misconceptions of maintenance and reliability - … · the ispe good practice guide on maintenance2...

March 2013

Misconceptions of

Maintenance and

Reliability A Biopharmaceutical Industry Survival Guide

BPOG Reliability Team

Misconceptions of Maintenance and Reliability A Biopharmaceutical Industry Survival Guide

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Authors and Reviewers

Authors:

Gerard Clarke, Reliability Engineer at Pfizer

James Baillargeon, Instruments and Control Manager at MedImmune

Paul Boles, Senior Technical Manager GMP Manufacturing at Genentech

Rob Christman, Associate Director Global Reliability Engineering at Genzyme

Steve Jones, Director at BioPhorum Operations Group

Reviewers:

Ken Trotta, Maintenance and Reliability Engineering at Bayer Healthcare

Keith Scruggs, Director of Engineering at Baxter Healthcare

BioPhorum Operations Group

At the BioPhorum Operations Group our mission is to CONNECT biopharmaceutical

organizations, provide an effective environment for the community to COLLABORATE on

shared issues and ACCELERATE improvement across the industry. BPOG currently consists of

over 500 active participants from 18 member companies: Abbvie; Amgen; Baxter; Bayer;

Biogen Idec; BMS; Gallus Pharmaceuticals; Genentech; Genzyme; GSK; Janssen (J&J); Lonza;

MedImmune; Merck Inc; Novartis; Pfizer; Regeneron; Sanofi. Find out more

at www.biophorum.com

http://www.biophorum.com/


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“Organizations are often

slow to adopt because

many of the new

concepts are counter-

cultural.”

Foreward

Anyone who cares to run a Google search

on ‘Maintenance Excellence and

Reliability Engineering’ will get an

indication how prominent the subject has

become within the corporate agenda

(more than six million results). This is

particularly true of the biopharmaceutical

industry – one of the most heavily

regulated – where such concepts are

becoming more widely adopted in

attempts to reduce risk and reduce costs.

Unfortunately, all is not smooth sailing.

Many techniques are still in their infancy

and, while leaders are pressing for wider

adoption, organizations are often slow to

adopt because many of the new concepts

are counter-cultural. Reliability Engineers

spearheading the change find themselves

constantly challenging existing mindsets,

having to educate the non-believers by

introducing sound reliability concepts.

Across a large organization this becomes a

difficult and time-consuming task.

In this brief Survival Guide, we go back to

basics, focus on common misconceptions

and we introduce some of the key

concepts behind Reliability Engineering –

very much in layman’s language. So, if you

are not sure about the difference

between random failure and a bathtub

curve, preventive and corrective

maintenance, or the reasons why

increasing the frequency of maintenance

can be counterproductive, please read on.

Concise enough to be consumed in a short

commute, we believe it will form a

valuable discussion document. We do

hope you find it useful.

BPOG - BioPhorum Operations Group


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“We start with a simple

definition of preventative

maintenance, and what we

mean by failure.”

“By understanding failure

mode, appropriate

maintenance strategies can be

established to help detect,

prevent or mitigate failure and

improve reliability of the

component.”

Misconception –

preventative maintenance

can prevent all failures

Failure is an unfortunate fact of life.

Systems have a natural tendency to break

and wear out, and the components of any

asset are subject to the effects of wear

and tear. Eventually, components fail.

It is a common misconception that simply

because preventive maintenance is

employed, or the frequency of

maintenance is increased, the risk of

failure can be eliminated.

While preventive maintenance can reduce

the risk of failure, so long as the failure

mode exists (the way in which a system,

subsystem or component fails to meet

design or performance requirements), the

risk of failure remains.

To quantify failure rates, engineers

employ a concept, ‘mean time between

failures’ (MTBF), or the expected time

between inherent failures of a system

during operation. However, even when

MTBF is known, there is still the

uncertainty of when the failure will occur.

Reliability is about managing the

probability of failure over time.

Look more closely at probabilities of

failure in the real world and it is possible

to construct a chart like the one shown on

page 5, first suggested by John Moubray1.

Note how, contrary to popular belief, only

a small percentage of equipment ages or

wears out at the end of its expected life.

In practice, most failures occur in early life

- infant mortality - or completely

randomly at any point in its life.

By understanding the failure mode,

appropriate maintenance strategies can

be established to help detect, prevent or

mitigate failure and improve the reliability

of a component. Nevertheless, 100%

reliability can never be guaranteed in

reality so long as the failure mode still

exists.

1 Reliability Centered Maintenance, 2

nd edition,

John Moubray, Industrial Press Inc., 1997


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Reliability Centered Maintenance, 2nd

edition, John Moubray, Industrial Press Inc., 1997


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“Other industries have

improved the way maintenance

is delivered using predictive

and condition-based

techniques.”

