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Class: Fitting

The Fitting class represents a pipe fitting used in hydraulic calculations.
It provides access to equivalent length (Le) and K-factor values for fittings,
which are essential in computing minor losses in pipelines.

Parameters

  • fitting_type (str)
    The type of fitting (e.g., "elbow_90", "tee_branch", "valve_gate").
    Must be recognized by the standards database (processpi.pipelines.standards). Standard Fitting Strings

    The following fitting_type are supported in ProcessPI:

    • gate_valve
    • globe_valve
    • angle_valve
    • ball_valve
    • plug_valve_straightway
    • plug_valve_3_way_through_flow
    • plug_valve_branch_flow
    • swing_check_valve
    • lift_check_valve
    • standard_elbow_90_deg
    • standard_elbow_45_deg
    • long_radius_90_deg
    • standard_tee_through_flow
    • standard_tee_through_branch
    • miter_bends_alpha_0
    • miter_bends_alpha_30
    • miter_bends_alpha_60
    • miter_bends_alpha_90
    • sudden_contraction
    • sudden_expansion
    • entrance_sharp
    • entrance_rounded
    • exit

  • diameter (Optional[Diameter], default=None)
    Internal diameter of the pipe associated with this fitting.
    Required for fittings where loss coefficients depend on pipe size.

  • quantity (int, default=1)
    Number of identical fittings of this type.
    Must be a positive integer.

Attributes

  • fitting_type (str) – Name/type of fitting.
  • diameter (Optional[Diameter]) – Pipe diameter associated with the fitting.
  • quantity (int) – Count of fittings.

Methods

equivalent_length() Computes the equivalent length (Le) of the fitting.
This is the effective pipe length that produces the same pressure drop as the fitting.

Returns
- Length (in meters) if available.
- None if not applicable.

Raises
- ValueError: If the equivalent length requires a diameter but none is provided.

k_factor() Retrieves the K-factor (dimensionless loss coefficient) of the fitting.

Returns
- float: K-factor value.
- None: If not applicable.

Raises
- ValueError: If diameter is required but not provided.

calculate() Returns a dictionary summary of the fitting, including geometry and loss data.

Returns

{
  "fitting_type": str,
  "quantity": int,
  "diameter_in": float or None,       # diameter in inches
  "diameter_m": float or None,        # diameter in meters
  "equivalent_length_m": float or None,
  "k_factor": float or None
}

✅ Example Usage 

from processpi.units import Diameter
from processpi.pipelines.fittings import Fitting

# Define a 90-degree elbow fitting for a 4-inch pipe
elbow = Fitting(fitting_type="standard_elbow_90_deg", diameter=Diameter(4, "in"), quantity=2)

# Get equivalent length and K-factor
print(elbow.equivalent_length())
print(elbow.k_factor())

# Export fitting details
print(elbow.calculate())