Piping Failure in Water Utilities

Piping Failure in Water Utilities 2011

0

Group Name Group 10 Student Name Student

Number Email Contact Phone

Contact Enji M. Lazuardi

07622805 [email protected] 0420907711

Hannibal Nasserie

07266553 [email protected] 0413535838

Mohammad Motamedi

06090613 [email protected] 0433930025

Wildan Pradana Yulianto Putra

07622848 [email protected] 0450882904

Piping Failure in Water Utilities ENB 432 – Asset Management and Maintenance Group Report

mailto:[email protected]





1

Work Plan Certificate The Work Plan shows the equitable distribution of work that everyone in the group is

satisfied with. Students as listed in the table certify that we worked equitably and

diligently on the research, preparation and submission of the report as per the Work

Plan.

This signature also certifies that this is our original work for this course and has not

been presented in any other course as part of any workplace task.

Group Name Group 10 Student Name Student

Number Responsibility (in the Report Part) Signature

Enji M. Lazuardi

07622805 Executive Summary, Introduction, Conclusion, Recommendation, FMECA Worksheet

Hannibal Nasserie

07266553 Description of Loss Production Event, Asset Management Issues Discussion, FMECA Worksheet

Mohammad Motamedi

06090613 Literature Review, FMECA and Risk Management Method Discussion, FMECA Worksheet

Wildan Pradana Yulianto Putra

07622848 Asset Management Issues Discussion, Loss Prevention and Mitigation Solution, FMECA Worksheet


2

Executive Summary

As we all know that the final report is about to manage the productive assets of the

water utility. We are concern to understand the faults and how they impact on the

production goals of the assets. The other things that concern are how these faults

can be prevented and how to maintain the productive assets of water utility.

After several discussions, we found out some of the faults in water utility. There are a

lot of things that affect the assets of water utility, such as; natural disaster, human

error, machinery failure, and failure in infrastructure that can cause a catastrophic

damage to the water utility component.

Therefore, the project that we are going to do for the final report is The Piping

Failure in Water Utilities. The reason we are doing this as our final report is failures

that occur in the pipeline needs a very expensive repairing cost, cutting water supply

to a large numbers of customers and sometimes producing millions of dollars in

damage. Understanding the causes of these failures is essential to preventing a

repetition on the same line.

We also want to describe briefly about the failure modes in the pipeline system in

water utility. We are going to describe the failure on the components of the pipeline

system, such as the fittings, valves, tapping, etc.

Last, some preventive measures will also be explained briefly in this report and some

action that must be done to maintain the water utility in its best performance.


3

Table of Contents

Work Plan Certificate ............................................................................................................................ 1

Executive Summary .............................................................................................................................. 2

Table of Contents .................................................................................................................................. 3

List of Table .......................................................................................................................................... 4

1.0 Introduction ..................................................................................................................................... 5

2.0 Literature Review ............................................................................................................................ 6

2.1 Inspection on FMECA Analysis ................................................................................................... 6

2.2 Inspection of Failures in Pipe ...................................................................................................... 7

2.3 The New SAE FMECA ................................................................................................................ 9

3.0 Description of Loss Production Event ........................................................................................... 10

4.0 FMECA and Risk Management Method Discussion ..................................................................... 12

4.1 Selection of Critical Components .............................................................................................. 12

4.2 Failure Mode and Effect Analysis .............................................................................................. 13

4.3 RPN and Corrective Actions ..................................................................................................... 13

4.4 FMECA discussion .................................................................................................................... 15

4.4.1 Fitting ................................................................................................................................. 15

4.4.2 Valves ................................................................................................................................ 15

4.4.3 Pipeline .............................................................................................................................. 16

4.4.4 Hydrants ............................................................................................................................. 16

4.4.5 Tapping Bands ................................................................................................................... 16

4.4.6 Pump .................................................................................................................................. 16

5.0 Asset Management Issues Discussion.......................................................................................... 17

5.1 Treatment of Piping Operation .................................................................................................. 17

5.2 Piping Main Repairs .................................................................................................................. 18

5.3 Source of Water Loss Due to Piping Leakage .......................................................................... 18

5.4 Risk Issues ................................................................................................................................ 19

6.0 Maintenance Management Issues Discussion .............................................................................. 20

7.0 Loss Prevention and Mitigation Solution Discussion ..................................................................... 23

7.1 Measurement of Unaccounted Water ........................................................................................ 23

7.2 Searching the Leakage ............................................................................................................. 24

7.3 Repair the leakage .................................................................................................................... 26

7.4 Measurement of Unaccounted Water (Second Measurement) ................................................. 28

8.0 Conclusion .................................................................................................................................... 30

9.0 Recommendation .......................................................................................................................... 31

10.0 Reference List ............................................................................................................................. 32


4

List of Table

FMECA Worksheet ............................................................................................................................. 34

RPN Format ........................................................................................................................................ 38


5

1.0 Introduction

Many water treatment companies run their company without knowing how to manage

their productive asset in the right way. They are aware that major disruptions to

production could be avoided if there was a better understanding of faults and failures

and how these could be addressed through better understanding and application of

asset management and maintenance practices. They realize that, for triple bottom

line reasons, they need to establish a new baseline of asset management protocols

within the organization.

