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CALCULATOR MODULE : API RP 1111 Pipeline Limit State Design Line Pipe Schedule   ±
CALCULATOR MODULE : API RP 1111 Pipeline Wall Thickness   ±

Calculate API RP 1111 limit state pipeline wall thickness from local pressure.

The pipe wall thickness should be calculated for the maximum pressure difference at all points on the pipeline or pipeline section. Internal pressure is calculated from reference pressure and elevation. The internal fluid density is assumed constant. External pressure should be calculated for the minimum local water depth (lowest astronomical tide and allowance for storm surge etc). API RP 1111 should only be used for line pipe with a weld joint factor = 1.0.

Note : The derated yield stress and tensile stress are used in the API RP 1111 calculations.

Reference : API RP 1111 : Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines (Limit State Design) (2011)

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CALCULATOR MODULE : API RP 1111 Pipeline Hoop Stress   ±
CALCULATOR MODULE : API RP 1111 Pipeline Test Pressure   ±
CALCULATOR MODULE : API RP 1111 Pipeline Axial Load   ±
CALCULATOR MODULE : API RP 1111 Pipeline Collapse Pressure   ±
CALCULATOR MODULE : API RP 1111 Pipeline Ovality   ±

Calculate API RP 1111 limit state pipeline out of roundness and ovality from tolerances, or from maximum and minimum diameter.

Out of roundness is equal to the maximum diameter minus the minimum diameter measured at the same cross section. Out of roundness ratio equals the out of roundness divided by either the nominal diameter or the mean diameter. DNV or ISO ovality is equal to the out of roundness ratio. API ovality is equal to half the DNV ovality (DNV or ISO ovality is equal to 2 x API ovality).

`Davg = (Dmax + Dmin) / 2 `
`OOR = (Dmax - Dmin) `
`ro = (OOR) / (Davg) `
`fa = (Dmax - Dmin) / (Dmax + Dmin) = (OOR) / (2.Davg) = (ro) / 2 `
`fd = 2.(Dmax - Dmin) / (Dmax + Dmin) = (OOR) / (Davg) = 2.fa = ro `

where :

OOR = out of roundness
ro = out of roundness ratio
Dmax = maximum diameter
Dmin = minimum diameter
Davg = average or mean diameter
fa = API ovality
fd = DNVGL or ISO ovality

Reference : API RP 1111 : Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines (Limit State Design) (2011)

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CALCULATOR MODULE : API RP 1111 Pipeline Combined Loading   ±

Calculate API RP 1111 limit state pipeline combined loading check.

For the external pressure check, the external pressure should be calcuated for the maximum water depth (highest astronomical tide plus storm surge). The internal pressure should be the maximum sustainable pressure (normally zero).

For the axial load check, the axial load can be calculated for either fully constrained pipeline, unconstrained pipeline, or user defined loads.

Reference : API RP 1111 : Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines (Limit State Design) (2011)

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CALCULATOR MODULE : API RP 1111 Pipeline Burst Pressure   ±
CALCULATOR MODULE : API RP 1111 Pipeline Temperature Derating   ±
CALCULATOR MODULE : API RP 1111 Pipeline Local Pressure   ±
CALCULATOR MODULE : API RP 1111 Pipeline Design Pressure   ±

Calculate API RP 1111 limit state pipeline maximum allowable design pressure from wall thickness and burst stress.

Burst stress is calculated from the average of the yield stress and the ultimate tensile stress. Burst pressure can be calculated from either equation 4, or equation 5. The maximum test pressure, incidental pressure and design pressure are calculated from the burst pressure. The allowable pressure is calculated so that the hoop stress equals the allowable stress. For submerged pipelines the allowable pressure equals the pressure difference (internal pressure minus external pressure).

Reference : API RP 1111 : Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines (Limit State Design) (2011)

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CALCULATOR MODULE : API RP 1111 Pipeline Mass And Weight   ±

Calculate API RP 1111 limit state pipeline unit mass (mass per length), unit weight (weight per length), and total mass.

