Clog Severity & Blockage Risk Calculator
Estimates clog severity index and blockage risk percentage based on pipe flow reduction, buildup thickness, pipe diameter, and material type.
Formulas Used
1. Area Reduction Ratio (ARR):
ARR = 1 − ((D/2 − t) / (D/2))²
Where D = pipe inner diameter (mm), t = buildup thickness (mm).
2. Flow Reduction Ratio (FRR):
FRR = 1 − (Qcurrent / Qdesign)
3. Age Factor (AF):
AF = min(1 + 0.02 × Age, 2.0)
Accounts for 2% increased risk per year of pipe age, capped at 2.0.
4. Clog Severity Index (CSI):
CSI = min((0.5 × ARR + 0.5 × FRR) × Km × AF × 100, 100)
Km = material severity coefficient (Grease=1.0, Scale=0.85, Sediment=0.75, Organic=0.65, Mixed=0.55).
5. Blockage Risk Percentage (BRP) — Hagen-Poiseuille basis:
BRP = (1 − (reff / r)4) × 100
Derived from Hagen-Poiseuille law: volumetric flow Q ∝ r4, so resistance increases as the 4th power of radius reduction.
Assumptions & References
- Buildup is assumed to be uniform and concentric around the pipe wall.
- The Hagen-Poiseuille relationship (Q ∝ r⁴) applies strictly to laminar, incompressible, Newtonian flow in straight circular pipes (Reynolds number < 2300). Results are indicative for turbulent or non-circular systems.
- The Age Factor is a simplified empirical approximation; actual degradation rates vary by material, water chemistry, and maintenance history.
- Material severity coefficients (Km) are based on relative clog formation rates from plumbing industry guidelines and drainage engineering literature.
- CSI is a composite index (0–100) combining geometric and hydraulic evidence of clogging; it is not a direct physical measurement.
- References: Hagen (1839), Poiseuille (1840); WRC Sewerage Rehabilitation Manual; ASCE Manual of Engineering Practice No. 36 (Design and Construction of Sanitary and Storm Sewers).
- This calculator is for estimation purposes only. A licensed plumber or drainage engineer should assess severe or critical cases.