In this project, we were given task to help the water treatment company to assist the

company itself to protect and maintain their valuable assets. Their concern is that

they do not understand faults and how they impact on the production goals of their

assets. So what we need is to work as a group and identify a major loss of

production or other risk that can happened to the company due to poor asset

management or maintenance practices. We have to analyse the loss the production

and by using the FMECA, we must identify at least 10 reasons for the event. In this

task we act as a consultant of water Utilities Company by providing the assistant of

managing the company by applying all methods and material that already given on

the course, and we also need to advise the client for what they need to do to prevent

or mitigate production loss events.


6

2.0 Literature Review

2.1 Inspection on FEMCA Analysis

In June 1996 in North Korea, the failure mode, effect and critically analysis

(FMECA) on mechanical Subsystems of Diesel Generator performed. In their report

it is discussed that for the implementation of RCM in nuclear power plant, three steps

are required; (1) Functional failure analysis (FFA), (2) Failure mode, effect and

criticality analysis (FMECA), (3) Logic tree analysis (LTA). It is stated that the

emergency or standby diesel generators in nuclear power plant take an important

role in the accident situations. In this report the FMECA results for six mechanical

subsystems of the diesel generators of nuclear power plants to improve the reliability

is performed. The six mechanical subsystems are (1) Starting air, (2) Lub oil, (3)

Governor, (4) Jacket water cooling, (5) Fuel, and (6) Engine subsystems. Generic

and plant-specific failure and maintenance records are reviewed to identify critical

components/ failure modes. Kim and Singh (1996).

In 2008 Jacques Virasak carried out the (FMECA) Analysis for a typical helicopter

main rotor Scissor bearing assembly. As he stated the main rotor scissor rotating

bearing assembly has only two functional failure modes:

1. Loss of its ability to allow relative motion between the rotating scissors and the

rotating swash plate.

2. Loss of its ability to accommodate various combinations of loads and motions

between the rotating scissors and the rotating swash plate.

The loss of relative motion between the rotating scissors and the rotating swash

plate will result in loss of the controllability of the main rotor, increase rotor vibration,

and decrease response to control input. The loss of load transmission from the

rotating scissor to the rotating swash plate will create an unbalanced rotor and

increase rotor vibration. Virasak (2008)


7

2.2 Inspection of Failures in Pipe

Pipe leakage in Australia is perceived to be a major problem by many water

authorities, both from an environmental point of view, as well as the associated costs

that are incurred due to overdesign of sewerage systems (to cope with wet weather

loads) and the treatment of additional potable water that is lost due to leakage.

Burn and Desilva (1999)

In many water distribution systems, a significant percentage of water is lost while in

transit from treatment plants to consumers. According to an inquiry made in 1991 by

the International Water Supply Association (IWSA), the amount of lost or

“unaccounted for water” (UFW) is typically in the range of 20–30% of production

(Cheong 1991). In the case of some systems, mostly older ones, the percentage of

lost water could be as high as 50% (AWWA 1987). In Australia and Canada the

problem is not quite as severe due to relatively newer systems. For example, water

authorities in Australia report UFW levels varying between 8 and 28% with the

average being 15% in 1997/98 (WSAA Facts 1998).

UFW is usually attributed to several causes including leakage, metering errors and

theft. According to the IWSA survey, however, leakage is the major cause. Water

leakage is a costly problem, not only in terms of wasting a precious natural resource

but also in economic terms. The primary economic loss due to leakage is the cost of

raw water, its treatment and transportation. Leakage inevitably also results in

secondary economic loss in the form of damage to the pipe network itself, e.g.

erosion of pipe bedding and major pipe breaks, and in the form of damage to

foundations of roads and buildings. Diminution of supply security as a result of a

reduction in water stored per capita may also represent a cost if such diminution

requires augmentation of supply to maintain security. Besides the environmental and

economic losses caused by leakage, leaky pipes create a public health risk, as every

leak is a potential entry point for contaminants if a pressure drop occurs in the

system. Burn and Desilva (1999).

Leakage occurs at both designed overflow points and from joints and cracks in

pipelines. The purpose of designed overflow structures is to relieve pressure in pipes


8

at controlled locations, i.e. adjacent to storm water drains, so that overflows do not

occur at private residences or businesses or environmentally sensitive locations.

They function when pipe capacity is exceeded due to infiltration or blockage during

storms. Except in the most poorly designed systems, they do not function in dry

weather when no blockage exists. Cracks, on the other hand, may function at any

time, releasing sewerage into local waterways or soils (exfiltration) or allowing storm-

flow to enter sewers (infiltration), leading to pressure build up and possible overflows

during heavy weather.

The environmental impacts of leakage include impacts on ecosystems, aesthetic

impacts and human health risk. These impacts, however, need to be considered in

context. The Sydney Water Corporation has recently completed a series of

Environmental Impact Statements (EISs) looking, in part, at the environmental effect

of overflows and sewer system leakage (Sydney Water Corporation 1998). These

documents listed the potential environmental effects of overflows as being:

Eutrophication as a result of nutrient-rich sewage reaching receiving waters.

Toxicant impacts (especially chlorpyrifos and dieldren (respectively,

organophosphate and organochlorine pesticides) copper and ammonia).

Faecal coliforms; oxygen reduction in receiving waters (which may lead to fish

kills and other impacts).

Increased turbidity and increased sediment loads (and litter).

Each of these has potentially serious impacts. Their actual environmental effect

depends, however, on the volume and concentration discharged and the receiving

water environment. So too must the general environmental conditions at the time of

discharge be considered (i.e. rain or dry weather).

