hydrant flow testing and dechlorination - kerr wood leidal · hydrant flow testing is a good way to...

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Hydrant Flow Testing Hydrant Flow Testing and Dechlorinationand Dechlorination

Jonathan Funk, E.I.TJonathan Funk, E.I.T

Neal Whiteside, M.A.Sc., P.Eng.Neal Whiteside, M.A.Sc., P.Eng.

Kerr Wood Leidal AssociatesKerr Wood Leidal Associates

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Hydrant Flow Testing & DechlorinationHydrant Flow Testing & Dechlorination

Hydrant flow testing contextHydrant flow testing contextWhat information can hydrant flow What information can hydrant flow testing provide?testing provide?Application to water modelingApplication to water modelingSetting up a flow test programSetting up a flow test programPractical considerations for a flow Practical considerations for a flow test programtest programDechlorination Dechlorination –– why and howwhy and how

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Hydrant Flow Testing & Hydrant Flow Testing & DechlorinationDechlorination

1.1. Water Models and CalibrationWater Models and Calibration

2.2. Hydrant Flow TestingHydrant Flow Testing

3.3. DechlorinationDechlorination

4.4. Interpreting the ResultsInterpreting the Results

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1. Water Models & Calibration1. Water Models & Calibration

What is a water model?What is a water model?

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Hydrant Flow Test Uses :Hydrant Flow Test Uses :

Confirmation of hydrant flow Confirmation of hydrant flow capabilitycapability

Development of CityDevelopment of City--wide fire flow wide fire flow mapsmaps

Hydraulic Model ValidationHydraulic Model Validation

Hydraulic Model CalibrationHydraulic Model Calibration

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Calibration vs. Validation:Calibration vs. Validation:

Calibration uses measured data to Calibration uses measured data to alter a modelalter a model’’s parameters to match s parameters to match modeled results to reality. modeled results to reality.

Validation uses measured data to Validation uses measured data to verify the correctness of a model. verify the correctness of a model. Typically, this does not involve Typically, this does not involve making permanent changes to the making permanent changes to the model.model.

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Calibration Flow Tests:Calibration Flow Tests:Isolation of a single parameter Isolation of a single parameter

i.e. Friction (Ci.e. Friction (C--Factor) TestingFactor) TestingClose valves to create a single flow Close valves to create a single flow route with multiple route with multiple PTsPTs

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Validation Flow Tests:Validation Flow Tests:

No isolationNo isolationGeneral system General system response is compared response is compared to hydraulic modelto hydraulic modelNonNon--isolated flow isolated flow testing (i.e. no closed testing (i.e. no closed valves)valves)Monitor source flows Monitor source flows and pressures and pressures (boundary conditions)(boundary conditions)

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Other Techniques for Model Other Techniques for Model Calibration or Validation:Calibration or Validation:

Pressure monitoring (long term)Pressure monitoring (long term)Water balanceWater balanceSCADA data comparisonSCADA data comparisonField verification of setField verification of set--points / points / controlscontrols

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2. Hydrant Flow Testing2. Hydrant Flow Testing

The basics: hydrant flow diffuser/meter, residual The basics: hydrant flow diffuser/meter, residual pressure monitorpressure monitor

Open (Open (““flowflow””) a hydrant, measure pressure drop) a hydrant, measure pressure drop

PDCCQ df2=

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When to use hydrant testingWhen to use hydrant testingValidation: Good for checking fireflows.Validation: Good for checking fireflows.

Calibration: <12Calibration: <12”” (300mm) pipes (not good (300mm) pipes (not good with large diameter transmission mains).with large diameter transmission mains).

Not good for calibration demand loading.Not good for calibration demand loading.

Choosing your site(s).Choosing your site(s).

Example: Port Coquitlam Citadel ZoneExample: Port Coquitlam Citadel Zone

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Program considerations:Program considerations:

Maximize flow rates (i.e. diffuser w. Maximize flow rates (i.e. diffuser w. pitotpitot tube, consider using 4tube, consider using 4”” port)port)

Other systems (i.e. turbine meters, Other systems (i.e. turbine meters, dechlorinating diffusers) may reduce dechlorinating diffusers) may reduce potential flow ratespotential flow rates

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Other Practical Considerations:Other Practical Considerations:

Elevation of residual hydrant loggerElevation of residual hydrant logger

High flow rates can cause property High flow rates can cause property damagedamage

Run flow test long enough to work Run flow test long enough to work out hydraulic transientsout hydraulic transients

Logging pressures vs. taking manual Logging pressures vs. taking manual measurementsmeasurements

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Static Pressure

Residual Pressure

Residual Flow

ΔP

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3. Dechlorination3. Dechlorination

