Water Meter Sizing Water Meter Sizing and Backflow and Backflow

PreventionPrevention

Cory HarmonCory HarmonSite Plan Plumbing CoordinatorSite Plan Plumbing Coordinator

City of AustinCity of Austin

Britt JonesBritt JonesUtility Development Services Project CoordinatorUtility Development Services Project Coordinator

Austin Water UtilityAustin Water Utility

Part IPart I

Water Meter Water Meter SizingSizing

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

Residential Water Meter SizingResidential Water Meter Sizing

Residential water meters are sized according to Residential water meters are sized according to the local amendments to the 2012 Uniform the 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 be Two family Dwellings and Townhomes shall be sized per the below requirements:sized per the below requirements:

Residential Water Meters Serving Fire Residential Water Meters Serving Fire Sprinkler SystemsSprinkler Systems

NFPA 13D systems are required to NFPA 13D systems are required to provide approximately 26 gpm, therefore a provide approximately 26 gpm, therefore a minimum ¾” water meter is required.minimum ¾” water meter is required.

Commercial Water Meter SizingCommercial Water Meter Sizing

Commercial water meters serving Commercial water meters serving domestic demand only are sized domestic demand only are sized according to Tables 610.0 and 610.4 or according to Tables 610.0 and 610.4 or Appendix A of the 2012 Uniform Plumbing Appendix A of the 2012 Uniform Plumbing Code.Code.

Fire Demand Water Meter Fire Demand Water Meter SizingSizing

Determine fire flow from International Fire Determine fire flow from International Fire Code and NFPA 13.Code and NFPA 13.

Determine domestic demand from Uniform Determine 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 to Size the fire demand meter according to

AWWA chart.AWWA chart.

Questions?Questions?

Part IIPart II

Backflow Backflow PreventionPrevention

Actual Cross-Connection Actual Cross-Connection IncidentIncident

What is Backflow?What is Backflow?

The The undesirableundesirable reversal reversal of flow of water in a of flow of water in a piping systempiping system

What causes a Backflow Incident?What causes a Backflow Incident?

Loss of pressure in the water system due Loss of pressure in the water system due to a water main break or use of a fire to a water main break or use of a fire hydrant can cause a negative or sub hydrant can cause a negative or sub atmospheric condition in other portions of atmospheric condition in other portions of the water line. This is an example of the water line. This is an example of Backsiphonage.Backsiphonage.

What causes a Backflow Incident?What causes a Backflow Incident?

Any pressure caused by a pump or simply Any pressure caused by a pump or simply the height of a water line (tall building) that the height of a water line (tall building) that overcomes the pressure of the water overcomes the pressure of the water source and causes a reversal of flow. This source and causes a reversal of flow. This is known as is known as Backpressure.Backpressure.

Types of HazardsTypes of Hazards

Pollutant-Pollutant- causes no actual health or causes no actual health or system threat to water but may be system threat to water but may be aesthetically objectionable (color, smell). aesthetically objectionable (color, smell). We refer to this type of hazard as We refer to this type of hazard as Low Low Hazard.Hazard.

Types of HazardsTypes of Hazards

ContaminantsContaminants- any toxic substances that - any toxic substances that if introduced into a potable water system if introduced into a potable water system would cause it to be unsafe for human or would cause it to be unsafe for human or animal consumption. We refer to this type animal consumption. We refer to this type of hazard as of hazard as High Hazard.High Hazard.

Containment vs. IsolationContainment vs. Isolation

Containment is a method of Containment is a method of providing backflow protection at providing backflow protection at the the service connectionservice connection. This . This protects the water supply at the protects the water supply at the main but does not protect against main but does not protect against cross-connections within the cross-connections within the facility or site.facility or site.

Containment vs. IsolationContainment vs. Isolation

Isolation- is a type or method of Isolation- is a type or method of providing backflow protection providing backflow protection commensurate with the degree of commensurate with the degree of hazard hazard withinwithin a customer’s a customer’s potable water system. This potable water system. This protects from cross-connections protects from cross-connections inside a facility or siteinside a facility or site..

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 Principle RPZ – Reduced Pressure Principle

AssemblyAssembly

Pressure Vacuum Breaker Pressure Vacuum Breaker AssemblyAssembly

Good for Hi or Low Hazard Good for Hi or Low Hazard BacksiphonageBacksiphonage only.only.

CanCan have valves downstream (designed for have valves downstream (designed for constant pressure)constant pressure)

Must be installed Must be installed 1212 inches above any inches above any downstream piping.downstream piping.

Testable device, if used for high hazard must Testable device, if used for high hazard must have annual test.have annual test.

Local code requires floor drain nearby if located Local code requires floor drain nearby if located indoors.indoors.

Pressure Vacuum BreakerPressure Vacuum Breaker

““Spill-proof” Pressure Vacuum Spill-proof” Pressure Vacuum BreakerBreaker

Double Check Valve AssemblyDouble Check Valve Assembly

Good for Good for Low HazardLow Hazard Backsiphonage and Backsiphonage and Backpressure.Backpressure.

Inside building-12 inches minimum off Inside 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 at Testable device- tested only 1 time at

installation (no annual) unless serving fire installation (no annual) unless serving fire line or fire sprinkler.line or fire sprinkler.

Used on irrigation, coffee maker, tea Used on irrigation, coffee maker, tea maker, fire line, fire sprinkler, etc.maker, fire line, fire sprinkler, etc.

Double Check Valve AssemblyDouble Check Valve Assembly

Reduced Pressure Principle Reduced Pressure Principle Assembly (RPZ)Assembly (RPZ)

Cadillac Cadillac of mechanical backflow devices.of mechanical backflow devices. Incorporates two check valves and a Incorporates 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 feet Minimum 12” above floor and 5 feet

maximum. Cannot be underground.maximum. Cannot be underground. Testable device, requires annual Testable device, requires annual

certification.certification.

Approved Backflow PreventersApproved Backflow Preventers

UCM Section 2.3.2(A) – Backflow UCM Section 2.3.2(A) – Backflow preventers must have approval from the preventers must have approval from the University of Southern California’s University of Southern California’s Foundation for Cross-Connection Control Foundation for Cross-Connection Control and Hydraulic Research (USC FCCC&HR) and Hydraulic Research (USC FCCC&HR)

Below Grade Backflow Below 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 of 12”-36” clearance from bottom of

assembly to floor of vault.assembly to floor of vault. 6”-36” clearance from top of assembly to 6”-36” clearance from top of assembly to

vault lid.vault lid.

100 Gallon Rule100 Gallon Rule

UCM Section 2.3.2 – Dead end fire lines UCM Section 2.3.2 – Dead end fire lines cannot contain more than 100 gallons cannot contain more than 100 gallons from the free-flowing main to the backflow from the free-flowing main to the backflow preventer.preventer.

General InfoGeneral Info

Plumbing Inspector inspects at time of Plumbing Inspector inspects at time of installationinstallation

Tracking of installation and testing done Tracking of installation and testing done by AWU Water Protection Division.by AWU Water Protection Division.

Water Protection Division’s “Water Water Protection Division’s “Water Protection Specialists” also do random Protection Specialists” also do random cross-connection surveys throughout cross-connection surveys throughout Austin to ensure the protection of our Austin to ensure the protection of our water supply.water supply.

QuizQuiz

What is wrong with these pictures?What is wrong with these pictures?

Questions?Questions?