The mass per joint can be calculated from the joint length. Construction quantities can be calculated from the total pipe length.

Pipe unit mass (mass per length) and pipe unit weight (weight per length) can be calculated for multi layer pipelines (dry empty, dry full, wet empty and wet full pipelines). The pipe diameter can be defined by either the outside diameter or the inside diameter. For multi layer pipelines, the first internal layer is the line pipe. The line pipe diameter and thickness are calculated from the pipe schedule. Change the number of layers on the setup page.

Use the Result Table option to display a table of pipe mass versus wall thickness for the selected diameter.

Reference : API RP 1111 : Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines (Limit State Design) (2011)

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CALCULATOR MODULE : API RP 1111 Pipeline Fluid Volume And Mass   ±

Calculate API RP 1111 limit state pipeline fluid volume and fluid mass for two phase gas liquid piping, and three phase black oil piping (gas water and oil).

The two phase fluid calculator can be used for single phase gas, single phase liquid, or two phase gas and liquid. The three phase black oil calculator can be used for single phase oil, single phase water, two phase oil and water, and three phase oil, water and gas. Water cut is the volume fraction of water in the liquid phase (ignoring the gas phase). Gas oil ratio (GOR) is the ratio of gas moles to liquid volume (ignoring the water phase). Gas moles are commonly measured as gas volume at standard conditions, eg SCM (Standard Conditions Meter) or SCF (Standard Conditions Feet).

Reference : API RP 1111 : Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines (Limit State Design) (2011)

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CALCULATOR MODULE : API RP 1111 Pipeline Fluid Velocity And Flow Rate   ±

Calculate API RP 1111 limit state pipeline fluid velocity and flow rate for two phase gas liquid piping, and three phase black oil piping (gas water and oil).

The two phase fluid calculator can be used for single phase gas, single phase liquid, or two phase gas and liquid. The three phase black oil calculator can be used for single phase oil, single phase water, two phase oil and water, and three phase oil, water and gas. Water cut is the volume fraction of water in the liquid phase (ignoring the gas phase). Gas oil ratio (GOR) is the ratio of gas moles to liquid volume (ignoring the water phase). Gas moles are commonly measured as gas volume at standard conditions, eg SCM (Standard Conditions Meter) or SCF (Standard Conditions Feet).

Reference : API RP 1111 : Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines (Limit State Design) (2011)

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CALCULATOR MODULE : API RP 1102 Pipeline Crossing Line Pipe Schedule   ±

Calculate API RP 1102 steel pipeline diameter, nominal wall thickness and pressure containment wall thickness.

For API RP 1102, the fabrication tolerance is included in the design factor. The fabrication tolerance is not required provided that the tolerance is within the relevant specification. The pressure containment wall thickness equals the nominal wall thickness minus the corrosion allowance. The pipe diameter can be defined by either the outside diameter or the inside diameter.

Use the Result Table option to display a table of pipe cross section versus wall thickness for the selected diameter.

Reference : API RP 1102 : Steel Pipelines Crossing Railroads and Highways (2012)

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CALCULATOR MODULE : API RP 1102 Pipeline Highway Crossing   ±

Calculate API RP 1102 pipeline highway crossings.

API 1102 is suitable for cased and uncased steel pipeline road and highway crossings.

Standard loads for single and tandem axle vehicles are included. The standard soil weight is 18.9 kN/m^3. Soil weight and wheel loads can also be user defined. The design factors are calculated from the figures. For input values outside the range in the figures the values are extrapolated (select either constant value or constant slope option). Extrapolated values should be used carefully.

Note : The calculations are based on the SI data values. User input values can be either US units or SI units. Change units on the setup page (click the Setup link on the calc bar). Units can be mixed, and do not need to be consistent.

Reference : API RP 1102 : Steel Pipelines Crossing Railroads and Highways (2012)

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CALCULATOR MODULE : API RP 1102 Pipeline Railroad Crossing   ±

Calculate API RP 1102 pipeline railroad crossings.