The key point to stress, however, is that quantification of leakage impacts and, by

expansion, the degree of corrective action required would depend on the situation

and the degree of risk we judge acceptable. That leakage causes environmental

impacts on receiving waters, land (e.g. water logging and nutrient enrichment),

recreational amenity, flora and fauna, and air quality is, however, undeniable.

Burn and Desilva (1999)


9

2.3 The New SAE FMECA

In regard to avoid some of the mathematical difficulties of the RPN analysis, the new

SAE FMECA has accomplished through three major changes.

The new standard describes the FMECA procedure as a process to be

used throughout the product development cycle, rather than as a task

to be done after the design is complete. It emphasizes the role of

functional and interfaces FMECAs as well as that of the traditional

piece part FMECA.

The concept of “failure mode equivalence” enables failure modes that

have equivalent effects to be analyzed together and reduces much of

the duplicative work generated by traditional component-by-component

fault analyses. This concept allows the analyses of functional failure

modes done early in the design process to be carried over to the

effects of interface and piece-part failure modes analyzed later in the

design.

Criticality is assessed using a Pareto ranking procedure based on the

probability and the severity of the failure mode. This is more broadly

applicable than the use of criticality numbers SAE J1739. Bowles

(1998)


10

3.0 Description of Loss Production Event

FMECA Description of loss production is an estimate of damage inflicted on an

industry in terms of quantities of finished products denied the enemy from the

moment of attack through the period of reconstruction to the point when full

production is resumed. This event can possibly cause by faults or failures due to

many reason (mostly poor asset management). Loss production may also occur

because of human error (like causing fire or contamination of water supply) or

natural disaster (such as volcanoes, flood, etc). There are several reasons of faults

or failures that may occur in this water utility. These failures if not being taken

seriously will cause greater damage to environment and will cost loss production,

even harm human being.

1. Breakdown in the water treatment system

2. Contamination of water supply

3. Clusters of illness potentially due to the former

4. Limitation of water supply due to droughts

5. Piping leakage due to failure of material

6. Disaster such as petrochemical accident

7. Infrastructure damage due to accident like fire

8. Corrosion in pipe, causing contamination to community’s water supply

9. Machinery damage due to poor asset maintenance

10. Infrastructure and machinery damage due to major natural disasters such as

volcanoes, flooding, insect plagues, etc

Piping failure in water utilities is chosen as the main topic, therefore this report will

mainly discuss about piping failure. The main reason why it is chosen is because

piping failure waste both money and a precious natural resource, and they create a

public health risk. The primary economic loss is the cost of raw water, its treatment,

and its transportation. Piping failure leads to additional economic loss in the form of

damage to the pipe network itself, e.g., erosion of pipe bedding and pipe breaks, and

to the foundations of roads and buildings (Figure 1). Risk to public health can be


11

caused by contaminants entering the pipe through leak openings if water pressure in

the distribution system is lost.

Figure 3. Leakage leads to damage to the pipe network, e.g., erosion of pipe bedding and

pipe breaks, and to foundations of roads and buildings.


12

4.0 FMECA and Risk Management Method Discussion

4.1 Selection of Critical Components

In terms of critical components, a few critical components in pipe are identified by

researching through the exits data of failures and maintenance in pipe.

Critical components are known as those kinds of components that have a critical failure

mode. A component failure mode having significant operational, safety or maintenance

effects that warrants the selection of maintenance tasks to prevent the failure mode from

occurring. Figure below shows logical diagram for critical component selection.

Consequences of the

failure mode

Impact on Safety?

Impact on Generation?

Impact on Cost of

Repairs?

Non-critical Components Critical Component

Yes

Yes

Yes

No

No

No


13

4.2 Failure Mode and Effect Analysis

Failure modes are the way in which a failure is observed, usually a description of

how a failure occurs. General types of failure modes are: I – premature operation, II

– failure to operate at a prescribed time, III – failure to cease operation at a

prescribed time, IV – failure during operations, V – intermittent failure, VI – and

dormant failure.

Once the failures are determined they need to be catalogued and analysed in a very

systematic and robust way. The three main analysis methods are: qualitative,

quantitative and risk priority number.

Failure effects are identified and inserted in each row of the FMECA matrix by taking

into consideration the criteria identified in the ground rules. Effects are categorized

as: I – local, II – next higher and III – end levels. System level effects would then

include system failures, degraded operation, system status failure, or no immediate

effect.

4.3 RPN and Corrective Actions

Risk Priority Number (RPN) is a measure used when assessing risk to help identify

critical failure modes associated with your design or process. It is rated using the

probability of the failure occurring, its severity and the unlikelihood of its detection.

These variables are rated with a number from 1 to 10 with 10 being the worst case.

The RPN values range from 1 (absolute best) to 1000 (absolute worst). The graphic

below shows the factors that make up the RPN and how it is calculated for each

failure mode. The risk priority number rating is found using the following formula:

Severity (S) - Severity is a numerical subjective estimate of how severe the customer

(next user) or end user will perceive the EFFECT of a failure.

Occurrence (O) - Occurrence is a numerical subjective estimate of the likelihood that

the cause, if it occurs, will produce the failure mode and its particular effect.


14

Detection (D) - Detection is a numerical subjective estimate of the effectiveness of

the controls to prevent or detect the cause or failure mode before the failure reaches

the customer. The assumption is that the cause has occurred.

