Unit 50 Condition Monitoring and Fault Diagnosis


Unit 50:

Condition Monitoring and Fault




Unit code:

QCF level:

Credit value:


This unit aims to provide learners with an understanding of condition monitoring techniques and will enable them to systematically locate and diagnose faults.

Unit abstract

Industrial process and power generation plant and many other engineering systems need to operate reliably for comparatively long periods of time. Condition monitoring can be of great assistance in ensuring this and is an essential element of preventative maintenance. It can signal the need for intervention to avoid expensive failures and system outages. Over a period of time, it can also provide data to assist in the planning and adjustment of a preventative maintenance programme.

This unit first examines the general concepts of condition monitoring, including the causes of failure, monitoring methods and the analysis of data. Learners will then look at a range of condition monitoring techniques such as those used to detect leaks, corrosion and cracking in engineering systems and plant.

Learners will study and apply a range of checks, tests and other techniques in order to diagnose, locate and identify system faults. Finally, learners will investigate the more common causes and effects of failure and, using a range of techniques, will analyse the cause and effect of such failure/s on system performance.

Learning outcomes

On successful completion of this unit a learner will:

1       Understand the concepts of condition monitoring

2     Understand the nature and use of condition monitoring techniques

3       Be able to locate faults in engineering systems

4       Be able to analyse the cause and effect of faults in engineering systems.

Unit content

1      Understand the concepts of condition monitoring

Failure and breakdown: degradation due to corrosion, cracking, fouling, wear, ageing, mal-operation, environmental effects, operational and maintenance considerations; statistical analysis of failure rates on plant and equipment

Monitoring: arrangements and measured parameters (‘online’ and ‘offline’ monitoring, fixed and portable monitoring equipment, continuous and semi-continuous data recording, stress analysis)

Data analysis: data analysis eg computerised systems, data acquisition techniques, use of generic computer software (such as spreadsheets, databases), fault analysis/diagnosis, plant down time analysis, data storage techniques, high-speed data capture, trend analysis, expert systems, condition monitoring integrated within ‘normal’ plant and machinery control and data acquisition systems

2      Understand the nature and use of condition monitoring techniques

Vibration: broad band defect detection; frequency spectrum analysis; shock pulse method; high-frequency analysis techniques

Leak detection: acoustic emission and surveillance; moisture sensitive tapes; radiotracer/radio-chemical methods

Corrosion detection: chromatography; eddy currents; electrical resistance; tangential impedance meter; IR spectroscopy; potential monitoring; thermograph; lasers

Crack detection: ultrasonic methods; optical fibres; lasers; strain gauges; electrical potential method; eddy currents; acoustic emission; thermography

Temperature: thermography; thermometry; thermistors; thermocouple devices; RTDs; optical pyrometers; IR pyrometers; lasers

3      Be able to locate faults in engineering systems

Information and documentation: plant personnel; alarm systems; component data sheets; block diagrams; flow charts; dependency charts; trouble shooting charts; wiring and schematic diagrams; circuit diagrams; system diagrams; operation and maintenance manuals; computerised records and data; use of internet

Inspection and test: characteristics of system; online/offline testing; test equipment; electrical/electronic/software based; self-diagnostic techniques; expert systems; safety requirements; safety and damage limitation

Fault location techniques: appropriate sources of information identified and selected; analysis of evidence; systematic and logical approach to fault finding; cause of fault evaluated and verified
4      Be able to analyse the cause and effect of faults in engineering systems

Causes of failure: mal-operation; environmental; lack of maintenance; operation outside design specifications; infrequent use, too frequent use; the ‘bath tub’ curve; reliability; common mode failure

Effects of failure: safety, economic, downtime, loss of production etc; failure states of components within a system

Analytical techniques: failure mode and effect analysis; fault tree analysis; cause and effect analysis
Learning outcomes and assessment criteria
Learning outcomes
Assessment criteria for pass
On successful completion of
The learner can:
this unit a learner will:

LO1 Understand the concepts of
describe the causes of failure and breakdown in plant
condition monitoring

and equipment and explain the use of statistical data for

analysing such failure/breakdown

describe plant and machinery monitoring arrangements

and explain the relative merits of each arrangement

provide a computer data analysis printout of machine

operating parameters

explain how condition monitoring may be integrated

within normal plant and machinery, control and data

acquisition systems

LO2 Understand the nature and
explain the nature of the condition monitoring
use of condition monitoring

techniques used to monitor temperature and vibration

and to detect leakage, corrosion and cracks

analyse an overall system for plant and machinery

condition monitoring and report findings

LO3 Be able to locate faults in
investigate and identify sources of information and
engineering systems

documentation used as an aid to fault finding and fault

location and report on their usefulness

select appropriate inspection and test equipment for

fault location

carry out appropriate fault finding procedures to locate

and verify faults in systems

LO4 Be able to analyse the cause
investigate and report on the causes of failure and
and effect of faults in

identify the failure states of components within a given
engineering systems


carry out a failure mode and effect analysis

carry out a fault tree analysis

prepare a cause and effect diagram.


This unit may be linked with other plant/process and engineering maintenance units, particularly

Unit 45: Plant Operation and Performance.

Successful completion of this unit will enable learners to meet, in part, the Engineering Council Standards for Professional Engineering Competence (UK-SPEC), detailed below:

       Engineering Technician (Eng Tech) B1 standard ‘identify problems and apply diagnostic methods to identify causes and achieve satisfactory solutions’

       Incorporated Engineer (IEng) standard A2 sub-paragraph 4 ‘Apply knowledge and experience to investigate and solve problems arising during engineering tasks and implement corrective action’.

Essential requirements

Centres delivering this unit must be equipped with, or have access to, industrial-standard condition monitoring equipment, instrumentation and facilities/equipment suitable for testing/fault finding. A range of system components for demonstration purposes and hands-on familiarisation will also need to be available.

Employer engagement and vocational contexts

Liaison with employers would prove of benefit to centres, especially if they are able to offer help with the provision of suitable industrial condition monitoring and fault-finding facilities and equipment.