API 1102 is suitable for cased and uncased steel pipeline railway crossings.

The design factors are calculated from the figures. Design factors are extrapolated for input values outside the range in the figures. Extrapolated values should be used carefully (select either constant value or constant slope option). The standard soil weight is 18.9 kN/m^3. Standard loads for single track and double track railroads are included. Soil weight and wheel loads can also be user defined.

Note : The calculations are based on the SI data values. User input values can be either US units or SI units. Change units on the setup page (click the Setup link on the calc bar). Units can be mixed, and do not need to be consistent.

Reference : API RP 1102 : Steel Pipelines Crossing Railroads and Highways (2012)

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CALCULATOR MODULE : API RP 1102 Pipeline Crossing Design Factor   ±

Calculate API RP 1102 highway and railroad pipeline crossing design factors.

The design factors are calculated from the figures using the US values. Use the constant slope option to extrapolate values outside the range in the figures. Extrapolated values should be used carefully. Use the Result Plot option to display the selected figure with preset values (click the Result Plot button on the plot bar, then click the Make Plot button).

Reference : API RP 1102 : Steel Pipelines Crossing Railroads and Highways (2012)

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CALCULATOR MODULE : API RP 1102 Pipeline Fatigue Limit   ±
CALCULATOR MODULE : API RP 1102 Pipeline Design Stress And Design Pressure   ±

Calculate API RP 1102 pipeline allowable stress and maximum allowable design pressure from wall thickness.

The allowable stress is calculated from the SMYS, diameter and wall thickness. The allowable pressure is calculated so that the hoop stress equals the allowable stress, allowing for pipe wall allowances. Use the Result Table option to display the calculated stress and allowable pressure values.

Reference : API RP 1102 : Steel Pipelines Crossing Railroads and Highways (2012)

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CALCULATOR MODULE : API RP 1102 Pipeline Local Pressure   ±

Calculate API RP 1102 local pipeline stationary internal pressure from elevation.

Elevation is measured relative to any arbitrary datum (+ve above the datum -ve below the datum). The internal fluid density is assumed constant. Use the Result Plot option to plot pressure versus elevation.

Reference : API RP 1102 : Steel Pipelines Crossing Railroads and Highways (2012)

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CALCULATOR MODULE : API RP 1102 Pipeline Mass And Weight   ±

Calculate API RP 1102 steel pipeline unit mass (mass per length), unit weight (weight per length), and total mass.

The mass per joint can be calculated from the joint length. Construction quantities can be calculated from the total pipe length.

Pipe unit mass (mass per length) and pipe unit weight (weight per length) can be calculated for multi layer pipelines (dry empty, dry full, wet empty and wet full pipelines). The pipe diameter can be defined by either the outside diameter or the inside diameter. For multi layer pipelines, the first internal layer is the line pipe. The line pipe diameter and thickness are calculated from the pipe schedule. Change the number of layers on the setup page.

Use the Result Table option to display a table of pipe mass versus wall thickness for the selected diameter.

Reference : API RP 1102 : Steel Pipelines Crossing Railroads and Highways (2012)

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CALCULATOR MODULE : API 5L Line Pipe   ±

Calculate API 5L line pipe diameter, wall thickness and mass schedule.

For some pipe codes (eg ASME B31.4, ASME B31.8, API RP 111 and AS 2885.1) the fabrication tolerance is included in the design factor, and provided that fabrication tolerances are within the relevant specification. For these codes the pressure design or pressure containment wall thickness equals the nominal wall thickness minus the corrosion and mechanical allowance.

For other codes (eg ASME B31.1, ASME B31.3 and ASME B31.5) the fabrication tolerance must be included in the pressure design calculation. For these codes the minimum wall thickness equals the nominal wall thickness minus the fabrication allowance. The pressure containment wall thickness equals the nominal wall thickness minus the fabrication allowance, and minus the corrosion allowance. Fabrication tolerance can be defined by either a fabrication allowance, or a fabrication fraction.

