Instrumentation Maintenance

8/11/2019 Instrumentation Maintenance

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Asset Management

Establishing a balanced maintenancestrategy for field instrumentation

Michael Herzog, Rinus van Kasteren, John Salusbury, Endress + Hauser

Field instrumentation devices are crucial to reliable process plant operation but often they are not included

in the maintenance plan since their reliability is relatively high, but effects of age and technological obsole-

scence lead to reduced plant performance over time. New legislation demands more control and re-calibra-

tion, manufacturers promise very stable and highly reliable instruments. The challenge is now to newly

balance the maintenance efforts and their payback.

This paper describes a methodology which allows a cost effective approach and improves the important

issues such as safety and plant reliability.The new method for maintenance analysis takes into account the

existing on-site equipment,considers its current maintainability and maintenance needs within the applica-

tion and makes the manufacturers knowledge available. It suggests criteria for the maintenance manager

to classify the criticality of the equipment within the process to focus the efforts, and finally explains how allplant data can be brought together to form an information base for the development of a new maintenance

plan. A rule based tool allows to focus on the three planning dimensions of breakdown plan, preventive

plan and migration plan. Exporting the maintenance related asset information to the local computerised

maintenance management system simplifies the calibration and maintenance scheduling task that has to

follow.

Experience in mid-size and large process plants suggests that equipment and plant availability is improved

whilst maintenance efforts are redirected from reactive trouble shooting to improved plant productivity. In

some instances the result is an increase in preventive activities, in other cases a reduction and redirection of

the efforts brings more productivity. Instrument replacement is now budgeted one year ahead and well

managed. The spares stock is reduced through standardisation, important training needs of the mainte-

nance staff are identified and maintenance efficiency is increased by focussed training.

Festlegung einer ausgewogenen Instandhaltungsstrategie fr die Feldinstrumentierung

Die Gerte der Feldinstrumentierung sind fr den zuverlssigen Betrieb der Prozessanlage von entscheiden-

der Bedeutung,werden aber hufig nicht in die Instandhaltungsplanung einbezogen,da ihre Zuverlssigkeit

vergleichsweise hoch ist. Durch Alterungseffekte und den Einfluss der technischen Weiterentwicklung geht

die relative Leistungsfhigkeit der Anlage im Laufe der Zeit jedoch zurck. Neue Gesetze verlangen einerseits

eine striktere Kontrolle und Nachkalibrierung,andererseits bieten die Hersteller immer stabilere und zuneh-

mend hochzuverlssige Messgerte an. Nun kommt es darauf an, den Instandhaltungsaufwand und den

dadurch erzielbaren Nutzen gegeneinander abzuwgen.

Dieser Artikel beschreibt eine Methodik, die einerseits einen kostengnstigen Ansatz gestattet und anderer-

seits Verbesserungen in wichtigen Aspekten wie Sicherheit und Anlagenzuverlssigkeit ermglicht. Die neue

Methode fr die Instandhaltungsanalyse bercksichtigt die vorhandenen Betriebsmittel, betrachtet ihre

Instandhaltbarkeit und ihren Instandhaltungsbedarf innerhalb des betreffenden Anwendungsbereichs und

ermglicht den Zugriff auf das Know-how des Herstellers. Die Methodik schlgt Kriterien vor, mit denen derInstandhaltungsleiter die Kritikalitt der Betriebsmittel innerhalb des Prozesses klassifizieren kann, um den

Aufwand entsprechend bndeln zu knnen. Sie erlutert, wie smtliche Anlagendaten zusammengefhrt

werden knnen, um eine Informationsbasis fr die Erarbeitung eines neuen Instandhaltungsplans aufzu-

bauen. Ein regelbasiertes Datenbank-Tool ermglicht, den Blick auf die drei Hauptabschnitte Ausfallpla-

nung,vorbeugende Planung und Migrationsplanung zu richten. Die nachfolgenden Schritte der Arbeits-

planung fr Instandhaltung und Kalibration werden durch den Export der instandhaltungsrelevanten Infor-

mationen in das lokale Instandhaltungs-Planungssystem vereinfacht.

Die Erfahrungen in mittelgroen und groen Prozessanlagen lassen erkennen, dass sich die Verfgbarkeit

der Betriebsmittel und Anlagen verbessert, whrend sich die Instandhaltung von der reaktiven Strungsbe-

seitigung zur Verbesserung der Anlagenproduktivitt verlagert. In einigen Fllen ergibt sich hieraus eine

Zunahme der vorbeugenden Manahmen,in anderen Fllen lsst sich mehr Produktivitt durch eine Redu-

zierung und Umlenkung der entsprechenden Manahmen erreichen. Der Austausch von Messgerten wirdjetzt bereits ein Jahr zuvor budgetiert und gut verwaltet. Die Lagerbestandsverwaltung wird durch Standar-

disierung vereinfacht.Wichtige Schulungsanforderungen der Mitarbeiter werden ermittelt, und durch zielge-

richtetere Schulungen wird die Effizienz der Instandhaltungsmanahmen verbessert.


