ARTG-GDL1

DRAFT GUIDELINE (TRIAL USE)

Ammonia
Refrigeration
Training Guideline

Publication of this draft guideline for trial use and comment was approved by the International Institute
of Ammonia Refrigeration and the Refrigerating Engineers & Technicians Association, October, 2005.
Distribution of this draft guideline for comment shall not continue beyond June 30, 2009.

Draft Guideline (Trial Use)

Ammonia Refrigeration Training Guideline

Foreword
Background
There is broad recognition that ammonia refrigeration systems exist in many different configurations, sizes and types
of facilities. It is also widely recognized that personnel responsible for operation of refrigeration systems (sometimes
referred to as operators, technicians, engineers, mechanics, etc.; hereafter referred to as operators) have
significantly different roles and responsibilities in different facilities. More importantly, the industry at large has come
to understand the importance of effectively training system operators. Furthermore, the industry believes that training
guidelines identifying the areas of study and learning objectives for training system operators eliminates confusion
and provides a road map for companies struggling with the task of meeting governmental regulations. This training
guideline identifies the core competencies in an effective training program.
There currently exist many examples of training best practices available to the industry. These best practices are
drawn from many different training venues that exist across the industry and include training programs developed by
end users; organizations such as RETA (Refrigerating Engineers & Technicians Association); IIAR (International
Institute of Ammonia Refrigeration), colleges/technical schools; and programs conducted by contractors and training
consultants.
The development of this Ammonia Refrigeration Training Guideline is in response to the industrys call for such a
resource. This collection of best training practices is purposely presented only as a guideline. While a standard-like
review and comment by balanced interest groups was used to ensure that the guideline has broad industry support, this
document should not be interpreted or represented as a formal industry standard.

Use of the Training Guideline

The learning objectives listed in this Guideline represent the consensus of a representative ammonia refrigeration
industry group that included consultants, contractors, educators, and end-users. The Guideline is intended for use by
companies developing new training programs or evaluating existing programs, and by training providers developing or
offering training programs. While no current training program includes all of the elements contained in this guideline,
it is hoped that all employers of ammonia refrigeration system operators as well as training providers will carefully
review their training programs and curricula to ensure that the programs address the relevant learning objectives and
competencies.
It is understood that regulatory agencies may use this guideline to evaluate whether a particular ammonia refrigeration
facility has adequately trained its operators. Facilities that have used the Guideline for internal
self-evaluation will be well prepared for such outside reviews.
The Guideline is intended to apply to the majority of typical ammonia refrigeration systems. However, because of
the wide variety of systems existing in the industry, certain portions of the Guideline may not be applicable to some
facilities. For example, references to Process Safety Management (PSM) and Risk Management requirements may not
apply to some facilities. Facilities are encouraged to use their professional judgment as they review and consider the
Guideline. The key is to ensure that the refrigeration operators are adequately trained.
The industry has endorsed the concept of multiple skill levels for its operators, with most firms recognizing three skill
levels. Accordingly, this Guideline supports a multi-level approach by grouping learning objectives and competencies
by level. It is recognized that a minority of operators will complete the highest skill level training. In some facilities,
the responsibilities and duties requiring such training are handled by supervisory personnel, engineering staff or outside
contractors and consultants rather than by operational staff. However, individuals carrying out these responsibilities
should still be trained in the competencies listed for this level.

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The OSHA Process Safety Management PSM standard (and its EPA cousin, the Risk Management RM
regulation) both require ammonia refrigeration facilities to have written operating procedures and to provide training to
operators on an overview of the process and on those procedures. This training is not the same as the training covered
by this Guideline. This Guideline discusses overall educational job competencies, while PSM/RM covers only the
narrow performance of specific regulated job tasks.
This Guideline is not intended to substitute for PSM/RM training, nor can training in a small number of operating
procedures replace a broad base of refrigeration knowledge. Do not assume that following this Guideline constitutes
PSM training.
Some small facilities may not be required to comply with PSM/RM. These facilities may still find it beneficial to
prepare and use operating procedures in their plants. Both OSHA and EPA enforce so-called general-duty clauses
calling upon them to handle chemicals such as refrigerants with due care. Written operating procedures can be of help
in this, if operators are trained in their use.
The guideline assumes that an experienced trainer familiar with the curriculum that addresses these learning objectives
will provide operator training. In addition to having quality training materials and instructors, it is recommended that
an appropriate assessment be conducted to measure training effectiveness. A thorough evaluation and verification
of training effectiveness may include verbal testing, written testing, certification programs, documentation of prior
education/training and/or hands-on site-specific demonstration of competencies.
It should also be noted that this industry-wide guideline primarily addresses classroom-type training. Such training is
supplemental to the critical hands-on, facility-specific training that should cover detailed operating procedures for the
various system components that comprise a working ammonia refrigeration system. The limited mention of such
hands-on training associated with those operating procedures should not be taken as an indication that it is any less
important than the learning objectives included in this guideline.