The pipe diameter can be defined by either the outside diameter or the inside diameter. Use the Result Table option to display a table of pipe schedule versus wall thickness for the selected diameter.

References :

API 5L : Specification for Line Pipe (2007)
ISO 3183 : Petroleum and Natural Gas Industries - Steel Pipe For Pipeline Transportation Systems (2007)

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CALCULATOR MODULE : API 5L Line Pipe Diameter Tolerance   ±

Calculate API 5L line pipe maximum and minimum diameter from nominal diameter and tolerance.

Tolerances can be calculated from API 5L, or specified as either a diameter allowance or a diameter fraction.

References :

API 5L : Specification for Line Pipe (2007)
ISO 3183 : Petroleum and Natural Gas Industries - Steel Pipe For Pipeline Transportation Systems (2007)

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CALCULATOR MODULE : API 5L Line Pipe Carbon Equivalent   ±

Calculate API 5L line pipe carbon equivalent from material composition. Carbon equivalent is an indicator of material weldability, and fracture toughness.

References :

API 5L : Specification for Line Pipe (2007)
ISO 3183 : Petroleum and Natural Gas Industries - Steel Pipe For Pipeline Transportation Systems (2007)

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CALCULATOR MODULE : API 5L Line Pipe Out Of Roundness Tolerance   ±

Calculate API 5L line pipe out of roundness and ovality from diameter and tolerance.

Out of roundness is equal to the maximum diameter minus the minimum diameter measured at the same cross section. Out of roundness ratio equals the out of roundness divided by either the nominal diameter or the mean diameter. DNV or ISO ovality is equal to the out of roundness ratio. API ovality is equal to half the DNV ovality (DNV or ISO ovality is equal to 2 x API ovality).

`Davg = (Dmax + Dmin) / 2 `
`OOR = (Dmax - Dmin) `
`ro = (OOR) / (Davg) `
`fa = (Dmax - Dmin) / (Dmax + Dmin) = (OOR) / (2.Davg) = (ro) / 2 `
`fd = 2.(Dmax - Dmin) / (Dmax + Dmin) = (OOR) / (Davg) = 2.fa = ro `

where :

OOR = out of roundness
ro = out of roundness ratio
Dmax = maximum diameter
Dmin = minimum diameter
Davg = average or mean diameter
fa = API ovality
fd = DNVGL or ISO ovality

Out of roundness can be calculated from API 5L, from user defined out of roundness, or from user defined maximum and minimum diameter. For diameter D ≥ 0.2191 m, the out of roundness can be calculated from the inside diameter. For D < 0.0603 m the out of roundness is included with the diameter tolerance. For D ≥ 1.422 m the out of roundness tolerance is to be agreed with the supplier. All tolerances should be entered as positive (+ve) values.

References :

API 5L : Specification for Line Pipe (2007)
ISO 3183 : Petroleum and Natural Gas Industries - Steel Pipe For Pipeline Transportation Systems (2007)

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CALCULATOR MODULE : API 5L Line Pipe Wall Thickness Tolerance   ±

Calculate API 5L line pipe maximum and minimum wall thickness from tolerance.

Wall thickness tolerance can be calculated from API 5L, or specified as either a wall thickness fraction, or a wall thickness allowance.

References :

API 5L : Specification for Line Pipe (2007)
ISO 3183 : Petroleum and Natural Gas Industries - Steel Pipe For Pipeline Transportation Systems (2007)

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CALCULATOR MODULE : API 5L Line Pipe SMYS And SMTS   ±

Calculate API 5L line pipe specified minimum yield stress (SMYS) and specified minimum tensile stress (SMTS). API 5L yield stress is normally measured at 0.5% strain.

