20step%20testing%20guidelines

1

Step Testing Module

Ranhill Water Services Sdn. Bhd.

Step TestingStep Testing

Step Testing Module


Objective of the Course

• To help delegates gain an understanding of the purpose of step testing, and its place within a leakage or NRW strategy

• To provide information on the methods used to carry out a test

• To provide sufficient information to enable candidates to take the combined TW/CABWI assessment

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Step Testing Module


Topics to be Covered

1. Meaning and purpose of step testing

2. Equipment required

3. Planning the test

4. Method of operation

5. Interpreting results

Step Testing Module


What is a Step Test?

A step test is a method of narrowing down the search for suspected leakage within a discrete area, by successively shutting parts of that area, and noting the effect on the supply.

The integrity of the area must be established, all boundary valves shut, and the status of all other valves known.

Supply should preferably be from a single source and metered.

3

Step Testing Module


District MeteringDistrict Metering

Step Testing Module


Typical 24hr Flow ProfileTypical 24hr Flow Profile

Flo

w l

/s

Minimum Night Flow

4

Step Testing Module


Step TestingStep Testing

11 22

3344

Flow InFlow In

Step Testing Module


Step Test ResultsStep Test Results

Flo

w l

/s

5

Step Testing Module


Valve Functions Within the Area

1. Boundary valves – permanently shut

2. Circulating valves – normally open but shut for the test

3. Step valves – normally open but shut progressively

4. Redundant sluice valves – permanently open

Step Testing Module



1. Boundary Valves

– valves isolating the area in question, whether a

DMA or not, from adjacent areas. They must be

sound, not let by, and will remain shut throughout

the test. If they are DMA boundary valves they will

be permanently shut.

6

Step Testing Module



2. Circulating Valves

– valves which are shut before the test starts to allow

division of the area into separate parts. After

shutting, and before the test starts, water will

circulate around these valves, and the pressure will

be the same either side.

BV

BV BVCV

Step Testing Module



3. Step Valves

– valves which are shut in turn to reduce the area being

metred in a series of ‘steps’.

BV

BV BVCVSV1

SV2 SV3

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Step Testing Module



4. Redundant Valves

– valves which remain open throughout the test and are

not used as part of the test.

- The example shown could be used as a step valve if

required

BV

BV BVCVSV1

SV2 SV3

Redundant valve

Step Testing Module


Plan of Step Test Area

1

2

3

4

5

6

7

8

9SV

BV

BV

BVBV

CV

CV

CV

SV

SVSV

SVSV

SV

SV

SV

8

Step Testing Module








Step Testing Module


Equipment Required for Proving

• Meter (check function)

• Valve key and bar

• Hydrant key and bar

• Swan neck

• Hose

• Lifting keys

• Crow bar?

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Step Testing Module


Equipment Required for Step Test

• Meter

• Flow logger

• Pulse unit

• Valve key and bar

• Lifting keys

• Crow bar?

• Software programme

Step Testing Module








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Step Testing Module


Planning the Test

• Obtain map of test area

• Identify boundary valves

• Number all valves on the map

• Plan sequence of steps

• Identify circulating valves and step

valves on the map

• Prove the test area

Step Testing Module


1- BV

2 - BV

3

4

5

7 – BV

8 – BV

10

11

12 - BV13

14

15

16

18

17

19

20

21

22 - BV

23

6

Obtain Map of Test Areanumber all valves and identify boundary valves

9 - BV

11

Step Testing Module


1- BV

2 - BV

3

4 - RV

5 - CV

7 – BV

8 – BV

10 - CV

11

12 - BV13 - RV

14

15 - CV

16

18

17

19

20

21

22 - BV

23

6 - RV

Plan Sequence of Stepswork from the furthest section towards the meter

Step 1

Step 2

9 - BVStep 3

Step 4

Step 5

Step 6

Step 7

Step 8

Step Testing Module


1- BV

2 - BV

3 - SV

4 - RD

5 - CV

7 – BV8 – BV

10 - CV

11 - SV

12 - BV13 - RD

14 - SV

15 - CV

16 -SV6

18 - SV

17 - SV

19 - SV

2 - SV0

21 - SV

22 - BV

23

6 - RV

Identify All Valves on the MapBVs, CVs, SVs, and RVs

9 - BV

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Step Testing Module


Prove Test Area• Operate and record status of boundary valves, count

number of turns, and shut all except last

• Check that circulating valves and step valves operate, record status and number of turns

• Carry out local proving if required

• Check that any redundant valves are open

• Open hydrant near final valve

• Shut final BV to check dry shut

• Return all valves to original status

• Report any unexpected results

Step Testing Module


Record Valve Status

No. Type Status Turns CC or AC Comments

1 B V S 9 CC m etal gate – double click

2 CV O 8 .5 C C probably soft faced

DMA No……………… Date………………….

