FlowGuard™ Flex
Chlorine Resistance
FlowGuard™ Flex 3 layer piping solution eliminates the variables affecting PEX piping material used in plumbing systems today: chlorine resistance, UV degradation and a combination of the two. With our extensive experience and R&D resources, we have developed state-of-the-art technology to address these factors and minimize the risk of premature failure.
To help alleviate potential concerns associated with chlorine resistance, NSF International developed a test protocol (NSF P171 Cl-R) to evaluate the chlorine resistance of PEX products.
This NSF Cl protocol is a voluntary program for PEX pipe manufacturers. This accelerated test evaluates PEX pipe at high temperature conditions until failure to determine a relative estimate of life expectancy. Only a few PEX products can meet both levels of this protocol testing today. FlowGuard Flex pipe is one.
A more stringent level of the NSF mark is Cl-R (Chlorine-Recirculation). This methodology assumes a constant temperature of 60°C 140°F) in the water system, similar to a recirculating system used in residential homes, hotels or commercial buildings where the occupants want hot water instantly.
Minimum Requirement. as per NSF P171 Protocol
We have committed to sell only FlowGuard Flex products that surpass NSF P171 Cl-R – the most stringent standard.
| Protocol Standard | Service w/o Design Factor | Design Factor(a) | Service with Design Factor | Usage | Temperature |
| NSF P171 – Cl-TD | 80 years | 0.5 | 40 years | 25% | 60°C (140°F) |
| NSF P171 – Cl-R | 80 years | 0.5 | 40 years | 100% | 60°C (140°F) |
| ASTM F2023 / F876 | 50 years | None | N/A (b) | 25% | 60°C (140°F) |
| ASTM F2023 / F876 | 50 years | 0.5 | 25 years | 25% | 60°C (140°F) |
(a) Design Factor –
A multiplier (<1.0) that is applied to the actual service life to take
all of the variables and the degree of safety involved in a plastic pressure
piping installation into consideration. |
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Please note that all PEX pipe per ASTM 876 must pass ASTM 2023 to be commercially available. The ASTM 2023 test is the minimum required test for PEX pipe concerning chlorine resistance. There is no required, industry accepted test for PEX pipe in the more aggressive application of hot water recirculation. If your PEX application has chlorinated water and/or a recirculation, check the PEX manufacturer's written warranty. Most PEX manufactuers don't warranty their products for levels of chlorine exposure or recirculatory systems. FlowGuard Flex pipe has no exception for levels of chlorine or hot water recirculatory systems.
To address this same issue, the American Standard for Testing and Materials has developed ASTM-F2023 standard entitled Chlorine Test Methodology. However, the ASTM 2023 chlorine test doesn't take into consideration the Design Factor as the NSF protocol does. Referring to the Protocol Standard chart, the NSF Cl-R protocol allows for 80 years of service at 100 percent hot water usage versus the ASTM F876 (2023) standard that allows for 50 years of service at 25 percent hot water usage with no design factor. Apply a 0.5 design factor to ASTM 2023 and the PEX requirement concludes that PEX pipe, in general, will have a service life of 25 years.
What caused polybutylene historic failures? Studies show a direct correlation between chlorine and other additives in the water supply and premature failure. It has been further documented that this attack is accelerated by higher temperatures.
Testing indicates that the mode of failure for polybutylene and PEX can be similar and therefore must be addressed through product design.