RPNs have no value or meaning in themselves. Although it is true that larger RPN

values normally indicate more critical failure modes, this is not always the case. For

example, here we have three cases where the RPNs are identical, but clearly the

second case would warrant the most attention.

Figure 4.a. RPN 1

As a general rule, any failure mode that has an effect resulting in a severity 9 or 10

would have top priority. Severity is given the most weight when assessing risk. Next,

the Severity and Occurrence (S x O) combination would be considered, since this in

effect, represents the criticality.

Below, the failure modes with the lowest RPN values are actually the most critical. It

shows that the first line is most critical even though it has the lowest RPN value, then

the second line, and finally the third line.

Figure 4.b.: RPN 2


15

4.4 FMECA discussion

Critical components/ failure modes of pipe subsystem are identified as below:

Leak at seal or gasket on fittings, valves, hydrants and tapping bands.

Internal corrosion on fitting and hydrants.

Ball valve jammed.

Rusty pipeline and pipe leakage on pipelines.

Spindle failure on gate valves

Over flow and over heat on pump.

4.4.1 Fitting

Fittings are used in pipeline systems in order to connect straight pipe or tubing

sections. It has various connections such as threaded pipe, solvent welding,

compression fittings, and flared fittings. It also can be made from many materials

provided by the nature, but most often it is the same base material as the pipe or

tubing being connected, for example copper, steel, brass, or PVC. Fittings have

many types, from reducer, elbow, tee, cap, plug, and nipple.

4.4.2 Valves

The most common control failure in the Pipe system is valve failure. Valves fail to

operate most frequently by not closing completely or sticking open. Dirt or water in

the air starting system may cause this to happen. Water transports dirt and metal

particles and creates rust. The valve may stuck because of dirt and/ or water but

additionally is susceptible to overheating and coil failure. If, there is no maintenance

for valves, then there is no need to find out the cause of failure. Only replacement is

the solution. So time should be fixed according to old failure and maintenance

records.


16

4.4.3 Pipeline

Polluted pipeline and leakage in pipe lines are two failure modes that can be occur

due to improper material as well as improper insulation. The effects of these failure

modes can be led up to stop the water supply or/and contaminate the water. The

severity of these failure modes is high and the RPN number is the highest. Highest

RPN number shows that these failure modes are the most critical failures.

4.4.4 Hydrants

Hydrant is an outlet from water main often consisting of an upright pipe with a valve

attached from water can be tapped. The most frequent hydrants failure is internal

corrosion. Internal corrosion can occur due to aging and improper material. The end

failure effect is having no water supply, so it can be classified as a critical failure

mode. Acoustic leakage detector method can be used to prevent this failure in

hydrant.

4.4.5 Tapping Bands

Tapping bands provide an economical and effective way of tapping into new or

existing pipelines. Leak at seal or gasket is the failure modes that can be occur due

to improper gasket or sealant. Loss of water can be the most important effect of

these failures on the pipeline.

4.4.6 Pump

We could assume that pump is a third-party component in the pipeline system, but it

is still an important component thus it pumps the water and distribute the water to the

consumer. The two primary failure modes of pumps over flowing and overheating of

the pump. Lack of lubrication in the pump can cause the overheating while wrong

pump setting can make overflow in the pipeline. Other reason that can make an

overflow is the pump breakdown (e.g. due to age) thus gives the wrong pressure to

the water. So we have to check the usage time of the pump and check periodically

the pressure that produce by the pump.


17

5.0 Asset Management Issues Discussion

There are several issues regarding of asset management for water utility system.

Infrastructures such as tank storage, source of water and of course piping system to

distribute the water need to be taken seriously. We need to do as best as we can to

prevent bad things that will happen to provide clean drinking water for the protection

of public health against cholera and other water borne diseases for examples. Later

challenges included:

Securing sufficient quantities of water often through the building of dams

Providing satisfactory water distribution systems

Building sewerage systems to protect the environment and public health

Responding to the growing expectations of the community and the impact of

competition policy

Water authorities were generally invested with strong powers and were, by design,

fairly independent from governments. This independence was thought to be

necessary to ensure that the building of long-life infrastructure was not compromised

by shorter-term considerations. This chapter will mainly discuss about some issues

that mainly occur in water utilities regarding to piping failure such as, treatment of

piping operation, piping main repairs, the source of water loss due to piping leakage

and risk issues that mostly occur from implementing a water loss management.

5.1 Treatment of Piping Operation

A number of factors can contribute to the condition of water pipes and cause them to

crack, break or leak, including ground movement, corrosion, and external traffic

loading. This will affect the quality of water source. It is important to keep regular

maintenance for the piping system to prevent such a failure. Maintenance can also

be tricky. It can cost lots of money if we don’t do it as the procedure. On the other

hand, if we didn’t do regular maintenance, we can’t be sure whether the piping

system is still in good condition or not. We will briefly discuss about maintenance

process in the next chapter.


18

5.2 Piping Main Repairs

Once we done the maintenance, we can actually found if there is any failure in that

pipe. Regarding to the failure, if it doesn’t do much damage to the pipe, we can try to

repair the pipe instead of replacing it. Replacing pipe can cost the company more so

if the failure is not too serious then repair seems to be the best option. Repairing is

not as easy as it seems. If it doesn’t do right as the procedure, it can cost lots of

money from the company. Moreover, bad repairing can cause more failures and

eventually producing malfunction to the entire piping system.

