This file is licensed to Abdual Hadi Nema (ahaddi58@yahoo.com) License Date: 6/1/2010 Related Commercial Resources CHAPTER 50 Licensed for single user © 2010 ASHRAE, Inc TERMINOLOGY OF REFRIGERATION T HIS chapter seeks to define some of the common terms used in industrial refrigeration systems, specifically those using ammonia as the refrigerant The following glossary was compiled from a variety of sources throughout the industry, including ASHRAE, the International Institute of Ammonia Refrigeration (IIAR), the U.S Occupational Safety and Health Administration (OSHA), and the U.S Environmental Protection Agency (EPA) Specific sources for entries are listed in the endnotes Minor edits for punctuation, conciseness, and consistency with usage elsewhere in the Handbook have been made In many cases, definitions of a single item from various sources may not fully agree However, multiple definitions are listed here only if they differ substantively This glossary does not seek to define the correct definition; rather, it leaves it to users to pick the appropriate definition for their application Accidental release Unanticipated emission of a regulated substance or other extremely hazardous substance into the ambient air from a stationary source.5 Actuator (1) Mechanism for transmission of movement or force.10, 11 (2) Device, either electrically, pneumatically, or hydraulically operated, that acts as a motor to change the position of movable devices such as valves or dampers.2 Adjusted flow capacity Estimated capacity of a relief valve assembly accommodating the reduction in flow caused by pressure drop in the three-way valve.15 Affected employee Any employee who works in the vicinity of an ammonia refrigeration system.5 Air-cooled condenser A refrigerant condenser in which heat removal is accomplished entirely by heat absorption by air flowing over condensing surfaces See also Condenser; Desuperheater; Double-pipe (tube-in-tube) condenser; Evaporative condenser; Shell-and-tube condenser.2, 7, 10, 12 Air-cooled desuperheater (1) That part of the system designed to cool ammonia refrigerant vapor after it is discharged from the compressor and before it enters the condenser It is provided with a means of forcing air circulation over the external surface of the desuperheater coil for the heat removal necessary to cool the refrigerant vapor on the inside of the tubes.7,10,12 (2) Heat exchanger, preceding the condenser or incorporated in it, for removing all or part of the superheat.2 Air duct A tube or conduit used for conveying air The air passages of self-contained systems are not air ducts.10,12 Ammonia Refrigerant-grade anhydrous ammonia.10,12 ANSI American National Standards Institute (www.ansi.org) Approved Acceptable to the jurisdictional authorities.1,7,10,12 ARIP Accidental Release Information Program, a U.S Environmental Protection Agency (EPA) database that can be reviewed for past ammonia refrigeration incidents ASHRAE American Society of Heating, Refrigerating and Air Conditioning Engineers, Inc (www.ashrae.org) ASME American Society of Mechanical Engineers (www asme.org) Authorized inspection agency An established and recognized agency or individual regularly engaged in conducting tests or furnishing inspection services, when such agency or individual has been approved by the jurisdiction involved.7,12 Automatic expansion valve A controlling device that regulates the flow of volatile liquid refrigerant into an evaporator of a closedcircuit ammonia refrigerating system, and is actuated by evaporator pressure.7,10 Automatic liquid refrigerant drain valve See High-side float valve Back pressure The static pressure existing at the outlet of an operating pressure relief device caused by pressure in the discharge line.1, 13 Balanced (safety) relief valve A pressure relief valve that incorporates means of minimizing the effect of back pressure on the operational characteristics of the valve (opening pressure, closing pressure, and relieving capacity).1, 13 Blends Refrigerants consisting of mixtures of two or more different chemical compounds, often used individually as refrigerants for other applications.1 Blocked in Having a piece of equipment, vessel, or piping isolated from the rest of the system by closed valves and/or blind flanges.13 Block flow diagram (BFD) A simplified schematic drawing showing the ammonia refrigeration system The primary purpose of the BFD is to show the major components of the ammonia refrigeration system and flow direction Temperatures and pressures may be shown for clarity.13 Blowdown (1) The difference between actual popping pressure of a pressure relief valve and actual reseating pressure, expressed as a percentage of set pressure or in pressure units.2, 13 (2) Discharge of water from a steam boiler or open recirculating system that contains high total dissolved solids The addition of makeup water reduces the concentration of dissolved solids to minimize their precipitation.2 Blowdown pressure The value of decreasing inlet static pressure at which no further discharge is detected at the outlet of a pressure relief valve after the valve has been subjected to a pressure equal to or above the popping pressure.13 Booster compressor (1) A compressor for discharging to the suction of a higher-stage compressor See also Compressor; Positive-displacement compressor.10 (2) Compressor for raising the pressure of a gas delivered to a following compressor.2 Brazed joint (high-temperature) Gastight joint obtained by joining metal parts with alloys that melt at temperatures higher than 800°C, but at less than the melting temperatures of the joined parts.2 Brazed joint (low-temperature) Gastight joint obtained by joining metal parts with metallic mixtures or alloys that melt at temperatures below 800°C but above 540°C.2 Brine (1) Any liquid used for the transmission of heat without a change in its state.7 (2) Formerly, any liquid cooled by a refrigerant and used for heat