In response to requests from Plumbing Manufacturers Intl. (PMI) and its members, as well as from other supporters of the U.S....
A large part of the testing performed by the Water Quality Association’s (WQA) lab is materials safety extraction testing. This testing demonstrates that the materials used to manufacture water treatment products that make direct contact with the water during use do not add contaminants at unsafe levels.
The WQA’s Product Testing Laboratory has been growing over the past several years. With the increase in testing projects, a new space was needed to perform these tests. The lab’s extraction room, completed this past July, was custom designed to make use of the available space and staff size.
The types of testing the lab needs to perform vary, and the new extraction room is versatile. Extractions performed on resins and other media sometimes include conditioning procedures, which often require backwashing the resin in a long glass column. This can easily be performed in the new room. The glass column is filled with resin and is plumbed into one of the test ports connecting it to a tank, which can be filled with either RO/DI water or other waters prescribed by the manufacturer. By installing a needle valve in-line, the backwash flow rate can be precisely controlled.
The first step in construction was to create a closed-off space within the laboratory. An area of 8 x 15 ft was chosen for this purpose. The space was walled in, a door was installed, and a ceiling was added with a ventilation system that creates a positive pressure space. This helps keep contaminants from the rest of the lab from entering.
A custom-designed system of tanks had to be built to fit into this space. Each tank is a closed system and can contain a different type of exposure water. Each of the five tanks is equipped with its own recirculation system. When in use, the pumps are continually on. If the water is not being drawn out, the pump takes a portion of the water and sends it back to the holding tank. This allows gentle mixing of exposure waters without adding extra components, such as propeller-type mixers. A needle valve is used to control how much water is recirculating, therefore regulating the pressure being delivered to each of the test unit stations.
The tanks are equipped with an automatic shut-off system. This allows the tanks to be filled with RO/DI water unattended. Once the water level in the tank reaches a certain point, a float valve is activated and relays a signal to a solenoid valve, which closes the RO/DI water supply to the tank station. The benefit of this is that analysts can work on another project or begin setting up test units for extraction while the tank is filling. It also prevents the tanks from overflowing.
The extraction room is equipped with a shelving system for storage of glassware that is reserved for extraction testing only. Pre-preserved sample bottles and vials are stored in this room as well. Keeping these materials separate is an important part of contamination prevention.
Having this system increases efficiency by allowing many extraction projects to run simultaneously. Fewer analysts need to be scheduled to perform these projects because one analyst can run several extraction projects at once. It is an efficient addition to the lab.