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Table of Contents
Foreword (Informative).................................................................................... i
Purpose.......................................................................................................... 1
Scope............................................................................................................. 1
Operator Classifications................................................................................. 1
Prerequisite Training and Skills Assessment................................................. 2
Assessment of Training Effectiveness........................................................... 3
Learning Objectives for Effective
Refrigeration Operator Training Programs..................................................... 5

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0


9.0


10.0


11.0


12.0


13.0


14.0

General Facility Information ....................................................................5

Engineering Units and Conversions.........................................................5
Refrigeration Thermodynamics................................................................5
Mechanical Vapor Compression Refrigeration Cycle...............................7
System Energy Efficiency.........................................................................7
Ammonia as a Refrigerant........................................................................8
Process Safety Information......................................................................8
Evaporators
Description, Theory of Operation and Maintenance.................................9
Compressors
Description, Theory of Operation and Maintenance.................................9
Condensers
Description, Theory of Operation and Maintenance...............................10
Metering Devices
Description, Theory of Operation and Maintenance...............................11
Pressure Vessels
Description, Theory of Operation and Maintenance...............................11
Piping and Accessories
Description, Theory of Operation and Maintenance...............................11
Liquid Ammonia Pumps
Description, Theory of Operation and Maintenance...............................12

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15.0


16.0


17.0


18.0


19.0

20.0

Controls and Control Valves

Description, Theory of Operation and Maintenance...............................12
Motors and Drives
Description, Theory of Operation and Maintenance...............................13
Purgers
Description, Theory of Operation and Maintenance...............................13
Other Components
Description, Theory of Operation and Maintenance...............................13
Operating Procedures and Practices.....................................................13
Regulatory Awareness...........................................................................14

Appendix A................................................................................................... 15
Pre-employment Screening

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AMMONIA REFRIGERATION TRAINING GUIDELINE

PURPOSE
This Guideline provides a set of recommended training objectives for personnel responsible for the operation of
ammonia refrigeration systems (operators, technicians, engineers, mechanics, etc.; hereafter referred to as operators).
Such training promotes the safe, efficient, and cost-effective operation of ammonia refrigeration systems and
equipment.

SCOPE
This Guideline lists refrigeration-specific concepts, skills, knowledge, and competencies (presented as learning
objectives) that should be included in training programs for ammonia refrigeration operators. Training addressing these
learning objectives should be combined with hands-on training focused on the various system and equipment-specific
written operating procedures. The learning objectives provided herein will provide the knowledge needed to properly
understand such operating procedures and to enhance decision-making abilities of the operator.
This Guideline also provides a recommended list of non-refrigeration, facility-specific training that is recommended
background training for individuals prior to commencing formal refrigeration operator training, but does not list
specific training objectives for these topics.
This Guideline does not prescribe specific curriculum materials or training methods.

OPERATOR CLASSIFICATIONS
The learning objectives in this Guideline are divided down into the following suggested skill level classifications:

Entry

Operational

Technical

It is recognized that some facilities may use a different approach to skill levels and this Guideline is not meant to
discourage such approaches. The guideline is purposely structured to be readily modified to rearrange the learning
objectives into fewer or more levels.
The Recommended Prerequisite Training section represents the recommended minimum set of skills, knowledge and
competencies for any person entering training as an ammonia refrigeration operator.
The learning objectives for the Entry skill level represent a recommended set of skills, knowledge and competencies
for personnel who:

Observe refrigeration system operations

Record pertinent operation parameters

Take control actions only under direct supervision of a supervisor or Operational level personnel

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The learning objectives for the Operational skill level represent a recommended set of skills, knowledge and
competencies for personnel who:

Have successfully performed at the Entry Level

Start and stop equipment

Adjust controls, actuate valves

Perform routine system maintenance

Assist in training of Entry level personnel

Perform system troubleshooting

The learning objectives for the Technical skill level represent a recommended set of skills, knowledge and
competencies for personnel who:

Have successfully performed at the Operational Level

Make decisions regarding operating strategies, setpoints, and limits

Optimize system operations for improved cost and reliability

Schedule and/or perform major repairs and rebuilds

Recommend system upgrades and improvements

Perform system inspections and mechanical integrity checks

Participate extensively in the Process Safety Management program

Perform complex troubleshooting

Oversee or inspect system construction/installation activities

Supervise Operational and Entry level operators

Coordinate shutdowns and pumpdowns

Administer preventive and predictive maintenance systems

The classifications are intended for guidance only, and are not intended to suggest that operational duties must be
organized into these three levels. Users whose staffs are organized differently should document the duties and
corresponding training objectives associated with their own set of classifications.

PREREQUISITE TRAINING AND SKILLS ASSESSMENT

This document assumes that the prospective operator trainee has been assessed for basic abilities and tendencies that
are widely accepted as being prerequisites for becoming an operator. There are a number of skill and/or aptitude
assessment tools available. In order to be ready to receive the training outlined in this guideline, a good candidate for
the job of a refrigeration system operator would typically have the following aptitudes and knowledge base:

Strong mechanical aptitude

Basic mechanical skills and knowledge of machinery

Basic electrical skills

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Basic communication skills

Basic math skills

Basic computer skills

Appendix A provides additional information on one approach to pre-employment screening.

This document is also based on a collection of assumptions about prior skill screening and training not specific to
ammonia refrigeration system operators. Such training not covered by this Guideline is subject to federal,
state and local regulations as well as a companys human resource policies.
Examples of such training are as follows:

Lock-Out/Tag-Out

Fall Protection

Hearing and Eye Protection

Hazard Communication Standard (HAZCOM)

Personal Protective Equipment (PPE)

Site and Product Security

Emergency Action Plan

Communication Skills

The required communication skills may include the ability to read and understand operating procedures; to fill out
operating logs and system status reports; and to orally communicate with co-workers and with emergency personnel,
to describe the current system status and the nature and location of dangerous or abnormal conditions.
The trainee should also be fully aware of any facility security requirements such as identification cards, controlled
access areas, traffic policies, and general evacuation and emergency notification procedures.
Lastly, it is assumed that the candidate has received appropriate familiarization and orientation concerning the nature
of the business done at the facility, any production processes that may take place in the facility and any other typical
employee orientation.
Upon successful completion of the above-described orientation and training, the refrigeration system operator trainee
should be ready for the specialized training described in this Guideline.

