Plumbing systems, metallic materials used

The concentration of zinc in drinking water may increase as a result of the distribution system and household plumbing (EPA 1987c). Common piping materials used in distribution systems often contain zinc, as well as other metals and alloys. Trace metals may enter the water through corrosion products or simply by the dissolution of small amounts of metals with which the water comes in contact. Reactions with materials of the distribution system, particularly in soft low-pH waters, very often have produced concentrations of zinc in tap water much greater than those in the raw or treated waters at the plant of origin (NAS 1977). The total quantity of annual releases of zinc from these sources has not been estimated. 

PEX is a medium- to high-density PE containing cross-links. Cross-linking reduces its flow and increases the continuous use temperature (CUT) and chemical resistance. Because tubes made of the material can be expanded to fit over a metal nipple and then slowly return to its original shape, forming a permanent, watertight connection PEX is used in potable water plumbing systems. 

A wide variety of general purpose cleansers is available with abrasive materials to facilitate the cleansing process. Conventional cleansers are petroleum-based and use pumice, sand, metal meshes, foams, rigid and textured plastics, and various composites as abrasive materials. Although these materials are effective, they are often too harsh for use in sensitive or soft areas. Further, many of the abrasives and their associated adhesives are not biodegradable so they remain in the plumbing and in the water system long after their use (2). 

The installation of a capture box will be required for those work place layouts where the floor drain is located in the same room as the sterilizer or in a room where workers are normally present. A capture box is a piece of equipment that totally encloses the floor drain where the discharge from the sterilizer is pumped. The capture box is to be vented directly to a non-recirculating or dedicated ventilation system. Sufficient air intake should be allowed at the bottom of the box to handle the volume of air that is ventilated from the top of the box. The capture box can be made of metal, plastic, wood or other equivalent material. The box is intended to reduce levels of EtO discharged into the work room atmosphere. The use of a capture box is not required if (1) The vacuum pump discharge floor drain is located in a well ventilated equipment or other room where workers are not normally present or (2) the water sealed vacuum pump discharges directly to a closed sealed sewer line (check local plumbing codes). 

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