WATER MAIN BREAKS
Water main failures are very expensive for municipalities because they typically result in expenses associated with repair costs, flood damage, and loss of revenue to affected businesses.
Water main failures also interrupt the operation of vital services, such as medical care and fire fighting operations. Currently, millions of dollars are spent annually by industry and by municipalities on the repair of failed components of the water distribution infrastructure, such as components that are made from gray cast iron or “gray iron” pipe.
The rate of municipal water main failure is expected to increase as the existing gray iron infrastructure continues to age. The cost of repairing damages caused by broken water mains (and subsequent flooding damage) may become an important item in many municipal budgets. The development of a non-destructive sensing technique to detect defects in the water distribution infrastructure to prevent catastrophic failure of water distribution infrastructure components would result in tremendous savings.
Galvanic Corrosion: Copper Service Line and Cast Iron Water Mains
Galvanic Corrosion: Copper Service Line and Cast Iron Water Mains
Copper pipes in contact with ductile or cast iron water mains can result in accelerated corrosion of cast iron pipe in corrosive conductive soils due to galvanic action. Team Matergenics can identify the corrosion mechanism responsible for the leaks and mitigate corrosion in your system by coating and cathodic protection
SOIL TESTING
Based on soil chemistry and corrosivity we can determine an estimated remaining life by predictive modeling.
CORROSION RISK ASSESSMENT
Our overall approach to corrosion risk assessment, locating “hot spots” and corrosion mitigation:
Pre-assessment stage:
This would involve a “desk study” of soil types (USGS data) in the area encompassing the affected water district. This tells us about the likely level and variation in soil corrosivity that can affect and accelerate external corrosion or internal corrosion followed by graphitization and “breaks.”
Indirect assessment stage
This involves a desk study, review of inspection, and failure reports and pre-assessment
- Collection of soil samples in areas with a higher concentration of breaks or corrosive soils
- Chemical and corrosivity analysis of soil samples in Matergenics soils lab and modeling for remaining life
- Electrochemical potential measurements in areas with higher and lower concentration of water main breaks
- Look for correlations among the above data to identify “hot” areas for the direct assessment stage.
Direct assessment stage
This involves the condition assessment of cast iron water mains through on site examination
- Schedule excavations in identified hot areas to perform direct observation and visual observation of pipe condition, with a major goal of determining whether the primary corrosion losses are internal (water side) or external
- Take physical measurements including wall thickness and pit depth
- Measure level of graphitization – which is basically the corrosion-related deterioration of the cast iron microstructure which severely weakens the pipes – using a proprietary sensor device
Recommendations & remediation
Matergenics will develop specific, practical mitigation strategies based on findings and data from the direct and indirect assessment phases. This will be performed by an experienced NACE Certified Cathodic Protection Specialist.