5.3 Source of Water Loss Due to Piping Leakage

System water loss can be over 30% in some schemes. Sources of water loss are illustrated

below

Figure 5. Schematic diagram of Sources of water loss


19

As we can see from the diagram above, leakage can produce real losses. It is

something that the company would like to avoid. For example, if the leakage

happens it will affect the water source. The water source will be gone fast, causing

drought in drain area during dry season, or worse; contamination. If the contaminate

water reach the consumer and causing public disease such as cholera and other

water borne diseases, surely it would become great disaster for people. That is why

real losses have to be taken seriously to prevent such a disaster.

5.4 Risk Issues

Risk is very closely related to reliability and product safety. Risk is defined as an

economic aspect of safety as:

Risk$ = probability of a failure*exposure*$consequences

The probabililty of failure (POF) and exposure elements in the calculation lie

between 0 and 1. Consequence $s for costs vary from 1 up to and including X

millions of dollars. This statement of risk is the expected monetary value for an event

or set of events. For business management, risk could hardly be absolutely

eliminated. No matter how hard we try to prevent such a loss, there always risk

issues that need to be considered. However, most of the risk can be avoided by the

implementation of effective strategies. The top priority of the company is to survive.

In considering about how to profit from the business operation, the company must

also take account of preventing loss and confronting unexpected risk. Potential risks

associated with implementation of piping leakage strategies include:

Quality of raw data;

Implementation of sub-optimal water loss reduction strategies; and

Sustaining the levels of water loss reduction.


20

6.0 Maintenance Management Issues Discussion

Water supply in general is a complex structure of different factors, i.e. .production,

transport and distribution. Within this structure, pipe networks represent one of the

largest infrastructure assets of industrial society. The management of potable water

networks encompasses all activities principally concerned with: the supply of water

from the outlet of the water treatment works to the customers’ taps; and all related

functions, including water resources provision, water treatment, customer relations,

business planning, human resources and information services.

Thus, maintenance planning designed to meet current and future system demands

of flow rate and pressure head, and to reduce future maintenance costs, represents

an integral part of a network management strategy.

Selection of the maintenance strategy for a water distribution system is a difficult

problem due to: a large number of system components, e.g. pipes, pumps, valves,

meters, etc.; dynamic evolution of the failure mode of deteriorating water pipe; the

existence of a certain degree of coupling among the various system components;

limited resources available for maintenance activities; and the associated difficulty in

quantifying many of the benefits and costs.

The problem has often been treated as a complex optimization problem with several

possible objectives used in isolation or combined, e.g. maximization of reliability,

minimization of downtime and the minimization of total maintenance costs.

A few analytic and optimization approaches have been published to assist in making

pipe replacement, relining or reinforcement decisions. Shamir and Howard (1979)

proposed an analytic model for making pipe replacement decisions based on pipe

breakage history and the cost of repairing and replacing pipes. They claim that the

optimal time for replacing existing pipes can be obtained using this methodology.


21

There are 4 most common issues that come up when maintain the water utilities;

1. On the surface — dealing with utility cuts

Surveys show that pavement restoration following underground work on

utilities is a major challenge facing municipalities and utility providers, with

huge cost implications for both. Carelessness and lack of attention will lead to

accidents related to water pipes can lead to water stoppage and flooding in

large areas, directly affecting civic life (and causing damage).

Figure 6. Excavator Burst a Pipeline in Hong Kong

2. A seal in time — road maintenance

Preventive maintenance is the key to delaying road reconstruction, and

sealing cracks as they occur is an increasingly important way to do this.

Effective crack sealing can increase pavement service life by 10-20 percent

and save municipalities more than $800 million over the next 20 years.

“Effective” is the key.

3. Going underground — managing large sewers

The failure of deeply buried large sewer structures (more than 900 mm in

diameter) can have enormous consequences, both physically and financially.

And maintaining these systems can be equally difficult and expensive.

4. The sound of running water — locating leaky pipes

Most of water distribution has a lost on its transit between treatment facilities

and consumer. The major cause of thing is usually a leakage. Leakages


22

usually caused by one of any failure occur on the piping system. In order to do

maintenance for this leakage, Water Company could use an acoustic device

to locate leaks, but as any other devices, it has a limitation, particularly in the

detection of plastic pipe, large diameter, or pipe in clay soils or below the

water table. To support this limitation, the use of combined leak detection

should be used.


23

7.0 Loss Prevention and Mitigation Solution Discussion

As described before, we can assume that all of the failure types lead to the piping

leakage that can produce a catastrophic damage to the pipeline system thus can

stop the distribution and of water. For this reason we need some preventive measure

to reduce the probability of failure. With some good preventive measures we also

can reduce the cost of maintenance of the water utility.

The main idea to prevent the loss of water is to search for the leakage on the

pipeline system and fix it immediately. We can make a very good pipeline system

design with a best precision, but in the actual situation there is still some leakages

even a small one. This figure shows the steps that can prevent the leakage that can

leads to massive loss of water, they are:

7.1 Measurement of Unaccounted Water

There is no current comprehensive national regulatory policy that limits the amount

of water loss from a public water supply’s distribution system. Most states, however,

do have policies and regulations that address excessive distribution system water

losses. The policies vary among states, but most set limits that fall within the range

Start

Measurement of Unaccounted Water Volume

(First Measurement)

Searching for Leaking Spot

Repair the Leakage

Measurement of Unaccounted Water Volume

(Second Measurement)

Done

Below permissible

volume

Above permissible

volume

Below permissible volume

Above permissible volume


24

of 10% to 15% as the maximum acceptable value for the amount of water that is lost

or “unaccounted-for.”

