📋 Case Study
Leak Localization in Tokyo’s Historic Cast-Iron Network Using ITA
Acoustic methods ineffective due to soil attenuation and ambient noise; conventional pressure zoning lacked resolution
🏗️ Project Overview
Detection and isolation of leaks in 80+ year-old underground CI pipes beneath dense urban corridors
🎯 Challenge
Acoustic methods ineffective due to soil attenuation and ambient noise; conventional pressure zoning lacked resolution
🔧 Design Approach
Inverse Transient Analysis (ITA) with synchronized pressure transient injection and multi-point sensor array (12 nodes)
📐 Key Calculations
Transient Wave Speed
a = √(K/ρ) / √(1 + (K/E)(D/e))
Result: 1,120 m/s
Critical input for wave travel time-based localization
Leak Severity Index
Q_leak / Q_nominal × 100%
Result: 4.2–11.7%
Prioritizes repair sequence based on volumetric impact
📊 Results
Leak location accuracy ±2.3 m (vs. ±15 m with acoustic); 83% reduction in leak survey time; $4.7M/year non-revenue water recovery💡 Lessons Learned
- •Sensor spacing ≤1.5× pipe diameter maximizes ITA resolution
- •Transient amplitude must exceed 5% static pressure for robust signal-to-noise
- •Historic pipe wall thickness variability requires site-specific wave speed calibration
✅ Key Takeaways
- 1Sensor spacing ≤1.5× pipe diameter maximizes ITA resolution
- 2Transient amplitude must exceed 5% static pressure for robust signal-to-noise
- 3Historic pipe wall thickness variability requires site-specific wave speed calibration
📐 Prerequisites
Understand these before this topic
🔗 Engineering Applications
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