ASSESSMENT OF TRAINING EFFECTIVENESS

Assessment is a key success factor for any curriculum. The application of reliable and accurate pre-assessment tools
determines a learners appropriate fit into a curriculum, having both the pre-requisite skills necessary to complete the
curriculum, and the personal interest and aptitude to do so. Ongoing assessment within the instructional modules can
inform the student of progress as well as provide feedback for selecting individual learning strategies and achieving
program-learning goals. Likewise, proper post-instructional assessment assures learners have demonstrated the
knowledge, skills and abilities of the programs terminal objectives. The following methods may be used for
measuring a trainees understanding of each learning objective, but are not meant or intended to be all-inclusive.
Assessments should be documented.
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Written Achievement Tests: Questions designed to verify the trainees comprehension of the subject matter should
be included in a traditional achievement test. True/False, Multiple Choice, and Essay are acceptable types.
Verbal/Oral Exam Interview: Verbal questions designed to verify the trainees comprehension of the subject
matter should be included in an oral exam administered by an individual knowledgeable in the subject matter.
Demonstration/Performance Exam: The trainee should be able to demonstrate the acquired knowledge by
performing tasks that require said knowledge. The Performance Exam should be administered and supervised by an
individual knowledgeable in the subject matter.
The Appendix contains an extensive listing of resources that may be helpful in the preparation of a curriculum needed
to provide effective instruction relative to these learning objectives.

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Learning Objectives for Effective

Refrigeration Operator Training Programs
This section is a collection of Learning Objectives that
are segregated into general topical areas and then into
three different Classification levels. The individual
Learning Objectives are not meant to itemize every
detailed concept or task that training should address.
Rather, they are intended to represent a collection of
related subjects that would typically be covered together.
The numbering system for the Learning Objectives
is solely for the purpose of organization and does not
represent or dictate a specific order of priority.

1.3 (Technical):

The Learning Objectives are brief statements describing

the topic content that the trainee is expected to learn and
understand.

1.0 General Facility Information

(see also Process Safety Information)

1.3.1 Non-refrigeration process P&IDs that

interface with the refrigeration system

2.0 Engineering Units and Conversions

2.1 (Entry):

2.1.1 Units of measurepressure (including

vacuum), temperature

2.1.2 Conversion from one system of measure

to others that will be encountered

2.2 (Operational):

2.2.1 Units of measure for energy (work),

power, refrigeration tonnage, density (and specific gravity), specific volume and various measure
of humidity

1.1 (Entry):

1.1.1 Ammonia-related site security including

ammonia theft prevention

2.2.2 Units of measure for volumetric and

mass flows

1.1.2 Location, operation and use of Personal

Protective Equipment (PPE)

2.2.3 Conversion from one system of measure

to others that will be encountered

1.1.3 Alarming procedures, evacuation routes,

assembly points

2.3 (Technical):

1.1.4 Importance of refrigeration to production

processes

1.1.5 Implications of refrigeration failure

1.1.6 Layout/location of refrigerated spaces

and processes

2.3.1 Units of measure unique to refrigeration

systems such as kW and bhp per ton, mass flow
rate of refrigerant per ton (lb/min-TR), compressor
capacity expressed in cfm per ton

2.3.2 Conversion from one system of measure

to others that will be encountered

1.2 (Operational):

1.1.7 Locations of Machinery Rooms and

other equipment

1.2.1 Product quality assurance programs

associated with refrigerationHandling and
documentation of deviations-who to contact
1.2.2 Environmental (temperature/humidity)
requirements of refrigerated spaces

Copyright 2007 The International Institute of Ammonia Refrigeration

3.0 Refrigeration Thermodynamics

3.1 (Entry):

3.1.1 Basic phase changes that substances

undergo

3.1.2 Predictable relationship between temperature and pressure of a pure substance when
liquid and vapor phases are present (use of
Pressure Temperature (PT) Tables)
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3.1.3 Basic concept of heat transfer

3.1.4 Basic psychrometric properties (dry bulb,

wet bulb, relative humidity)

3.1.5 Basic understanding of condensation/

frost build-up and implications

3.1.6 Basic concept of fluid flow (high to low,

pressure drop with flow)

3.1.7 Awareness of behavior of brine and

glycol solutions

3.2 (Operational):

3.2.1 Concept of specific heat, typical units

of measure

3.2.2 Specific heats of pertinent substances

3.2.3 Relationship between specific heat and

heat capacity

3.2.4 Sensible Heat portion of the total

refrigeration load

3.2.5 Awareness of calculations of Sensible

Heat Load

3.2.6 Latent heat of fusion (freezing/thawing)

3.2.17 Basic implications of Pressure/Volume/

Temperature (P/V/T) relationships for ammonia
vapor

3.2.18 Properties of brines and glycols

3.3 (Technical):

3.3.1 Tables of specific heats of common

substances and sense of the typical values of
specific heats for different categories of
substances such as fluid solutions, metals, foods,
and gases

3.3.2 Detailed Sensible Heat Load calculations

3.1.8 Basic Pressure Enthalpy (PH) diagrams

3.2.7 Latent heat of vaporization (evaporation/

condensation)
3.2.8 Latent heat portion of the total
refrigeration load
3.2.9 Modes of heat transferconduction,
convection (and radiation)

3.3.3 Tables of latent heats of fusion for

commonly frozen substances

3.3.4 Latent heat of vaporization as found in

thermodynamic property tables

3.3.5 Calculation of Latent Heat Load

3.3.6 Calculation of transmission loads, infiltration loads, motor loads and respiration loads
3.3.7 Calculation of Total Heat Load

3.3.8 Typical conduction and convection heat

transfer coefficient ranges

3.3.9 Effects of fouling and scaling

3.3.10 Basic formulas for each type of heat

transfer:

3.3.10.1 Types of heat transfer

coefficients: thermal resistance R,
convection coefficient h, emittance e

3.3.10.2 Conditions or characteristics

that lead to increases or decreases in heat
transfer coefficients
3.3.11 Piping system pressure drop calculations

3.2.10 Parameters affecting heat transfer

(phase changes, velocity)

3.2.11 Conductors and insulators

3.2.12 Pressure drop due to flow or elevation

change

3.3.12 Reducing piping pressure drop

3.2.13 Pressure drop tables for flowing

ammonia refrigerant vapor and liquid

3.3.13 Detailed understanding of PVT

relationships for ammonia vapor

3.3.14 Psychrometric processes and chart usage:

3.2.14 Basic pipe sizing using tables

3.2.15 Beneficial pressure drop

3.2.16 Detrimental pressure drop and associated

negative impacts

3.3.14.1 Air chilling/conventional

dehumidification

3.3.14.2 Conditions for frost formation

3.3.14.3 Specialized dehumidification

reheat, dessicants

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4.0 Mechanical Vapor Compression

Refrigeration Cycle

4.1 (Entry):

4.1.1 Cycle comprised of four thermodynamic

processes:

4.2.4 Expansion Process:

4.2.4.1 Role of expansion process

4.2.4.2 Impact of subcooling

4.2.4.3 Flash gas generation

4.3 (Technical):

4.1.1.1 Basic evaporation process

4.1.1.2 Basic compression process

4.1.1.3 Basic condensation process

4.3.1.1 Single stage compression

4.1.1.4 Basic expansion (throttling)

process

4.3.1.2 Two-stage compression with

intercooling

4.2 (Operational):

4.2.1.1 Role of evaporation process

4.2.1.2 Impact of inadequate liquid

supply

4.2.1.3 Impact of frost build-up

4.2.1.4 Impact of temperature differential

4.3.3.3 Lb/min per ton refrigerant flow

4.2.1.5 Impact of contaminants

including water

4.3.3.4 Flash gas fraction

4.2.1 Evaporation Process:

4.3.2 Correlation of diagram with

Thermodynamic Property Tables

4.3.3 Calculations related to refrigeration

cycle:

4.2.1.6 Superheat
4.2.2 Compression Process:

4.3.1 Representation of refrigeration cycle on

P-H diagram:

4.3.3.1 Theoretical horsepower per ton

4.3.3.2 Cfm per ton (theoretical and
actual)

4.3.3.5 Coefficient of Performance

(COP)
4.3.4 Typical refrigeration system application
parameters (Ammonia Data Book Appendix B)

4.2.2.1 Role of compression process

4.2.2.2 Impact of liquid carryover

5.0 System Energy Efficiency

4.2.2.3 Energy input (electric motor/

gas engines)

4.2.2.4 Compression ratio

4.2.2.5 Brake horse power per ton

5.1.1 Effect of condensing pressure/

temperature

4.2.2.6 Two-stage compression with

intercooling

5.1.2 Effect of suction pressure/temperature

4.2.2.7 Compressor displacement/

volumetric efficiency
4.2.3 Condensation Process:

4.2.3.1 Role of condensation process

4.2.3.2 Impact of non-condensibles

4.2.3.3 Impact of desuperheating

4.2.3.4 Impact of subcooling

4.2.3.5 Impact of temperature differential

Copyright 2007 The International Institute of Ammonia Refrigeration

5.1 (Entry):

5.2 (Operational):

5.1.3 Evaporative condenser winter operation

5.2.1 Effect of evaporator and condenser

temperatures on compression work
5.2.2 Effect of temperature differentials
between ammonia and process load

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5.2.3 Effect of temperature differentials

between ammonia and ambient

5.2.4 Liquid subcooling benefits

5.2.5 Vapor superheating issues

5.2.6 Efficient flash gas removal

6.2.1.3 Tolerance for contamination

6.2.1.4 Favorable operating pressure

range

6.2.2 Thermodynamic properties:

6.2.2.1 Familiarity with saturation
tables

5.2.7 Two-stage vs. single stage compression

5.2.8 Multiple suction pressure systems

6.2.3 Corrosion considerations

5.2.9 Impact of compressor economizer/

side port use

6.2.4 Ammonia and Water:

6.2.4.1 Affinity for moisture

5.2.10 Fan power/application of variable speed

drives and 2 speed motors

6.2.4.2 Discharging ammonia into

water

5.2.11 Benefits of effective purging/

noncondensible elimination

6.2.4.3 Waters effect on evaporating

temperature

5.2.12 Part-load operation of compressors

5.3 (Technical):

5.3.1 Demand management strategies

including process scheduling and thermal storage
5.3.2 Optimization of evaporator temperature
differentialsdesign and operation

6.2.5 Oil solubility in ammonia

6.2.6 Ammonia releases to the environment

6.3 (Technical):

6.3.1 Ammonia Pressure-Enthalpy (Mollier)

Diagram:

6.3.1.1 Vapor dome and mixture quality

5.3.3 Optimization of condenser temperature

differentialsdesign and operation

6.3.1.2 Saturated liquid line

5.3.4 Efficiency measuresbhp/TR, kW/TR,

COP

6.3.1.3 Saturated vapor line

6.3.1.4 Superheat region

5.3.5 Optimization of component (ie.

compressors, condensers, etc) sequencing

6.3.2 Superheated vapor property tables

6.3.3 Ammonia-water solutionspH

6.0 Ammonia as a Refrigerant

7.0 Process Safety Information

6.1 (Entry):

7.1 (Entry):

6.1.1 Choice of ammonia as system refrigerant

6.1.1.1 Environmental advantages
6.1.1.2 DetectabilitySelf-alarming
quality

6.1.1.3 Cost and availability

6.2 (Operational):

