Slow Crack Growth/Rapid Crack Propagation


Slow Crack Growth: The majority of field failures in piping are attributable to slow crack growth (SCG) fractures. These fractures are characterized by the stable growth of a crack with little deformation in the plastic material. SCG testing involves accelerating the growth mechanism and can be done through elevated temperature, concentrated stress, constrained geometry, surfactants or some combination of these factors. These test methods are applicable to polyethylene (PE), polypropylene (PP) and polybutylene (PB) piping.

Rapid Crack Propagation: Rapid crack propagation (RCP) is a fast fracture type of failure. Cracks are thought to initiate at internal defects on an impact of impulse event and can travel long distances quickly. RCP occurs in pressurized systems with enough stored energy to drive cracks faster than energy is released. Cracks tend to have a smooth fracture surface. RCP is affected by temperature, energy driving force, material, pipe size and processing efforts. Through our Advanced Pipe Test Facility II, located in Canada, we can test a variety of pipe diameters including 4”, 8”, 10”, 12” and 110 mm.

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Why Work with NSF?

Plastic piping plays an essential role in the distribution of gas, drinking water and wastewater. Testing and certification of plastic piping products to internationally-recognized standards verifies they have met the required durability, performance and safety criteria for use in commercial and residential applications. For nearly 50 years, NSF has served as a global provider of testing and certification for the plastic pipe industry. NSF developed the American National Standards for pipes and other products that treat or come into contact with drinking water and certified more than 60,000 products to these standards.


To ensure the strongest combination of consulting and laboratory technical expertise for our plastic pipe clients, NSF has developed an agreement with Jana, a project-based consulting firm that serves the global water and plastic pipe industries, to benefit both organizations’ clients. Through the agreement, NSF will be able to provide testing services to Jana’s clients, and Jana will be able to provide independent consulting services to NSF clients. The two organizations also will work together in the development of new standards.