Unit 54 Industrial Plant Services

Unit 54:

Industrial Plant Services

Unit code:

QCF level:

Credit value:


This unit will develop learners’ understanding of electrical supply systems, industrial compressors, steam services and refrigeration and heat pumps used in a range of engineering industrial plant.

Unit abstract

This unit will investigate and evaluate a range of services that are generally found in manufacturing and process plant. The approach is broad-based to reflect the fact that plant engineering encompasses more than one discipline. Its intention is to encourage learners to develop a holistic approach to the design, operation, installation and maintenance of plant services.

In learning outcome 1, learners are introduced to the operating principles of electrical power and lighting systems together with the relevant sections of the IEE regulations. Learning outcome 2 considers the principles of industrial compressed air systems and the associated health and safety considerations. In learning outcome 3, the provision of steam is examined for both power generation and process plant. Learning outcome 4 introduces learners to the applications and principles of operation of refrigeration plant and heat pumps.

Learning outcomes

On successful completion of this unit a learner will:

1     Understand the use and applications of electrical supply systems

2       Be able to apply the gas laws to industrial compressors

3     Understand the provision of steam services for process and power use

4       Understand industrial applications of refrigerators and heat pumps.

Unit content

1      Understand the use and applications of electrical supply systems

IEE regulations: relationship to Health and Safety at Work Act 1974 and other legislation; codes of practice; regulations for given plant requirements; regulations regarding earthing and hazardous environments

Lighting: lighting fundamentals; SI units of lighting; efficacy; colour rendering; lamps and luminaires; stroboscopic effect; lighting circuits/layout and their design

Starting and speed control: classification of systems – manual and automatic DC starters, star-delta starter, autotransformer starter; speed control for AC and DC motors

Transformers: sub-stations; single-phase and three-phase transformers; transformer installation requirements; cooling; transformation ratio; magnetisation current; determination of values for transformer outputs

Power factor: causes; effect on cost of supplies; power factor correction

2      Be able to apply the gas laws to industrial compressors

Gas laws: Boyle’s law, Charles’ law, combined gas equation; characteristic gas equation; relationship between pressure-volume (pV) diagram and work; adiabatic, polytropic and isothermal work; compressor efficiency; effect of multi-staging; pressure and volume ratios

Industrial compressor systems: positive displacement eg reciprocating compressors, helical and spiral-lobe compressors, sliding vane compressors, two-impeller straight-lobe compressors and blowers; dynamic eg centrifugal compressors, axial compressors; associated equipment eg coolers, dryers, air receivers; safety factors eg Health and Safety at Work Act and related legislation, insurance requirements, safety fittings, diesel effect and other hazards

3      Understand the provision of steam services for process and power use

Process steam: wet and dry saturated steam; temperature control; enthalpy of evaporation; available energy; condensate collection; pipeline energy losses; lagging; feed tanks; effect of boundary layer on energy transfer; air contamination; pipe sizing; overall plant efficiencies for process

Power steam: superheated steam; steady flow energy equation applied to turbines; turbine efficiency; Rankine cycle with and without reheat; condensers; cooling towers; overall plant efficiency for power

Combined heat and power: back pressure system; pass out system; desuperheating; appropriateness of application to relative demand; comparisons of overall plant efficiency for combined heat and power; illustrative sketches eg Sankey diagrams, circuit layouts

4      Understand industrial applications of refrigerators and heat pumps

Reversed heat engines: reversed Carnot and Rankine cycles; vapour compression cycle; second law of thermodynamics; temperature-entropy diagrams; pressure-enthalpy diagrams; refrigeration tables and charts; refrigerant fluids; environmental effects

Refrigerators: refrigeration effect; coefficient of performance; refrigerator cycle

Heat pumps: heating effect; coefficient of performance; economics of heat pumps; pump cycles

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 use and

use the relevant sections of the IEE regulations

applications of electrical

design appropriate lighting circuits

supply systems

classify starting and speed control mechanisms

determine appropriate values for transformer outputs

perform power factor correction calculations

LO2 Be able to apply the gas laws

derive formulae with reference to the gas laws

to industrial compressors

apply the gas laws to an industrial compressor system

LO3 Understand the provision of

explain the requirements for process steam according to

steam services for process


and power use

discuss the need for superheated steam for power use

determine overall plant efficiencies for process, power

and combined heat and power systems

produce illustrative sketches of heat distribution in


LO4 Understand industrial

determine coefficient of performance, heating effect and

applications of refrigerators

refrigeration effect of reversed heat engines

and heat pumps

use refrigeration tables and charts

sketch refrigerator and heat pump cycles

discuss the economics of heat pumps

explain the apparent contradiction between refrigeration

cycles and the second law of thermodynamics.



This unit has links with Unit 2: Engineering Science and Unit 43: Plant and Process Principles.

Essential requirements

Centres will need to provide access to electrical and heat engine laboratory facilities.

Employer engagement and vocational contexts

Liaison with plant engineering and process companies would be useful to give learners the opportunity to witness industrial plant services first-hand.