Pipes and valves play a vital role in our water systems, transporting water throughout treatment and distribution systems. It is imperative these drinking water system components do not contribute any harmful levels of contaminants to drinking water in the interest of public health.
Most states and municipalities in North America require pipes used in drinking water systems to be certified to NSF/ANSI/CAN 61- Drinking Water System Components- Health Effects. For manufacturers, certifying their products to this standard allows access to many markets in North America as well as a competitive advantage within the market. There are various testing methods used within this standard to ensure the products are suitable for use with drinking water. As an industry, it is our responsibility to ensure that our communities receive water from pipes that meet these strict health standards.
Regulation for Pipes & Valves
NSF/ANSI/CAN 61 sets the minimum health effects requirements for chemical contaminants and impurities that are indirectly transmitted into drinking water from drinking water system components and materials. Products that bear the NSF/ANSI/CAN 61 certification mark have met the rigorous health effects requirements of the globally recognized standard.
The standard covers a wide range of water system components and materials used in our drinking water infrastructure from source to tap, including protective barrier materials, joining and sealing materials, mechanical devices (including treatment products), pipes and related products, mechanical plumbing devices, and process media.
Every U.S. state, except Hawaii, has published requirements for drinking water system components to comply with or be certified to NSF/ANSI/CAN 61 and all major U.S. plumbing codes cite NSF/ANSI/CAN 61. Canadian plumbing codes reference the Canadian Standards Association (CSA) standards which in turn require drinking water system components to comply with NSF/ANSI/CAN 61. 11 of the 13 Canadian provinces/territories require drinking water system components to meet this requirement for compliance to NSF/ANSI/CAN 61.
Third party certification through certifiers like NSF is the most trusted means to verify a product’s compliance with the health effects requirements of NSF/ANSI/CAN 61. Certification provides a mark of trust that products have been independently reviewed to meet this globally accepted and respected standard.
Putting Pipes & Valves to the Test
There are several test methods in NSF/ANSI/CAN 61 used for pipes and valves, depending on the product type and its end-use conditions in the field, but all products tested to NSF/ANSI/CAN 61 are subject to the same basic testing steps:
Product Review and Sample Preparation
Before testing, all products are reviewed to determine the field use parameters and chemical composition of all wetted materials. This information is used to request an appropriate sample from the manufacturer and to prepare a test plan for chemical extraction testing. The standard specifies the minimum required test battery for each water contact material, and test batteries include material-specific analyses that cover the specific chemical composition of the materials within the product being evaluated. These tests may include analysis for metals such as lead, copper, and other regulated and non-regulated metals; and/or organic analysis including volatile and semi-volatile compounds.
Products are prepared so that the lab surface-area-to-volume ratio is equal to or greater than the surface-area-to-volume ratio in which the product is intended for use in the field. Additionally, all test samples are rinsed with cold tap water, external cosmetic ink markings are removed, and products are prepared so that only normally wetted surfaces are exposed to the test water.
Single Time Point Conditioning, Exposure and Analysis
Products being tested are subjected to various buffered pH waters at one of three temperature options - cold, domestic hot and commercial hot, depending on the analyses that must be performed and product end-use conditions.
Products are either filled with exposure water for an in-product exposure or submerged in exposure water for an in-vessel exposure. The samples undergo a series of water changes across a timeframe that can range in length from one day to 17 days for pipes and valves. At the end of the exposure period, test water is collected from the samples and preserved for storage until the samples can be analyzed for any contaminants that may have leached from the product.
Testing products intended for contact with drinking water is crucial to ensure the products are not leaching harmful levels of contaminants into our drinking water.
Pick Your Pipeline
Water systems are comprised of many different components that deliver safe drinking water to our communities. Piping systems and their associated valves are made in a wide range of designs and materials, depending on the application within the water system. Some of the most common types of pipes and valves used to provide easy access to safe, clean drinking water include:
Cement Mortar-Lined Pipes
Cement mortar-lined pipes are a popular choice for water supply systems that service major cities. They are durable for up to a century and provide great corrosion protection.
Ductile Iron Pipes
Ductile iron pipes have been used to transport potable water in major cities for centuries, standing the test of time. They are easier to install, stronger, and more corrosion resistant than some of the other pipe material options.
Steel pipes are a great option for water systems since they can withstand high water pressure while still being lightweight. For regions that experience extreme temperatures and precipitation, they might not be the best option because they require special preparation to ensure they can endure different weather conditions.
Cast-iron pipes are another popular type of pipe that is commonly used in water systems. They are durable with a high resistance to corrosion which makes them good pipes for long-term use. Additionally, cast-iron is a cheaper material to work with, resulting in lower costs.
Gate valves are one of the most common types of valves used for general and residential plumbing. They are commonly used in either the fully open or closed positions and not for flow regulation. The valve manually opens and closes slowly, which prevents creating a banging sound along the pipeline.
Ball valves are designed to operate in the fully open or fully closed positions and are commonly used for branch line shutoffs. They are a reliable option and provide a great seal when in a closed position. They do not offer flow control because of their positive stops.
Butterfly valves are lighter than other types of valves because they are compact and short. They are an economic option and can regulate the water flow but are sometimes less durable than other types of valves.
Pressure Relief Valves
Pressure relief valves are a reliable and commonly used type of valve in plumbing systems. These valves operate using a spring and diaphragm. They are a great option to help reduce the chances of a pipe system bursting by reducing pressure within the water line.
Whether it be for their unique performance properties or their durability, many of these drinking water system components have proven themselves over the course of centuries and are still the preferred options for water distribution systems today. This only goes to show, if the pipe is not broken, why fix it?
Choosing the best product for the job is important for any water utility with a mission to provide safe drinking water to their communities. Utilizing pipes, valves, and other drinking water system components certified to NSF/ANSI/CAN 61 is critical for meeting this mission. Water quality is only as good as the water treatment and distribution system that provides it.