References :

API 5L : Specification for Line Pipe (2007)
ISO 3183 : Petroleum and Natural Gas Industries - Steel Pipe For Pipeline Transportation Systems (2007)

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CALCULATOR MODULE : API 5L Line Pipe Mass Tolerance   ±

Calculate API 5L line pipe unit mass (mass per length) and total mass from diameter, wall thickness and density.

Pipe mass can be calculated with API 5l tolerances, or as mass schedule with no tolerances. Tolerances can be calculated from API 5L, or specified as either a mass allowance or a mass fraction. To calculate mass per joint, enter the joint length as the pipe length. For construction quantities, enter the total pipe length as the pipe length. The API 5L negative tolerance is reduced if the total mass is greater than 18 tonne.

References :

API 5L : Specification for Line Pipe (2007)
ISO 3183 : Petroleum and Natural Gas Industries - Steel Pipe For Pipeline Transportation Systems (2007)

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CALCULATOR MODULE : API RP 14E Platform Piping   ±
CALCULATOR MODULE : API RP 14E Maximum Erosional Velocity   ±

Calculate API RP 14E maximum allowable erosional velocity for platform piping systems.

The fluid density can be calculated for single phase gas, single phase liquid, two phase gas liquid, or three phase black oil (gas oil and water). The erosional velocity is calculated from the fluid density and the C Factor. Equation 2.14 in API RP 14E uses FPS units. The API RP 14E calculators have been factored to use SI units.

For fluids with no entrained solids a maximum C value of 100 for continuous service, or 125 for intermittent service can be used. For fluids treated with corrosion inhibitor, or for corrosion resistant materials a maximum C value of 150 to 200 may be used for continuous service, and upto 250 for intermittent service. For fluids with solids, the C value should be significantly reduced.

Gas oil ratio (GOR) is the ratio of gas moles over oil volume. Gas moles are commonly measured as gas volume at standard conditions (eg SCF or SCM). Water cut is the volume ratio of water in liquid (oil and water).

Reference : API 14E Recommended Practice For Design and Installation of Offshore Production Platform Piping Systems

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CALCULATOR MODULE : API RP 14E Fluid Velocity   ±

Calculate API RP 14E fluid velocity and flowrate for single phase gas, single phase liquid, two phase gas liquid, and three phase gas, oil and water (black oil).

Flow rate can be calculated for mass flow rate, volume flow rate, mole flow rate and velocity. Gas density is calculated from temperature and pressure, and either specific gravity or molar mass. Liquid density can be calculated from specific gravity, degrees Baume, degrees Twaddell, or degrees API. Black oil is a three phase mixture of oil, water and gas. Water cut is measured relative to the total liquid volume (gas volume is ignored). Gas oil ratio (GOR) is measured relative to the oil volume at standard conditions (water volume is ignored).

Reference : API 14E Recommended Practice For Design and Installation of Offshore Production Platform Piping Systems

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CALCULATOR MODULE : API RP 14E Fluid Density   ±
CALCULATOR MODULE : API RP 14E Piping Wall Thickness   ±
CALCULATOR MODULE : API RP 14E General Gas Piping Pressure Loss Equation   ±

Calculate API RP 14E gas piping pressure loss from the general equation.

The pressure loss is calculated using the Darcy-Weisbach form of the Moody diagram. For low Reynolds numbers Re < 2000, the fluid flow is laminar and the Hagen-Poiseuille laminar flow option should be used. In the transition region 2000 < Re < 4000, the flow is unstable and cannot be reliably calculated. For turbulent flow (Re > 4000), either the original Colebrook White equation or the modified Colebrook White equation can be used. Minor losses are used to account for pipeline fittings such as bends, tees, valves etc.

Reference : API 14E Recommended Practice For Design and Installation of Offshore Production Platform Piping Systems

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CALCULATOR MODULE : API RP 14E Weymouth Gas Piping Pressure Loss Equation   ±

Calculate API RP 14E gas piping pressure loss from the Weymouth equation.