transmission without a change in its state, having no flash point or a flash point above 66°C Now called a secondary coolant (3) A secondary coolant that is a solution of salt in water.2,3 Built-up back pressure Pressure existing at the outlet of a pressure relief device caused by flow through that device into a discharge system.15 CAS Chemical Abstracts Service.5 The preparation of this chapter is assigned to TC 10.1, Custom Engineered Refrigeration Systems 50.1 Copyright © 2010, ASHRAE This file is licensed to Abdual Hadi Nema (ahaddi58@yahoo.com) License Date: 6/1/2010 Licensed for single user © 2010 ASHRAE, Inc 50.2 Catastrophic release A major uncontrolled emission, fire, or explosion involving ammonia that presents serious danger to employees in the workplace, to public health, or to the environment.4,5,17 Certify To acknowledge in writing that statements are true, accurate, and complete.5 CFR Code of Federal Regulations Charging The process of adding liquid ammonia to a system.5 Check valve A valve allowing fluid flow in one direction only.2,7,10 Classified information As defined in the Classified Information Procedures Act, 18 U.S Code (USC), App 3, section 1(a), “any information or material that has been determined by the United States Government pursuant to an executive order, statute, or regulation, to require protection against unauthorized disclosure for reasons of national security.”4,5,17 Closed-circuit ammonia refrigerating system A refrigerating system using mechanical compression to remove the refrigerant from the low-pressure side and to deliver it to the high-pressure side of the system.10 Code authority Any group or body recognized by the jurisdiction involved, and which has authority over the rules and regulations governing design, fabrication, testing, and assembly of refrigeration and related equipment.12 Codes Standard practices, typically issued by national organizations A code becomes a legal document, which can be enforced by a regulatory authority, when it is adopted by an authority such as a state legislature.5 Commissioning (1) Completion of the start-up process, which demonstrates the performance of the system.12 (2) Process for achieving, verifying, and documenting the performance of a building to meet the building’s operational needs within the capabilities of the design and to meet the design documentation and the owner’s functional criteria, including preparation of operator personnel.2 Companion (block) valve Pairs of mating stop valves that allow sections of a system to be joined before opening these valves or separated after closing them.1,2,7 Compressor (1) Device for mechanically increasing the pressure of a gas.2 (2) A machine used to compress refrigerant vapor.1,5 (3) A specific machine, with or without accessories, for compressing ammonia refrigerant vapor See also Booster compressor; Positive-displacement compressor.7,10,12 Compressor unit (1) A condensing unit less the condenser and liquid receiver.7 (2) A compressor with its prime mover and accessories.1 Computerized maintenance management system (CMMS) A computerized database for planning, scheduling, tracking, and recording the completion of quality assurance, testing, inspection, and other preventative maintenance tasks A CMMS can also perform other tasks related to preventative maintenance such as planning and issuing work orders, maintenance of equipment history data, material and spare parts inventory and ordering, issuing purchase orders, and maintenance of work instructions and procedures Condenser (1) The part of the refrigerating system where refrigerant is liquefied by removal of heat.1,7,10,12 (2) Heat exchanger in which vapor is liquefied by rejection of heat into a heat sink.2 Condenser coil (1) That part of a condenser constructed of pipe or tubing not enclosed in a pressure vessel.7,10,12 (2) Condenser constructed of pipe or tubing, not enclosed in a pressure vessel.1,2 Condensing unit A specific refrigeration machine combination consisting of one or more power-driven compressors, condensers, liquid receivers (when required), and the regularly furnished accessories.1,7 Container A cylinder used for the transportation of refrigerant.1, Contractor (1) In construction terminology, the person or entity responsible for performing the work and identified as such in an owner-contractor agreement.2 (2) A company or individual who 2010 ASHRAE Handbook—Refrigeration (SI) will provide services, labor, materials, and tools to perform specific work under contract or purchase order from the employer.5 (3) The organization or corporation that assumes contractual responsibility for installation, setting, and tying together of the various components of the refrigerating system in its final operating form.7 Control valve All valves except shutoff valves Examples include solenoid valves, check valves, and regulating valves.10,11 Controlled-pressure receiver An intermediate pressure receiver used to flash cool refrigerant and to control the feed pressure See also Pressure vessel.2,10 Conventional safety relief valve A pressure relief valve with its spring housing vented to the discharge side of the valve Operational characteristics (opening pressure, closing pressure, and relieving capacity) are directly affected by changes of pressure at the outlet of the valve.15 Corrective action An action taken to eliminate the causes of a deficiency in a product, procedure, process, or system.5 Corridor An enclosed passageway that limits travel to a single path.1 Corrosion (1) Dissolving or wearing away of a material; often refers to chemical attack on a metal.5 (2) Rusting or deterioration of a substance (usually a metal) or its properties because of a reaction with its environment.2 Covered process A process that has a regulated substance present in more than a threshold quantity as determined under RMP § 1910.119 or § 68.115.4,5 Critical pressure A point on the saturation curve where refrigerant liquid