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Physics calculator

Pipe Tee Calculator

Compute equal-area sharp 90° T loss h = K v_c² / (2g) from dividing or combining flow and branch or run split. Runs locally. Not catalog K, not a bend, not pipe-entrance, not pipe-exit, and not Q=Av.

Instant result
Result
—

Enter values to calculate.

Inputs—
Mode—
Formula—
Trust summary Engine tested · Source checked · 6/6 tests · Production surface contract 1/1 · v1.0.0
Input interpretation
Enter values to calculate.
Result
—
Model
Equal-area sharp 90° T head from common-channel speed, dividing or combining pattern, branch or run, and q=Q_path/Q_c. Invert v_c. Optional Δp from ρ.
Scope
Equal-area sharp 90° T: h = K v_c² / (2g); K referenced to common-channel speed; K is reported, not an input
Verification
Engine tested · 6/6 tests · Production surface contract 1/1 · Source checked · v1.0.0
Named expert review
Optional · Not performed
Sources
  • ISO 80000-4 — Mechanics — Length, speed, pressure
  • Idelchik — Handbook of Hydraulic Resistance — Diagrams 7-18 / 7-20 No.1 (dividing) and 7-1 / 7-4 (combining), equal-area 90° T
Sources
Evidence
6 property · Production surface contract 1/1 · Artifact integrity PASS
Production
Embedded snapshot: STALE · Last attested schema matched 1.0.0 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status PASS (0 stale; 164 CURRENT) @ 2026-09-17T23:04:35.003Z
Semantic contract
PASS

Formulas

Core equations used by this calculator.

Head lossh = K v_c² / (2g)
Dividing / combining branchK_s = 1 + q²
Dividing runK_st = 0.4 (1 − q)²
Combining runK_st = 1.55 q − q²
Pressure dropΔp = ρ K v_c² / 2
iSI. q = Q_path/Q_c in [0, 1]. v_m_s is the common-channel speed v_c, not the path speed. α is fixed at 90°. g defaults to 9.80665 m/s². Do not send query v — that is calculation_version.

How to use

1

Choose pattern

dividing (split from the common inlet) or combining (merge into the common outlet). URL field is kind.

2

Choose path

branch (90° takeoff) or run (straight through). URL field is path.

3

Enter q and v_c

q_ratio = Q_path/Q_c. v_m_s is the common-channel speed. Invert on the v tab.

Example calculations

Common configurations with formula and result.

ϟ

Dividing branch, q=0.5, v_c=2 m/s

Half the inlet flow leaves through the 90° branch

K=1+q²=1.25, h=K v_c²/(2g)
h≈0.25493 m · K=1.25 · Δp=2500 Pa at ρ=1000
ϟ

Dividing run, q=0.5

Same split on the straight through

K=0.4(1−q)²=0.1
K=0.1

Pipe Tee calculator specification

Version 1.0.0 · Engine tested

Calculation status

Review policy · Evidence

Definition
Equal-area sharp 90° T. K is referenced to the common-channel speed v_c and reported from the flow pattern and q = Q_path/Q_c. Dividing: branch K=1+q², run K=0.4(1−q)². Combining: branch K=1+q², run K=1.55q−q². Not a catalog fitting K, not a bend, not inlet/exit geometry.
What it calculates
Equal-area sharp 90° T head from common-channel speed, dividing or combining pattern, branch or run, and q=Q_path/Q_c. Invert v_c. Optional Δp from ρ.
Inputs
  • mode?
  • kind?
  • path?
  • q_ratio
  • v_m_s|h
  • rho?
  • g?
Outputs
  • h
  • v
  • K
  • kind
  • path
  • q
  • q_ratio
  • g
  • rho
  • dP
  • alpha_deg
  • mode
  • model
Formula
h = K v_c² / (2g); dividing branch 1+q²; dividing run 0.4(1−q)²; combining branch 1+q²; combining run 1.55q−q²
Assumptions
  • Equal-area sharp 90° T: h = K v_c² / (2g); K referenced to common-channel speed; K is reported, not an input
  • Dividing: branch K=1+q², run K=0.4(1−q)². Combining: branch K=1+q², run K=1.55q−q². q=Q_path/Q_c in [0,1]; default g=9.80665 m/s²; default ρ=1000 kg/m³
  • Not catalog minor-loss K given, not circular-arc R/D, not mitered n, not pipe-entrance geometry, not pipe-exit K=1, not a non-90° wye, not Q=Av
Units
  • SI; v_c in m/s; h in m; q dimensionless; ρ in kg/m³; Δp in Pa; K dimensionless
Boundary conditions
  • missing v_m_s, h, or q_ratio when required → MISSING_REQUIRED_INPUT
  • v_m_s ≤ 0 or h ≤ 0 → VALUE_MUST_BE_POSITIVE
  • q_ratio > 1 or K=0 on velocity invert → VALUE_OUT_OF_RANGE
  • K, rd, n_miters, θ, α, f, Q, A, v1/v2, ri_d → MIXED_INPUT_ENCODING
  • flush, circular, or unknown kind/path/mode → INVALID_MODE
Example
v_m_s=2 kind=dividing path=branch q_ratio=0.5 → h=K v_c²/(2g) K=1.25
Validation cases

