1. Water Meter SizingWater Meter Sizing
and Backflowand Backflow
PreventionPrevention

2. Cory HarmonCory Harmon
Site Plan Plumbing CoordinatorSite Plan Plumbing Coordinator
City of AustinCity of Austin
Britt JonesBritt Jones
Utility Development Services Project CoordinatorUtility Development Services Project Coordinator
Austin Water UtilityAustin Water Utility

3. Part IPart I
Water MeterWater Meter
SizingSizing

4. Types of Water MetersTypes of Water Meters
 Positive Displacement AWWA C700-09Positive Displacement AWWA C700-09
 Turbine Class II AWWA C701-12Turbine Class II AWWA C701-12
 Compound AWWA C702-10Compound AWWA C702-10
 Fire Service/Demand Type III C703-11Fire Service/Demand Type III C703-11

5. Residential Water Meter SizingResidential Water Meter Sizing
 Residential water meters are sized according toResidential water meters are sized according to
the local amendments to the 2012 Uniformthe local amendments to the 2012 Uniform
Plumbing Code.Plumbing Code.
 610.1.1 Size of Water Meters for One-and-610.1.1 Size of Water Meters for One-and-
Two Family Dwellings and Townhomes.Two Family Dwellings and Townhomes.
Austin Water Utility Meters provided to One-and-Austin Water Utility Meters provided to One-and-
Two family Dwellings and Townhomes shall beTwo family Dwellings and Townhomes shall be
sized per the below requirements:sized per the below requirements:

7. Residential Water Meters Serving FireResidential Water Meters Serving Fire
Sprinkler SystemsSprinkler Systems
 NFPA 13D systems are required toNFPA 13D systems are required to
provide approximately 26 gpm, therefore aprovide approximately 26 gpm, therefore a
minimum ¾” water meter is required.minimum ¾” water meter is required.

8. Commercial Water Meter SizingCommercial Water Meter Sizing
 Commercial water meters servingCommercial water meters serving
domestic demand only are sizeddomestic demand only are sized
according to Tables 610.0 and 610.4 oraccording to Tables 610.0 and 610.4 or
Appendix A of the 2012 Uniform PlumbingAppendix A of the 2012 Uniform Plumbing
Code.Code.

12. Fire Demand Water MeterFire Demand Water Meter
SizingSizing
 Determine fire flow from International FireDetermine fire flow from International Fire
Code and NFPA 13.Code and NFPA 13.
 Determine domestic demand from UniformDetermine domestic demand from Uniform
Plumbing Code.Plumbing Code.
 Domestic demand must exceed 160 gpm.Domestic demand must exceed 160 gpm.
 Add fire flow and domestic demand.Add fire flow and domestic demand.
 Size the fire demand meter according toSize the fire demand meter according to
AWWA chart.AWWA chart.

14. Questions?Questions?

15. Part IIPart II
BackflowBackflow
PreventionPrevention

16. Actual Cross-ConnectionActual Cross-Connection
IncidentIncident

21. What is Backflow?What is Backflow?
TheThe undesirableundesirable reversalreversal
of flow of water in aof flow of water in a
piping systempiping system

22. What causes a Backflow Incident?What causes a Backflow Incident?
 Loss of pressure in the water system dueLoss of pressure in the water system due
to a water main break or use of a fireto a water main break or use of a fire
hydrant can cause a negative or subhydrant can cause a negative or sub
atmospheric condition in other portions ofatmospheric condition in other portions of
the water line. This is an example ofthe water line. This is an example of
Backsiphonage.Backsiphonage.

23. What causes a Backflow Incident?What causes a Backflow Incident?
 Any pressure caused by a pump or simplyAny pressure caused by a pump or simply
the height of a water line (tall building) thatthe height of a water line (tall building) that
overcomes the pressure of the waterovercomes the pressure of the water
source and causes a reversal of flow. Thissource and causes a reversal of flow. This
is known asis known as Backpressure.Backpressure.

24. Types of HazardsTypes of Hazards
 Pollutant-Pollutant- causes no actual health orcauses no actual health or
system threat to water but may besystem threat to water but may be
aesthetically objectionable (color, smell).aesthetically objectionable (color, smell).
We refer to this type of hazard asWe refer to this type of hazard as LowLow
Hazard.Hazard.

25. Types of HazardsTypes of Hazards
 ContaminantsContaminants- any toxic substances that- any toxic substances that
if introduced into a potable water systemif introduced into a potable water system
would cause it to be unsafe for human orwould cause it to be unsafe for human or
animal consumption. We refer to this typeanimal consumption. We refer to this type
of hazard asof hazard as High Hazard.High Hazard.

26. Containment vs. IsolationContainment vs. Isolation
Containment is a method ofContainment is a method of
providing backflow protection atproviding backflow protection at
thethe service connectionservice connection. This. This
protects the water supply at theprotects the water supply at the
main but does not protect againstmain but does not protect against
cross-connections within thecross-connections within the
facility or site.facility or site.

