Using Functional Analysis

This methodology could help “guide” your operations to the top.

Using FunctionalAnalysis For Improved

Troubleshooting

JULY 2005 www.pump-zone.com PUMPS & SYSTEMS22

The troubleshooting guide created by the Failure Modesand Effects Analysis (FMEA) portion of ReliabilityCentered Maintenance (RCM) activities is a valuable

side benefit of the process. Just how important can these guidesbe in building higher levels of equipment availability, and howdo you turn the FMEA into such a tool? Moreover, how cansmaller facilities accomplish the functional analysis necessary tocreate troubleshooting guides of their own?

The troubleshooting guide created by the Failure Modesand Effects Analysis (FMEA) portion of ReliabilityCentered Maintenance (RCM) activities is a valuable

side benefit of the process. Just how important can these guidesbe in building higher levels of equipment availability, and howdo you turn the FMEA into such a tool? Moreover, how cansmaller facilities accomplish the functional analysis necessary tocreate troubleshooting guides of their own?

Using FunctionalAnalysis For Improved

Troubleshooting By Bill Keeter, ARMS Reliability Engineers – USA, INC.

Seeking higher levels of equipment availability?

July05PUMPS&SYSp22-28 6/22/05 3:49 PM Page 22

Availability,Reliability,Maintainability

As shown in the following

equation, availability is a func-

tion of reliability and maintain-

ability. Two common measures

used for reliability and maintain-

ability are Mean Time Between

Failures (MTBF) and Mean

Time to Repair (MTTR).

There are three levels of

equipment availability (see

Figure 1). Intrinsic availability

describes the availability built

into the equipment. It assumes

that parts and resources are

immediately available in the

event of a failure—and that there

is no scheduled maintenance

downtime. Achievable availabili-

ty describes the availability of the

equipment when scheduled

maintenance and facility design

are considered. Operational

availability describes the level of

availability seen every day in the

facility. It takes into account all

the inefficiencies that exist in

day-to-day activities.

Top-level decisions impact-

ing all three types of availability,

as shown in Table 1 (on the next

page), are made throughout the

life of the facility.

Importance ofTroubleshootingGuides

The presence of trouble-

shooting guides has a major

impact on equipment availabili-

ty. The absence of such guides

means you may be relying on the

memories of craft personnel to

PUMPS & SYSTEMS www.pump-zone.com JULY 2005 23

Figure 1. The three levels of availability

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Availability = MTBFMTBF + MTTR

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JULY 2005 www.pump-zone.com PUMPS & SYSTEMS24

TTaabbllee 11.. TToopp LLeevveell DDeecciissiioonn FFaaccttoorrss ffoorr RReelliiaabbiilliittyy aanndd MMaaiinnttaaiinnaabbiilliittyy

FFiigguurree 22..AA ffuunnccttiioonnaall

ppllaanntt hhiieerraarrcchhyy

July05PUMPS&SYSp22-28 6/22/05 4:57 PM Page 24

JULY 2005 www.pump-zone.com PUMPS & SYSTEMS26

Figure 5.Pump failure modes

About ARMS Reliability EngineersSince opening its first office in Melbourne, Australia,10 years ago, ARMS Reliability Engineers has

been dedicated to helping businesses align their asset management strategies to their business goals by

using proven Reliability Engineering Methods and powerful simulation software. Today, from offices in

the U.S. and Canada, as well as Australia, ARMS provides support for Reliability Centered Maintenance,

Availability Simulation and Modeling and Rapid Reliability Assessment. The company’s staff of experi-

enced engineers comes from a wide variety of industries, including mining, petroleum, chemicals and

continuous process manufacturing.

For more information, you can visit ARMS on the web at www.armsus.com or

www.reliability.com.au. Or, depending on your location and needs, call one of the following numbers:

USA — (888) 673-8360

Canada — (250) 753-2426

Australia — +61 (3525) 553 57

July05PUMPS&SYSp22-28 6/22/05 3:52 PM Page 26

provide the most effective means

of fault-finding when a system

has failed. The problem with this

situation is twofold. People don’t

have infinite memories—and

craft personnel are often con-

fronted with failures in equip-

ment on which they have worked

infrequently.