The Weymouth equation was developed for fully developed turbulent flow in long pipelines. It is not suitable for low Reynolds number, or short piping sections. Minor losses are used to account for pipeline fittings such as bends, tees, valves etc. Compare the results for the Weymouth equation, the general equation (Moody diagram), and the Panhandle A and B equations.

Reference : API 14E Recommended Practice For Design and Installation of Offshore Production Platform Piping Systems

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CALCULATOR MODULE : API RP 14E Panhandle Gas Piping Pressure Loss Equation   ±

Calculate API RP 14E gas piping pressure loss from the Panhandle equation.

The Panhandle equations were developed for fully developed turbulent flow in long pipelines. They are not suitable for low Reynolds number, or short piping sections. Minor losses are used to account for pipeline fittings such as bends, tees, valves etc. Compare the results for the Weymouth equation, the general equation (Moody diagram), and the Panhandle A and B equations.

Reference : API 14E Recommended Practice For Design and Installation of Offshore Production Platform Piping Systems

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CALCULATOR MODULE : API RP 14E Liquid Piping Pressure Loss Equation   ±

Calculate API RP 14E liquid piping pressure loss from the Moody diagram.

The pressure loss is calculated using the Darcy-Weisbach form of the Moody diagram. For low Reynolds numbers Re < 2000, the fluid flow is laminar and the Hagen-Poiseuille laminar flow option should be used. In the transition region 2000 < Re < 4000, the flow is unstable and cannot be reliably calculated. For turbulent flow (Re > 4000), either the original Colebrook White equation or the modified Colebrook White equation can be used. Minor losses are used to account for pipeline fittings such as bends, tees, valves etc.

Reference : API 14E Recommended Practice For Design and Installation of Offshore Production Platform Piping Systems

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CALCULATOR MODULE : API RP 14E Piping Mass And Weight   ±

Calculate API RP 14E platform piping unit mass (mass per length), unit weight (weight per length), and total mass from length.

The mass per joint can be calculated from the joint length. Construction quantities can be calculated from the total pipe length.

Pipe mass and pipe unit weight (weight per length) can be calculated for multi layer pipelines (dry empty, dry full, wet empty and wet full pipelines). For multi layer pipelines, the first internal layer is the line pipe. Change the number of layers on the setup page. The line pipe layer diameter and thickness are calculated from the pipe schedule.

Use the Result Table option to display a table of pipe mass and weight versus wall thickness for the selected diameter.

Reference : API 14E Recommended Practice For Design and Installation of Offshore Production Platform Piping Systems

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CALCULATOR MODULE : API 520 Pressure Relief Device   ±
CALCULATOR MODULE : API 520 Gas Pressure Relief Valve   ±

Calculate API 520 gas pressure relief valve (PRV) and rupture disk size.

The flow through the relief valve nozzle is assumed to be sonic (M = 1), adiabatic, and isentropic. If the back pressure is greater than the critical (sonic) pressure the flow is subsonic (M < 1).

Friction losses are accounted for using the discharge coefficient Kd. For initial sizing of PRV's the effective nozzle diameter should be used with the discharge coefficient Kd = 0.975. The actual nozzle diameter and the rated coefficient of discharge should be used to verify that the selected PRV is suitable for the required flow rate. The PRV effective diameter is taken from API 526 (letter designation D to T). Changes in phase are not accounted for.

The calculation can also be used for rupture disks. The rupture disk diameter should be substituted for the nozzle diameter, with a discharge coefficient Kd = 0.62. Rupture disks can also be analysed as part of a relief vent system using the flow resistance method.

Note : The ideal gas calculators use the ideal gas compressible flow equations. The API 520 gas and steam calculations use an approximation of the ideal gas compressible flow equations. Use the ideal gas calculators for a comparison with the API 520 calculators.

Reference : API 520 Sizing, Selection And Installation Of Pressure Relieving Devices (2014)

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CALCULATOR MODULE : API 520 Steam Pressure Relief Valve   ±

Calculate API 520 steam pressure relief valve (PRV) and rupture disk size.

