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Safety Code of Practice for Ammonia Refrigerant R717 (Group B2L).

IOR report ammonia front

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Safety Code of Practice for Ammonia Refrigerant R717 (Group B2L).

The publication provides essential industry guidance for owners, designers, installers and operators of vapour compression refrigerating systems that use ammonia refrigerant. It covers properties of refrigerants, decommissioning, testing and maintenance as well as design issues with useful appendices such as typical schedules for inspection and maintenance, system register details, machinery rooms, definitions and an updated list of relevant standards.  The Code has been prepared by the IOR Technical Committee as a reference source and guide to interpretation of current safety standards such as BS EN378:2016 and legal requirements such as PED, PSSR and PUWER.  

The IOR publishes four Safety Codes of Practice specific to refrigerant type.  

  • Non Flammable, Lower Toxicity Refrigerants Group A1 
  • Flammable Lower Toxicity Refrigerants Group A2L, A2 and A3 
  • Carbon Dioxide R744 
  • Ammonia R717

The Code is supplied as a 85 page PDF.


May 2019 - addendum added Section 11: CLP and DSEAR

Aug 2019 - minor text updated to Appendix F Section 4.1

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Full Contents list

Section 1 – Scope and Limitations 

Section 2 – Relevant Properties of Ammonia 
2.1 Physical properties 
2.2 Chemical Properties and Potential Hazards 

Section 3 – Design of Components 
3.1 General 
3.2 Component Design and Test Pressures 
3.3 Compressors
3.4 Pressure Vessels and Heat Exchangers 
3.5 Liquid Ammonia Pumps 
3.6 Ammonia Control Valves and Sensing Devices 

Section 4 – System Design and Installation 
4.1 General 
4.2 Material Selection 
4.3 Steel Piping Systems 
4.4 Copper Pipework 
4.5 Location and Arrangement of Piping 
4.6 Arrangement of Isolating Valves 
4.7 Instrumentation 
4.8 Protection against Excess Pressure 
4.9 Protection against Environmental Effects
4.10 Notification to Local Authorities 
4.11 Refrigerant Detection 
4.12 System Labelling 
4.13 Allowable Refrigerant Charge 
4.14 Protection for Indirect Circuits 
4.15 Additional Requirements for Ammonia 

Section 5 – System Testing 
5.1 General 
5.2 Strength Test Procedure 5.3 Tightness Test Procedure 
5.4 Test Certificates 7

Section 6 – Commissioning of New Installations 
6.1 General 
6.2 Evacuation and Dehydration 
6.3 Charging 
6.4 Protection Devices 

Section 7 – Inspection and Maintenance 
7.1 General 
7.2 System Log 
7.3 Routine Inspection 
7.4 Major Inspection 
7.5 Pressure System Examination 

Section 8 ‐ Documentation 
8.1 General 
8.2 Risk Assessment 
8.3 Health and Safety File 
8.4 Written Scheme of Examination and Records 
8.5 Commissioning Records 
8.6 Refrigerant Inventory Record 
8.7 Contingency Provisions 
8.8 The System Register 
8.9 System Log 
8.10 Instruction Manuals 

Section 9 ‐ Decommissioning 
9.1 General 
9.2 Recovered Refrigerant 

Section 10 – References, Standards and Legislation (all refrigerants)

Section 11 - Addendum: CLP and DSEAR 

Appendix A ‐Definitions 
Appendix B – Maximum Allowable Pressure and Strength Test Procedure 
Appendix C – Pneumatic Strength Pressure Test Procedure
Appendix D – Marking and Name Plate Data 
Appendix E ‐ Handling, Transport and Storage of Refrigerant Cylinders
Appendix F – Commissioning of New Installations 
Appendix G – Machinery Rooms and Auxiliary Safety Equipment 
Appendix H – Typical Schedule for Inspection and Maintenance 
Appendix I – Sample Details for Register 
Appendix J ‐ Sample Compressor Operating Data and System Log
Appendix K – IOR Policy on Refrigerant Choice 
Appendix L ‐ Stress Corrosion Cracking