6.2.1 Operational Advantages:

6.2.1.1 Cycle efficiency

6.2.1.2 Lower mass flows

7.1.1 Ammonia Properties, Health Effects and

Hazards
7.1.2 Personal Protective Equipment
7.1.3 Concentration Measurement
7.1.4 Flammability Issues

7.1.5 Ammonia Inventory Awareness

7.1.6 Block flow or Process Flow Diagrams

7.1.7 P&ID awareness

7.1.8 Operating limits

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7.1.9 Implications of deviations outside

operating limits

8.1.1.8 Fan coil air units (forced and

induced draft units)

7.1.10 Compatibilitymaterials of construction

8.1.1.9 Other

7.1.11 Controlscutouts, alarms, detectors

8.2 (Operational):

8.2.1 Evaporator isolation and pump-out

procedures

7.1.14 Electrical classification awareness

8.2.2 Defrost methods for air units

7.1.12 Relief system awareness

7.1.13 Ventilation system awareness

7.1.15 Mass and energy balance awareness

7.1.16 Design code and standard awareness

8.2.4 Safety considerations for evaporators

7.2 (Operational):

8.2.5 Evaporator troubleshooting

8.3 (Technical):

7.3 (Technical):

8.3.1 Capacities of evaporators

7.3.1 Ammonia inventory calculations

8.3.2 Proper and improper applications

7.3.2 Relief system design basis/calculations

7.3.3 Ventilation system design basis/

calculations

9.0 Compressors-Description, Theory of

Operation and Maintenance

7.2.1 Working knowledge of P&IDs

7.3.4 Design codes and standards

8.2.3 Maintaining evaporator efficiency

9.1 (Entry):

9.1.1 Different compressor categories:

7.3.4.1 Mechanical

7.3.4.2 Fire

7.3.4.3 Electrical

9.1.1.1 Positive displacement

compressors

9.1.1.2 Dynamic (centrifugal)

displacement compressors

9.1.2 Different types of compressors:

9.1.2.1 Rotary screw

7.3.4.4 Pressure Vessels

8.0 Evaporators-Description, Theory

of Operation and Maintenance

8.1 (Entry):

8.1.1 Types of evaporators:

8.1.1.1 Shell and tube (flooded and

direct expansion)

9.1.2.2 Reciprocating piston

9.1.2.3 Vane rotary
9.1.2.4 Other

9.1.3 Basic theory of compressor operation

8.1.1.2 Plate and frame (flooded and

direct expansion)

9.1.4 Effect of a liquid slug on a positive

displacement compressor

8.1.1.3 Falling film plate chillers

8.1.1.4 Ice builders and ice makers/

harvesters

9.1.5 Impact of different conditions such as

warm start-up on the operation of the compressor

8.1.1.5 Hydro-coolers

8.1.1.6 Plate freezers

8.1.1.7 Swept surface heat exchangers

Copyright 2007 The International Institute of Ammonia Refrigeration

9.1.6 Compressor rotation direction

9.1.7 Types of compressor drive arrangements
9.1.8 Typical safe operating limits

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9.1.9 System specific list/description of

compressors in use

9.3.2 Alignment procedures

9.3.3 Vibration monitoring and/or analysis

9.2 (Operational):

9.3.4 Compressor shaft seals

9.2.1 Various methods of starting and stopping

compressors

9.3.5 Volumetric and compression efficiency

characteristics

9.2.2 Compressor isolation and pump-out

procedures

9.3.6 Compressor overhaul/rebuild

considerations

9.2.3 Compressor safety controls

10.0 Condensers-Description, Theory of

Operation and Maintenance

9.3.7 Compressor mass/energy balances

9.2.4 Lubrication methods/systems

9.2.5 Correct method of adding and draining

oil from compressors

9.2.6 Oil sampling and analysis

10.1 (Entry):

9.2.7 Oil separation methods

9.2.8 Oil filtration systems

10.1.1.1 Evaporative condensers

9.2.9 Causes and effects of refrigerant

migration to compressors

10.1.1.2 Water-cooled condensers

10.1.1.3 Air-cooled condensers

10.1.1.4 Other

9.2.11.2 Thermosyphon

10.2 (Operational):

9.2.10 Effect of suction vapor superheat on the

compressor

9.2.11 Various types of oil cooling:

10.1.1 Different condenser types:

10.1.2 System specific list/descriptions of

condensers in use

9.2.11.1 Water or glycol cooled

9.2.11.3 Liquid injection

9.2.11.4 Other

9.2.12 Compressor oil dynamics

9.2.13 Operation of the economizer (side) port

9.2.14 Part-load characteristics of compressors

9.2.15 Compressor relief arrangement and why

it is needed

9.2.16 Discharge check valves

10.2.1 Maintaining the condenser system

10.2.2 Condenser capacity and operational
control:
10.2.2.1 Summer vs. winter operation

10.2.2.2 Single speed vs. two speed vs.

VFD

10.2.2.3 Flow control on water-cooled

10.2.3 Condenser isolation and pump-out

procedures

9.2.17 Compressor control system

10.2.4 Water makeup/blowdown systems

9.2.18 Compressor troubleshooting

10.2.5 Water treatment systems and fouling

9.3 (Technical):

10

9.3.1 Compressor motor installation and/or

replacement

10.2.6 Condenser troubleshooting

10.3 (Technical):

10.3.1 Condenser mass/energy balance

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11.0 Metering Devices-Description,

Theory of Operation and Maintenance

11.1 (Entry):

11.1.1 Types of metering devices:

12.2 (Operational):

12.2.1 Pressure vessel maintenance

12.2.2 Pressure vessel troubleshooting

12.3 (Technical):

