NSF International NSF International The Public Health and Safety Company NSF/ANSI Standard 42, 53, 55, 58, 62 Maximum Units Exposed for Material Safety Testing DWTU Joint Committee November 12, 2008 Live Safer ™ ™

How Many Samples are Enough? The Standards currently state: “If the water holding volume of the product is less than 2 L, sufficient samples shall be exposed to provide the required 2-L volume of extractant water. “ This is fine for almost all systems and most components. This is a problem for components with internal volumes that are very small such as fittings that can have internal volumes of only a few milliliters.

Determining Minimum Volume So if you are going to expose less than 2L of internal volume with 2L of test water, where do you draw the line? If we use the rationale that the minimum volume draw from a DWTU is 250 mL (8 oz or 1 cup), then you need to determine how many devices can contribute to this minimum volume. –For systems this is simple, one system will be delivering the volume, so you draw a minimum of 250 mL from each system. This results in a maximum of 8 systems exposed (2L).

Determining Minimum Volume (cont) This is also straight forward for components that are used once in the construction of a system, such as faucets, diverters, or RO shutoff valves. The minimum volume is again 250 ml from each test unit. The difficulty comes when you are working with small fittings that have a internal volume of a few mL. These fittings can also be used more than once in a DWTU.

Determining Minimum Volume (cont) A proposed model is that for every housing or device in a DWTU, you normally have two fittings in the product water path, inlet and outlet. Larger systems may contain multiple housings and contain more fittings, but the internal volume of such systems is much greater than 250 mL. So if you accept this model, then any component that is used multiple times in a system, the minimum exposure volume would be 125mL. This would result in a maximum of 16 components exposed.

Ballot Language The maximum number of samples exposed shall not exceed 16 with 125 mL of extractant water drawn from each sample. If the component can be identified as one that is used only once in a system (such as diverters, faucets, RO shutoff valves, or specialty components) then a volume of 250 mL shall be drawn from each sample.

Thank You for Your Attention. Any Further Discussion?