Neither the term “unaccounted-for-water” nor the use of percentages as measures of

water loss is sufficient to completely describe the nature and extent of losses in

water utility operations. Unaccounted-for-water is a term that has been historically

used in the United States to quantify water utility losses. Unaccounted-for-water,

expressed as,

We can assume that if the unaccounted-for-water above 10% so we have to

continue with the second step that is searching the leakage.

7.2 Searching the Leakage

There are several methods that can be use to find the leakage in pipeline system,

they are:

Method by residue chlorine

Method by electric conductivity

Method by pH value

Method by water temperature

Method by trihalomethane

Method by acoustic leakage detector

Nowadays, the most common used method is the acoustic leakage detector. Water

leaks in underground, pressurized pipes may make many different sounds:

• “Hiss” or “Whoosh” from pipe vibration and orifice pressure reduction

• “Splashing” or “Babbling Brook” sounds from water flowing around the pipe

• Rapid “beating/thumping” sounds from water spray striking the wall of the soil

cavity

• Small “clinking” sounds of stones and pebbles bouncing off the pipe


25

The “Hiss” or “Whoosh” sound, which often sounds like constant static noise, is the

only one, which is always present for leaks in pipes with 30 psi or higher water

pressure. The other sounds may or may not be present, and usually they are not as

loud. So we decide whether there is leak or no, by listening the “Hiss” or “Whoosh”.

The device that used in this method is the acoustic leakage detector. It can receive

the sound from the underground where the pipes located.

Figure 7.2.a. Man using the leakage detector

First thing that we have to do in searching for leakage is to survey in every hydrant,

valve, and service line is a possible location to hear the sounds of water leaks when

there is no obvious evidence like water flowing on the streets. Since the sounds

travel on the pipe walls better than through the soil, always listen at the hydrants,

valves, and meters first. As you get closer to the leak, the sound gets louder. Finally,

decide which two of these locations are the loudest. After this we can start with water

leak pinpointing.


26

Figure 7.2.b. Listening leak sounds on hydrant Figure 7.2.c. Listening leak

sounds on meter

Water Leak Pinpointing is the term applied to the process of pinpointing the exact

leak location. For Acoustic Leak Detection, the exact leak location is usually the spot

where the leak sounds are the loudest.

Figure 7.2.d. Pinpointing

This activity can also be done regularly, for example every month check the leaking

sound, so we can prevent the loss of water.

7.3 Repair the leakage

After we find the exact spot of leakage we can determine the leaking cause. It can be

because of:


27

Corrosion

o Water and other pollutant can cause the pipe corrosion.

Piece blown out

o Removal of a piece of pipe wall. This form of failure is brittle in nature.

Size can be vary depend on pipe material but generally greater than

100 cm2.

Broken back (circumferential break)

o A single crack extending part or full way around the pipe

circumference.

Longitudinal Split

o A crack along the pipe axis. The length can vary from a few mm to the

full length of the pipe.

Pipe rupture or tear

o A rupture to the pipe wall where the material tears and creates an

opening in the pipe wall. This form of failure is ductile in nature.

Leaking joint

o Water leakage through the joint. Often a result of a displaced rubber

ring joint or debris left in the ring groove during installation of RRJ

pipes. Lead jointed steel pipe can also leak.

Aging

o Due to long period, pipe experience many interference that can reduce

the performance itself.

Some of preventives measure can be taken before the leakage bigger and break the

pipeline system, such as change the components that leak especially at joints or

fittings, we can also use the anti-corrosive material to reduce the probability of

rusted, or we can use Split Repair Sleeve like in Osaka, Japan, they used this sleeve


28

to cover up the leaking pipe so they can prevent the loss of water.

7.4 Measurement of Unaccounted Water (Second Measurement)

We again measure the unaccounted for water like the first one, then the number

decides do we have to look for the leakage again or finished up the preventive

measure of loss of water.

With this method we can prevent the loss of water and reduce the cost. It can be

very expensive if the pipeline system damage catastrophically, it can stop the water

distribution, the water quality, also the traffic on the ground if the water blows up.

Figure 7.3.a. Pipe leakage in Osaka pipeline

Figure 7.3.b. The leakage covered with the Sleeve split

sleeve


29

Figure 7.4. Pipeline damage that have to be prevented


30

8.0 Conclusion

In this report, the failure mode effect and critically analysis of the pipeline in common

water utilities. It describes of piping failure, especially on leakage on the basis of

functional analysis for pipeline itself. This report should be helpful to select the

appropriate maintenance step and prevention method to reduce any bigger losses.

With the right method of maintenance and prevention, the water distribution will not

be disturbed in a big scale.

To summarise, we think that although many of the risks that initially faced the system

have now been resolved, some risks still exist. However, with the contingency plans

(particularly the standalone system) that we have put into action, we feel that these

risks can be minimised.

We feel that risk management is a useful technique and it would have been useful to

have learnt more about it nearer to the beginning of the project rather than at this

late stage. Still, we feel that even now it can be useful and we will try to use it to

good effect in the remaining six weeks of the project.

For further preventive action, we also have some recommendation for you that will

be written in another part of this report.


