CROSS-CONNECTION &

BACKFLOW

THE BASICS

SERVING THE BLACKSTONE VALLEY SINCE 1877

Installation Testing Clean, Safe Drinking Water

=+

What is a Cross-Connection ?A cross connection is any arrangements of

pipes, fixtures, or fittings that directly or indirectly connects a non potable water source (hazardous pollutants) to the drinking water.

Example: A garden hose connected to an outside faucet attached to a garden sprayer.

Example: A hose connected to a slop sink.

Example: A Garden hose left in your swimming pool.

WHEN A DROP IN WATER PRESSURE TAKES PLACE, CHEMICALS OR DIRTY WATER CAN BE SUCKED BACKWARDS INTO YOUR

HOUSEHOLD PLUMBING SYSTEM. EXAMPLE GARDEN HOSE CONNECTED TO A HOME

FERTILIZER SPRAYER, A HOSE CONNECTED TO A SLOP SINK

AND A GARDEN HOSE USED TO FILL A SWIMMING POOL

How does a backflow occur ?Two methodsA) BACKPRESSURE – This can occur when

the pressure inside a bldg exceeds the pressure entering a bldg.

Example of Backpressure: Booster Pumps or Boiler Systems.

B) BACK-SIPHONAGE - This can occur in the event the pressure in the supply piping entering the bldg drops suddenly and a vacuum-like suction begins.

Example of Back-Siphonage: Water Main Breaks or the use of fire hydrants

Both examples will allow polluted and/or contaminated water back into the internal plumbing of a home or business and also out to the public drinking water.

EXAMPLE OF BACKPRESSURE

EXAMPLE OF BACK SIPHONAGE

A boiler using a circulating pump with pressure of 8O psi, and the street pressure coming in at 6O psi, - Result - 8O psi at the boiler over-exceeds the 6O street pressure which would then push the boiler water backwards.

With a water main break, water in the system would drop suddenly, triggering a vacuum-like effect causing water in your building to flow backwards.

60

80 PUMPBoiler

Water

Reverse flow

TWO TYPES OF HAZARDS AND WHERE THEY MAY BE FOUND.HIGH HAZARDS LOW HAZARDS

Buildings such as:HospitalsFuneral HomesCar Wash

Internal plumbing such as:

X-Ray processing equipment

Commercial BoilersPost Mix Carbonators

Buildings such as:Coffee ShopAssisting LivingResidential Home

Internal Plumbing such as:

Sinks w/ Threaded Connections

Residential BoilersDishwashers

LET’S SEE WHAT COULD HAPPEN

DURING A WATER MAIN BREAK

GOOD PRESSUREAT

THE WATER MAIN

GOOD PRESSUREAT

THE WATER MAIN

COOLING TOWERCOOLING TOWER

X-RAY EQX-RAY EQ

BUBBLERBUBBLER

AUTOPSY TABLEAUTOPSY TABLE

WATER MAIN

METERMETER

EVERYONE IS HAPPY AND FEELING GOOD

OH WHAT A

BEAUTIFUL

DAY!

BUSINESS IS

GOOD

PWSB WATER

TASTES SO

GOOD

FLOW

COOLING TOWERCOOLING TOWER

X-RAY EQX-RAY EQ

BUBBLERBUBBLER

AUTOPSY TABLEAUTOPSY TABLE

WATER MAIN WATER MAIN

METERMETER

BANG! WATER MAIN BREAK

BANG! WATER MAIN BREAK

Call

the

PWSB

HURR

Y!!!!!!

!!

WHAT HAPPENS NOW WITH THE

WATER?

WHERE DOES THE

WATER GO?

