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Vintage Plastic Piping Calculator

Prioritize Aldyl A replacements to better manage risk in your pipelines

Many utilities in North America are faced with the challenge of managing the aging vintage plastic piping – specifically Aldyl A – in their distribution systems. The ability to accurately predict current and future pipeline performance is critical to the optimization of Integrity Management Plans for these aging assets. In the end, much of this vintage plastic piping needs to be replaced. The question, then, is: what should be replaced first? How do we, as an industry, understand and manage this risk? How do you, as a gas operator, optimally leak survey and prioritize replacements? How do you develop and successfully communicate the optimum replacement program in a Rate Case? How do we all keep risk under control? Unless the entire vintage plastic piping system can be replaced at once, we must have a detailed understanding of the asset base to answer these questions.

To address these various challenges and answer these key questions, JANA has developed a Vintage Plastic Piping Calculator, providing a valuable aid to utility engineers and asset managers conducting risk assessments for vintage gas distribution piping systems. The Vintage Plastic Piping Calculator provides leak rate projections based on the properties of each specific pipeline segment, including its material type, year of installation and operating conditions. The leak rate projections are based on mechanistic-probability (MP) models that combine laboratory testing results for exhumed piping combined with in-service data representing over 100,000 mile-years of leak history data. The resulting projections can be used for risk ranking, replacement optimization, rate case development, leak survey optimization, and maintenance planning.

JANAdvantage™ Aldyl Calculator

The JANAdvantage™ Aldyl Calculator is simple to operate, requiring minimal inputs of system details. All five Aldyl generations are included, each with different risk. Environmental considerations are layered on top of the base piping material, including rock impingement, squeeze-off and bending stresses. Offered as a cloud-based software solution or on your own systems, data is uploaded via batch Excel® data files - allowing you to run calculations for a single piping system or generate risk assessments for systems throughout your entire network through the use of the bulk input feature - and a report is automatically generated.

Example of JANAdvantage™ Aldyl Calculator Output

Vintage-Pressure Heat Map for a typical gas distribution network in 2014

In addition to the JANAdvantage™ Aldyl Calculator, JANA has developed our J-DIMPTM Aldyl Risk Rank module to address these challenges in greater detail, for a specific asset base. A full risk management process for Aldyl assets must deal with the potential for third-party damage, operational damage, etc., through a parallel process in addition to the estimates provided by the JANAdvantage™ Aldyl Calculator (which provides leak estimates based solely on the SCG mechanism), and these risk assessment results must be input and coordinated with other risk management tools to properly handle the risk associated with operating a gas distribution system containing Aldyl piping systems. The results of the JANAdvantage™ Aldyl Calculator may be used as an input to risk-based decision tools that are used to manage Aldyl piping systems; however, the JANAdvantage™ Aldyl Calculator is not intended to replace a thorough risk assessment.

Combining our expertise in plastic piping performance validation – garnered through over 300,000,000 hours of laboratory testing and 15 years of pipeline failure analysis – with state-of-the-art reliability analysis, JANA has created a mechanistic-probabilistic Aldyl pipe leak rate forecaster. Once data-tuned for an asset base, this module provides accurate forecasts of future performance on a segment-by-segment basis, along with a risk ranking of those individual segments. As is clear from the figure below, the J-DIMP™ mechanistic probability models have the capability to provide extremely good forecasts of future pipeline performance right down to a segment-specific location.

J-DIMP™: Predicted Leaks vs. Observed Leaks, by Vintage of Aldyl Piping


Contact us to learn more about the JANAdvantage™ Aldyl Calculator or to request a free demo. 

Understanding the history of Aldyl piping

Learn more about the existence of many generations of Aldyl piping – some that perform better than others – operating under a multitude of conditions. When you throw in the impact of rock impingement, squeeze-off and bending stresses, the outcome is a broad range of risk. Layered on top of this are installation or maintenance-related factors such as the impact of rock impingement, squeeze-off and bending stresses, etc., as well as the different potential consequences of a leak based on the local environment. Combined, these factors result in a broad range of risk throughout the Aldyl piping population.


Generations of Aldyl A Piping in Gas Distribution


Aldyl Resin 1

Years of Manufacture







Original Alathon Resin






Density Increased




Manufacturing Issue




DR 9.3 for Class 4 Areas





Co-monomer Changed





Co-monomer Increased



After 1989


Co-monomer on HMWT 3 Fraction


Notes: 1 All resins marketed as Aldyl A, 2 Low Ductile Inner Wall, 3 High Molecular Weight

green pipe

Mechanistic Probabilistic Modeling

You can call it MP Modeling. We call it the better approach to modeling risk for your pipeline integrity.

See What It’s All About

Gas Transmission

  • Intelligent and scalable risk management
  • Exceed regulations with best-in-class compliance
  • Prioritize tasks in your asset management
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Gas Distribution

  • Ensure continuity of service through prevention
  • Achieve optimal compliance more efficiently
  • Resolve issues and meet strategic goals
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