Why Dechlorinate?Why Dechlorinate?Downstream aquatic habitats, Downstream aquatic habitats, Jurisdictional requirementsJurisdictional requirements

Common Techniques / EquipmentCommon Techniques / EquipmentDechlorinating diffusersDechlorinating diffusers

Dechlorination Dechlorination andand flow testing for flow testing for calibration requires high flowscalibration requires high flows

Use a simple diffuser & dechlorinate Use a simple diffuser & dechlorinate downstreamdownstream

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ChallengesChallenges

Flooding / WashFlooding / Wash--outout

DrainageDrainage

Residual Chlorine TestingResidual Chlorine Testing

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Residual chlorine testingResidual chlorine testingAdditional treatment Additional treatment measures (if necessary)measures (if necessary)

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What chemical to use?What chemical to use?Sodium Thiosulfate: relatively inexpensive, Sodium Thiosulfate: relatively inexpensive, possible harm to downstream aquatic possible harm to downstream aquatic habitats (can have oxygen demand).habitats (can have oxygen demand).

Ascorbic Acid: more expensive, often Ascorbic Acid: more expensive, often more effective. Not damaging to more effective. Not damaging to downstream habitats, except when overdownstream habitats, except when over--used (can lower pH in certain used (can lower pH in certain circumstances.circumstances.

Many others: know your application and Many others: know your application and choose carefully.choose carefully.

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3. De3. De--chlorinationchlorination

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Dechlorination resultsDechlorination results

Burden of proof (i.e. in ppm or mg/L)Burden of proof (i.e. in ppm or mg/L)

Colorimeter field test kitColorimeter field test kit

Typical 80Typical 80--100% reduction in free 100% reduction in free chlorine.chlorine.

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4. Interpreting the Results4. Interpreting the Results

Zone Validation Zone Validation

Single Pipe CalibrationSingle Pipe Calibration

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Validation:Validation:Accuracy Accuracy –– 10% of what?10% of what?Error in static P Error in static P --> wrong boundary > wrong boundary conditionsconditionsError in dp Error in dp --> friction factors off, > friction factors off, boundary conditions off, or demands boundary conditions off, or demands / flow off/ flow offMeasured flow alone is not very Measured flow alone is not very usefuluseful

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Calibration:Calibration:

PT errorPT error

Developing frictionDeveloping friction--factor relationships factor relationships ––how does material / pipe age relate to how does material / pipe age relate to roughnessroughness

What is mechanism for friction What is mechanism for friction degradation?degradation?

HazenHazen--Williams vs. Darcy WeisbachWilliams vs. Darcy Weisbach

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Calibration EquationsCalibration Equations

HazenHazen--Williams Eqn.Williams Eqn.

Empirical (1920)Empirical (1920)

CC--factor used to factor used to represent pipe represent pipe coefficientcoefficient

CC--factor weakly linked factor weakly linked to velocity to velocity

CC--factor weakly linked factor weakly linked to pipe dia.to pipe dia.

Simple (no Simple (no interpolation)interpolation)

852.187.4852.1 )/( QDCLCh fL •=

081.)/( oo VVCC =

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Calibration EquationsCalibration Equations

DarcyDarcy--WeisbachWeisbach

Harder to calculateHarder to calculate

εε -- equivalent sand roughness (mm), equivalent sand roughness (mm), meaningful value meaningful value

εε -- Not linked to velocity or dia.Not linked to velocity or dia.

)/8( 522 gDLQfhL π=

29.0 )]Re/74.57.3//[ln(325.1 += Df ε

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SummarySummary

Hydrant flow testing is a good way to calibrate & test Hydrant flow testing is a good way to calibrate & test modeled hydraulic losses in small diameter modeled hydraulic losses in small diameter watermains.watermains.Design program to achieve resultsDesign program to achieve resultsGood flow = good Good flow = good dpdp = good results = good results Consider DarcyConsider Darcy--WeisbachWeisbach eqn.eqn.Establish your dechlorination requirements. If Establish your dechlorination requirements. If necessary, there are several ways to dechlorinate necessary, there are several ways to dechlorinate hydrant discharge.hydrant discharge.To maximize flow rates while dechlorinating To maximize flow rates while dechlorinating andand flow flow testing, use downstream treatment (diffuser & cage).testing, use downstream treatment (diffuser & cage).

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Acknowledgements:Acknowledgements:

Rose Sinnott, KWLRose Sinnott, KWL

City of Port CoquitlamCity of Port Coquitlam

Questions?Questions?

hydrant flow testing and dechlorination - kerr wood leidal · hydrant flow testing is a good way to...

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