Brochure

Man has long recognized the
need for pure drinking water,
but only in the last 50 or 60
years has there been any real
effort to prevent contamination
caused by cross-connections.
Although double check valves
came into use around the turn
of the century to isolate fire
mains and industrial water lines
from the potable water supply,
little interest was shown in the
individual treatment of plumb-
ing fixtures.
In 1929 the major breakthrough
came when a device consist-
ing of two check valves with a
relief valve between them was
successfully tested in Danville,
Illinois. However, this valve was
not produced commercially and
it was not until the late 1930’s
that the real development of
effective vacuum breakers and
backflow preventers took place.
It was in this period that ordi-
nances for cross-connection
control began to be enforced.
The Safe Drinking
Water Act, signed into law by
President Ford, placed more
emphasis on the responsibility
for drinking water protection.
The need for cross-connection
control exists in all types of
premises, whether industrial or
residential. Backflow preven-
tion devices help protect the
public safety by preventing
potable water contamination in
such critical areas as municipal
water systems, food process-
ing plants, medical and dental
water supplies, and many
industrial applications.
Contents
Page
Backflow — What is it? ............................................................... 1
Case Histories ........................................................................ 2 - 3
Typical Cross-Connections ................................................... 4 - 5
Backflow Prevention Devices .................................................... 6
How Backflow Prevention Devices Work ................................. 7
Device Selection ......................................................................... 8
Installation .............................................................................. 8 - 9
Testing ........................................................................................ 9
A Brief History of
Cross-Connection
Control
Bibliography
“Cross-Connection Control
Manual” (EPA-570/9-89-007)
U.S. Environmental Protection
Agency, Water Supply Division,
Washington D.C. (1973)
Recommended Practice for
Backflow Prevention and
Cross-Connection Control,
AWWA M14, American Water
Works Association, Denver,
CO, 1990.
“Manual of Cross-Connection
Control,” Foundation for
Cross-Connection Control and
Hydraulic Research, University
of Southern California;
Los Angeles, Calif. 90007
American Society of Sanitary
Engineering (ASSE), Professional
Qualification Standards,
Backflow Prevention Assemblies
- Series 5000, Bay Village,
Ohio.
Canadian Standards Association,
Manual for Selection,
Installation, and Field Testing,
CAN/CSA-B64.10-94
An informative booklet, for the
purpose of a better dissemination
of the facts about potential
hazards to public health through
backflow contamination.
Copyright 1997