11.1.1.1 Hand metering valves

12.3.1 Requirements for coded vessels

11.1.1.2 Float-actuated valves

12.3.2 Gas/liquid separation

11.1.1.3 Modulating valves

11.1.1.4 Fixed orifices

11.1.1.5 Thermal expansion valves

11.1.1.6 Other

11.2 (Operational):

11.2.1 Metering device troubleshooting

11.2.1 Metering device maintenance and

rebuilds

11.3 (Technical):

11.3.1 Capacities of metering devices

11.3.2 Proper and improper applications

12.0 Pressure Vessels-Description,

Theory of Operation and Maintenance

12.1 (Entry):

12.1.1 Function of the pressure vessels:

13.0 Piping and Accessories-Description,

Theory of Operation and Maintenance

13.1 (Entry):

13.1.1 Categories of piping:

13.1.1.1 Liquid

13.1.1.2 Discharge vapor

13.1.1.3 Suction vapor

13.1.1.4 Two-phase flow

13.1.1.5 Other

13.2 (Operational):

13.1.2 Pipe labeling

13.2.1 Piping system troubleshooting:

13.2.1.1 Noise

13.2.1.2 Movement

13.2.1.3 External corrosion

12.1.1.1 Pump receivers

13.2.2 Minimizing risk of physical impact/damage

12.1.1.2 High pressure receivers

13.2.3 Insulation maintenance:

12.1.1.3 Surge drums

13.2.3.1 Vapor barrier

12.1.1.4 Intermediate vessels

13.2.3.2 Physical damage

12.1.1.5 Oil pots

12.1.1.6 Suction accumulators

13.2.4 Line opening procedures including

system re-start

12.1.1.7 Oil Separators

12.1.1.8 Thermosyphon receiver

12.1.1.9 Controlled pressure receivers

12.1.1.10 Other
12.1.2 Acceptable operating pressure and level
limits

Copyright 2007 The International Institute of Ammonia Refrigeration

13.2.5 Types of service valves:

13.2.5.1 Angle valves

13.2.5.2 Globe valves

13.2.5.3 Ball valves

13.2.5.4 Butterfly valves

13.2.5.5 Other

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13.2.6 Operation and maintenance of service

valves:

13.2.6.1 Opening and closing

13.2.6.2 Trapped liquid

13.2.6.3 Packing

13.2.6.4 Other
13.2.7 Safety relief system:

15.0 Controls and Control Valves-Description, Theory of Operation

and Maintenance

15.1 (Entry):

15.1.1 Types:
15.1.1.1 Solenoid valves

13.2.7.1 Compressor

15.1.1.2 Downstream pressure regulators

13.2.7.2 Relief discharge piping

15.1.1.3 Back pressure regulators

13.2.7.3 Pressure vessel

15.1.1.4 Check valves

13.2.7.4 Hydrostatic relief

13.2.7.5 Other

15.1.1.5 Motorized or modulating

valves

13.3.1 Piping component replacement

13.3.2 Mechanical integrity inspections

13.3.3 Piping materials, types, and pressure/

temperature ratings

14.0 Liquid Ammonia Pumps-Description, Theory of Operation

and Maintenance

14.1 (Entry):

14.1.1 Pump Types:

14.1.1.1 Positive displacement

14.1.1.2 Centrifugal

14.1.1.3 Mechanical seals vs. seal-less

15.1.1.6 Awareness of programmable

logic controller (PLC) and microprocessor-based controls

15.1.1.7 Other

13.3 (Technical):

14.2 (Operational):

15.2 (Operational):

15.2.1.1 Procedures for testing safety

controls (e.g. high-level cutouts)

15.2.2 Control and/or automation/information

systems:

15.2.2.1 Microprocessors

15.2.2.2 Relays, timers, switches

15.2.2.3 PLCs

15.2.2.4 Other

15.2.2.5 Consequences of failure

15.2.2.6 Troubleshooting

14.2.1 Liquid ammonia pump safety features

14.2.2 Operation and maintenance of liquid

ammonia pumps

14.2.3 Liquid ammonia pump troubleshooting

14.3 (Technical):

12

15.2.1 Operation and maintenance of control

valves:

15.1.2 Functions of each type

15.3 (Technical):

15.3.1 Sizing of control valves

15.3.2 Advanced troubleshooting using automation/information systems

14.3.1 Proper and improper applications

(including use of pump curves/charts)

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16.0 Motors and Drives-Description,

Theory of Operation and Maintenance

16.1 (Entry):

16.1.1 Types of motor enclosures

16.1.2 Motor alignment
16.1.3 Bearing lubrication
16.1.4 Full load amps

17.2 (Operational):

17.2.1 Sources, impacts, and detection of

non-condensible gases

17.2.2 Basic operation of automatic and manual

purgers

17.2.3 Manual removal of non-condensibles

17.3 (Technical):

17.3.1 Proper and improper applications

16.1.5 Rotation

16.1.6 Speeds available

16.2 (Operational):

16.2.1 Wiring

18.1 (Entry):

16.2.2 Hot starts per hour

18.1.1 Awareness of manual overpressure

control systems

18.0 Other Components-Description,

Theory of Operation and Maintenance

16.2.3 Motor service factor

16.2.4 Loaded start

16.2.5 Awareness of starter typesfull voltage,

reduced voltage, incremental

18.1.2 Awareness of insulation and vapor

barrier systems

16.2.6 Unbalanced voltages

18.1.3 Awareness of freezer underfloor heating

systems

16.2.9 Starter transition times

18.2 (Operational):

16.2.7 Voltage tolerance

16.2.8 Surge voltage

18.1.4 Awareness of freezer enclosure venting

during rapid pull-down

16.2.10 Auxiliary contacts

16.2.11 Gear boxes

16.2.12 Variable frequency drives

18.2.1.1 Manual overpressure control

system

16.3 (Technical):

