Page 93 - Vessel Sanitation Program 2018 Construction Guidelines
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VSP 2018 Construction Guidelines
recommendation. Provide all manufacturers’ literature for installation,
operation, and maintenance.
22.14.2.2 Free Halogen Probes
Use probes to measure free HALOGEN and link them to the
analyzer/controller and chemical dosing pumps.
22.14.2.3 Backup Halogenation Pump
Provide a back-up HALOGENATION pump with an automatic
switchover that begins pumping HALOGEN when the primary (in-use)
pump fails or cannot meet the HALOGENATION demand.
22.14.2.4 Chemical Injection Dosing Point
A check valve or nonreturn valve must be installed between the
distribution halogen and pH pumps and the injection points. In
addition,
• The potable water distribution halogenation and pH chemical
injection dosing points must be located on the delivery line
downstream of the potable water pumps, OR
• If the injection dosing point is before the potable water pumps,
it must be located above the chemical dosing tanks.
22.14.2.5 Probe/Sample Location
Locate the HALOGEN analyzer probe at a distant point in each
distribution system loop where significant water flow exists.
22.14.2.6 Alarm
Provide an audible alarm in a continually occupied watch station (e.g.,
the engine control room or bridge) to indicate low or high free
HALOGEN readings at each distant point analyzer.
22.14.2.7 Backflow Prevention
Provide POTABLE WATER taps with appropriate BACKFLOW
prevention at HALOGEN supply tanks.
22.14.2.8 Free Halogen Analyzer-Chart Recorder
Provide continuous recording free HALOGEN analyzer-chart
recorder(s) that have ranges of 0.0 to 5.0 MG/L (ppm) and indicate the
level of free HALOGEN for 24-hour time periods (e.g., circular 24-
hour charts).
Electronic data loggers with CERTIFIED DATA SECURITY
FEATURES may be installed in lieu of chart recorders. Acceptable
data loggers produce records that conform to the principles of operation
and data display required of the analog charts, including printing the
records. Use electronic data loggers that log times in increments of
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