ASME B31.3 Process Piping Hydrotest Pressure

Calculate test pressure and hoop stress for low pressure steel pipe (ASME B31.3 section 345).

For hydrotest the test factor = 1.5. The R factor is required if the allowable stress at the test temperature is greater than the allowable stress at the design temperature. The R factor is the ratio of allowable stress at the test temperature over the allowable stress at the design temperature. The hoop stress should be less than or equal to yield. For components, the test pressure should be less than or equal to 1.5 x the rated pressure.

For pneumatic test the test factor = 1.1. The hoop stress should be less than or equal to 90% of yield. The test pressure should be less than or equal to 1.33 x the design pressure, and less than or equal to 1.35 x the rated pressure for components.

Note : The choice of high pressure versus low pressure service is at the discretion of the owner (section FK300). The ASME B16.5 Class 2500 pressure temperature rating for the material group is often used as a criteria.

Tool Input

• schdtype : Pipe Schedule Type
• diamtype : Pipe Diameter Type
  • ODu : User Defined Outside Diameter
  • IDu : User Defined Inside Diameter
• wtntype : Wall Thickness Type
  • tnu : User Defined Wall Thickness
• ttoltype : Wall Thickness Fabrication Tolerance Type
  • xfu : User Defined Negative Wall Thickness Fraction
  • tfu : User Defined Negative Wall Thickness Allowance
• yfactype : Y Factor Type
  • Yu : User Defined Y Coefficient
• walltype : Hoop Stress Wall Thickness Type
• rfactype : R Factor Type
  • St : User Defined Allowable Stress At Test Temperature
  • S : User Defined Allowable Stress At Design Temperature
  • Ru : User Defined R Factor
• testtype : Test Pressure Type
  • Pru : User Defined Component Rated Pressure
  • Ptu : User Defined Test Pressure
  • Tu : User Defined Test Pressure Factor
• c : Corrosion Allowance
• Td : Design Temperature
• P : Design Pressure
• Sy : Yield Stress At Test Temperature

Tool Output

• ID : Pipe Inside Diameter
• OD : Pipe Outside Diameter
• OD/tn : Diameter Over Wall Thickness Ratio
• Pt : Test Pressure
• Pt/P : Test Pressure Over Design Pressure Ratio
• Py : Yield Pressure
• R : R Factor St/S
• Sh : Hoop Stress [ Pa ]
• Sh/Sy : Hoop Stress Over Yield Stress Ratio (≤ 1)
• T : Test Pressure Factor
• Y : Y Factor
• t* : Wall Thickness For Hoop Stress Calculation
• tf : Wall Thickness Fabrication Allowance
• th : Pressure Containment Wall Thickness
• tm : Minimum Wall Thickness
• tn : Nominal Wall Thickness

Calculate test pressure and hoop stress for low pressure plastic pipe (ASME B31.3 section A345).

For hydrotest the test factor = 1.5. The R factor is required if the allowable stress at the test temperature is greater than the allowable stress at the design temperature. The R factor is the ratio of allowable stress at the test temperature over the allowable stress at the design temperature. The test pressure should be less than or equal to 1.5 x the rated pressure of the lowest rated component in the system.

For pneumatic test the test factor = 1.1. The test pressure should be less than or equal to 1.33 x the design pressure, and less than or equal to 1.35 x the rated pressure for components.