and vapor have identical volume, density, and enthalpy, and there is no latent heat.1,2 Crossover valve A valve that allows interconnection of two different portions of a refrigeration system that normally operate at different pressures.10 Cutter/welder An individual performing hot work operations.5 Cylinder A container used for the transportation of ammonia refrigerant.12 Designated agency The state, local, or federal agency designated by the state under the provisions of 40CFR68.215(d) (definition from EPA’s RM Program regulations).5 Design pressure (1) The maximum pressure for which a specific part of a refrigeration system is designed.1,5,7,10,12 Design working pressure (1) In the United States, the maximum working pressure for which an apparatus has been designed (2) In some countries, the design pressure is greater than the maximum working pressure.2 Desuperheater A device that provides sensible cooling to the refrigerant vapor prior to condensing.10, 12 Desuperheating coil Heat exchanger, preceding the condenser or incorporated in it, for removing all or part of the superheat.2 Device (1) Term for shutoff valves, control valves, and strainers.10 (2) Piece of equipment or a mechanism designed to serve a special purpose or to perform a special function; refer to specific device of interest.2 Direct expansion (DX) Evaporator arrangement whereby liquid refrigerant is fed through an expansion valve or device and evaporates completely before leaving as vapor.10 Direct-expansion (DX) coil Coil used in direct refrigeration method.2 DOT U.S Department of Transportation (www.dot.gov) Double-pipe (tube-in-tube) condenser Condenser constructed of concentric tubes in which refrigerant circulates through the annular space and the cooling medium through the inner tube.2 Double-pipe (tube-in-tube) condenser/desuperheater A type of condenser/desuperheater constructed of one or more assemblies of two tubes, one within the other, in which refrigerant vapor is condensed/desuperheated either in the annular space or the inner tube See also Air-cooled condenser; Condenser; Desuperheater; Evaporative condenser; Shell-and-tube condenser.10,12 This file is licensed to Abdual Hadi Nema (ahaddi58@yahoo.com) License Date: 6/1/2010 Licensed for single user © 2010 ASHRAE, Inc Terminology of Refrigeration Downstream A direction, given relative to a piece of equipment, that is the same as the main system flow (e.g., a compressor’s discharge piping is downstream from its suction piping).5 Downstream power regulator (1) A control valve that regulates flow of oil or refrigerant gas or liquid through the device, which is actuated toward open by pressure falling below regulator set point downstream of the valve.11 (2) A controlling device that regulates flow of refrigerant gas or liquid or oil through the device from a section of the system to a lower-pressure section of the system, and that is actuated toward open by pressure falling below regulator set point downstream of the regulator orifice.7 Dual pressure relief device (1) Two pressure relief devices (valves or rupture members) mounted on a three-way valve that allows one device to remain active while the other is isolated See also Pressure relief device; Pressure relief valve.1,10 Duct (1) A tube or conduit used to convey or encase For example, an air duct is a tube or conduit used to convey air (air passages in self-contained systems are not air ducts); a pipe duct is a tube or conduit used to encase pipe or tubing.1 (2) Tube or conduit for conveying or encasing purposes (3) Passageway made of suitable material, not necessarily leaktight, used for conveying air or other gas at low pressures.2 Electrical classification Classification of areas in a plant according to the flammability of the various materials present and the probability of these materials being released from the normal containment system.5 Emergency action plan An emergency action plan is a plan that complies with the provisions of 29CFR1910.38(a) and covers those designated actions employers and employees should take to ensure employee safety from fire and other emergencies.5 Emergency operation Procedures for operating the system under emergency conditions, such as pumping out a component or part of the system where a leak has occurred, or transferring liquid from an overfilled vessel.5 Emergency pressure control system (EPCS) A system consisting of pressure sensors, independent compressor cut-off controls, and automatically controlled crossover valves that allows a high-pressure portion of a system to connect to a lower-pressure portion of a system when opened.10 Emergency response A response effort by employees from outside the immediate release area or by other designated responders (e.g., mutual-aid groups, local fire departments) to an occurrence that results, or is likely to result, in an uncontrolled release of a hazardous substance Responses to incidental releases of hazardous substances where the substance can be absorbed, neutralized, or otherwise controlled at the time of release by employees in the immediate release area or by maintenance personnel are not considered to be emergency responses within the scope of the hazardous waste operations and emergency response regulation Responses to releases of hazardous substances where there is no potential safety or health hazard (e.g., fire, explosion, chemical exposure) are not considered to be emergency responses.5 Emergency response plan A plan that complies with the provisions of 29CFR1910.120(q) to handle anticipated emergencies prior to the commencement of emergency response operations.5 Emergency situation An occurrence with an ammonia refrigeration system that requires immediate response from operations personnel (e.g., a large leak might be considered an emergency situation requiring isolation and pump-out of equipment).5 Engineering code authority Any group or body recognized by the jurisdiction involved, and who has