Emergency Discharge Line

The following directive is being issued by a provincial safety manager pursuant to section 30 of the Safety Standards Act (the Act) to clarify the requirements for emergency discharge line in refrigeration systems. 

Definitions 

Refrigeration System: means a refrigeration plant. 

Refrigeration Equipment: means machinery in which refrigerants are capable of being vaporized, compressed, and liquified. 

Refrigeration Plant: means an assembly of refrigeration equipment and includes a pressure plant connected to it.

General Details: 

Refrigeration systems and equipment are subject to the requirements of the Power Engineers, Boiler, Pressure Vessel and Refrigeration Safety Regulation (the Regulation) unless specifically exempt from the application of the Regulation under section 3(2)(f), 3(2)(j), or 3(2)(r). 

The CSA B52, which is adopted under the Regulation, sets out the requirements for emergency discharge systems in clause 6.10.  

This directive outlines when an emergency discharge system is required, and the requirements applicable to the systems control and operation when integrated as a part of a refrigeration system design.  

Specific Details: 

Clause 6.10 of the CSA B52:23 requires that an emergency discharge system be provided as required by the authority having jurisdiction. Additionally, it states that: 

• emergency discharge systems are not required for new or existing systems when the relief system complies with the current requirements of Annex H; and

• for existing systems where the relief piping is not in compliance with Annex H, an emergency discharge system shall be considered per Annex B.

This directive provides clarification on when an emergency discharge system is required by Technical Safety BC, as the authority having jurisdiction, and outlines the requirements applicable to emergency discharge system management to ensure they are maintained and operated safely. 

New Refrigeration System Designs: 

All new refrigeration system designs must meet the requirements of CSA B52:23, including designing and installing plant relief piping in compliance with the requirements of Annex H. In such cases, an emergency discharge system is not required and may be eliminated from the design.  

Refrigeration Systems Containing an Emergency Discharge System: 

1. If the plant relief piping complies with the current requirements of Annex H in CSA B52:2023 and contains an emergency discharge line, the owner must ensure one of the following requirements is met:
   1. remove the emergency discharge line; or
   2. implement a method to control the safe operation of the emergency discharge valve as required by the Safety Standards Act, section 69 (3), and create, implement, and maintain an Emergency Discharge Valve Safe Operating Procedure.
2. If the plant relief piping does not comply with the current requirements of Annex H in CSA B52:2023, both of the following requirements must be met:
   1. an emergency discharge system must be maintained as a part of the refrigeration system design until the relief piping has been upgraded to conform with the current requirements of Annex H; and 
   2. implement a method to control the safe operation of the emergency discharge valve as required by the Safety Standards Act, section 69 (3), and create, implement, and maintain an Emergency Discharge Valve Safe Operating Procedure.

Emergency Discharge Valve Control and Safe Operating Procedures: 

All new or existing refrigeration systems which contain an emergency discharge system must implement a method of controlling access to the emergency discharge valve which may include, but is not limited to, enclosure (valve box), lock out, access restriction, etc. In addition, an Emergency Discharge Valve Safe Operating Procedure must be developed addressing, at a minimum, the following requirements: 

• circumstances in which the emergency discharge valve is allowed to be operated;

• person(s) authorized to operate the emergency discharge valve;

• access controls to emergency discharge valve;

• contamination control plan after the emergency discharge valve is operated; 

• staff training plan and training record keeping; and

• process for annual review and continual improvement.

The Emergency Discharge Valve Safe Operating Procedure must be easily accessible to those authorized to operate the valve in emergency situations. 

Provincial Safety Manager – Boiler, Pressure Vessel, and Refrigeration. 

References: 

Safety Standards Act 

Power Engineers, Boiler, Pressure Vessel & Refrigeration Safety Regulation 

CSA B52: 2023, Mechanical Refrigeration Code