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Asset Management

1. Objective of a maintenance strategy

1.1 Guidelines in standards

According to the new European Standard EN 13306 Mainte-

nance Terminology [1] it is the responsibility of any mainte-

nance manager to define a maintenance strategy accordingto these main criteria:

to ensure the availability of the item for the required

function, often at the optimum costs,

to consider the safety requirements associated with

the item for both maintenance and

user personnel, and where necessary, any impact on

the environment,

to uphold the durability of the item and/or the quality

of the product or service provided,

considering where necessary, costs.

The GAMP Good Practice Guide: Calibration1

Manage-ment[2] asks the process owner to identify the critical para-

meters, the process variables, and to derive acceptable

limits thus supporting a focussed approach.To obtain this

focus, maintenance planning is preceded by maintenance

analysis. It should include a criticality analysis as described in

[3] as the systematic analysis for identification and evalua-

tion of required maintenance activities, including estimation

of time and resources needed for the maintenance perfor-

mance.

1.2 Strategic priorities

This seems straightforward enough however further evalua-

tion of the needs of the different stakeholders, representing

business processes and functions usually reveals contradic-

ting targets. Some typical examples are listed in Table 1.

When a maintenance plan is produced, its defined priorities

are likely to be challenged from a number of different angles.

Therefore a sound approach should define the priorities first,

get them accepted and then proceed to produce a matching

maintenance strategy and plan. A well designed mainte-

nance plan also needs to take into account the changes that

occur over time its structure must be flexible enough so

that it can be easily adapted to changing requirements.

Field instrumentation devices are crucial to stable andproductive plant operation and yet,often they are not inclu-

ded in the maintenance plan since their reliability is relati-

vely high. Even the basic updating of instrument-lists in the

item register3 is frequently neglected due to other priorities.

This renders the maintenance plan practically useless and

will lead to instabilities in plant operation sooner or later.

Once the vicious circle is entered,fire-fighting will further

reduce the available time to plan and execute the necessary

preventive tasks. Therefore the most important feature of a

maintenance plan is to be current and to be followed at all

times.

The key issues for a good maintenance plan are listed in

Table 2.The priorities will vary from industry to industry and

will depend on plant or corporate strategies.

2. Contents of maintenance planning

2.1 The activity oriented maintenance plan

According to [1] maintenance types, strategies can be classi-

fied in many different ways including preventive, scheduled,

pre-determined, predictive, condition based, corrective,

remote, deferred, immediate and on-line or off-line. On the

other hand the resulting activities can also be vast: inspec-

tion,monitoring,function check-out,repair, overhaul,routine

maintenance, calibration, etc.A practical approach is to look

at maintenance considering three main operational situati-

ons: preparation for a failure or breakdown event (contin-

gency plan for corrective maintenance),

Glossary of terms

1 Calibration is an essential element in ensuring regulatory compliance in

the pharmaceutical industry.The ISPE issues Good Practice Guides[2] to

provide guidance in setting up a calibration management system

2 According to [1], maintenance effectiveness is the ratio between the

maintenance performance target and the actual result

3 According to [1],an item register is a record of the individually identified

items together with location. An item is any part, component, device,

subsystem functional unit equipment or system that can be individually

considered.

Table 1: Examples for objectives of maintenance planning.

Reduce the risk to people, environment and equipment

Satisfy regulatory requirements (Legal, Environment, Safety and

Health)

Reduce fluctuations of product quality (e.g.Six Sigma)

Support management systems such as ISO 9001[4], ISO 14001[5]

Satisfy corporate guidelines for maintenance cost (reduction) or

outsourcing strategy

Adapt to evolving plant requirements, e.g. an additional shift per day

Provide a base for decision making within (new) management

systems (TPM, RCM, RBM)

Increase equipment reliability to reduce losses and improve delivery

performance

Improve maintenance effectiveness2 or other quantifiable objectives

Optimise inventory and improve supply chain for spares

Identify replacement needs and budget replacement ahead of time

Reduce operating costs,e.g. unplanned shutdowns and product loss

Table 2: Key Features of a good maintenance plan.

Provides good maintenance effectiveness

Reduces complexity and provide focus (do the right things)

Offers traceability

Is up-to-date and flexible

Takes into account the available resources (internally and externally)

Deals with the loss of instrumentation and calibration know-how

Makes suppliers knowledge available to maintenance personnel

Takes into account all devices (completeness)

Fosters continuous improvement


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Asset Management

the important planned activities (preventive mainte-

nance),

general life cycle issues of the field devices such as

planned replacement or migration.

Process plants are usually designed to operate over more

than 710 years. Frequently, an economic life span of over

1015 years is expected and plants often exceed 20 years of

operation. During this period they are expected to deliver

increasing output at an improving level of quality.

In contrast to this,developers of field instrumentation are

changing and improving the technical design at a much fas-ter pace in order make use of new technologies to stay com-

petitive. The manufacturers also have to consider new legal

requirements such as ATEX, Functional safety (IEC61508) or

the Pressure Equipment Directive: They have triggered new

designs or product options and made other older designs

obsolete.Last not least, the developments in bus technology

regularly lead to software updates.