authority over the rules and regulations governing design, fabrication, testing and assembly of refrigeration and related equipment.7 Environmental receptors Natural areas such as national or state parks, forests, or monuments; officially designated wildlife sanctuaries, preserves, refuges, or areas; and federal wilderness areas.4,5 50.3 Erosion Wearing away of a material by mechanical energy Erosion often occurs by impingement of solid particles or liquid drops on a surface.5 Evaporative condenser (1) A condenser that obtains cooling effect by evaporation of water in an air stream on the external surface of the tubes for the heat removal necessary to liquefy refrigerant vapor on the inside of the tubes See also Air-cooled condenser; Condenser; Desuperheater; Double-pipe (tube-in-tube) condenser; Shell-and-tube condenser.7,10,12 (2) Condenser in which heat is removed from the refrigerant by evaporation of water from the exterior of the condensing surface, induced by the forced circulation of air and sensible cooling by the air.2 Evaporator The part of a refrigeration system that is designed to vaporize liquid refrigerant to produce cooling.1,2,5,7,10,12 Evaporator coil That part of an evaporator constructed of pipe or tubing not enclosed in a pressure vessel.1,2,7,10,12 Evaporator-pressure regulator (1) A controlling device that regulates the flow of primarily gaseous refrigerant from an evaporator section and is actuated toward open by a pressure above set point upstream of the valve.7,10 (2) Automatic valve or control device used to maintain the pressure, and thereby the temperature, in an evaporator above a predetermined minimum.2 Exit A passageway adjacent to the door through which people leave a building.5,10,12 Experience modification rating (EMR) An annual safety rating of how a specific contractor compares to other contractors in the same type of work in the state where the contractor is working.5 Extremely hazardous substance (EHS) Any chemical listed in 40CFR68, or any other chemical that may, after short-term exposures through releases to the air, cause death, injury, or property damage because of their toxicity, reactivity, flammability, volatility, or corrosivity.5 Facility The buildings, containers, or equipment that contain a process.5,17 Facility plan view Schematic that typically shows the facility’s orientation and general location of the ammonia refrigeration equipment; it may also include the location of important emergency devices such as the main liquid shutoff valve (king valve) and switches for ventilation systems.5 Field test A test performed in the field to prove system tightness.7,10,12 Fire watch An individual who shares responsibility for fire safety with the cutter/welder A fire watch is required in locations where a minor fire might develop, where there are wall or floor openings within 10.7 m, or where there is combustible material within 10.7 m of the hot work, or in other situations specified by local codes The fire watch should maintain a constant vigil during the operation (including lunch and coffee breaks) to watch for stray sparks, ignition sources, or other fire hazards This individual should be specifically trained in the use of a fire extinguisher, small hose, and/or bucket of sand and should stay with this equipment He/she should be familiar with the facilities and also know how to sound the fire alarm.5 Flammable materials From the Hazard Communication Standard (29CFR1910.1200), any liquid with a flash point of less than 37.8°C, or any gas with a lower flammability limit (LFL) of less than or equal to 13%, or a difference between the upper and lower flammability limits greater than or equal to 12%, regardless of LFL.5 Float switch (1) Appliance incorporating a buoyancy component that responds to changing liquid level to mechanically actuate an electrical switch.11 (2) Device in which a float ball, through variations on the level of liquid, operates one or more sets of electrical contacts to activate or deactivate other controls or alarms.2 Flow regulator (1) A control valve that regulates the flow of liquid through the device, and is actuated by flow rate changes to maintain a predetermined flow rate.10 (2) A controlling device that This file is licensed to Abdual Hadi Nema (ahaddi58@yahoo.com) License Date: 6/1/2010 Licensed for single user © 2010 ASHRAE, Inc 50.4 regulates the flow of liquid refrigerant through the device from a section of the system to a lower-pressure section, and is actuated by flow rate changes to maintain a predetermined flow rate.7 Flow-regulating valve Valve designed to throttle flow.11 Forced-feed oil lubrication A lubrication system in which oil is provided by an internal or external mechanical oil pump This does not include splash- or drip-type compressor lubrication systems.7, 10 Forced-feed oiling Lubricating system with oil fed under pressure by a pump.2 Fusible plug Safety device for release of pressure by melting a contained substance with a predetermined melting temperature.1, Gage pressure The part of the pressure differing from atmospheric pressure, which is generally assumed to be 101.35 kPa at sea level.2, Generic Indicates wide applicability to facilities, systems, and equipment, irrespective of specific variations (e.g., scenarios identified for a generic compressor apply to various types, such as a rotary screw, rotary vane, and reciprocating).5 Good engineering practices Accepted written technical methodologies that govern mechanical integrity activities The sources for good engineering practices may include federal, state, and local laws and regulations, and consensus codes and standards (e.g., the ASME Boiler and Pressure Vessel Code, ANSI codes, IIAR bulletins) They may also include internal design, operations, and maintenance guidelines where appropriate.5 Hazard A potential for an accident with undesirable consequences, usually involving a loss of containment of flammable, combustible, highly