High Purity Water Design Parameters
- Polyvinylchloride (PVC) schedule 80
- Must be cut with an approved PVC cutter all burrs cleaned off. Chamfering tool to be used to round edges.
- Polyvinylidenefluoride (PVDF)
- Polypropylene (PPE)
- Stainless Steel (Heat Sanitizable)
- Use of any other metals other than 316 SS is not permitted.
- 90 degree turns the turns should be accomplished with 45 degree angles. When at all possible, a return loop should be used to minimize bacterial growth through movement of water in the system.
- Return velocity must by a minimum of 3FPS with averages 4-7 FPS. Much higher than that you can get noise.
- Dead legs must be avoided. The length of an unused portion of pipe should be between 3-5 times of the pipe diameter as a maximum. Best practice is 3 times when at all possible. Dead-leg definition: An unused portion of pipe greater in length than six diameters of the unused pipe measured from the axis of the pipe in use.
- Approved ball true union valves should be used that are less restrictive than gate valves.
Water Storage Storage
- Storage of the water should be in a conical bottom tank if cleaning are to be done on a regular basis. Spray balls or a spray bar have the added advantage of reducing bacterial growth in theory.
- A hydrophobic vent filter should be installed on the tank and a sealed system otherwise. This is to control airborne bacteria from entering the tank.