Table 3 suggests some change ratesfor plant instrumen-

tation.Technology check-ups can open up important impro-

vement potentials: Better and tighter process control, higher

process efficiency and longer up time due to longer time to

failure4 and reduced repair time5 are observed when techno-

logy upgrades are implemented on critical components of a

plant.

Evolution of technology can be advantageous, but also

has its drawbacks: Whilst spare parts for older generation

equipment may become unavailable, the new devices may

have different dimensions that need adaptation to the

installation. Also, the electrical connection specifications

may have changed. Successor compatibility can be impossi-

ble to achieve for the instrument manufacturer, for example

when new standards for external dimensions arrive as was

the case for electromagnetic flowmeters. The implications

for the spare parts stock and training requirements must be

examined as well.

The three main aspects of the maintenance plan for

instrumentation are therefore:

breakdown plan and associated aspects preparation for

the development of a contingency, streamlining of spares stock according to the chosen

repair strategy,

planning for the training of personnel, managing the

know-how,

support requirements from (internal or external) service

provider(s),

preventive plan includes triggered (predictive) and all

scheduled activities,

definition of verification and calibration intervals and

methods,

streamlining consumables and wear parts stock (supply

chain), definition of outsourcing needs,

migration plan Managing technological improvements,

controlling actively the move to new generation devi-

ces,

implementing improvements in process control,

planning ahead to secure the investment.

2.2 Opportunities and considerations with smartdevices

Hart-Protocol, ProfiBus and Foundation Fieldbus have arri-

ved and web technology is now emerging in the field of pro-

cess automation. In combination with so called asset mana-

gement systems (or solutions) they are promising to sim-

plify the maintenance of all connected devices. Every

re-calibration, every exchange of a device can be registered

and becomes traceable for any inspector that has to verify

the action.(A risk of omission exists,though, if not all devices

are connected to the bus). As field devices are becoming

more sophisticated, some will report their maintenance

needs and send an alert via the communication link to the

asset management system to enable predictive mainte-

nance. This ability can be used as a base to consider exten-

ded inspection or calibration intervals in some applications.

But unless two or more redundant sensors are used, a self-diagnostic function cannot be very reliable in detecting a

calibration drift, resulting in a measurement error induced by

an effect (physical/chemical) to the primary sensing ele-

ment.The big advantage that bus-system based field device

architectures offer is the self-documenting feature that

allows no change (or tampering) to go unnoticed, particu-

larly concerning device parameterisation. For maintenance

planning the advantage is that the instrument lists in the

item register can be electronically updated. Table 4 depicts

the areas of improvement that suppliers typically indicate for

technologically more advanced field instrumentation equip-

ment.If considering such an electronic recording system it is

worth noting the FDA standard 21CFR Part 11 [6] that speci-

fically deals with this topic. As the food industry is moving

Table 3: Technological life cycles in comparison.

Software design,patches and improvements 618 months

Hardware design (internal modifications) 1 3 years

New generation, complete design overhaul 4 8 years

Basic technology change (e.g.PD-meters Coriolis) 1020 years

4 Repair time[1] is defined as Part of active corrective maintenance time

during which repair is carried out on an item.5Time to failure[1] is defined as Total time duration of operating time of

an item, from the instant it is first put in an up state, until failure or, from

the instant of restoration until next failure.

Table 4: Improvements & benefits offered by newtechnology.

Improvement Benefit

Modular design Quicker repair time, flexibility (stock)

Improved accuracy,stability Tighter process control

Higher ratings (e.g.temperature) Better reliability in the application

Lower energy consumption Energy savings

Scalable, upgradeable software Better price/benefit ratio

Digital Communication Many bus related advantages

Better support tools Easier and more efficient

maintenance


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towards adoption of Good Automated Manufacturing Prac-

tices (GAMP) the correct maintainability of the existing

installations needs to be examined. Thus the gap between

the current plant status and the required level of maintaina-bility is documented. Upgrading to smart devices can be an

effective way to close this gap.

3. Review and classification of field devices

The starting point to introducing or upgrading a mainte-

nance strategy is to audit and review all applications. Some-

times an instrument register does already exist but needs

updating. A complete inventory of all field devices needs to

be carried out.The quality of this review process is crucial to

the determination of maintenance priorities later on: Any

shortcomings of the installation, such as inadequate up-

stream or downstream straight runs for a flowmeter or

improper cabling need to be registered.

All special applications should be verified to identify

heavy conditions that demand special attention. If instru-

mentation hasnt been tagged before, this is the time to do

it. For a practical example on what could be registered when

sampling the installed base, see Fig. 1. If the plant has hazar-

dous areas, then it is worthwhile to include the zone rating

for the individual sub-locations.

Some field devices are more important than others and

should be classified as Critical to the process. If they fail, or

even worse, if their output signal slowly drifts away from thecorrect value, the correct operation of the production pro-

cess, the plant, personnel or the environment are in danger.