hazardous (e.g., ammonia), or reactive materials.5 Hazard analysis techniques Analytical techniques that aid in identifying and evaluating process hazards Typical hazard analysis techniques include the what-if (or checklist) technique and the hazard and operability (HAZOP) technique Other techniques that may be used for specific circumstances are discussed in the Guidelines for Hazard Evaluation Procedures (2008) published the American Institute of Chemical Engineers’ Center for Chemical Process Safety.5 Hazardous location A location where flammable gases, vapors, or combustible dust are (or may be) present in the air in sufficient quantities to provide a fire or explosion.5 Hazardous substance Any substance that results or may result in adverse effects on the health or safety of employees after exposure: formally, “any biological agent or other disease-causing agent which, after release into the environment, and upon exposure, ingestion, inhalation or assimilation into any person, either directly from the environment or indirectly by ingestion through food chains, will or may reasonably be anticipated to cause death, disease, behavioral abnormalities, cancer, genetic mutation, physiological malfunctions (including malfunctions in reproduction), or physical deformations in the offspring of exposed people.” These substances are defined under section 101(14) of the U.S Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA; also known as Superfund); 40CFR261.3; 49CFR171.8; and 49CFR172.101 and its appendices.5 Header A primary pipe or tube component of a refrigerating system to which several other secondary pipes or tubes are connected.1,2, 7,10, 12 Heat pump (1) A refrigerating system used to transfer heat into a space or substance.1 (2) Thermodynamic heating/refrigerating system to transfer heat The condenser and evaporator may change roles to transfer heat in either direction By receiving the flow of air or other fluid, a heat pump is used to cool or heat.2 High side Those parts of a closed-circuit ammonia refrigerating system subjected to approximate condenser pressure.1,7,10,12 High-side float valve (1) A control valve that regulates the flow of refrigerant or oil This type of valve is actuated open by rising liquid level upstream of the valve.10 (2) A controlling device that reg- 2010 ASHRAE Handbook—Refrigeration (SI) ulates the flow of volatile liquid refrigerant from a higher pressure section of the system into a lower pressure section and is actuated toward open by a rising liquid level upstream of the valve.7 Highly hazardous chemical A material covered by the PSM Standard and listed in appendix A of OSHA’s PSM Standard (e.g., anhydrous ammonia).5 Horsepower (1) The power delivered from the prime mover to the compression device of a refrigerating system.1 (2) Unit of power in the I-P system: work done at the rate of 745.7 W.2 Hot-gas bypass regulator (1) A control valve that regulates the flow of refrigerant gas and is actuated toward open by a pressure falling below regulator set point downstream of the valve.10 (2) Automatic valve operated by the suction pressure, which it maintains above a give value by diverting a certain quantity of highside vapor to the low side of the system.2 (3) A controlling device that regulates the flow of refrigerant hot gas through the device from a higher-pressure section of the system to a lower-pressure section of the system and is actuated toward open by a pressure falling below regulator set point downstream of the regulator orifice.7 Hot-work operations Any operation that could cause a source of ignition in a hazardous area A hot-work permit is required for any hot-work operations.5 Hydraulic shock The occurrence of liquid moving through piping at high velocity, impacting interior pipe walls, and resulting in vibration/noise; also referred to as a liquid slugging or liquid hammer.5 Hydrostatic pressure (1) The large pressure resulting from liquid thermal expansion, also referred to as hydraulic pressure (e.g., the pressure that develops in a liquid-full and blocked-in component that undergoes a temperature rise).5 (2) Pressure exerted by a fluid at rest (3) Normal force per unit area that would be exerted by a moving fluid on an infinitesimally small body immersed in it if the body were carried along with the fluid.2 Hydrostatic relief valve A pressure actuated valve held closed by a spring or other means and designed to automatically relieve hydrostatic pressure in excess of its setting caused by the heating and resulting thermal expansion of liquid contained between stop valves, check valves, or automatic control valves These relief valves are used to protect piping and other components from excess pressure and are not rated for flow capacity or for service with ASME vessels.15 Immediately dangerous to life or health (IDLH) The maximum concentration from which unprotected persons are able to escape within 30 minutes without escape-impairing symptoms or irreversible health effects.1 Implementing agency In the United States, the state or local agency that obtains delegation for an accidental release prevention program under subpart E of 40CFR63 The implementing agency may be, but is not required to be, the state or local air permitting agency If no state or local agency is granted delegation, the EPA is the implementing agency for that state.4,5 Incident A release (e.g., of ammonia), fire, or explosion; or any event that could have resulted in a release, fire, or explosion; also referred to as accidents Not to be confused with occupational safety accidents, such as the laceration of a finger.5 Informative appendix An appendix that is not part of the standard but is included for information purposes only.1,10,12 Injury Any effect on a human that results either from direct exposure to toxic concentrations; radiant heat; or overpressures from accidental releases or from the direct consequences of a vapor cloud explosion (such as flying