Machine Criticality 101 Don Silcock

GE Energy

Why is this topic important?

3

Scenario Your customer wants to expand

the System 1® on his critical machines to manage other assets in his plant. How would you go about deciding

which of our solutions to advocate?

4

Why is this important?

Technology / Solution

Maintenance Strategy

Improved Business Performance

Customer Business Objectives

Business objectives drive the maintenance strategy, which in turn drives the technologies and solutions applied.

Maintenance strategy definition and development is a critical success factor in the

customer’s value chain.

Terminology

6

Terminology

The four main maintenance strategies are:

• Reactive Maintenance (RM)

• Preventive Maintenance (PM)

• Predictive Maintenance (PdM)

• Proactive Centered Maintenance (PCM)

7

Terminology

Reactive maintenance (RM):

• Maintenance performed after a failure or after an obvious, unforeseen threat of immediate failure.

•In reactive maintenance, machines are operated in a run-to-failure (RTF) mode

• Daily maintenance activities are driven by unforeseen problems from assets breaking down without detection of the impending failure.

8

Terminology

Preventive Maintenance (PM):

• Maintenance tasks conducted at regular, scheduled intervals based on average statistical/anticipated lifetime to avoid failure

• Includes inspection, service and/or replacement

• Intervals may be calendar or operating time.

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Terminology

Predictive Maintenance (PdM):

• Maintenance based on the actual asset condition (objective evidence of need)

• Assessment data obtained from in-situ, non-invasive tests and operating & condition measurements

• Also referred to as Condition Based Maintenance (CBM).

10

Terminology

Proactive-Centered Maintenance (PCM):

• A program of continuous maintenance optimization

• Based on feedback from Root Cause Failure Analysis (RCFA) repairs, quantitative PM’s, PdM routines, CM systems and operations.

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Terminology – other acronyms…

• MTBE: Mean Time Between Events

• MTBF: Mean Time Between Failure

• MTBR: Mean Time Between Repairs

• MTTR: Mean Time To Repair

• MRO: Maintenance, Repair, Overhaul

• OEM: Original Equipment Manufacturer

• O&M: Operating and Maintenance

• ERP: Enterprise Resource Planning

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Terminology

Condition Monitoring (CM):

• The process of recording measurements that define condition without disrupting operation

• Examples are vibration, fluid & electrical characteristics and thermal gradients

• Measurements are compared to their limits.

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Terminology

Reliability Centered Maintenance (RCM):

• A systematic, disciplined process to ensure safety and mission compliance that defines system boundaries and identifies system functions, functional failures, and likely failure modes for equipment and structures in a specific operating context.

• RCM develops a logical identification of the causes and effects (consequences) of system and functional failures to arrive at an efficient and effective asset management strategy to reduce the probability of failure.

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Terminology

Functional Failure:

• The System is no longer capable of performing the intended function.

• For example, a pump that is designed to produce 100 gpm at 200 psi is considered to have functionally failed if it can only produce 90 gpm at 200 psi.

Maintenance strategies

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Time based

Wait until it breaks..

Data based

Information based Type of

maintenance

Top

Quartile

Lower

Quartile

Proactive >20% 0%

Predictive >45% ~12%

Preventive >25% ~31%

Reactive <10% ~55%

Sources:

•Society of Maintenance & Reliability

Professionals Survey

•The Business Case for Reliability

Robert DiStefano, John Schultz

(Eff

ec

tive

ne

ss

)

Org

an

iza

tio

n &

Av

aila

bilit

y

Maintenance Cost Expenditures

Preventive

Reactive

(Efficiency)

A

B

Predictive

Proactive

>65%

~86%

100% 100%

Maintenance strategies

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$10

$15

PdM PCM PM RM

$20 M

ain

ten

an

ce C

ost

$/h

p/y

r

$5

From EPRI Power Generation Study

Maintenance Strategies

Note: This chart represents established programs

Comparative maintenance spend

Asset criticality ranking

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Asset criticality ranking Asset Criticality ranking helps determine the right level of asset management resources (technology, parts, and people) for each asset. This enables the business risk of each asset to be managed in an appropriate manner.