Tool Input

• schdtype : Pipe Schedule Type
• diamtype : Diameter Type
  • ODu : User Defined Outside Diameter
  • IDu : User Defined Inside Diameter
• wtntype : Wall Thickness Type
  • tnu : User Defined Wall Thickness
  • DRu : User Defined Dimension Ratio SDR OR SIDR
• ttoltype : Wall Thickness Tolerance Type
  • xfu : User Defined Negative Wall Thickness Fraction
  • tfu : User Defined Negative Wall Thickness Allowance
• walltype : Hoop Stress Wall Thickness Type
• rfactype : R Factor Type
  • St : User Defined Hydrostatic Design Stress At Test Temperature
  • S : User Defined Hydrostatic Design Stress At Design Temperature
  • Ru : User Defined R Factor
• testtype : Test Pressure Type
  • Pru : User Defined Component Rated Pressure
  • Ptu : User Defined Test Pressure
  • Tu : User Defined Test Pressure Factor
• c : Mechanical Allowance
• P : Design Pressure
• HDB : Hydrostatic Design Basis At Test Temperature

Tool Output

• CVG : Convergence Factor
• DR : Dimension Ratio (SDR or SIDR)
• ID : Pipe Inside Diameter
• OD : Pipe Outside Diameter
• Pt : Test Pressure
• Pt/P : Test Pressure Over Design Pressure Ratio
• Py : Yield Pressure
• R : R Factor St/S
• Sh : Hoop Stress [ Pa ]
• Sh/HDB : Hoop Stress Over HDB Ratio (≤ 1)
• T : Test Pressure Factor
• t* : Wall Thickness For Hoop Stress Calculation
• tf : Wall Thickness Fabrication Allowance
• th : Pressure Containment Wall Thickness
• tm : Minimum Wall Thickness
• tn : Nominal Wall Thickness

Calculate ASME B31.3 gas volume and liquid chemical dose rate for gas leak test.

The dose rate can be calculated from dose volume fraction, dose mass fraction or dose gas ratio. The average fluid density includes the dose chemical. The calculated volume does not include the effect of pipe expansion due to the test pressure.

Tool Input

• schdtype : Pipe Schedule Type
• diamtype : Pipe Diameter Type
  • ODu : User Defined Outside Diameter
  • IDu : User Defined Inside Diameter
• wtntype : Wall Thickness Type
  • tnu : User Defined Wall Thickness
• dosetype : Dose Rate Type
  • Xvu : User Defined Dose Volume Fraction
  • Xmu : User Defined Dose Mass Fraction
  • Rvu : User Defined Dose Volume Over Gas Moles Ratio
  • Rmu : User Defined Dose Mass Over Gas Moles Ratio
• voltype : Fluid Volume Type
  • Vgu : User Defined Gas Volume
  • Mgu : User Defined Gas Mass
  • Ngu : User Defined Gas Moles
  • Vfu : User Defined Total Fluid Volume
  • Mfu : User Defined Total Fluid Mass
  • Lu : User Defined Pipeline Length
• ρd : Dose Chemical Density
• P : Fluid Pressure
• T : Fluid Temperature
• Z : Gas Compressibility Factor
• SG : Gas Specific Gravity

Tool Output

• ρf : Fluid Average Density
• ρg : Gas Density (At T P)
• ID : Inside Diameter
• L : Pipe Length
• Md : Dose Mass
• Mf : Total Fluid Mass
• Mg : Gas Mass
• Ng : Gas Moles
• Rm : Dose Mass Over Gas Moles Ratio
• Rv : Dose Volume Over Gas Moles Ratio
• Vd : Dose Volume
• Vf : Total Fluid Volume
• Vg : Gas Volume
• Xm : Dose Mass Fraction
• Xv : Dose Volume Fraction
• vg : Gas Mole Volume (At T P)

Calculate low pressure metal pipe SMYS (Specified Minimum Yield Stress), SMTS (Specified Minimum Tensile Stress) and basic allowable stress schedule (ASME B31.3 table A-1).

Use the Result Table option to display the stress values for the selected stress schedule (click the Result Table button, and then click the make table button).