Misconception – all

preventative maintenance

is time-based

Historically the biopharmaceutical

industry has adopted mainly time-based

maintenance but, in fact, other more

effective strategies can be used.

Increasingly the industry is improving the

way maintenance is delivered by using

predictive and condition-based

techniques. These techniques are used

extensively in the aerospace and

automotive industries to great effect.

Predictive and condition-based techniques

can be used to anticipate failure ahead of

time, enabling maintenance to perform

repairs in a planned and scheduled

manner, well before failure.

In summary, preventative maintenance

can be divided into three categories:

1. Time-based or age-related. This

type of preventive maintenance applies

where the failure rate increases over time,

so the component is replaced ahead of

expected life to prevent failure in service.

The earlier chart, however, showed that

this pattern applies only to a small

percentage of failures in the real world.

Clearly, it does not make sense for this to

be our primary approach to preventative

maintenance.

2. Run-based or usage-related. This

type of preventive maintenance applies

where the failure rate increases with

usage.

This strategy is a development of the

time-based or age-related approach. If a

component deteriorates only when in

service (ie no deterioration over time if

not used), then maintenance based on

usage is appropriate.

Examples falling into this category are

valve diaphragms replaced after a

predetermined number of process cycles

or stressed component needing

replacement after a number of duty

cycles.

3. Predictive or Conditioned-based.

This type of preventive maintenance

applies to situations in which failure rates

appear randomly, where neither time nor

usage provide good early failure

indicators.

As shown in the earlier chart, this is the

most common pattern of failure and, to

be truly effective, preventative

maintenance programs should reflect this

fact.


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“Other industries have

improved the way maintenance

is delivered using predictive

and condition-based

techniques.”

In the biopharmaceutical industry,

vibration monitoring of bearings, motors

and gearboxes in plant and equipment is

increasingly common practice, where an

increase in detected vibration can be used

to indicate failure. Such systems provide a

step increase in reliability compared to

invasive time-based replacement.

Similarly, thermography can be used to

monitor the condition of electrical

controls to signal early onset of failure.

On the shop floor, visual inspections

carried out by operators provide early

signals as part of a structured Total

Productive Maintenance system.


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Misconception – more

frequent maintenance

leads to increased

reliability

The idea that increasing frequency of

invasive maintenance leads to better

reliability is a fallacy.

In many situations, opening up a system

or removing a functioning asset from

production in order to perform invasive

maintenance, may actually increase the

chances of failure.

The concept of iatrogenic (technician-

caused) failures, also referred to as ‘infant

mortality’, speaks to the dangers of

introducing potential failure modes to an

asset by invasively performing tasks on

components that may be working

acceptably, but are placed in a

compromised state by the technician

inadvertently infringing the operational

integrity of equipment.

Adding more frequent intervals can also

introduce high degrees of waste, when

the costs of extra wrench-time, added

materials, and diverted resources is taken

into account. More frequently performed

maintenance also reduces the availability

of equipment for production.

Unfortunately, many preventive

maintenance (PM) programmes set

maintenance frequencies using generic

industry practices without consideration

of the asset and the operating

environment. Worse still, time-based

intervals are often arbitrarily tightened in

a knee-jerk response to failures and

deviations.

Such actions can, in fact, worsen the

situation by inadvertently introducing

infant mortality, leading to poor reliability.

A far more effective approach is to

understand the failure modes and develop

specific strategies to address them.


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“A failure with a low

probability of occurrence many

still occur, even under the most

robust maintenance strategy.”

Misconception – asset

failure means the

maintenance strategy is

ineffective

Clearly, asset failure could signal a failing

in the maintenance strategy - but not

necessarily. Further analysis and

investigation is required before a

maintenance strategy is deemed to be

ineffective.

The effectiveness of a maintenance

strategy should be evaluated against

targets such as quality, health & safety,

environmental integrity, production

output, operating costs, etc.

For Example:

Quality: Is the maintenance strategy

effective in meeting targets such as

equipment deviations?

Operating Costs: Is the maintenance

strategy effective in meeting targets such

as the MRO budget?

Production Output – Is the maintenance

strategy effective in meeting targets such

as units/month, etc?

Remember, a preventive maintenance

strategy cannot completely eliminate the

risk of failure. Failure with a low

probability of occurrence may still occur,

even under the most robust maintenance

strategy.

An effective maintenance strategy

manages asset-failure to a tolerable risk,

aligned with the business objectives. If

you are meeting your objectives, then the

asset maintenance strategy is effective

with respect to your business objectives.