Sometimes this information can be deducted from the origi-

nal plant design or a Hazard and Operability Study (HAZOP)

that was conducted. Rather elaborate and very systematic

methods to assess each plant components criticality exist

for example the Norsok Standard Z008 [3].

A simple and practical approach is to first sort all field

devices into three different categories. If no other guidelines

exist, then for common process plants the three-tier distri-

bution can be targeted as a starting point.Table 5 highlights

examples of the important criteria that can be applied. Fur-ther refinements can then be made by looking at external

(e.g. regulatory) requirements for regular inspection or cali-

bration.The final defining of criticality values should be done

with a team that includes as much experience and know-

ledge of the process as possible.

The next step is to assess the risk from a possible lack of

maintainability. All devices must be evaluated (refer to

Table 6) in order to assess the remaining useful lifetime and

the fitness for the purpose within the process.Depending on

the chosen repair strategy you need to know whether a suc-

cessor product is compatible:Can it be installed in lieu of the

old device in case of a breakdown without mechanical or

electrical modifications? Spares availability has to be asses-

sed and obsolete equipment to be identified.The instrument

manufacturers can usually provide a lot of support and infor-

mation providing opportunities for optimising spares and

managing consumables and guidelines about maintenance

needs for the more than thirty different measurement para-

meters that exist.Keep it practical and limit the technical and

commercial questions you ask the suppliers to the really

necessary! A spreadsheet or database should be set up for

this purpose to align information on the level of device-ty-

pes and individual tag numbers. It should list the respective

ratings for criticality to the process as well.

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Asset Management

Fig.1: Example of information to register.

Table 5: Parameters defining criticality of devices to the process.

Criticality Description

High High, direct safety impact (GAMP Safety critical, IEC 61508:

SIL 2/3/4, Ex-Zone)

High, direct impact on product quality (GAMP Product

critical, ISO9000)

High, direct environmental impact (GAMP Environmentalcritical, ISO14000)

High production cost (GAMP Process/System critical,

e.g.costly secondary failures)

High financial cost (e.g.custody transfer duty,product loss)

Medium Medium safety impact (IEC 61508:SIL 1)

Medium impact on product quality

Possible indirect environmental impact

Medium production cost (manual control for some time

possible)

Medium financial cost

Low Low or no safety/environmental/product quality process

impact (GAMP Non-critical)

Negligible financial impact

Table 6: Check-Points to evaluate the maintainability of field devices.

The product is current,spares, documentation and training areavailable and the lead time to reorder product/spares is fitting

the need

The supplier has announced some special product status, such as

phase-out,obsolete,sales-stop or other

The supplier has gone out of business,the product has been

discontinued for some years

An identical replacement product is not readily available any more

The successor may not be fully compatible (e.g.mechanical/

electrical connection,bus connectivity)

Spare parts and repairs availability is difficult, the spare parts are not

manufactured any more (used parts!)

Operating experience of the product highlights the need for regular

intervention

The product has a much higher need for regular maintenance than

state of the artdevices

Combinations of the above


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Asset Management

4. Structure of the maintenance plan

Once a picture of the installed base has been established,the

analysis which will lead to the first view of the maintenance

requirements can begin. Any serious attempt at bringing all

this information together for more than 100 instruments and

organise it along the lines of the main chapters of break-down, preventive and migration plans should involve the

use of a database tool. In the process of maintenance analy-

sis a rule based tool significantly reduces complexity and

places data within a well structured frame to provide usable

information from the abundant data. Ideally the tool will

enable collaborative work between the team that conducts

the maintenance analysis and the instrument suppliers.

The Installed Base Analystwas conceived as a rule based

software tool to support Endress+ Hausers service advisors

in their consulting service Instrument Management Soluti-

ons [7] which utilises the methodology described in this

paper.It has the ability to register the entire installed base ofinstruments and group them into over 40 classes of measu-

rement principles and types.

In the following paragraphs the general logic used to

structure the information about the installed base are high-

lighted.

4.1 Breakdown plan

In case of a breakdown, either the complete device or parts

of it need to be replaced.

The focus here is on the devices with the highest critica-

lity ratings. For them, repair training and on-site spare-parts

or spare devices must be considered to keep down time

short. These decisions depend on the processes require-

ments for repair times and current repair time performance.

Fig. 2 shows the areas of attention.

Two basic repair strategies are utilised mainly:

replacement of the complete device in case of a failure or

repair of the device without taking it off the process

physically by use of spare parts (modules).

The first method may be achieved with less trained per-

sonnel. On the other hand, emptying a vessel or pipe to

replace a complete device can be very time consuming and

expensive. Unless the application produces heavy wear onthe sensor, it is statistically speaking the part that will rarely

fail in an instrument without moving parts. Even pressure

peaks are generally handled well by the newer transmitters.

Changing the electronics insert (module) can be an easy

repair if it is prepared properly.This is where standardisation

plays an important role: The preparation work is not econo-

mical for only a few instruments.