Tool Input

• syutype : Stress Schedule Type
• mattype : Material Type
  • SMTSu : User Defined Specified Minimum Tensile Stress
  • SMYSu : User Defined Specified Minimum Yield Stress
  • Su : User Defined Basic Allowable Stress

Tool Output

• S : Basic Allowable Stress
• S/SMTS : Basic Allowable Stress Over SMTS Ratio
• S/SMYS : Basic Allowable Stress Over SMYS Ratio
• SMTS : Specified Minimum Tensile Stress
• SMTS/SMYS : SMTS Over SMYS Ratio
• SMYS : Specified Minimum Yield Stress
• SMYS/SMTS : SMYS Over SMTS Ratio

Calculate ASME B31.3 general pipe test pressure and hoop stress check from operating pressure, diameter, wall thickness, wall thickness tolerance and design stress.

If the test temperature is lower than the operating temperature, the design pressure should be multiplied by the ratio of the design stress at the test temperature, over the design stress at the operating temperature (except for low pressure pneumatic test).

For low pressure pipe, select the Barlow's equation with ASME Y factor option, with the pipe nominal diameter. The test pressure ratio = 1.5 for hydrotest, and 1.1 for pneumatic leak test.

For high pressure pipe select the log equation option. For high pressure high temperature pipe the design stress should be divided by 1.155. The pipe inside or outside diameter should be the maximum allowed by the code. The test pressure ratio = 1.25 for hydrotest and for pneumatic leak test.

For plastic pipe use the Barlow's equation mid wall option, with the pipe nominal diameter. The test pressure ratio = 1.5 for hydrotest, and pneumatic leak test.

For most cases external pressure can be ignored. Wall thickness negative tolerance can be defined by either a fraction tolerance, or an allowance tolerance (positive value). The maximum hoop stress allowed is 100% of yield for hydrotest, and 90% of yield for pneumatic tests (the test pressure should be reduced if the hoop stress is exceeded).

Tool Input

• pletype : External Pressure Type
  • Peu : User Defined External Pressure
• wtntype : Wall Thickness Type
  • tnu : User Defined Wall Thickness
• ttoltype : Wall Thickness Tolerance Type
  • xfu : User Defined Negative Wall Thickness Fraction
  • tfu : User Defined Negative Wall Thickness Allowance
• syutype : Stress Table Type
• mattype : Yield Stress Type
  • SMYSu : User Defined Specified Minimum Yield Stress
• schdtype : Pipe Schedule Type
• diamtype : Pipe Diameter Type
  • ODu : User Defined Outside Diameter
  • IDu : User Defined Inside Diameter
• sdtype : Design Stress Type (F x SMYS)
  • Fu : User Defined Design Factor
  • Sdu : User Defined Design Stress
• walltype : Hoop Stress Wall Thickness Type
  • Yu : User Defined ASME Y Factor
• hooptype : Hoop Stress Wall Thickness Type
• testtype : Test Pressure Type
  • Tu : User Defined Test Factor
  • Ptu : User Defined Test Pressure
• tc : Corrosion Allowance
• Pi : Operating Pressure

Tool Output

• ID : Pipe Inside Diameter
• OD : Pipe Outside Diameter
• OD/tn : Pipe Diameter Over Wall Thickness Ratio
• Pe : External Pressure
• Pt : Test Pressure
• PtΔ : Test Pressure Difference
• SMYS : Specified Minimum Yield Stress
• Sd : Design Stress
• Sh : Hoop Stress
• Sh/SMYS : Hoop Stress Over Yield Stress Ratio
• T : Test Pressure Factor
• tf : Fabrication Allowance
• tfx : Fabrication Fraction
• th : Hoop Stress Thickness (Pressure Containment)
• tm : Minimum Wall Thickness
• tn : Nominal Wall Thickness

Calculate test pressure for qualification of bonds on plastic pipe and fittings (ASME B31.3 annex A328.2.5). For RTR laminated and filament wound pipe, the test pressure should be three times the manufacturers allowable pressure rating.

Tool Input

• D : Nominal Outside Diameter
• T : Nominal Wall Thickness
• S : Design Stress

Tool Output

• D/tn : Pipe Diameter Over Wall Thickness Ratio
• Pt : Qualification Test Pressure