glass, debris, and other projectiles) from an accidental release and that requires medical treatment or hospitalization.4,5 Inlet size The nominal pipe size of the inlet of a pressure relief valve, unless otherwise designated.15 Inside dimension Inside diameter, width, height, or cross-sectional diagonal.1 This file is licensed to Abdual Hadi Nema (ahaddi58@yahoo.com) License Date: 6/1/2010 Licensed for single user © 2010 ASHRAE, Inc Terminology of Refrigeration Internal gross volume The volume as determined from internal dimensions of the container, with no allowance for the volume of the internal parts.1, 2, 7, 10 IIAR International Institute of Ammonia Refrigeration (www iiar.org) Inventory The mass of refrigerant contained in the system, in any section of the system, or in any component of the system (i.e., charge) Inventory does not include refrigerant stored in portable containers that are not permanently connected to the system.5 King valve The main liquid shutoff valve in an ammonia refrigeration system.5 Kv Valve flow coefficient: the flow (m3/h) of 15°C water that passes through the valve at 100 kPa pressure drop.11 Leak test pressure The pressure applied to test a system or any part of it for pressuretightness.7,12 Limited-charge system A system in which, with the compressor idle, the design pressure will not be exceeded when the refrigerant charge has completely evaporated.1,2 Liquid hammer The occurrence of liquid moving through piping at high velocity, impacting interior pipe walls, and resulting in vibration/noise; also referred to as a liquid slugging or hydraulic shock.5 Liquid level transmitter Appliance that senses liquid level and relays the level position by means of electrical, electronic, or pneumatic signal.11 Liquid receiver A vessel permanently connected to a refrigerating system by inlet and outlet pipes for storage of liquid refrigerant.1,2,7,12 Liquid relief valve A pressure-actuated valve closed by a spring or other means, designed to automatically relieve liquid pressure in excess of its setting, rated in litres per second of 15.6°C water flow at 110% of its setting, and for use with ASME pressure vessels.15 Listed (1) Equipment that has been tested and is identified as acceptable by an approved nationally recognized testing laboratory.7,10,12 (2) Equipment or materials included in a list published by an approved, nationally recognized testing laboratory, inspection agency, or other organization concerned with product evaluation that maintains periodic inspection of production of listed equipment or materials and whose listing states that the equipment or material either meets nationally recognized standards or has been tested and found suitable for use in a specified manner.1 Lithium bromide/water absorption system An absorption system where water (R-718) is the refrigerant and lithium bromide (LiBr) is the absorbent.1 Lobby A waiting room or large hallway serving as a waiting room.1 Lost workday cases experience rate The number of lost days multiplied by 200,000 and divided by the total worker-hours worked.5 Lower flammability limit (LFL) The minimum concentration of the refrigerant that propagates a flame through a homogeneous mixture of refrigerant and air.1 Low side (1) The parts of a closed-circuit ammonia refrigerating system subjected to approximate evaporator pressure and/or the high-stage suction (interstage) pressure of a two-stage system.10 (2) The parts of a mechanical refrigerating system subjected to approximately the same pressure as the evaporator.7,12 Low-side float valve A controlling device that regulates the flow of volatile liquid refrigerant into an evaporator-pressure section of the system from a higher-pressure section and is actuated toward closed by a rising liquid level downstream of the valve.7, 10 Machinery The refrigeration equipment forming a part of the refrigeration system, including but not limited to the following: compressor, condenser, liquid receiver, evaporator, and connecting piping.1,5,7,12 Machine room (1) A space that is designed to safely house refrigerating equipment, which may include, but is not limited to, 50.5 compressors, condensers, high-pressure receivers, economizers, purgers, refrigerant pumps, or other refrigerant liquid pumping and/ or transfer equipment.10 (2) A space that is designed to safely house compressors, pressure vessels, or associated refrigerating equipment.7,12 (3) A room in which mechanical equipment is permanently installed and operated (4) Main computer room.2 (5) A space that is designed to safely house compressors, pressure vessels, and associated refrigeration equipment It is not intended for this definition to include evaporators and associated equipment (e.g., surge drums) located in a cold storage room, refrigerated box, air-cooled space, or other enclosed space.5 (6) A space, meeting the requirements of sections 8.11 or 8.12 of ASHRAE Standard 15, that is designed to house compressors and pressure vessels.1 Management system Explicit arrangements for planning, organizing, implementing, and controlling activities.5 Manufacturer (1) The company or organization that creates and affixes its name, trademark, or trade name to a product.10 (2) The company or organization that evidences its responsibility by affixing its name, trademark or trade name to refrigeration equipment.1,7,12 Maximum allowable pressure Maximum gage pressure permitted on a completed system; the setting of the pressure-relieving devices protecting the system.2 MAWP Maximum allowable working pressure.10, 11 Means of egress A continuous and unobstructed path of travel from any point in a building or structure to a public way.1 Mechanical actuating float Buoyancy component that responds to changing liquid level to mechanically modulate a valve element controlling fluid flow.11 Mechanical integrity Ability of a system to exist under all likely conditions without hazard.7 Mechanical joint (1) A gastight joint obtained by