The flow through the relief valve nozzle is analysed using the Napier equation. For temperatures above 1200 F (922 K), the gas PRV calculation should be used. If the back pressure is greater than the critical (sonic) pressure the flow is sub sonic (M < 1).

Friction losses are accounted for using the discharge coefficient Kd. For initial sizing of PRV's the effective nozzle diameter should be used with the discharge coefficient Kd = 0.975. The actual nozzle diameter and rated coefficient of discharge should be used to verify that the selected PRV is suitable for the required flow rate. The PRV effective diameter is taken from API 526 (letter designation D to T). Changes in phase are not accounted for.

The calculation can also be used for rupture disks. The rupture disk diameter should be substituted for the nozzle diameter, with a discharge coefficient Kd = 0.62. Rupture disks can also be analysed as part of a relief vent system using the flow resistance method.

Note : The ideal gas calculators use the ideal gas compressible flow equations. The API 520 gas and steam calculations use an approximation of the ideal gas compressible flow equations. Use the ideal gas calculators for a comparison with the API 520 calculators.

Reference : API 520 Sizing, Selection And Installation Of Pressure Relieving Devices (2014)

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CALCULATOR MODULE : API 520 Liquid Pressure Relief Valve   ±

Calculate API 520 liquid pressure relief valve (PRV) and rupture disk size (certified and non certifed devices).

The flow through the relief valve nozzle is analysed using the Bernoulli equation. Friction losses are accounted for using the discharge coefficient Kd. For initial sizing of PRV's the effective nozzle diameter should be used with the discharge coefficient Kd = 0.65 for certified PRV's and Kd = 0.62 for non certified PRV's. The actual nozzle diameter and rated coefficient of discharge should be used to verify that the selected PRV is suitable for the required flow rate. The PRV effective diameter is taken from API 526 (letter designation D to T). Changes in phase are not accounted for.

The PRV calculation can also be used for rupture disks. The rupture disk diameter should be substituted for the nozzle diameter, with a discharge coefficient Kd = 0.62. Rupture disks can also be analysed as part of a relief vent system using the flow resistance method.

Reference : API 520 Sizing, Selection And Installation Of Pressure Relieving Devices (2014)

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CALCULATOR MODULE : API 520 Correction Factor   ±
CALCULATOR MODULE : API 520 Critical Flow Ratio   ±
CALCULATOR MODULE : API 520 Darcy Friction Factor   ±

Calculate API 520 Darcy friction factor and pressure loss factor for single phase liquid and single phase gas.

The Darcy friction factor can be caclulated from either the Moody diagram or the Von Karman rough pipe equation (API 520 Annex E).

At high Reynolds numbers the Moody diagram friction factor is fully turbulent and is dependent on the pipe roughness only. The pressure loss factor (fLe/ID) includes minor losses. Minor losses can be entered as either a K factor, an equivalent added length, or an equivalent added length over diameter ratio.

Reference : API 520 Sizing, Selection And Installation Of Pressure Relieving Devices (2014)

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CALCULATOR MODULE : API 520 Pressure Relief Vent   ±

Calculate API 520 flow rate through a constant diameter pressure relief vent.

The vent entry is assumed to be a pressure vessel or piping at stagnation pressure (valid when the pipe or vessel diameter is much greater than the vent diameter). The calculated vent exit pressure is flowing pressure (stagnation pressure minus dynamic pressure).

Vent pressure losses are calculated from the vent pressure loss factor (fld = fL/D + K). Minor losses should include the vent entry, valves and bends etc. The vent exit should not be included. The discharge coefficient can be used to factor the flow rate, depending on the design requirements.

For rupture disks, the flow resistance factor of the rupture Kr should be included in the minor losses (the resistance factor should be factored for the vent diameter). A discharge coefficient of 0.9 or less should be used for rupture disks. Alternatively, the PRV calculators can be used for rupture disk calculations.

