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ASME B31.8 Gas Pipeline Plastic Component

Calculate ASME B31.8 plastic piping wall thickness, hoop stress, test pressure and MAOP.

Select the appropriate plastic pipe schedule (ASME or ISO etc), or use the user defined options. For plastic piping the pressure design thickness equals the nominal wall thickness minus the mechanical allowance. The mechanical allowance includes allowances for threads, gluing, crimping, erosion, corrosion, and mechanical damage. The dimension ratio (SDR or SIDR) is calculated from the pressure design wall thickness. Elevation and external pressure are ignored for the plastic piping calculations.

Reference : ANSI/ASME B31.8 : Gas Transmission And Distribution Piping Systems (2018)

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CALCULATOR : ASME B31.8 Section 842.2 Plastic Pipe Wall Thickness And Operating Pressure From Hoop Stress [FREE]   ±

Calculate plastic pipe wall thickness and design pressure from hoop stress (ASME B31.8 section 842.2). Pipe parameters may be defined from either the wall thickness, the diameter ratio, or the design pressure.

Tool Input

  • satype : Hydrostatic Design Stress Type
    • HDB : User Defined Hydrostatic Design Stress
    • Dfu : User Defined Design Stress Factor
    • Sau : User Defined Allowable Stress
  • 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
  • walltype : Wall Thickness Calculation Type
  • c : Mechanical Allowance
  • P : Design Pressure

Tool Output

  • CVG : Convergence Factor
  • D : Pipe Outside Diameter
  • DR : Dimension Ratio (SDR or SIDR)
  • PR : Rated Pressure
  • S : Hydrostatic Design Stress
  • Sh : Hoop Stress (≤ S)
  • Sh/Sd : Hoop Stress Over Design Stress Ratio (≤ 1)
  • d : Pipe Inside Diameter
  • t : Pressure Design Wall Thickness
  • tn : Nominal Wall Thickness
CALCULATOR : ASME B31.8 Section 842.3 Plastic Pipe Hoop Stress [FREE]   ±

Calculate plastic pipe hoop stress from internal pressure (ASME B31.8 842.3). Pipe parameters may be defined from either the wall thickness, the diameter ratio, or the design pressure.

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
  • satype : Hydrostatic Design Stress Type
    • HDB : Hydrostatic Design Basis Stress
    • Dfu : User Defined Design Stress Factor
    • Sau : User Defined Hydrostatic Design Stress
  • walltype : Hoop Stress Wall Thickness Type
  • c : Mechanical Allowance
  • P : Design Pressure

Tool Output

  • CVG : Convergence Factor
  • D : Pipe Outside Diameter
  • DR : Dimension Ratio (SDR or SIDR)
  • S : Hydrostatic Design Stress
  • Sh : Hoop Stress
  • Sh/S : Hoop Stress Over Allowable Stress Ratio (≤ 1)
  • d : Pipe Inside Diameter
  • t* : Wall Thickness For Hoop Stress Calculation
  • th : Pressure Containment Wall Thickness
  • tn : Nominal Wall Thickness

CALCULATOR : ASME B31.8 Section 842.5 Plastic Pipe Test Pressure And Hoop Stress Check [FREE]   ±

Calculate plastic pipe test pressure and hoop stress from maximum operating pressure (ASME B31.8 section 842.5).

The test pressure for thermoset plastic pipes shall not exceed 3 times the design pressure. For thermoplastic plastic pipe, the leak test pressure shall not exceed 3 times the design pressure for pipes operating below 100 degrees Fahrenhite, or 2 times the design pressure for pipes operating above 100 degrees Fahrenhite.