joining metal parts with a positive-holding mechanical construction such as flanged, screwed, or flared joints or compression fittings.1,2 (2) A gastight joint, obtained by the joining of metal parts through a positive holding mechanical construction.7 Mechanical refrigerating system (1) A refrigerating system using mechanical compression to remove the refrigerant from the low-pressure side and to deliver it to the high-pressure side of the system.2,7,12 See also Closed-circuit ammonia refrigerating system.10 Medical treatment Treatment, other than first aid, administered by a physician or registered professional personnel under standing orders from a physician.4,5 Mitigation or mitigation systems Specific activities, technologies, or equipment designed or deployed to capture or control substances upon loss of containment to minimize exposure of the public or the environment Passive mitigation means equipment, devices, or technologies that function without human, mechanical, or other energy input Active mitigation means equipment, devices, or technologies that need human, mechanical, or other energy input to function.4,5 MOPD Maximum operating pressure differential for which the device has been designed.11 Motorized valve A valve operated by an electric motor.2,7,10 MSSPD Maximum seat sealing pressure differential for which the device has been designed.11 Multifunction valve Valve designed to fulfill the function of both control and shutoff.11 Near miss An incident where serious consequences did not occur, but could reasonably have done so.5 NH3 Abbreviation and chemical formula for anhydrous ammonia.5 NH3(l) Abbreviation for anhydrous ammonia liquid.5 NH3(v) Abbreviation for anhydrous ammonia vapor.5 NIOSH National Institute for Occupational Safety and Health (www.cdc.gov/niosh) This file is licensed to Abdual Hadi Nema (ahaddi58@yahoo.com) License Date: 6/1/2010 Licensed for single user © 2010 ASHRAE, Inc 50.6 Nonpositive-displacement compressor (1) A compressor in which the increase in vapor pressure is attained without changing the internal volume of the compression chamber.1,7 (2) Rotary compressor in which the compression is obtained without reduction of internal volume of the compression chamber.2 Normative appendix An integral part of the mandatory requirements of the standard, which, for reasons of convenience, is placed after all other normative elements.1,10,12 Occupied space That portion of the premises accessible to or occupied by people, excluding machinery rooms.1 Offsite Areas beyond the property boundary of the stationary source, and areas within the property boundary to which the public has routine and unrestricted access during or outside business hours (definition from EPA’s RM Program regulations).4 Oil drain float valve (oil purge valve) (1) Valve for draining out the oil from all collection points in a system.2 (2) A high-side float valve that controls oil.7,10 OSHA Occupational Safety and Health Administration, of the U.S Department of Labor (www.osha.gov) OSHA recordable incident rate Total OSHA recordable incidents multiplied by 200,000 and divided by the total worker-hours worked.5 See also Incident Outlet size Nominal pipe size of the outlet of a pressure relief valve, unless otherwise designated.15 Overpressure (1) The pressure increase over the set pressure of a pressure relief valve, usually expressed as a percentage of set pressure.15 (2) Pressure in excess of the designed normal operating range.2 Owner or operator Any person who owns, leases, operates, controls, or supervises a stationary source.5 Owner’s representative Person(s) authorized to function in the owner’s interests in matters pertaining to execution of testing, adjusting, and balancing of systems.2 Pilot-operated pressure relief valve A pressure relief valve in which the major relieving device is combined with and is controlled by a self-actuated auxiliary pressure relief valve.15 Pilot-operated relief valve A pressure relief valve in which the major relieving device is combined with and is controlled by a selfactuated auxiliary pressure relief valve.1 Pilot-operative valve A valve that regulates flow in response to a signal from a pilot.7 Piping (1) The pipe or tube mains for interconnecting the various parts of a refrigerating system Piping includes pipe; flanges; bolting; gaskets; valves; fittings; pressure-containing parts of other components such as expansion joints, strainers, and devices that serve purposes such as mixing, separating, snubbing, distributing, metering, or controlling flow; pipe-supporting fixtures; and structural attachments.1,7,10,12 (2) System of pipes for carrying fluids (3) Pipe or tube mains for interconnecting the various parts of a refrigerating system.2 Piping and instrument diagram (P&ID) A mechanical schematic drawing of the plant refrigeration equipment Details such as utility tie-ins, piping, relief valves, refrigeration control valve type, defrost drain condensate piping, valves, instruments, line numbers, and refrigeration equipment are shown The P&ID, being a schematic drawing, is not drawn to scale; however, relative sizes and locations should be depicted where possible Instrumentation including such details as tie-in points, instrument numbers, control valve numbers, and panel or local control mounting details are shown The name and design features of the refrigeration equipment are shown on the P&ID.5 Piping system (1) A piping system includes all ammonia refrigerant piping and fittings, hand valves, control valves and other devices that are mounted in the refrigeration lines Pipe insulation is also considered part of the piping system Pipe supports, hangers, brackets or other piping accessories are not considered part of the piping system.8 (2) System to carry fluids, including pipe, flanges, 2010 ASHRAE Handbook—Refrigeration (SI) bolting, gaskets, valves, fittings, the pressure-containing parts of other components such as expansion joints, strainers