increase in material costs, pressure drops, and loss of pump efficiency.
Using flexible piping with bends and turns, use of expansion loops between fixed locations, or use of expansion joints between two anchor points of a pipe run.
Flexibility analysis assures that there is not any overstress or fatigue, leakage at joints or distortions are piping connections or terminals.
To produce neither excessive stress within the configuration and limit excessive end reaction at the piping terminal.
Conventional and nuclear power plant, petroleum refinery, chemical industry, natural gas transmission, food processing and pharma industry, water and sewage plants, air conditioning and refrigeration system.
Fluctuating temperatures, changes in pressure, and modification in flow rate.
Fluid velocity is controlled to prevent operational problems such as water hammer, steam hammer, relief valve discharge loading, and vibrational loads.
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Piping systems use pumps to develop the pressure or head required to maintain the system design flow rates.
Piping system pressure drops must be maintained within reasonable values to limit the installed size of the system pumps and their prime movers.
Dynamic head is the equivalent height of a fluid that is to be pumped, taking into account the friction losses in the pipe.
System static head is the internal energy of
Back
Backflow or
Back Pressure is a
The syphon principle is a system in which syphon principle is employed to carry water through elevated parts.
The first critical value of piping size criteria is allowable pressure drop for the entire network.
To add pseudo loops in the Hardy Cross method, you should add
To assign direction, you should assign base direction and indicate whether to go clockwise or counterclockwise.
In the number system in the Hardy Cross Method, you should assign complete numbers of the entire system.
The Hardy Cross Method determines flow inside the piping network.
To determine the flow in the Hardy Cross Method, you should create a skeleton drawing of
To number loops in the Hardy Cross Method, you should number all loops in the sequence in arbitrary fashion.
Branching pipes are pipes that do not run parallel or in series.
The goal in
Two-pipe systems are said to be equivalent when same head loss produces the same discharge in both systems.
Power piping systems refer to piping within facility intended to generate electricity.
Power piping systems are intended to convey steam and water.
Series piping has the same fluid flowing through all the piping and head losses are cumulative.
A service system provides cooling water to plant’s component, heat exchangers, and other required service areas by plant.
Process piping systems refers to piping within chemical/petroleum processing unit.
Process piping systems intend to convey petroleum, raw, intermediate, and finished chemicals, gas, steam, air and water, fluidized solids, refrigerants, and cryogenic fluids.
The two main purposes of water distribution are to supply sufficient quantity of water to all parts of system and to maintain adequate pressure at all times and in all conditions.
A condenser system circulates water to condense steam exhausted by turbines in plants.
Distribution mains carry material from transmission lines and distribute to service area.
Transmission lines carry water from the main source to the distribution system.
The in-plant utility’s common industrial use is the condenser-circulating system and service cooling water systems.
Services lines use small diameter pipes that run from distribution mains to user.
The four general types of water distribution are transmission lines, in-plant utility, service lines, and distribution mains.
Three types of piping systems discussed are water, process, and power.
Isolation valves are usually provided if the location of the nozzle is below the column level or on small bore lines which are more susceptible to damage.
In regards to design considerations of pressure vessels, when are isolation valves usually provided?
Flanged connections should be outside of the skirt to minimize leakage in confined space.
Pipe supports will be attached to the side of the vessel.
Configurations of water distribution systems include loop, grid, and tree.
Piping should drop or rise immediately upon leaving the tower nozzle and run parallel along the side of the vessel using the wind load on the nozzle as constraint.
The nozzle location is controlled by the vessel engineer.
The thermal expansion should be taken into account between the vessel and the piping.
Flammable liquids are filled near the bottom of tank to prevent static electricity buildup.
Vessel specifications will be determined by the process engineer. Specifications include the size/capacity, pressure rating, wall thickness, material, type of connection, etc.
Feed tanks separate feed and discharge systems.
Block valves are supplied on any nozzles below tank level.
The technostructure functions as a differential settlement between the tank and the piping supports.
The support staff functions as the weight of piping, valves, and contents.
The three application guidelines of tanks include feed tanks, block valves, and flammable liquids.
An operating core has tank shell radial movements and nozzle rotations while filling and emptying tank.
The strategic apex designs pressure of the system.
The middle line functions as the thermal expansion of piping.
A pressure vessel is a storage device meant to hold fluid media while simultaneously containing reactions at pressures above atmospheric pressure.
A tank is a storage device meant to hold fluid media, either liquid or gas. Pressure developed is a function of the tank size and not a result of any external forces.
A pump curve provides details of pump efficiency, net positive suction head (NPSH), various impeller diameters, and pump power consumption.
Application guidelines for centrifugal pumps are location of flat when using eccentric reducers, all pump suction lines must be designed to accommodate, the suction of any centrifugal pump must continuously flooded and suction pumping shall contain no vertical loops or air pockets.
A pump head is a measure of fluid energy.
Regulating valves are used extensively to regulate the flow of fluid. Different types of regulating valves are globe, needle, butterfly, ball, plug and diaphragm valves.
Backflow prevention is used to prevent backflow. In backflow prevention the valves are self actuating and the valve disc is kept open by the forward flow of fluid.
Protection valves are used to protect piping and equipment from being subjected to pressures. Protection valves include a rupture disc designed to burst open at a predetermined pressure.
Stop or isolation valves include gate, globe, ball, butterfly, play and diaphragm valves are all types of stop or isolation valves.
An increase in pipe diameter = lower pump capacity, and increased piping material cost.
A decrease in pipe diameter = increase in flow velocity and more pressure loss.
Reduction in length, directional changes, and diameter variations decrease cost.
Head Loss is calculated using a number of calculations depending on type of piping and attached equipment.
Higher viscosity fluid = powerful pumpings of fluid and supporting of pipe.
Selection of pipe thickness would be dependent on same parameters utilized in piping size selection criteria.
The Reynolds Number is a dimensionless number. It is defined as the ratio of the dynamic forces of mass flow to the shear stress due to viscosity.
Loads are parameters that affect state of stress of the piping system. For example forces, moments, pressure changes, temperature changes and thermal gradients.
The four design basis to consider are
1.) Materials
2.) Physical Attributes
3.) Loading Conditions
4.) Environmental Factors
The Maximum Shear Theory states that pipe failure happens and the maximum shear stress exceeds shear stress at yield point of tensile test. (ASME B31.3)
The second critical value of pipe sizing criteria is adjusted volumetric flow rates at the design point of the network.
Flexibility ensures that a piping system operates safely.
The purpose of the syphon principle is to reduce pumping power.