3 published on this page · 6/6 tests · Production surface contract 1/1 · View evidence

  • v_m_s=2 kind=dividing path=branch q_ratio=0.5 → h=K v_c²/(2g) K=1.25
  • v_m_s=2 kind=dividing path=run q_ratio=0.5 → K=0.1
  • v_m_s=2 kind=dividing path=branch q_ratio=0.5 K=1.25 → MIXED_INPUT_ENCODING
Sources
  • ISO 80000-4 — Mechanics — Length, speed, pressure
    Supports: h is a head; v is a speed; Δp is a pressure
  • Idelchik — Handbook of Hydraulic Resistance — Diagrams 7-18 / 7-20 No.1 (dividing) and 7-1 / 7-4 (combining), equal-area 90° T
    Supports: Branch K=1+q²; dividing run K=0.4(1−q)²; combining run K=1.55q−q²; K referenced to v_c. Not catalog K, not a bend, not entrance/exit
Calculation version
1.0.0

Background

Interpretation and common distinctions.

Compute pipe-tee loss from common-channel speed, dividing or combining flow, and the branch or run split.

Supported and not supported

Supported — h from v_c, kind, path, and q · invert v_c · API physics.fluid.pipe_tee

Not supported — catalog minor-loss K, circular-arc R/D, mitered n, pipe-entrance geometry, pipe-exit K=1, non-90° wye, Darcy f, Q=Av

Agent / API notes

Capability id: physics.fluid.pipe_tee · tool id: pipe-tee · pin 1.0.0.

{ "v_m_s": 2, "kind": "dividing", "path": "branch", "q_ratio": 0.5 }

Modes: head (default), pressure, velocity. Kinds: dividing (default), combining. Paths: branch (default), run. Errors: MISSING_REQUIRED_INPUT, INVALID_NUMBER, VALUE_MUST_BE_POSITIVE, VALUE_OUT_OF_RANGE, MIXED_INPUT_ENCODING, INVALID_MODE.

Calculator URL stays /calc/physics/pipe-tee. There is no /calc/fluid.

Other calculators in this family: Minor loss, Pipe bend, Pipe entrance, Pipe exit, Pipe wye .

K Minor loss › h Pipe bend › h Pipe entrance › h Pipe exit › h Pipe wye ›
}

Frequently asked questions

Key distinctions behind the calculation.

Is this minor-loss K?

No. Catalog fitting K is /calc/physics/minor-loss. Sending K is MIXED_INPUT_ENCODING. This page reports K from kind, path, and q.

Is this circular-arc pipe-bend?

No. Smooth R/D ≥ 1 is /calc/physics/pipe-bend. Sending rd or θ is MIXED_INPUT_ENCODING. This T is a fixed 90° junction.

Is this pipe-entrance or pipe-exit?

No. Inlet geometry is /calc/physics/pipe-entrance. Exit K=1 is /calc/physics/pipe-exit. Sending ri_d or treating this as K=1 is MIXED_INPUT_ENCODING.

Is this Q = A·v?

No. Volumetric flow is /calc/physics/flow-rate. Sending Q or A is MIXED_INPUT_ENCODING. q_ratio is the dimensionless split Q_path/Q_c.

Can I send a wye angle?

No. α is fixed at 90°. Sending alpha_deg is MIXED_INPUT_ENCODING. A non-90° wye is /calc/physics/pipe-wye.

Where does this run?

Locally in the browser by default. REST and MCP call the same fluid-engine pipeTee wrapper.