Four Consideration Factors when Evaluating a Geomembrane Warranty

Geomembrane warranties are typically provided by the manufacturer. Standard warranties are usually included at no additional cost and vary among manufacturers and products, in coverage, duration and other factors. It can be confusing trying to understand what a warranty really says. What needs to be considered when evaluating a geomembrane warranty? 

When comparing geomembranes, it is common to fall into the trap of looking no deeper than the number of years stated in the warranty. Exceptionally long warranties are usually offered with a price upcharge. While warranty time is a vital component of geomembrane selection, there are several, equally as important, aspects of an offered warranty to consider. To take that a bit further, there are probably more items stated as not covered as there are those that are covered.

We did a limited geomembrane-wide survey of standard manufacturer’s warranties which were easily accessed through an internet search. To be objective, we included our XR-5® geomembrane warranty. No names will be mentioned to protect the innocent (or accuse the guilty), so here are some exclusions found in various warranties: 

• “Specific use, no warranty regarding merchantability for a specific use or application. 
• Damages and defects from acts of God 
• Damage from subgrade if not free of all foreign and sharp objects. 
• Damage from foreign sources, equipment, animals, machinery 
• Improper site preparation or installation 
• Void if moved; void if mixed with other geomembrane products; void with new owner 
• Defects from normal wear and tear 
• Harmful chemicals 
• Chemical resistance is the responsibility of the owner 
• Damages from covering material 
• No warranty of fitness for a particular purpose or merchantability” 

As an engineer and not an attorney, I had to do a bit of research to understand “merchantability,” which generally implies a manufacturer’s guarantee that a product is suitable for a specific use. Diligent manufacturers will however review and approve a specific application for their product. The XR-5 geomembrane warranty for instance, specifically refers to a document completed by the owner and approved by the manufacturer which details the application, including the liquid contact. Both owner and manufacturer agree to the proposed application. A test immersion is usually required (more information on that subject can be found at this blog series). The inclusion or exclusion of a specific product application should be an important warranty component for a specifying engineer. The membrane utilization/application warranty offered for the XR-5 geomembrane is unique.

There are other industry inclusions, but they are limited and primarily reference manufacturing defects: 

• Free of manufacturing defects, 
• Free of defects in materials and workmanship at the time of sale, and against deterioration due to the effects of ozone, UV, or other normal weathering, 
• Extended warranties available. 

Even as long ago as 2006, some in the industry (GRI White Paper #9, 2006) have made note of the fallacies which can be encountered by warranties which have time length as the main feature of it. While a lifetime prediction of 400+ years, based on theoretical laboratory steady state conditions, in a buried, undisturbed, constant temperature environment was noted, the concept of geomembrane warranties is questionable. The GRI paper concludes that many applications are more aggressive and with the rigorous QA/QC used in all aspects of a geomembrane project, thorough diligence on the front end should supersede a warranty which is attractive simply by nature of the number of years. And many designers simply conclude that it covers something, often unknown or undefined. 

Extended warranties on industrial equipment are essentially insurance contracts, often issued by 3^rd parties.  

When selecting a geomembrane, consider these factors for the warranty: 

1. Look for a material that has a warranty that is application-specific, and that application is approved by the manufacturer. 
2. Make sure proper testing exists or is performed to support no. 1. 
3. Keeping in mind that all warranties have exclusions, position your geomembrane selection decision based on supporting data, and design features that take advantage of the properties of the material.  
4. The length of the warranty is often only a promotional technique and is less important than nos. 1 - 3 above. 

Understand the properties and support data for geomembranes and select one based on performance. 

Installed 1984

Photo Taken 2019

XR-5 Lined Sewage Lagoon, Mammoth Cave National Park
Kentucky, USA