COOLING TOWERCOOLING TOWER

X-RAY EQX-RAY EQ

BUBBLERBUBBLER

AUTOPSY TABLEAUTOPSY TABLE

WATER MAIN WATER MAIN

METERMETER

BECAUSE OF THE WATER MAIN BREAK A SUDDEN DROP IN WATER PRESSURE OCCURS ALLOWING THE INTERNAL WATER TO REVERSE FLOW

BECAUSE OF THE WATER MAIN BREAK, A SUDDEN DROP IN WATER PRESSURE OCCURS, ALLOWING THE BUILDINGS

WATER TO REVERSE DIRECTION, EFFECTING THE INTERNAL PLUMBING

AND YOUR NEIGHBORS

COOLING TOWERCOOLING TOWER

X-RAY EQX-RAY EQ

BUBBLERBUBBLER

AUTOPSY TABLEAUTOPSY TABLE

WATER MAIN WATER MAIN

METERMETER

REPAIRS ARE MADE AND THE WATER PRESSURE IS

RESTORED

REPAIRREPAIR WATER MAIN WATER MAIN

ALL WATER CONNECTIONS CONNECTED TO THE EQUIPMENT, SUCH AS THE

COOLING TOWER, X-RAY MACHINE AND THE AUTOPSY TABLE GET

RE-PRESSURIZED

AND

OOPS!

NO BFPA’S WERE INSTALLED

OOPS!

NO BFPA’S WERE INSTALLED

COOLING TOWERCOOLING TOWER

X-RAY EQX-RAY EQ

BUBBLERBUBBLER

AUTOPSY TABLEAUTOPSY TABLE

WATER MAIN WATER MAIN METERMETER

WITHOUT BFPA’S INSTALLED AT THOSE LOCATIONS MARKED , THE NEW PRESSURIZED WATER WOULD RETURN WITH ALL THE BAD CONTAMINATES REACHING PLACES LIKE THE DRINKING BUBBLER.

REPAIRREPAIR WATER MAIN WATER MAIN

MAN HOSPITALIZED

FROM DRINKING

CONTAMINATE

D WATER!

WITH THE PROPER INSTALLATION OF BACKFLOW PREVENTION

ASSEMBLIES (BFPA’S) INSTALLEDAND WITH THE WATER PRESSURE

NOW RESTORED

WITH THE PROPER INSTALLATION OF BACKFLOW PREVENTION

ASSEMBLIES (BFPA’S) INSTALLEDAND WITH THE WATER PRESSURE

NOW RESTORED

COOLING TOWERCOOLING TOWER

X-RAY EQX-RAY EQ

BUBBLERBUBBLER

AUTOPSY TABLEAUTOPSY TABLE

WATER MAIN WATER MAIN METERMETER

BFPA’S REALLY WORK

REPAIRREPAIR WATER MAIN WATER MAIN

ALL CONTAINMENTS OR POLLUTED WATER WERE IMMEDIATELY STOPPED AT THE HIGH HAZARD FIXTURES, WHICH PREVENTED CONTAINMENTS REACHING THE DRINKING BUBBLER

OH

WHAT A

BEAUTIF

UL DAY

IT IS

AGAIN!

THANKS

TO THE

PWSB

BFPA’S REALLY WORK

YES, BACKFLOW PREVENTION ASSEMBLIES DO WORK, BUT ONLY

IF THEY ARE MAINTAINED AND TESTED AT LEAST ANNUALLY TO ASSURE THEIR EFFECTIVNESS AGAINST BACKPRESSURE AND BACK- SIPHONAGE DOES NOT

OCCUR

TESTABLE BFPA ASSEMBLIES TOP PHOTOS SHOWS A RPZ VALVE

(REDUCE PRESSURE ZONE VALVE) AND ARE USED IN HIGH HAZARD APPLICATIONS.

BOTTOM PHOTOS SHOWS A DCVA (DOUBLE CHECK VALVE ASSEMBLY) AND ARE USED FOR LOW HAZARDS APPLICATION.

THIS PHOTO SHOWS A PVB (PRESSURE VACUUM BREAKER) AND ARE UESD MOSTLY ON RESIDENTIAL LAWN IRRIGATION.

NON-TESTABLE DEVICES LEFT PHOTO SHOWS A

RESIDENTAL DUEL CHECK AND ARE USED FOR CONTAINMENT AT RESIDENTIAL METERS. RIGHT PHOTO SHOWS A HOSE BIBB VACUUM BREAKER AND ARE USED ON THREADED CONNECTIONS SUCH AS GARDEN HOSES

TOP PHOTO SHOWS A STAINLESS STEAL DUEL CK WITH VENT AND ARE USED FOR POST CARBONATORS MIXERS AND THE BOTTOM PHOTO ALSO SHOWS A DUEL CK WITH VENT AND ARE COMMONLY USED AT RESIDENTIAL BOILERS