The Primary criticality ranking criteria are:

• Safety,

• Environment & Regulatory Compliance,

• Production,

• Maintenance & Operating Costs

• Product quality

Plus other criteria if relevant

The criticality ranking process produces a balanced ranking of All Assets in the plant – each with a 4-digit numerical criticality number.

A cross-functional team is usually assembled to agree on criteria weighting and asset evaluation.

Typical Asset Criticality

Ranking Tool

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Asset criticality ranking On the Asset Criticality Pareto Chart, natural “break points” appear to segregate the assets into identifiable criticality classifications

For the most critical assets (typically 10-15% of assets), a Reliability Centered Maintenance (RCM) approach is used to determine the appropriate maintenance strategy.

Critical assets are assessed using Failure Modes & Effects Analysis (FMEA) process.

Less Critical assets are assigned a strategy using standard Templates

Non-Critical assets Run-to-failure

Distribution of Assets

15%

Cri

tica

lity

Ra

nk

ing

30% (typical) 50% (typical) 5%

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Mechanical Asset Example (Centrifugal Pump)

Quantitative PM P-F

Interval 5-8 weeks

• The P-F interval is the interval between the occurrence of a potential failure and the decay into a functional failure • Time can be

measured in seconds, minutes, days, months or years. • P1-Px indicate detectability intervals by various techniques or technologies.

Vibration P-F interval 1-9

months

Wear Debris in oil P-F

interval 1-6 months

Audible noise P-F

interval 1-4 weeks

Heat by touch P-F

interval 1-5 days

P1 P2

P5

P6

F

IR Thermography P-F

interval 3-12 weeks

P3 P = Potential Failure Is an identifiable condition which indicates

that a functional failure is either about to

occur or is in the process of occurring

F = Functional Failure The point at which the asset fails to

deliver to it’s intended purpose

P4

P7

Process Performance Data (highly

dependent on tuning of system /

instruments) ~1 week – 6 months

Time

P

Relays

The P-F interval

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Maintenance Management Maintenance Management is the process of managing failure modes to ensure the asset performs its intended function. This is an integral part of our Customer’s asset management and business processes, directly related to their key performance indicators.

There are four Maintenance Strategies commonly employed, each with particular attributes and suited to certain applications.

Selection of the maintenance strategy should support the objectives of our customer’s business.

Today, the top performers in industry are deploying effective maintenance strategies, supported by technologies, resources and sound procedures to keep their assets performing high on the P-F curve.

Time

Failure Mode #1

F1

P1

Time

Failure Mode #2

F2

P2

Time

Failure Mode #3

F3

P3

The P-F Curves illustrate progression of multiple

failure modes on one machine - from Potential

Failure Initiation (P), to Functional Failure (F)

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Technology Maintenance Strategy

RCM

FMEA

PM Templates

Run to Failure

Protection, on-line diagnostics, process data, performance &

Decision Support

On-line scanning & process data

Off-line portable & process data

Process data

Plant equipment criticality

Protection, on-line diagnostics & process data

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Bently Nevada Solutions Maintenance Strategy

RCM

FMEA

PM Templates

Run to Failure

3500 & 3701, System 1, Bently Performance/EMAP &

Decision Support

Trendmaster DSM & wireless

Snapshot PDC

Plant equipment criticality

3500 & 3701 & System 1

System 1

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System 1 asset management platform

Online - Continuous

monitoring & protection

Critical Assets • Gas Turbines

• Steam Turbines

• Compressors

• Main line Pumps

3500 & TDI 3300 &

TDXNet or TDE

Online – Periodic

(scanning) monitoring

Wired Wireless

Essential Assets • Fans

• Pumps

• Blowers

• Etc…

Snapshot PDC

BOP Assets • Vibration

• Portable Devices

• Lube Oil

• Thermography

• MCA, etc…

Offline – Periodic

walk-around monitoring

Switch/Hub

Questions?