4.2 Preventive plan

To prevent unnecessary maintenance and to reduce the risk

of costly downtime, the tool performs queries to highlight

the priorities for periodic maintenance,calibration or inspec-tion related to the specific requirement of the instrument

types and the process. Time based replacement require-

ments of consumables and wear parts are highlighted in

addition. Fig. 3 shows the guidelines to select the instru-

ments that might need attention.

The schedule of a maintenance plan for critical devices is

influenced by several factors such as the level of self-diag-

nostics and the effect on the process when a failure or an

error condition exists:Would a drift be noticed in time to pre-

vent quality problems or is a periodic inspection [1] or even

calibration necessary and what should the periodicity6 be?

Some instruments do have a clear demand for inspection,

maintenance or calibration. pH-sensors, for example, need

regular calibration and electrode replacement irrespective

of the criticality to the process and other demands. Their

exchange schedule can be optimised and very cost effective

delivery contracts can be established with the supplier

thus reducing the cost of keeping stock. Standardisation is

very helpful in this domain.

In other cases the need to maintain an instrument on a

regular basis is influenced by particular process- and envi-

ronmental conditions a typical example for this is strong

abrasion in a flow line.

In addition, internal or external quality demands and the

criticality determine the recommended periodic inspection,maintenance or calibration regime.

The devices that now emerge with a defined maintenance

need must undergo scheduling. Exporting the maintenance

related asset information to the local (CMMS) system simpli-

fies the calibration and maintenance scheduling task that has

to follow. A particular situation exists for flow calibration.

Since this type of calibration is not easily feasible on a plant

and since indirect methods are not standardised, flowmeters

are often excluded from the calibration schedule even

though they can be crucial to plant performance. On the

other hand you can find pressure and temperature calibrati-

ons that many plants carry out on a monthly basis. Often

Breakdown plan

priority area

Risk to the maintainability

Critical

ity

tot

he

process

High Medium Low

High

Medium

Low

Fig. 2: Priority area

for the breakdown

plan.

Guidelines to analyse the needfor maintenance

Instrument demands? Application demands? Internal demands? External demands? Criticality?Fig. 3: Guidelines for

the preventive plan.

6 Calibration periodicity[2] is defined as frequency of scheduled calibra-

tions.


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these easy to do check-ups are repeated too frequently as

modern instruments rarely need calibration intervals of less

than several years under normal industrial conditions.

4.3 Migration plan

The field devices need to be examined for updating require-

ments. Managing the migration / modernisation process

over time allows control of the level of variety or degree of

standardisation and tighter budget control.Instruments that

are critical to the process and are close to or beyond its use-

ful life or no longer suitable due to changes in legislation or

requirements from the duty must be identified. Fig. 4 shows

the areas of attention for updating/migration needs. Along

with the migration policy for the instruments, the upgrade

path for spares and must be defined.This is also an opportu-

nity for the reduction in spares variety.

Taking the migration need of an instrument as an oppor-

tunity for process optimisation can yield helpful side effects.

A positive displacement flowmeter that gets replaced by a

Coriolis mass flowmeter can continue to give a volumetric

output but also offers a massflow reading that can be used

to optimise the chemical process through improved accu-

racy of mixture ratios. Sometimes the replacement of an

electromagnetic flowmeter by a newer model can reduce

the energy consumption by over 50%, and other examples

can be given for improvements of control loop response or

dosing and batching applications.

5. Practical experience

5.1 Benefits of the method

Well-defined priorities in the overall maintenance plan can

be successfully defined by following the described process.

The method allows an estimation of the required resources

to carry out the defined tasks as well as defining an effective

migration plan. Since the method combines a bottom-up

approach (application and device audit) with general top-

down strategies for the most important business cases, the

work generates transparency and traceability. The outcome

is a view of the installed base from three perspectives whichallow the design of a plan of maintenance activities in order

to get a good balance between plant availability and all

maintenance efforts. Fig. 5 shows the relationship between

the degree of maintenance done and the corresponding

total cost for the plant.Doing too little maintenance leads to

increased cost because of reduced process availability and

fire-fighting. It may also compromise product quality and

cause problems in the spare parts supply. Exercising too

much maintenance (or not the most effective measures!) will

unnecessarily increase the cost of labour and inventory, andit usually leads to other problems: The saying if it aint bro-

ken dont fix it has its virtues still.

The described method will greatly assist in deciding on

the individual optimum strategy: Its focus on critical and dif-

ficult to maintain instruments as well as on good preparation

for failure events will decrease down-time while keeping

maintenance efforts focussed. The migration plan will keep

the instrumentation easy to maintain.

5.2 Case examples

The methodology described has evolved from practicalexperience working with many maintenance managers and

their teams. It was checked in process by the joint efforts of

the service provider and end user in real situations.The out-

come of this work has always shown that equipment reliabi-

lity can be improved, process plants can be optimised and

total cost can be reduced.The two following representative

case stories highlight the wealth of individual options and

the flexibility: Case A is an example of an under-serviced

situation in a food-production plant, Case B is an over-ser-

viced coating plant serving the automobile industry.The two

cases are constructed from real experience. The results and

comments are typical.

