Regression analysis found plastic pipes failed 5x t0 9x more often than metal. 

When designing and specifying water distribution systems, the choice of piping materials can have significant implications for performance, maintenance, and long-term durability. Recent research from Akdeniz University published in the journal Water Supply sheds light on failure rates of certain pipe materials, particularly polyvinyl chloride (PVC) and high-density polyethylene (HDPE or PE). For architects and engineers prioritizing reliability and sustainability, these findings underscore the importance of material selection in building systems.

The Study: Analyzing Pipe Failures

A recent study analyzed two years of data on pipe failures in a water distribution system, identifying key factors contributing to failures, including pipe material, age, and operational pressures. Logistic regression modeling revealed critical insights into the vulnerabilities of common pipe materials.

PVC and PE: High Failure Rates

The findings for PVC and PE pipes are particularly noteworthy:

• PVC Pipes: The study found PVC failed 5.3 times more often than metal pipes.
• HDPE Pipes: PE pipes exhibited an even higher failure likelihood, failing 9 times more frequently than metal pipes.

Factors at Play

While material type was a significant independent factor in failure rates, pipe age also played a crucial role. Pipes older than 20 years were 1.675 times more likely to fail than those installed more recently. This correlation emphasizes the need for proactive maintenance and replacement planning for older infrastructure. Additionally, operational factors such as burst pressure and average water pressure contribute to failure likelihood, although the study found that material and age were the most decisive variables.

Implications for Architects and Engineers

These findings hold important implications for building design and system specification:

1. Material Durability: Architects and engineers must weigh the trade-offs between initial costs and long-term performance. While PVC and PE pipes may offer cost savings upfront, their higher failure rates can lead to significant maintenance and replacement costs over time.
2. Lifecycle Analysis: Incorporating lifecycle cost analysis during the design phase can provide a clearer picture of the true economic and environmental impact of material choices. Durable materials like copper, iron and steel often prove more sustainable and cost-effective over the lifespan of a system.
3. Maintenance Planning: For existing systems using PVC or PE, proactive inspection and maintenance programs are essential to mitigate failure risks and extend service life.
4. Sustainability Considerations: Beyond failure rates, architects and engineers should consider the broader environmental and health impacts of piping materials. PVC and PE are derived from petrochemicals and can pose sustainability challenges, whereas alternatives like copper or cast iron align more closely with green building principles.