TABLE 1
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---|---|
Sizes of Overflow Pipes for Water Supply
Tanks
| |
Maximum Capacity
of Water Supply
Line to Tank
(gallons per minute)
|
Diameter of
Overflow Pipe
(inches ID)
|
0 to 50
|
2
|
50 to 100
|
2 1/2
|
100 to 200
|
3
|
200 to 400
|
4
|
400 to 700
|
5
|
700 - 1,000
|
6
|
Over 1,000
|
8
|
TABLE 2
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Cross-Connections Where Protective Devices
Are Required and Critical Level (C-L)
Settings for Vacuum Breakers
| |
Fixture or Equipment
|
Method of Installation
|
Aspirators and ejectors
|
C-L at least 6 inches above flood level of receptacle
served
|
Dental units
|
On models without built-in vacuum breakers C-L
at least 6 inches above flood-level rim of bowl
|
Dishwashing machines
|
C-L at least 6 inches above flood level of machine.
Install on both hot and cold water supply line
|
Flushometers (closet and urinal)
|
C-L at least 6 inches above top of fixture supplies
|
Garbage can cleaning machine
|
C-L at least 6 inches above flood level of machine.
Install on both hot and cold water supply lines
|
Hose outlets
|
C-L at least 6 inches above highest point on
hose line
|
Laundry machines
|
C-L at least 6 inches above flood level of machine.
Install on, both hot and cold water supply lines
|
Lawn sprinklers
|
C-L at least 12 inches above highest sprinkler
or discharge outlet
|
Steam tables
|
C-L at least 6 inches above flood-level
|
Tank and vats
|
C-L at least 6 inches above flood-level rim
or line
|
Trough urinals
|
C-L at least 30 inches above perforated flush
pipe
|
Flush tanks
|
Equip with approved ball cock Where ball cocks
touch tank water, equip with vacuum breaker at least 1 inch above
overflow outlets. Where ball cock does not touch tank water, install
ball cock outlet at least 1 inch above overflow outlet or provide
vacuum breaker as specified above
|
Hose bibs (where aspira- tors or rejectors could
be connected)
|
C-L at least 6 inches above flood level of receptacle
served
|
NOTES:
| |
---|---|
1 Critical level (C-L) is defined as the level
to which the vacuum breaker may be submerged before backflow will
occur. Where the C-L is not shown on the preventer, the bottom of
the device shall be taken as the C-L.
|
TABLE 3
|
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Partial List of Cross-Connections Which
May Be
Subject to Backpressure
|
Chemical lines
|
Dock water outlets
|
Individual water supplies
|
Industrial process water lines
|
Pressure tanks
|
Pumps
|
Steam lines
|
Swimming pools
|
Tank and vats, bottom inlets
|
Hose bibs
|