5.3 Case A

The management of one of the biggest and successful cho-

colate factories in Germany took stock of the business risk

from possible problems in the production process:An instru-

ment failure on a critical measurement point with no spares

in stock would lead to in a complete shutdown of the manu-

facturing plant for 24 hours.Such a shutdown could result in

lost production to the value of about one million Euro.

Reason enough to turn attention to integrated mainte-

nance strategies and to look for new solutions to optimise

the life cycle of the field devices. In particular, one plantwhich had been modified and expanded over many years

was considered the highest risk despite a most modern pro-

cess control system and routine maintenance. Smaller inci-

dents in the recent past had demonstrated the difficulties

and led to inquiries into the following subjects:

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Asset Management

Migration

planpriority

area

Risk to the maintainability

Criticalitytoth

eprocess

High Medium Low

High

Medium

Low

Fig. 4: Priority area

for the migration

plan.

Totalcost

Degree of Maintenance

Nomaintenance

Too muchmaintenance

Optimum point:

Minimum cost

Fig.5: Total cost as a

function of mainte-

nance activities.


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Asset Management

Identification of the manufacturer and evaluation of the

reparability of the device

Availability, specification and lead time of a replacement

device

Possibility to replace a device by a similar one located in a

non-critical application

Since the plant had been modified several times to incre-

ase capacity and to allow continuous operation (24/7), what

was needed most was:

clear information of the status of all on-site devices,

assessment of the process-critical devices,

creation of a schedule for maintenance and calibration,

standardisation and type reduction in production and

spares stock.

As a first step all 800 instruments were registered and the

spare parts stock was checked.Several meetings of the main-

tenance team and Endress+ Hausers service advisor yieldeda common view on the priorities:

high dependence on quality,

high importance for a smooth process operation,

safety or process critical.

The service advisor discussed every important measure-

ment point with the team. He provided useful hints on how

to improve the level of preventive maintenance without

increasing costs too much and provided alternatives for dis-

cussion, for example about maintenance-intensive devices:

Replace by a modern type or continue to maintain?

Based on the maintenance analysis an action plan was

worked out by the maintenance team with the objective to

improve the existing maintenance, inspection and calibra-

tion intervals to reduce the risk of unplanned shutdowns.

Some obsolete devices were identified and replacements

were ordered and commissioned.The spares stock was clea-

ned of unusable parts. Complete replacement devices and

up-to-date spare parts were added. These devices were con-

figured in a way that they would fit several applications

when needed.

The preventive measures within the system have now

improved instrumentation availability, operating safety of

the plant and product quality. The final Installed Base

Report records the results of the analysis and the commondiscussion.It served as a basis for the decisions in the action

plan. The registration tool was obtained from End-

ress+ Hauser and an operator was trained.All future additi-

ons or changes to the instruments will now be registered.

Some maintenance and calibration measures were out-

sourced for lack of resource and tools. A training pro-

gramme for the maintenance team was defined and agreed

to. The budget for the following planning period was well

detailed and signed off quickly by management since the

reasons were convincing and traceable to the Installed Base

Report.

For this plant, the main benefits of Instrument Manage-ment Solutions were given as:

transparency of the installed device basis,with the ability

to register devices from all manufacturers

improved quality control through better control of mea-

surement devices,

cost reduction through higher plant availability and

reduction of fire fighting.

5.4 Case B

Serving the automobile industry, this coating plant was

always maintained in a very complete way. As the business

environment had become increasingly competitive, the new

owner had reduced the staff in several cuts. The mainte-

nance team was organised as a cost centre.The workload for

annual the re-calibration of the more than 2000 sensors was

exceeding the available resources by more than 30%. The

site manager was faced with two challenges:

1. to keep the high standards of quality without increasing

cost or taking unknown risks

2. to check the instrumentation for its ATEX7 status?

Since the calibration team maintained records for every

instrument, only the instruments that were not being re-ca-

librated had to be registered in to the tool.The site audit was

carried out jointly by a member of the maintenance team

and the E+H service advisor. Eventually, further data were

downloaded from the calibration database. After the down-

load was completed and the data imported to the tool the

team noticed that the exact model numbers of the instru-

ments had never been completely recorded. The available

application information was not detailed enough for the

common discussions.Therefore,all other devices were regis-

tered as well.

In a previous attempt to streamline plant operations all

devices critical to the process had been identified.The main-

tenance team reviewed the criticality. An interesting point

was noted: Most of the process critical flowmeters had never

been wet-calibrated.For some of them there were no spares

available any more since the technology had become obso-

lete.

After several working sessions, it was demonstrated by

the team leader in a management meeting, that the scree-

ning process had resulted in a new calibration schedule that

could be handled by the current organisation without pus-

hing the resources to their limits any more. The increase in

risk through the reduction of calibration frequency on theless critical devices and by avoiding the re-calibration of

uncritical instruments was seen to be completely acceptable

by management and was thought to be easy enough to

explain to any auditors. In fact, the project team was compli-

mented on their good practice.