18.2.1.2 Purpose of insulation and

vapor barrier systems

16.3.1 Motor selection criteria

18.2.1.3 Underfloor heating systems

16.3.2 Starter type details and troubleshooting

16.3.3 Mechanical drives-engines, turbines

17.0 Purgers-Description, Theory

of Operation and Maintenance

17.1 (Entry):

17.1.1 Basic awareness of non-condensibles

and purging

18.2.1.4 Freezer enclosure vents

18.3 (Technical):

18.3.1 Proper and improper applications

19.0 Operating Procedures and

Practices

19.1 (Entry):

Copyright 2007 The International Institute of Ammonia Refrigeration

18.2.1 Operation and Maintenance:

19.1.1 Basic operating procedures

19.1.2 Use of automated systems
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19.1.3 Routine monitoring and logging

19.1.4 Safe operating limits

19.1.5 Production-required operating limits

19.1.6 Alarms and proper response

20.1.2 General Duty Clause awareness

20.1.3 Location of program documents

20.1.4 Local, state and Federal reporting

requirements

19.2.2 Adding oil

20.2 (Operational):

19.2.3 Draining oil

20.3 (Technical):

20.3.1 Administration of the PSM and RM

programs

20.3.2 Record maintenance and storage

19.1.7 Good housekeeping

19.2 (Operational):

19.1.8 Detection of leaks

19.2.1 Advanced operating procedures

19.2.4 Visual inspections for corrosion

19.2.5 Inspection of insulation
19.2.6 Causes and implications of hydraulic
shock
19.2.7 Hazards of trapped liquid expansion

19.2.8 Manual operations caused by automation

failures

19.2.9 Actions during power failure

19.2.10 Recovery from power failure

19.2.11 Special operations caused by extreme

weather conditions

19.2.12 Charging system

19.2.13 Pumpdowns and pumpouts

19.2.14 Emergency operations and shutdowns

19.2.15 Manual purging

20.2.1 In-depth knowledge of the elements of

the PSM and RM Programs

19.2.16 Assist in developing operating

procedures

19.3 (Technical):

19.3.1 Non-destructive testing for corrosion

19.3.2 Identifying/correcting potential hydraulic

shock situations

19.3.3 Identifying/correcting trapped liquid

situations

19.3.4 Developing good operating procedures

14

20.1 (Entry):
20.1.1 Elements of the PSM and RM
programs

20.0 Regulatory Awareness

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Appendix A

Pre-employment Screening
Completion of successful training as an Industrial Refrigeration Operator requires a substantial commitment from the
employee, as well as the company. The employer should discuss this commitment with prospective trainees.
A prospective trainee must understand and agree that safety is the most important expectation of employment. All
work performed will adhere to all OSHA, USEPA and plant safety regulations.
A prospective trainee should demonstrate proficiency in applied technology skills, observation skills, locating
information skills, reading for information skills, and applied mathematics skills, based on pre-employment screening.
The following information may be used as an aid in pre-employment screening, or as an aid for determining
qualification of an existing employee who wishes to transfer to the role of an operator. An ACT (American College
Testing) work keys profile study was conducted in 2001. This study involved testing and evaluating 29 refrigeration
operators from 13 companies throughout the United States.
The results of this study indicate that prospective refrigeration operators should have the following minimum
proficiencies:

Applied Technology

Level 4

Observation

Level 5

Locating Information

Level 4 to 5

Reading for Information

Level 4

Applied Mathematics

Level 5 to 6

Descriptions of proficiencies for pre-employment screening

Applied Technology:
Level

Skills

Understand the operation of tools, machine components, and uncomplicated systems, such as piping
systems, simple electric heaters, or other equipment found in the home, school, or workplace.
Apply elementary principles underlying the operation of physical systems, such as the workings of
plumbing components or uncomplicated electrical circuits.

Understand the operation of moderately complex tools, machines, and systems, such as appliances,
pulley driven equipment, or piping systems that carry more than one fluid.
Apply elementary principles underlying the operation of physical systems, such as block and tackle
or cooling fins.

Apply physical principles to machines which have several components, perform complex operations, and
sometimes interact with other systems.
Understand complex machines and systems, such as the operation of gasoline engines, complex
appliances, or an electrical system in a building.

Apply principles that affect certain properties of a system such as phase change or pressure equilibrium.
Troubleshoot complex systems in which a variety of mechanical, electrical, thermal, or flow faults are
potential sources of difficult problems.

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Observation:
Level

Skills

Pay attention.
Watch and listen to a strongly cued demonstration or set of instructions.
Remember a few strongly reinforced details of a process or procedure.

Sustain focused attention on the demonstrated instructions, process, or procedure.

Select and attend to important details.
Remember a few important, moderately reinforced details about the demonstrated process or procedure.

Focus attention on and remember several important aspects of the information presented.
Ignore irrelevant background information through selective attention to important details.
Maintain attention to detail.
Remember several important details about unfamiliar material.

Notice and remember several details that are relevant to the process or procedure being shown.
Take in and recall incoming sensory information so it can be used to make predictions, comparisons, or
evaluations.
Visualize how a detail or task fits into the entire process or procedure demonstrated.
Interpret if-then and cause-effect relationships.

Locating Information:
Level

Skills

Find one or two pieces of information in graphics such as simple order forms, bar graphs, tables,
flowcharts, or floor plans.
Fill in one or two pieces of information that are missing from these types of elementary graphics.

Find several pieces of information in workplace graphics such as basic order forms, line graphs,
tables, instrument gauges, maps, flowcharts, and diagrams.
Summarize and/or compare information and trends in a single graphic.
Summarize and/or compare information and trends among more than one workplace graphic, such
as a charge slip and an invoice showing related information; in order to accomplish this, the
examinee must determine the relationship among the graphics.