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
  • walltype : Hoop Stress Wall Thickness Type
  • tfactype : Test Pressure Factor Type
    • Tu : User Defined Test Pressure Factor
  • testtype : Test Pressure Type
    • Ptu : User Defined Test Pressure
  • HDB : Hydrostatic Design Basis Stress
  • c : Mechanical Allowance
  • P : Design Pressure

Tool Output

  • CVG : Convergence Factor
  • D : Pipe Outside Diameter
  • DR : Dimension Ratio (SDR or SIDR)
  • Phdb : HDB Test Pressure
  • Pt : Test Pressure
  • Pt/Pli : Test Pressure Over Operating Pressure Ratio
  • Sh : Hoop Stress
  • Sh/HDB : Hoop Stress Over Allowable Stress Ratio (≤ 1)
  • T : Test Pressure Factor
  • d : Pipe Inside Diameter
  • t : Wall Thickness For Hoop Stress Calculation
  • th : Pressure Containment Wall Thickness
  • tn : Nominal Wall Thickness

CALCULATOR : ASME B31.8 Plastic Pipe Diameter And Wall Thickness Schedule [FREE]   ±

Calculate ASME B31.8 plastic pipe diameter and pressure design wall thickness from pipe schedule or user defined diameter and wall thickness (ASME B31.8 section 842.2).

Select the pipe schedule (NPS or ISO), pipe diameter and wall thickness, or use the user defined option. Use the Result Table option to display the results for the selected diameter. Fabrication tolerance is included.

Tool Input

  • schdtype : 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 Fabrication Tolerance Type
    • xfu : User Defined Negative Wall Thickness Fraction
    • tfu : User Defined Negative Wall Thickness Allowance
  • c : Wall Thickness Mechanical Allowance

Tool Output

  • CVG : Convergence Factor
  • DR : Pipe Dimension Ratio (SDR Or SIDR)
  • ID : Nominal Inside Diameter
  • OD : Nominal Outside Diameter
  • tf : Wall Thickness Fabrication Allowance
  • tm : Minimum Wall Thickness
  • tn : Nominal Wall Thickness
  • tp : Pressure Design Wall Thickness
CALCULATOR : ASME B31.8 Plastic Pipe Mass Per Length And Total Mass Schedule [FREE]   ±

Calculate ASME B31.8 plastic pipe unit mass and total mass from pipe schedule or user defined pipe diameter and wall thickness.

Select the pipe schedule (NPS or ISO), pipe diameter and wall thickness, or use the user defined option. Use the Result Table option to display the results for the selected diameter.

Tool Input

  • schdtype : 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 Fabrication Tolerance Type
    • xfu : User Defined Negative Wall Thickness Fraction
    • tfu : User Defined Negative Wall Thickness Allowance
  • modptype : Material Property Type
    • ρpu : User Defined Pipe Density
  • c : Wall Thickness Mechanical Allowance
  • L : Pipe Length

Tool Output

  • ρp : Pipe Density
  • CVG : Convergence Factor
  • DR : Pipe Dimension Ratio (SDR Or SIDR)
  • ID : Nominal Inside Diameter
  • M : Pipe Total Mass
  • OD : Nominal Outside Diameter
  • m : Pipe Mass Per Length
  • tf : Wall Thickness Fabrication Allowance
  • tm : Minimum Wall Thickness
  • tn : Nominal Wall Thickness
  • tp : Pressure Design Wall Thickness

CALCULATOR : ASME B31.8 Section 841.3 Plastic Pipe MAOP From Test Pressure And Design Pressure [FREE]   ±

Calculate plastic pipe maximum allowable operating pressure (MAOP) from test pressure and design pressure (section 845.2). The MAOP is the minimum value calculated for the piping system and components.

Tool Input

  • Pd : Design Pressure
  • Pt : Test Pressure

Tool Output

  • MAOP : MAOP
CALCULATOR : ASME B31.8 Section 842.2 Plastic Pipe Allowable Stress [FREE]   ±

Calculate allowable stress (SDf) for plastic piping (ASME B31.8 section 142.2).

The allowable stress equals the hydrostatic design basis (HDB) times the design factor (Df). SDf = HDB x Df.

Tool Input

  • satype : Allowable Stress Type
    • HDB : Hydrostatic Design Basis Stress
    • Dfu : User Defined Design Stress Factor
    • Sau : User Defined Allowable Stress

Tool Output

  • Sa : Allowable Stress
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