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Step Testing Module








Step Testing Module


1. Decide area to be worked – DMA ‘league table’

2. Use VIS for quick wins

3. Break area down into smaller parts by:- step testing- sound survey

- noise logging

4. Correlate to give approximate noise location

5. Pinpoint and report

6. Repair

7. Return and re-log etc until clear

Step Testing as part of a Leakage Strategy

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Step Testing Module


1 – Decide area to be worked

• Monitor DMAs – monthly readings

• Arrange ‘league table’ of worst areas to

give priorities

• Monitor burst frequency

• Monitor customer complaints

• Use local knowledge


Step Testing Module


2 – VISVisual Inspection Survey

• Tour the area - best on foot

• Any obvious leaks – water above ground?

• Look for quick wins


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Step Testing Module


3 - Break Area Down into Smaller Parts

1. Step testing

2. Sound survey

3. Noise logging

3 possible methods:


Step Testing Module



Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

Step 8

Step 91 - SV

2 - BV

7 - BV

11 - BV14 - BV

6 - CV

9 - CV

5 - CV

10 - SV

14 - SV13 - SV

12 - SV13 - SV

15 - SV

16 - SV

4 - SV

3

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Step Testing Module


Record of Step Valve Operations

Valve No. Type Turns Time Open Time Shut Comments

DMA……………………………………………………………….. Date…………………………………………………………….

7 CV 13 none none already open

12 CV 12.5 00.14 none found throttled – left open

17 SV 12.5 00.27 05.15

12 SV 13 00.39 05.04

Step Testing Module


Disadvantages of Step Testing

• Relatively crude method – works best with large leaks

• Potential water quality problems

• Interrupts customers supply

• Usually requires night work

• Labour intensive

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Step Testing Module








Step Testing Module



1

2

3

4

5

6

7

8

9SV

BV

BV

BVBV

CV

CV

CV

SV

SVSV

SVSV

SV

SV

SV

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Step Testing Module


Flow Graph During Step Test

Valve nos. 1 2 3 4 5 6 7 8 9 9 8 7 6 5 4 3 2 1

T i m e

F l o w

Step Valve Step Valve

Opening Closure

Step Testing Module



1

2

3

4

5

6

7

8

9SV

BV

BV

BVBV

CV

CV

CV

SV

SVSV

SVSV

SV

SV

SV

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Step Testing Module


1- BV

2 - BV

3

4 - RV

5 - CV

7 – BV

8 – BV

10 - CV

11

12 - BV13 - RV

14

15 - CV

16

18

17

19

20

21

22 - BV

23

6 - RV


Step 1

Step 2

9 - BVStep 3

Step 4

Step 5

Step 6

Step 7

Step 8

Step Testing Module


Graph of Flow Logger Results

Flow

Time

Large step indicates leak location

Step 1 2 3 4 5 6 7 8

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Step Testing Module


1- BV

2 - BV

3

4 - RV

5 - CV

7 – BV

8 – BV

10 - CV

11

12 - BV13 - RV

14

15 - CV

16

18

17

19

20

21

22 - BV

23

6 - RV


Step 1

Step 2

9 - BVStep 3

Step 4

Step 5

Step 6

Step 7

Step 8

Step Testing Module


Time

Flow

Open & Close Sequence

Step Valve

Closure

Step Valve

Opening

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Step Testing Module


DMA 01 05/09/00 to 07/09/00

Minimum Night Flow = 28.13 Litres / second

Step Testing Module


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Step Testing Module


DMA 01 08/10/00 to 10/10/00

Minimum Night Flow = 18.75 Litres / Second

MNF Reduced by 9.38 Litres / Second

Step Testing Module


THANK YOUTHANK YOUTHANK YOUTHANK YOUTHANK YOUTHANK YOUTHANK YOUTHANK YOU

20step%20testing%20guidelines

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