31

9.0 Recommendation

From the report above we understand that every business has it own risk. To reduce

the chance on getting a bigger loses from your asset, you need to do some

prevention for your assets. In this case, you must protect your asset from piping

failure that can cause a catastrophic damage that have a negative impact to your

business. So, our recommendation is that you must protect your asset by any

means.

To prevent the water loses, you can do a periodically maintenance for your

asset, for example you can use an acoustic leakage detector to find any leak

along the pipeline. The faster you know the leakage location, the more loss

can be reduced.

You need to calculate the usage time of each of your asset so that you can

plan to spend some of your money on renewing your asset. For example, pipe

has it owns lifetime, and pipe needs to be replaced by the end of its lifetime.

Calculating this renewal cost can reduce your chance from getting trouble

from aging.

It is also good to prevent unwanted accident during maintenance, like we

have mentioned before, you need to pay more attention to heavy machinery

that used for maintenance purposes.

We also recommending to you to increase the security for the facility, to

prevent the illegal usage of your asset. For example, irresponsible people

may take out the water without your permission due to low supervision. This

kind of illegal usage of this facility can increase in water loses that lead to

bigger losses for your assets.


32

10.0 Reference List

seqwater.(2000). seqwater.Available: ttp://www.seqwater.com.au/public/home.

Last accessed 13th May 2011.

AWE. (2010). Water loss control. Available:

http://www.allianceforwaterefficiency.org/Water_Loss_Control_-_What_Can_Be_Done.aspx.

Last accessed 13th May 2011.

NSW government. (2004). NSW health responce protocol. Available:

http://www.health.nsw.gov.au/publichealth/environment/water/response.asp. Last accessed

13th May 2011.

Quiggin, John. (2000). Urban water supply in Australia: the option of diverting water from

irrigation. School of Economics and School of Political Science and International Studies

University of Queensland

Sydney Water Corporation (1998), Licensing Sewerage Overflows, Environmental Impact

Statement: Volume 1 – Sydney-wide Overview.

AWWA (1990), Water Audits and Leak Detection, Manual of Water Supply Practices No. M36,

American Water Works Association, Denver, CO.

Drucker, Professor Peter F. (1999). The End of Distance. Sydney Morning Herald, 18th November,

1999 (reproduced from the Atlantic Monthly).


33

Horvath, B., Leakage Management: Assessing the effect of pressure reduction on losses from water

distribution systems, Urban Water Research Association of Australia, Research Report No. 5,

December 1989.


34

Asset: WATER UTILITIES' PIPELINE

Function

SUFFICIENT WATER SUPPLY

Notes: RPN=Severity X Occurrence X Detection

System:

WATER UTILITIES

Function #:

SUPPLY FRESH WATER

Sub-system:

PIPELINE Analyst:

a b c d e f g h i j k l m n o p q

Failure Mode Failure Cause Failure Effects Operational Indication

Ref

Item Functio

n Letter

Description

Numbe

r

Description

Local Next

Higher End Normal Abnormal

Failed

Severity

Occurrence

Detection

RPN

Action

1 FITTIN

GS

CONNECTING PIPELI

NE

A

LEAK AT

SEAL OR

GASKET

1 IMPROPE

R SEALANT

WATER DRIPPING

FROM LEAKAGE

WATER LOSS

INCREASED

NO WATER COULD SUPPLI

ED

SUFFICIENT

WATER SUPPLY

LESS WATER

SUPPLIED

NO WATER SUPPLIED

6 4 4 96 USE THE

RIGHT SEALANT

2 2

IMPROPER

INSTALLATION

WATER DRIPPING

FROM LEAKAGE

WATER LOSS

INCREASED


ED

SUFFICIENT

WATER SUPPLY

LESS WATER

SUPPLIED

NO WATER SUPPLIED

6 4 3 72

FOLLOW THE

STANDARD

PROCEDURE OF

INSTALLATION

3 B

INTERNAL

CORROSION

1 AGING CONTAMINATING WATER

CAN CAUSE MAJOR

LEAKAGE


ED

SUFFICIENT

WATER SUPPLY

WATER SUPPLY

CONTAMINATED

BAD WATER QU

ALITY

9 6 3 162

CHECK THE TIME-USAGE OF

THE COMPONE

NT

4 2 IMPROPE

R MATERIAL

CONTAMINATING WATER

CAN CAUSE MAJOR

LEAKAGE


ED

SUFFICIENT

WATER SUPPLY

WATER SUPPLY

CONTAMINATED

BAD WATER QU

ALITY

9 6 4 216

USE ANTI-CORROSI

VE MATERIAL


35

5 VALV

ES

REGULATING THE

FLOW

A

LEAK AT

SEAL OR

GASKET

1

IMPROPER GASKET

OR SEALANT

WATER DRIPPING

FROM LEAKAGE

WATER LOSS

INCREASED


ED

SUFFICIENT

WATER SUPPLY

LESS WATER

SUPPLIED

NO WATER SUPPLIED

6 4 4 96

USE THE RIGHT

SEALANT/GASKET

6 B

BALL VALVE JAMME

D

1

ACCUMULATED

POLLUTION

VALVE DIFFICULT

TO OPERATE

THE VALVE GOT

STUCK


ED

VALVE OPERAT

E REGULA

RLY

NO FLOW THROUGH THE VALVE

NO WATER SUPPLIED

6 4 4 96

CLEAN UP THE

COMPONENT

7 2 MISSALIG

NMENT

VALVE DIFFICULT

TO OPERATE

THE VALVE GOT

STUCK


ED

VALVE OPERAT

E REGULA

RLY

NO FLOW THROUGH THE VALVE

NO WATER SUPPLIED

6 4 4 96

FOLLOW THE

STANDARD

PROCEDURE OF

INSTALLATION

8 PIPEL

INE

WATER DRAINAGE

A PIPELINE GOT RUSTY

1 IMPROPE

R MATERIAL

CONTAMINATING WATER

CAN CAUSE MAJOR

DAMAGE TO THE

PIPE

BROKEN PIPE

SUPPLYING THE WATER

HALT THE WATER SUPPLY

PROCESS

NO WATER SUPPLIED

8 5 3 120

USE ANTI-CORROSI

VE

9 2

IMPROPER

INSULATION

CONTAMINATING WATER

CAN CAUSE MAJOR

DAMAGE TO THE

PIPE

BROKEN PIPE

SUPPLYING THE WATER


PROCESS

NO WATER SUPPLIED

9 7 6 378

USE THE RIGHT

INSULATION

METHOD

10

B

PIPE LEAKA

GE 1

IMPROPER

INSTALLATION

DECREASING

WATER FLOW

CAUSING MAJOR

DAMAGE TO

PIPELINE

BROKEN PIPE

SUPPLYING THE WATER


PROCESS

NO WATER SUPPLIED

9 7 6 378

FOLLOW THE

STANDARD

PROCEDURE OF

INSTALLATION


36

11

2 ACCIDENT

AL EVENTS

DECREASING

WATER FLOW

CAUSING MAJOR

DAMAGE TO

PIPELINE

BROKEN PIPE

SUPPLYING THE WATER


PROCESS

NO WATER SUPPLIED

6 4 4 96

INCREASE PROTECTI

ON TO PIPELINE

12

GATE VALV

ES

USED IN LOW PRESS

PIPE

A

LEAK AT

SEAL OR

GASKET

1

IMPROPER GASKET

OR SEALANT

WATER DRIPPING

FROM LEAKAGE

WATER LOSS

INCREASED


ED

SUFFICIENT

WATER SUPPLY

LESS WATER

SUPPLIED

NO WATER SUPPLIED

6 5 3 90

USE THE RIGHT

SEALANT /GASKET

13

B

SPINDLE

FAILURE

1 BEARING FAILURE

UNUSUAL NOISE

DEACREASE IN TOOL LIFE

SCRAP

SPINDLE OPERAT

S REGULA

RLY

6 5 3 90

CHECK THE TIME-USAGE OF BEARING

14

HYDRANTS

SUPPLY

ADEQUATE

WATER

A

LEAK AT

SEAL OR

GASKET

1

IMPROPER GASKET

OR SEALANT

WATER DRIPPING

FROM LEAKAGE

WATER LOSS

INCREASED


ED

SUFFICIENT

WATER SUPPLY

LESS WATER

SUPPLIED

NO WATER SUPPLIED

6 2 2 24

USE THE RIGHT

SEALANT / GASKET

15

B

INTERNAL

CORROSION

1 AGING CONTAMINATING WATER

MAJURE LEAKAGE


ED

SUFFICIENT

WATER SUPPLY

WATER SUPPLY

CONTAMINATED

BAD WATER QU

ALITY

9 6 6 324

CHECK THE TIME-USAGE OF

THE COMPONE

NT

16

2 TEMPERA

TURE

CONTAMINATING

THE WATER

BROKEN

HYDRANTS

GOOD WATER DISTRIBUTION

AFFECT THE

WATER QUALITY

STOP

THE WATER SUPPLY

7 3 3 63

USE ANTI-CORROSI

VE MATERIAL


37

17

3 OXIDATIO

N

CONTAMINATING

THE WATER

BROKEN

HYDRANTS


AFFECT THE

WATER QUALITY

STOP

THE WATER SUPPLY

7 3 3 63

USE ANTI-CORROSI

VE MATERIAL

18

TAPPING

BANDS

GIRIPPING THE PIPE AND

PROVIDING THE

WATERTIGHT SEAL

A

LEAK AT

SEAL OR

GASKET

1

IMPROPER GASKET

OR SEALANT

WATER DRIPPING

FROM LEAKAGE

WATER LOSS

INCREASED


ED

SUFFICIENT

WATER SUPPLY

LESS WATER

SUPPLIED

NO WATER SUPPLIED

6 4 4 96

USE THE RIGHT

SEALANT AND

INSTALL IT

CORRECTLY

19

PUMP PUMP THE

WATER A

OVERFLOW

1 REGULAT

OR FAILURE

STRESS ON PIPE

OVER STRESS ON PIPE

WATER COME OUT

FROM THE PIPE

GOOD WATER FLOW

TOO MUCH FLOW

INSIDE THE PIPE

WASTE ON WATER

9 6 6 324

CHECK THE TIME-USAGE OF THE PUMP

20

B OVER HEAT

1 LACK OF

LUBRICATION

COMPON

ENTS FAILURE

PUMP STOP

WORKING


REDUCE WATER

DISTRIBUTION

NO WATER SUPPLY

9 6 6 324

CHECK THE

PERFORMANCE OF

THE PUMP REGULAR

LY


38

RPN Format

Date post:	12-Mar-2015
Category:	Documents
Upload:	enji-m-lazuardi
View:	78 times
Download:	5 times

Piping Failure in Water Utilities

Documents