27. Containment vs. IsolationContainment vs. Isolation
Isolation- is a type or method ofIsolation- is a type or method of
providing backflow protectionproviding backflow protection
commensurate with the degree ofcommensurate with the degree of
hazardhazard withinwithin a customer’sa customer’s
potable water system. Thispotable water system. This
protects from cross-connectionsprotects from cross-connections
inside a facility or siteinside a facility or site..

28. 6 Types of Backflow Protection6 Types of Backflow Protection
 AG – Air GapAG – Air Gap
 AVB – Atmospheric Vacuum BreakerAVB – Atmospheric Vacuum Breaker
 PVB – Pressure Vacuum BreakerPVB – Pressure Vacuum Breaker
 SVB – “Spill-proof” Vacuum BreakerSVB – “Spill-proof” Vacuum Breaker
 DCVA – Double Check Valve AssemblyDCVA – Double Check Valve Assembly
 RPZ – Reduced Pressure PrincipleRPZ – Reduced Pressure Principle
AssemblyAssembly

29. Pressure Vacuum BreakerPressure Vacuum Breaker
AssemblyAssembly
 Good for Hi or Low HazardGood for Hi or Low Hazard BacksiphonageBacksiphonage
only.only.
 CanCan have valves downstream (designed forhave valves downstream (designed for
constant pressure)constant pressure)
 Must be installedMust be installed 1212 inches above anyinches above any
downstream piping.downstream piping.
 Testable device, if used for high hazard mustTestable device, if used for high hazard must
have annual test.have annual test.
 Local code requires floor drain nearby if locatedLocal code requires floor drain nearby if located
indoors.indoors.

30. Pressure Vacuum BreakerPressure Vacuum Breaker

31. ““Spill-proof” Pressure VacuumSpill-proof” Pressure Vacuum
BreakerBreaker

32. Double Check Valve AssemblyDouble Check Valve Assembly
 Good forGood for Low HazardLow Hazard Backsiphonage andBacksiphonage and
Backpressure.Backpressure.
 Inside building-12 inches minimum offInside building-12 inches minimum off
floor; 5 feet maximum.floor; 5 feet maximum.
 Outside- can be installed underground.Outside- can be installed underground.
 Testable device- tested only 1 time atTestable device- tested only 1 time at
installation (no annual) unless serving fireinstallation (no annual) unless serving fire
line or fire sprinkler.line or fire sprinkler.
 Used on irrigation, coffee maker, teaUsed on irrigation, coffee maker, tea
maker, fire line, fire sprinkler, etc.maker, fire line, fire sprinkler, etc.

33. Double Check Valve AssemblyDouble Check Valve Assembly

38. Reduced Pressure PrincipleReduced Pressure Principle
Assembly (RPZ)Assembly (RPZ)
 CadillacCadillac of mechanical backflow devices.of mechanical backflow devices.
 Incorporates two check valves and aIncorporates two check valves and a
differential relief valve.differential relief valve.
 Good for hi and low hazard,Good for hi and low hazard,
backsiphonage and backpressure.backsiphonage and backpressure.
 Minimum 12” above floor and 5 feetMinimum 12” above floor and 5 feet
maximum. Cannot be underground.maximum. Cannot be underground.
 Testable device, requires annualTestable device, requires annual
certification.certification.

41. Approved Backflow PreventersApproved Backflow Preventers
 UCM Section 2.3.2(A) – BackflowUCM Section 2.3.2(A) – Backflow
preventers must have approval from thepreventers must have approval from the
University of Southern California’sUniversity of Southern California’s
Foundation for Cross-Connection ControlFoundation for Cross-Connection Control
and Hydraulic Research (USC FCCC&HR)and Hydraulic Research (USC FCCC&HR)

42. Below Grade BackflowBelow Grade Backflow
Installation StandardsInstallation Standards
 UCM Section 2.3.3UCM Section 2.3.3
 Cannot be located is a traffic area.Cannot be located is a traffic area.
 24” clearance on service side.24” clearance on service side.
 12” clearance on non-service side.12” clearance on non-service side.
 12”-36” clearance from bottom of12”-36” clearance from bottom of
assembly to floor of vault.assembly to floor of vault.
 6”-36” clearance from top of assembly to6”-36” clearance from top of assembly to
vault lid.vault lid.

43. 100 Gallon Rule100 Gallon Rule
 UCM Section 2.3.2 – Dead end fire linesUCM Section 2.3.2 – Dead end fire lines
cannot contain more than 100 gallonscannot contain more than 100 gallons
from the free-flowing main to the backflowfrom the free-flowing main to the backflow
preventer.preventer.

44. General InfoGeneral Info
 Plumbing Inspector inspects at time ofPlumbing Inspector inspects at time of
installationinstallation
 Tracking of installation and testing doneTracking of installation and testing done
by AWU Water Protection Division.by AWU Water Protection Division.
 Water Protection Division’s “WaterWater Protection Division’s “Water
Protection Specialists” also do randomProtection Specialists” also do random
cross-connection surveys throughoutcross-connection surveys throughout
Austin to ensure the protection of ourAustin to ensure the protection of our
water supply.water supply.

46. QuizQuiz
 What is wrong with these pictures?What is wrong with these pictures?

50. Questions?Questions?