A download to Excel allowed the easy collating of an

instrument list that was segmented by manufacturer.This lis-

ting will then be used to check compliance with the ATEX

regulations in order to to determine replacement needs well

in advance of the 2006 deadline. All existing hazardous area

work places in use before June 30, 2003 must comply with

7The new European Use Directivewill soon require (by law) that a com-

plete,documented analysis has been conducted on sites that may have a

potentially explosive atmosphere.


8/10

10

Asset Management

the appropriate minimum requirements of ATEX 137 [8] no

later then June 30, 2006. The main benefits noted here were

the following:

establishment of technological status of all devices,

maintain quality control at reduced maintenance levels,

detection of obsolete material in the plant and in the spa-

res stock, well documented results in the Installed Base Report offer

traceability for inspectors and auditors.

The exercise described was repeated on another plants of

the same site later on.

6. Conclusion

The described collaborative effort between manufacturer

and end-user to carry out maintenance analysis and define a

well balanced maintenance strategy has proven to be aneffective approach. Its focus on process-critical and diffi-

cultto-maintain instruments as well as on good preparation

for failure events reduces down-time while keeping mainte-

nance efforts focussed. The migration plan will keep the

instrumentation easy to maintain.

The traceability simplifies budgeting and cost control.

Plant reliability is enhanced through better control of main-

tenance risks.

References

[1] EN 13306:2001 de/fr/en European Standard on Maintenance Termi-

nology.

[2] ISPE, GAMP Good Manufacturing Practice Guide: Calibration Mana-

gement.

[3] Norsok Standard,Z-008,Rev.2, Nov 2001, Criticality analysis for main-

tenance purposes.

[4] ISO 9001 covering quality management system.

[5] ISO 14001 covering environmental management system.

[6] FDA 21 CFR Part 11: FDA regulations concerning compliance for elec-

tronic Records and Signatures.

[7] Instrument Management Solutions: Service Overview SD007H/29/

en/08.01 Endress+Hauser.

[8] Use Directive ATEX 137, Directive 99/92/EC of the European Parlia-

ment of 28. January, 2000.

Acronyms

ATEX from the French phrase atmosphres explosives

CFR Code of Federal Regulations

CMMS Computerised Maintenance Management System

FDA Food and Drug Administration (U.S. Department of Health &

Human Services)

GMP Good Manufacturing Practice

GAMP Good Automated Manufacturing Practice

HAZOP Hazard and Operability

IEC International Electrotechnical Commission

ISO International Organization for Standardization

ISPE International Society for Pharmacoepidemiology

PD Positive Displacement

RBM Risk Based Maintenance

RCM Reliability Centered Maintenance

SIL Safety Integrity Level

TPM Total Productive Maintenance

Dipl.-Ing.ETH Michael Herzog has worked in various

management positions in Marketing, R&D and Ser-

vices at European and North American End-

ress +Hauser group companies since 1984 when he

joined the group. He grew up in Japan and holds a

diploma in electrical engineering from the ETH in

Zrich/Switzerland. Today, as Director Customer

Services he is responsible for the development of

the world-wide group activities in after-sales ser-vices. He is based in the corporate headquarters in

Reinach, Switzerland.

Adresse: Endress+ Hauser Consult AG, Kgenstr. 7,

CH-4153 Reinach, Tel. +41-61-715-7756, Fax -7758,

E-mail: [email protected]

Rinus van Kasteren joined the E+H group in 1990

and is based in the Sales and Service organisation

of Endress+ Hauser in the Netherlands.As a service

advisor he is responsible for the realisation of main-

tenance projects with a specific focus towards the

implementation of maintenance strategies for field

instrumentation. He has worked closely with main-

tenance managers and/or reliability engineers from

production companies such as Cargill, Unilever,Heinz, DSM, Huntsman and so on. In his 20 years in

various positions in customer service and mainte-

nance he assimilated valuable knowledge about

the problems and solutions in this field that he

makes available to customers of Endress+ Hauser

today.

Adresse:Endress +Hauser NL B.V., Nikkelstraat 612,

NL-1411 AK Naarden, Tel. +31 (0) 356 958-611, Fax

-825, E-mail: [email protected]

John A.Salusburys present position is within corpo-

rate management of Endress+ Hauser, based in

Switzerland, responsible for global marketing of

products and services. He started his career with

British Steel serving a four year apprenticeship inInstrumentation combined with studies at the

North E Wales Institute resulting in a diploma in

Industrial Measurement and Control. As an Instru-

ment Engineer he has worked for various compa-

nies including ICI, Sasol, Shell (both onshore and

offshore) and Kraft foods. He joined the E+ H group

in 1985 holding various management positions

including responsibility for the UK Flow measure-

ment division.

