25 May 2005
Protection of Potable Water. Protecting potable water supplies, as it
applies to an industrial water system, involves preventing contamination of the potable
water system. Eliminating cross-connections in the water system and using backflow
prevention devices or air gaps to provide an interconnection barrier between the water
systems are ways to achieve this prevention.
Cross-connections. A cross-connection is a physical connection between
a potable water supply system and a non-potable water system (such as an industrial
water system) through which contaminated water can enter the potable water system.
Cross-connections are eliminated to maintain the safety of potable water supplies.
Backflow prevention devices are installed to prevent cross-connections where potable
water is supplied to industrial water systems.
Backflow Prevention Devices. Class III backflow prevention devices (air
gap or reduced pressure principle devices) are required when connecting a potable
water supply system to an industrial water system that uses a source of non-potable
water. They are also required when connecting a potable water supply system to an
industrial water system to which chemicals have been added.
Air Gaps. If potable makeup water is supplied to a tank or other type of
open system, proivide an air gap between the water inlet and the maximum overflow
level of the tank, device, or system.
Restrictions on Direct Steam Use. Neutralizing amine chemicals, which
are added to the steam to protect the condensate lines from corrosion, make the steam
and condensate unfit for consumption or for other uses normally reserved for potable
water. Treated steam should not come into direct contact with food and should not be
used for heating food trays or for humidification. For these applications, steam-to-steam
heat exchangers can be used to provide amine-free steam (see paragraph 3-2.7.6).
Record-Keeping Requirements. Procedures for industrial water
treatment and testing may vary from one installation to another based on differences in
the characteristics and quality of the water, as well as on differences in the type and
size of the systems. Water system specifications are developed to address local factors
such as the installation's mission, geographic location, and climate. The data and
information records and logs used to record the results of industrial water treatment and
testing can be developed to reflect the minimum documentation requirements needed to
verify adequate operation and control of the treatment program. Computer-generated
logs require regularly scheduled backup. Chapter 6 provides recommended
frequencies for sampling and testing various industrial water systems.
Control Charts. Control charts can be developed to identify the following
information: the treatment chemicals used; the chemical levels required to be
maintained in the system; other required testing procedures (e.g., conductivity, pH); and
the information specific to the particular water system (especially for the larger boilers