Creating a BasicTroubleshootingGuide

A facility can be brokendown into a functional hierarchylike the one shown in Figure 2.Each item of equipment in thefacility has a function that can be

lost due to failures in its compo-nents. The purpose of the func-tional analysis is to determine thefailure modes or failed parts thathave created the loss of function.

The FunctionalAnalysis

If we think about equipmentfailures in terms of lost function,it quickly becomes apparent thata functional analysis of theequipment will yield a good basictroubleshooting guide for use bycraft personnel. Functional anal-ysis considers the structure, func-tions, functional failures and fail-ure modes of the equipment. Thefunctions of a pump might look

something like what is shown inFigure 3.

For each function there isone or more functional failuresthat describe the loss of the item’sintended functions. A list offunctional failures may be likethe ones shown in Figure 4.

For each functional failurethere will be one or more failuremodes, like those in Figure 5,that are represented by failedcomponents or operating errors,such as putting valves in thewrong position.

The pump failure modes arethe basis for the creation of thetroubleshooting guide. The func-tional structure can be put into a

PUMPS & SYSTEMS www.pump-zone.com JULY 2005 25

FFiigguurree 33..PPuummpp ffuunnccttiioonnss

FFiigguurree 44..FFuunnccttiioonnaall ffaaiilluurreess

July05PUMPS&SYSp22-28 6/22/05 4:57 PM Page 25

spreadsheet like the one in Table 2, so that field personnelcan filter on functional failure todetermine potential failuremodes or causes for the loss offunction. The result might besomething like Table 3.

Who Should Do theAnalysis?

Functional analysis of equip-

ment for the purpose of creating

troubleshooting guides can be

accomplished by a small team of

electrical and mechanical craft

personnel with just a minimal

amount of training and some

spreadsheet software. Failure

Modes and Effects Analysis for

the purpose of performing Reli-

ability Centered Maintenance

requires a team made up of

maintenance craft, operators, a

member of either maintenance

or operating supervision, and a

trained facilitator to ensure that

the chosen maintenance tasks

PUMPS & SYSTEMS www.pump-zone.com JULY 2005 27

Table 2. Unfiltered Failure Modes

Table 3. Failure Modes Filtered on Low Flow

Troubleshooting

guides will

save time

and generate

higher

availability

July05PUMPS&SYSp22-28 6/22/05 3:52 PM Page 27

prevent functional failures. RCM

requires a significant amount of

documentation and is best done

using sophisticated software that

will allow project information to

be stored in a single resource.

ConclusionTroubleshooting guides will

save time and generate higher

availability. They can be created

either as a side benefit of the

RCM process, or as the result of

a simple functional analysis de-

pending on the resources avail-

able to the facility. P&S

Bill Keeter, CMRP, is

President of ARMS Reliability

Engineers, USA, Inc., based in

Titusville, FL. During his 20 years

as a maintenance professional, he

has successfully implemented

maintenance improvement pro-

grams in a variety of operations.

His experience includes mainte-

nance leadership positions in the

US Military, the nuclear industry,

chemicals, paper converting and

plastic film manufacturing. He

also has provided training and

reliability consulting services to

process, mining and defense indus-

tries in the U.S., Europe and the

Middle East, and has developed

competency maps for Reliability,

Availability, and Maintainability

Engineering in the petroleum

industry. Keeter holds a B.S. in

Business Administration from

Coker College, as well as a B.S. in

Electrical Engineering from the

University of South Carolina. He

is a Certified Maintenance and

Reliability Professional. E-mail

him directly at bkeeter@-

armsus.com

JULY 2005 www.pump-zone.com PUMPS & SYSTEMS28

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