Managing failure modes

The purpose of an asset maintenance

strategy is to identify those failure modes

which will be managed through

preventive maintenance and those which

will be managed through corrective

maintenance.

If the failure mode is not adequately

addressed by the maintenance strategy,

there may be a need for revision to better

address the failure mode.

If, however, the failure mode is addressed

by the maintenance strategy, then a

review of the strategy may be necessary.

Does an effective maintenance strategy

equate to 100% reliability?

Despite a perfect world goal of 100%

reliability, all assets have failure modes


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and all failure modes have a failure rate

and a failure pattern.

This is not to say that we give up trying to

improve reliability, on the contrary,

periodic maintenance effectiveness

reviews are used to identify root causes of

recurring failures and drive continuous

improvement in reliability that are

quantifiable to the business.


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“In practice we find that less

than 5% of maintenance tasks

are critical to product quality,

the rest are there for business

reasons.”

“Having a maintenance

strategy of run-to-failure is

perfectly acceptable when a

failure mode cannot be

detected and the equipment is

deemed to be non-critical.”

Misconception – all

biopharmaceutical

maintenance is critical

If failure impacts product quality, then yes

it’s critical, but if it doesn’t have product

impact, then it needn’t be. In practice we

find that only a small percentage of

maintenance tasks are critical to product

quality, the rest being there for business

reasons.

The ISPE Good Practice Guide on

Maintenance2 cites, “The maintenance

program should help to ensure that the

equipment is continually maintained in a

qualified state and is suitable for intended

use.”

The primary goal of maintenance in the

biopharma industry is to reduce the risk of

a failure that may impact product drug

quality. In this way, the qualified state of

the equipment is preserved through

planned activities with expected

outcomes.

2 ISPE Good Practice Guide on Maintenance,

March 2009

Not all functional failures of an asset,

however, impact drug quality.

Differentiating between those failure

modes that do and those that do not

enables effort to be focused where it is

needed most.

Having a maintenance strategy of run-to-

failure is perfectly acceptable when a

failure mode cannot be detected and the

equipment is deemed to be non-critical.

Conversely, monitoring the condition of

critical equipment provides constant

assurance that the equipment is safely

operating in its qualified state, whilst

providing early signals of wear that may

lead to a failure that affects product

quality.

Managing failure and risk in a complex

biopharmaceutical plant is a complicated

task that can best be handled using risked-

based maintenance methodologies, such

as Reliability Centered Maintenance

(RCM). Reliability-centered maintenance

is a process used to determine what must

be done to ensure that any physical asset


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continues to do what its users want it to

do in its present operating context3.

3 Reliability Centered Maintenance, 2

nd edition,

John Moubray, Industrial Press Inc., 1997


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Misconception – any

deviation from a PM

schedule will lead to

equipment not fit for use

Another misconception and perhaps the

most dangerous.

Let’s begin with the most demanding

case; critical equipment. Performing

critical maintenance outside the optimum

time interval may increase the risk of a

functional failure that impacts the

qualified state.

However, execution of PM outside of the

optimum interval does not in itself cause

the asset to be no longer qualified or

suitable for intended use, unless the

qualified state or suitability for use is

dependent upon the execution of the PM

task at a specific point.

In the majority of circumstances, this

condition does not apply.

To further illustrate this important point,

consider this example. Forgetting to check

the brake fluid level in your vehicle does

not mean the brakes are about to fail.

What it does mean a higher risk that the

brake fluid might be low, which in turn

might cause a brake failure. The increased

level of risk will depend upon the

condition of the brake system.

So, apart from a very small number of

specific exceptions, deviation from PM

schedule increases risk, but does not

directly cause the asset to be no longer fit

for use. This is not to say that PM tasks

are unimportant; they are important

because they reduce risk and save money.

If an organization falls behind with its

maintenance schedule, it is important to

prioritize work so that the bigger risks are

still addressed and slippage is allowed

only on the lower risk items.

Schedule-adherence at an aggregate level,

therefore, provides a fantastic leading

indicator on the risks that the business is

running. When organizations fall behind,

the most important priority is to clear the

backlog to get back on track.

It is paradoxical that, at this point, many

organizations choose instead to burden

technicians with unnecessary paperwork,

which in turn may cause further delay and

increase the very real risks that they are

busily documenting.

Conclusions

We hope that you find this survival guide

useful. We have deliberately set out to

make this document provocative to gain

your attention and create dialogue. We

encourage you to share it with your

colleagues to enable your organization to

more quickly recognize these

misconceptions whenever they arise and

to stay focused on the actions that will

accelerate the journey towards

maintenance effectiveness.

misconceptions of maintenance and reliability - … · the ispe good practice guide on maintenance2...

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