Adresse: Endress+Hauser Consult AG, Kgenstr. 7,

CH-4153 Reinach, Tel. +41 61715-7769, Fax 7762,

E-mail: [email protected]


9/10

Instrument Management SolutionsStriking the right balance in maintenance

The pressure on maintenance depart-

ments today is greater than ever before.

Companies are constantly looking atdownsizing, a genuine skill shortage existsand yet the overall company demand isconstantly to produce more. It becomesseemingly impossible for maintenancemanagers to improve planned maintenanceand at the same time reduce their costs.

The maintenance strategy is howeverexpected to fall in line with that of theoverall requirements of the companystrategy! If this is not difficult enough its

probably not appreciated that themaintenance engineer is constantly faced

with different types of equipment, fromdifferent generations of technology, someof which you may no longer be able toobtain spares for...

So management of the installed baserapidly turns into a headache!

If you recognise just some of these

points within your organisation, you

could undoubtedly benefit from

Endress + Hausers unique solution.


10/10

Austria

Endress+Hauser Ges.m.b.H.Lehnergasse 4

A-1230 WienTel.: +43 (1) 88 05 6-0Fax: +43 (1) 88 05 6-335E-Mail: [email protected]

Belgium

Endress+Hauser S.A./N.V.Rue Carli Straat 13B-1140 Bruxelles

Tel.: +32 (2) 2 48 06 00Fax: +32 (2) 2 48 05 53E-Mail: [email protected]

Canada

Endress+Hauser (Canada) Ltd1440 Grahams Lane, #1CDN-Burlington. OntarioCanada L7S 1W3


Denmark

Endress+Hauser A/SPoppelgrdvej 10-12DK-2860 Sborg

Tel.: +45 (70) 13 11 32Fax: +45 (70) 13 21 33E-Mail: [email protected]

Finland

Metso Endress+Hauser OyLaippatie 4CP.O. Box 310FIN-00881 Helsinki


France

Endress+Hauser3 rue du Rhin B.P. 150F-68331 Huningue Cedex


Germany

Endress+HauserMesstechnik GmbH+Co. KGColmarer Str. 6D-79576 Weil am RheinGermany

Tel.: +49 (76 21) 9 75 01Fax: +49 (76 21) 9 75 55 5E-Mail: [email protected]

Italy

Endress+Hauser S.p.A.Via Donat Cattin 2/AI-20063 Cernusco s/N -MI-

Tel.: +39 (02) 92 19 21Fax: +39 (02) 92 19 23 62E-Mail: [email protected]

Netherlands

Endress+Hauser B.V.Nikkelstraat 6-12Postbus 5102NL-1410 AC Naarden


Norway

Endress+Hauser A/SPostboks 62N-3420 Lierskogan

Tel.: +47 32 85 98 50Fax: +47 32 85 98 51E-Mail: [email protected]

Poland

Endress+HauserPolska Sp. e o.o.ul. Pilsudskiego 49-57PL-50-032 Wroclaw


Rep. South Africa

Endress+Hauser (Pty.) Ltd5 Commerce Crescent West.Eastgate Ext. 13P.O. Box 783996RSA-2146 Sandton


Singapore

Endress+Hauser(S.E.A.) Pte. Ltd01-11/12 The Synergy1 International Business ParkSGP-609817 Singapore

Tel.: +65 65 66 82 22Fax: +65 65 66 68 48E-Mail: [email protected]

Spain

Endress+Hauser S.A.Constitucion 3. Bloque A.E-08960 Sant Just Desvem


Sweden

Endress+Hauser ABP.O. Box 7006S-19207 Sollentuna


Switzerland

Endress+Hauser Metso AGSternenhofstr. 21CH-4153 Reinach / BL1


United Kingdom

Endress+Hauser Ltd.Floats RoadGB-Manchester M23-9NF

Tel.: +44 (161) 2 86 50 00Fax: +44 (161) 9 98 18 41E-Mail:[email protected]

USA

Endress+Hauser Inc.2350 Endress PlaceP.O. Box 246USA-46143 Greenwood,Indiana


All other countries

Endress+HauserInstruments InternationalColmarer Str. 6D-79576 Weil am RheinGermany

Tel.: +49 (76 21) 9 75-02Fax: +49 (76 21) 9 75-345E-Mail: [email protected]

Endress+Hauser Sales Centers

W@M Life Cycle Management with Endress+Hauser

At Endress+Hauser we have concentratedon the support of our instrumentationwithin all process industries for over fiftyyears. This expertise is now focused on arange of tools, products and services thatoffer a complete life cycle supportpackage for your process.

Under the umbrella of our revolutionaryW@M concept, an unique set of toolsallow you to plan your installation andconfirm the suitability plus expectedperformance of your application whilst still

in the engineering phase. A portfolio ofe-business solutions allows easy, costeffective procurement of goods. The newField Check (and Installed Base Analyst)allows you to manage test and validateyour installed instrumentation during itscomplete operating life.

Couple this with Endress+Hausersrenowned range of products and acomplete suite of on-site services and youcan be confident that your instrumentation

and process are supported properly andrunning at their optimum.The result - maximum process

efficiency and complete peace of mind.

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