Note : The ideal gas calculators use the ideal gas compressible flow equations. The API 520 gas and steam calculations use an approximation of the ideal gas compressible flow equations. Use the ideal gas calculators for a comparison with the API 520 calculators.

Reference : API 520 Sizing, Selection And Installation Of Pressure Relieving Devices (2014)

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CALCULATOR MODULE : API 520 Back Pressure   ±

Calculate API 520 back pressure from mass flow rate through a constant diameter vent.

The calculated vent entry and exit pressures are flowing pressure (stagnation pressure minus dynamic pressure). Minor losses should include bends and valves etc. The vent entry and exit should not be included in the minor losses. The discharge coefficient can be used to factor the mass flow rate, depending on design requirements.

Where multiple pressure relieving devices share a common vent, the back pressure should be calculated for the total mass flow rate.

For relief vents with sections of increasing diameter, the back pressure should be calculated for each constant diameter section, going backwards from exit. The (flowing) exit pressure for each section equals the (flowing) inlet pressure for the previous section.

For pressure relief valves or rupture disks, the (flowing) inlet pressure for the vent is used as the (flowing) back pressure for the pressure relief device. This is valid provided that the vent diameter is greater than the diamter of the PRV nozzle or rupture disk.

Note : The ideal gas calculators use the ideal gas compressible flow equations. The API 520 gas and steam calculations use an approximation of the ideal gas compressible flow equations. Use the ideal gas calculators for a comparison with the API 520 calculators.

Reference : API 520 Sizing, Selection And Installation Of Pressure Relieving Devices (2014)

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CALCULATOR MODULE : API 520 Fluid Property   ±

Calculate API 520 gas and steam properties.

Properties include density, specific heat constant pressure, specific heat constant volume, specific heat ratio, molar mass, gas constant, gas specific gravity, and gas compressibility factor. The gas compressibility factor is calculated from the critical point temperature, critical point temperature, and the accentric factor using either the Peng Robinson, Soave, Redlich Kwong or Van Der Waals equations of state (EOS).Steam properties are calculated from IAPWS R7-97, industrial properties of steam.

Gas specific gravity at standard conditions is approximately equal to the gas molar mass divided by the molar mass of dry air. The molar mass of dry air is taken as 28.964 kg/kg-mole.

Reference : API 520 Sizing, Selection And Installation Of Pressure Relieving Devices (2014)

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CALCULATOR MODULE : API 520 Effective Nozzle Size   ±
CALCULATOR MODULE : Single Phase Liquid Specific Gravity   ±

Calculate liquid specific gravity for single phase liquid.

Liquid specific gravity is calculated relative to the density of water (1000 kg/m^3). Liquid density can also be defined as degrees API (liquids lighter than water), degrees Baume (liquids lighter than water or liquids heavier than water), or degrees Twaddell (liquids heavier than water).

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DATA MODULE : Pipeline Surface Roughness ( Open In Popup Workbook )   ±

Pipeline surface roughness and efficiency data.

Typical pipe surface roughness values, API 14E Panhandle equation efficiency factors for pipeline pressure drop, and Hazen Williams and Manning coefficients for pipeline pressure loss.

    Related Modules :

    DATA MODULE : Line Pipe Diameter And Wall Thickness ( Open In Popup Workbook )   ±
    DATA MODULE : Line Pipe Manufacturing Tolerance ( Open In Popup Workbook )   ±
    DATA MODULE : Line Pipe Joint Length ( Open In Popup Workbook )   ±
    DATA MODULE : Pipe Fitting And Valve ( Open In Popup Workbook )   ±
    DATA MODULE : Material Tensile Strength ( Open In Popup Workbook )   ±
    DATA MODULE : ASME ANSI API Design Factor ( Open In Popup Workbook )   ±
    DATA MODULE : Soil Properties : Density Uplift Coefficient Shear Strength And Friction Factor ( Open In Popup Workbook )   ±

    Soil properties, soil density, uplift coefficient, shear strength and friction factors.

      Related Modules :

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