Code of Practice to eliminate halocarbon emissions from refrigeration and air conditioning systems: chapter 3

3.0 Installation

• 3.1 Siting
• 3.2 Compatibility
• 3.3 Selection of a Cooling System and its Components
• 3.4 Performance

The term “cooling” is used throughout the document and refers to both refrigeration and air conditioning.

3.1 Siting

Siting can have a significant impact on the performance of cooling systems, including reducing the potential for refrigerant releases.

Factors to consider when installing a cooling system:

• Accessibility of all indoor and outdoor components of the cooling system, including electrical outlets associated with the system.
• Keeping refrigerant lines as short as possible between indoor and outdoor components to minimize loss of cooling effect to the atmosphere. This could influence where mechanical rooms, chillers and other systems are located at a facility.
• Keeping the outdoor unit at a height above the indoor unit to prevent having to pump the refrigerant against gravity, which could reduce the efficiency of the system.
• Installing components of the system at a sufficient distance from areas where noise could pose a problem. Variable speed drives can further reduce noise.
• Installing components of the system to prevent vibration that may cause noise or create stress on a system.
• Shielding the system from weather conditions that could shorten its life or reduce its efficiency by making use of the natural environment (for example, using trees to create shade) or using a fence or a wall to protect the system from the wind or the snow.
• Providing adequate protection from debris, dust, moisture and physical damage.
• Identifying or labeling controls, switches and sensors.
• Affixing appropriate signs to the mechanical room (for example, for flammability).
• Installing an emergency switch outside the mechanical room to cut off all electrical power when refrigerants that are flammable are used.
• Locating the system at a suitable distance from electrical devices, such as switches and relays, that may generate sparks.
• Installing a grounding system if applicable.
• Installing a refrigerant monitoring system in the mechanical room.
• Venting air purge outdoors.
• Allowing proper airflow and adequate ventilation in the area surrounding the system.
• Providing appropriate lighting in the area surrounding the system.

3.2 Compatibility

In order to prolong the system's life, enhance its efficiency, prevent leaks and ensure a safe environment, all system components need to be compatible. For example, mineral oil can't generally be used with hydrofluorocarbons (HFCs); explosion-proof electrical components may be needed when using a refrigerant that is flammable.

Factors to consider when installing or servicing a system are the following:

• Compatibility of the refrigerant, oil and the system, as well as the compatibility of the materials in the various system components.
• Characteristics of the fluid used in the system may cause scaling, corrosion or erosion failure. Careful selection of tubes, valves, and evaporator and condenser materials can help minimize catalytic corrosion. When a system contains non-ferrous materials, sacrificial anodes can be used to reduce corrosion pitting. Sacrificial anodes are effective only when the water is flowing through the system.
• Corrosion protection to prevent rusting of steel components.
• Air and moisture can cause acid generation and oil breakdown; particular attention needs to be given to material selection and the environment where the system will be located.
• Particulate matter can cause damage to motor windings and compressor components.

3.3 Selection of a Cooling System and its Components

The selection of a system can make a difference on the overall environmental performance. Certain components are integrated at the design phase, while others are installed on site. In addition to considering the cooling needs of the facility and the requirements in the applicable jurisdiction, contemplate choosing a system with the following components or adding them at the time of installation or service:

• Filter-dryer appropriately sized with the following properties:
  • filter to remove particulate matter,
  • desiccant to remove moisture,
  • isolation valves and refrigerant recovery connections to allow for servicing.
• Strainer or strainers-driers to capture solid contaminants.
• Compressor with a sight glass to indicate moisture.
• Valves allowing isolation of all components of the system in order to minimize the risk of refrigerant loss during servicing.
• Self-reseating relief valve for all systems containing over 10 kg (22 lb) of refrigerant.
• High-efficiency air purge system.
• Refrigerant alarm that gives a warning before reaching the threshold limit value or 25% of the lower explosive limit for a particular refrigerant.

3.4 Performance

System components should be installed and serviced while considering the manufacturers' recommendations and complying with the requirements of the applicable jurisdiction; this will prolong the system's life, enhance its performance and prevent harmful effects on the environment.

A clean and dry system is essential for prolonged system effectiveness.