Summarize and/or compare information and trends in a single complicated workplace graphic, such
as detailed forms, tables, graphs, maps, instrument gauges, and diagrams. Summarize and/or compare
information and trends among more than one workplace graphic, such as a bar chart and a data table
showing related information; in order to accomplish this, the examinee must sort through
distracting information.

Draw conclusions from the information presented in very detailed graphs, charts, tables, forms, maps, and
diagrams. Apply information from these types of graphics to specific situations.
Make decisions and/or predictions requiring judgments based on the information presented in these types
of graphics; in order to accomplish this, the examinee must analyze the data within the graphics.

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Reading For Information:

Level

Skills

Identify uncomplicated key concepts and simple details in basic reading materials, such as company
policies, procedures, and announcements.
Recognize proper placement of a step in a sequence of events, or the proper time to perform a task.
Identify the meaning of a word that is defined within the text.
Identify the meaning of a simple word that is not defined within the passage.
Recognize the application of instructions given in the text to situations that are also described in the text.

Identify important details that are less obvious than those in level 3.
Recognize the application of more complex instructions, some of which involve several steps, to
describe situations.
Recognize cause-effect relationships.
Determine the meaning of words that are not defined in the reading material.

Identify the paraphrased definition of a technical term or jargon that is defined in text with more details,
greater complexity, and broader topics than those in level 4.
Recognize the application of technical terms or jargon to stated situations.
Recognize the definition of an acronym that is defined in the text.
Identify appropriate definition of a word with multiple meanings.
Recognize the application of instructions from the text to new situations that are similar to those described
in the reading materials.
Recognize the application of more complex instructions to described situations, including conditions and
procedures with multiple steps.

Generalize beyond the stated situation and recognize implied details and the probable rationale behind
policies and procedures contained in more complex presentation of information such as regulatory and
legal documents as well as more elaborate procedures and concepts.
Recognize the application of jargon or technical terms to new situations.
Recognize the application of complex instructions to new situations.
Recognize, from context, the less common meaning of a word with multiple meanings.
Generalize from the text to situations not described in the text.
Identify implied details.
Explain rationale behind a procedure, policy, or communication.
Generalize from the text to a somewhat similar situation.

Recognize the definitions of difficult, uncommon jargon or technical terms, based on the context of more
difficult text. Figure out the general principles underlying described situations and apply them to situations
neither described in, nor completely similar to, those in the text.

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Applied Mathematics:
Level
3

Skills
Perform single-step basic operations (addition, subtraction, multiplication, and division) using whole
numbers.
Change a number from one form to another, using whole numbers, fractions, decimals, and percentages.
Add and subtract negative numbers as well as positive numbers.

4
Perform one or two mathematical operations, such as addition, subtraction, or multiplication on several

positive or negative numbers.

Add commonly known fractions, decimals, or percentages (e.g. 1/2, 0.75, 25%), and three fractions that
share a common denominator.

Calculate averages, simple ratios, proportions, and rates, using whole numbers and decimals.
5

Perform single step conversions within and between English and non-English systems of
measurement.
Calculate perimeters and areas of basic shapes.
Calculate percentage discounts and markups.
Compute the best deal using one- and two-step calculations and then comparing costs.

Calculate using negative numbers, fractions, ratios, and mixed numbers.

Calculate multiple rates and then compare the rates or use them to perform other calculations.
Find basic areas and volumes of rectangular solids.
Calculate the best deal using the results in another problem.
Identify and correct errors in calculations.

Solve problems involving more than one unknown.

Calculate the percentage of change.
Calculate multiple areas and volumes of spheres, cylinders, and cones.
Setup and manipulate complex ratios and proportions.
Determine the best economic value of several alternatives.
Find mistakes in multiple-step calculations.

This study or equivalent may be used for pre-employment screening.

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Request for Comment

The International Institute of Ammonia Refrigeration
(IIAR) and the Refrigerating Engineers & Technicians
Association (RETA) have approved the publication of
Draft Guideline for Trial Use Ammonia Refrigeration
Training Guideline for comment. Comments will be
accepted through June 30, 2010. Following the close
of the comment period, IIAR and RETA intend to
review the comments, make any and all appropriate
revisions, and publish the revised draft standard as a
formal industry guideline which may include application
for approval as an industry guideline to the American
National Standards Institute.
Comments should be directed to IIAR Headquarters,
ARTG-GDL 1 Comments, 1110 North Glebe Road,
Suite 250, Arlington, Virginia 22201, by E-mail to
special@iiar.org, or by Fax to 703/312-0065.

Date:__________________________________________
Commenter Name:_ ______________________________
Company:_ _____________________________________
Mailing Address:_________________________________
______________________________________________
Phone:_________________________________________
E-mail:_________________________________________

Comment:

Please return comments to: IIAR Headquarters, ARTG-GDL 1 Comments,

1110 North Glebe Road, Suite 250, Arlington, Virginia 22201
E-mail to special@iiar.org, or Fax to 703/312-0065.
Copyright 2007 The International Institute of Ammonia Refrigeration

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Copyright 2007 The International Institute of Ammonia Refrigeration

An Industry Project
Cosponsored by

1110 North Glebe Road

Suite 250
Arlington, VA 22201
Phone: (703) 312-4200
Fax: (703) 312-0065
www.iiar.org

IARW-WFLO
1500 King Street
Suite 201
Alexandria, VA 22314
Phone: (703) 373-4300
Fax: (703) 373-4301

Refrigerating Engineers &

Technicians Association
PO Box 1819
Salinas, CA 93902
Phone: (831) 455-8783
Fax: (831) 455-7856
www.reta.com