Factors to consider when installing or servicing a system, in order to prevent refrigerant leak and avoid equipment failure are the following:

Piping, tubing, fittings and connections

Each connection represents a potential for leak. Each connection method is unique in that each is intended for specific applications or circumstances. Technical information regarding the applications and limitations of each method can be found in the literature.

Here is a summary of the terms used in this code:

Compression fittings are especially useful in installations that may require occasional disassembly or partial removal for maintenance since these joints can be broken and remade without affecting the integrity of the joint. They could be used in applications where the fitting will not be subject to flexing or bending.

Compression fittings are relatively quick to install and easy to use; however, they may be bulkier than, and not as robust as, soldered fittings.

Soldering is a process in which two or more metal components are joined together by melting and flowing a filler metal into the joint, the filler having a lower melting point than the work piece. There are several forms of soldering, each requiring a different temperature. Higher temperatures produce a stronger joint. A soldered joint is highly tolerant of flexing and bending, such as when pipes shake from sudden pressure changes.

Brazing is similar to soldering but requires a higher temperature due to the melting point of the filler material. Brazing is usually the preferred method of joining pipe to fittings, valves and other components. In both soldering and brazing, the pipe and the fitting are heated to the melting temperature of the filler material, but they do not melt.

Welding differs from soldering and brazing in that the connection is made without adding a material to complete a joint. Instead, the material of the pipe itself is partially melted and the fitting and pipe are directly fused together. Generally this requires that the piping and the fitting be made of the same or closely compatible material. Welded joints are robust, very reliable and long lasting; however, they are usually restricted to high-performance applications.

Manufacturers can also provide support. The following represents some basic information regarding the different ways of connecting the various system components, as well as some factors to consider and best practices:

• Installing the system,--including tubing and pipe diameters, bend radii and lengths, and all connections,--in accordance with the manufacturer's instructions and current regulations.
• Installing the system in such a manner as to minimize the number of fittings and connections.
• Providing adequate protection of piping and piping connections against external abrasion due to movement.
• Providing adequate support of piping connections to avoid stresses on the system.
• Allowances could be made for expansion and contraction, especially at anchors and bends. Insulated hangers could be used for non-ferrous pipe.
• Connecting certain components to the system via flexible fittings so that vibrations are absorbed.
• Labeling the system and its components to facilitate further servicing and to prevent accidental addition of improper refrigerant or oil during servicing. Ideally, labels would be permanent, weatherproof and displayed prominently. Information could include the following:
  • system manufacturer,
  • refrigerant type,
  • American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) refrigerant number,
  • ASHRAE/Workplace Hazardous Material Information System (WHMIS) safety designation,
  • refrigerant quantity,
  • refrigerant oil type, quantity and viscosity.
• Insulating pipes to prevent heat gain and condensation.
• Utilizing strainers or strainers-driers to capture solid contaminants.
• Deburr and remove metal filings from all cut pipes to prevent damage to the system's components.
• Clean all tubes and fittings prior to assembly.
• Ensure, before brazing, that both the outside of the tube and the inside of the fitting are bright and clean.
• Ensure that filler metal is compatible with the types of materials being joined (brazing and soldering).
• Consider using a small amount of grease or light oil for some compression fittings.
• Use these preferred methods of connections:
  • welding or brazing for pipe sizes greater than 19 m (3/4") outside diameter,
  • compression-type fittings for small pipe sizes.
• Use welding or brazing in new systems instead of threaded connections.

Valves

A valve is a pipe fitting that regulates, directs or controls the flow of a fluid by opening, closing or partially obstructing various passageways. Technical information regarding each category of valve can be found in the literature. The following is a summary of the terms used in this code:

• Isolation valves are used to isolate components to allow servicing in specific sections of the system.
• Access valves are used for charging and evacuating a system.
• Relief valves are used to release pressure so as not to damage the system or its components.

The following are best practices:

• Install isolation valves on all major components of the cooling system to facilitate servicing of that component (for example, at the suction and discharge sides of a compressor).
• Use valves to protect gauges from pressure surges and to permit removal of these devices for repair or calibration.
• Mount the compressor on the system's frame in such a way as to prevent vibration and minimize stress on piping connections, including valves.
• Add vibration eliminators.
• Ensure that the compressor is accessible and removable for leak testing and repairs.