and devices that serve such purposes as mixing, separating, snubbing, distributing, metering or controlling flow, and pipe-supporting fixtures and structural attachments It does not include pressure vessels, compressors or pumps, and heat exchangers including coil type, but does include all connecting refrigerant and brine piping starting at the first joint adjacent to such apparatus It does not include support structures.2 Plate heat exchanger (1) Multiple corrugated plates arranged to form a discrete flow path within the boundary of the plates for each of the fluid media between which heat is transferred.10,12 (2) Fixed plates that separate and keep separate the hot and cool fluids.2 PM Preventative maintenance.5 Popping pressure The value of increasing inlet static pressure at which the disk moves in the opening direction at a faster rate as compared with corresponding movement at higher or lower pressures It applies only to safety or safety relief valves on compressible-fluid service.15 Population The public.4,5 Positive-displacement compressor A compressor in which an increase in pressure is attained by changing the internal volume of the compression chamber.1,7,10 (2) Machine that increases the pressure of refrigerant vapor by reducing the volume of the compression chamber through work applied to the mechanism.2 Premises A tract of land and the buildings thereon.1 Pressure (1) Force per unit area, considered as both above and below atmospheric.11 (2) Thermodynamically, the normal force exerted by a homogeneous liquid or gas, per unit of area, on the wall of the container (3) Force exerted per unit area Note: the terms head and pressure often are used interchangeably; however, head is the height of a fluid column supported by fluid flow, whereas pressure is the normal force per unit area For liquids, it is convenient to measure the head in terms of the flowing fluid With a gas or air, however, it is customary to measure pressure on a column of liquid.2 Pressure-containing envelope Enclosure that isolates the contained ammonia from the atmosphere or other fluid(s).11 Pressure-containing seal cap Seal cap designed as an extension of the pressure-containing envelope.11 Pressure-imposing element (1) Any device or portion of the equipment used to increase the refrigerant pressure.1,7,10 (2) Device for increasing the pressure on a fluid (e.g., refrigerant or other gases).2 Pressure-limiting device (1) A pressure responsive mechanism designed to automatically stop the operation of the pressure-imposing element at a predetermined pressure.2,7,10 (2) A pressureresponsive electronic or mechanical control designed to automatically stop the operation of the pressure-imposing element at a predetermined pressure.1 Pressure relief device (1) A pressure-actuated valve or rupture member designed to automatically relieve excessive pressure See also Dual pressure relief device; Pressure relief valve.1,5,7,10,12 (2) Means for relieving internal pressure and preventing explosive shattering of the housing.2 Pressure relief valve A pressure-actuated valve held closed by a spring or other means and designed to automatically relieve pressure in excess of its setting; also called a safety valve.1,2,7,10,12 It may be used for either compressible or incompressible fluids, depending on design, adjustment, or application.15 See also Dual pressure relief device; Pressure relief device Pressure safety appliances Safety relief valves within the scope of Section VIII of the ASME Boiler and Pressure Vessel Code {4.2.1} and relief valves intended specifically for hydrostatic protection.11 Pressure sensor A mechanical or electronic device that measures ammonia pressure.10 This file is licensed to Abdual Hadi Nema (ahaddi58@yahoo.com) License Date: 6/1/2010 Licensed for single user © 2010 ASHRAE, Inc Terminology of Refrigeration Pressure test A test following the installation of new equipment or modification of existing equipment where the equipment is placed under pressure to ensure that it will not leak Examples include hydrostatic tests and pneumatic tests.5 Pressure vessel (1) Any vessel that meets ASME’s definition of a pressure vessel in effect when the vessel was installed Refer to Section VIII, ASME Boiler and Pressure Code, Pressure.5 (2) Any refrigerant-containing receptacle in a closed-circuit ammonia refrigerating system, except for the following items: (a) evaporators where each separate evaporator section does not exceed 0.01 m3 of refrigerant-containing volume regardless of the maximum inside dimension; (b) evaporator coils; (c) compressors; (d) condenser coils; (e) controls; (f) headers; (g) pumps; (h) piping; (i) plate heat exchangers See also Controlled-pressure receiver; Receiver.1,2,7,10,12 Procedure qualification record (PQR) A document providing the actual welding variables used to produce an acceptable test weld, and the results of qualification tests conducted on the test weld.16 Process (1) Any activity involving ammonia, including any use, storage, manufacturing, handling, or on-site movement of ammonia, or any combination of these activities For the purposes of this definition, any group of vessels that are interconnected and separate vessels that are located such that ammonia could be involved in a potential release shall be considered a single process.4,5,17 (2) Change in thermodynamic state that can be defined as any change in the properties of a system Note: A process is described by specifying the initial and final equilibrium states, the path (if identifiable), and the interactions that take place across system boundaries during the process (3) A sequence of events.2 Process chemistry The chemical reactions that are relevant to the possible release of any hazardous materials The process chemistry includes the reactions associated with the formation and handling of any raw materials, intermediates, products, by-products, and waste products that might take place in credible normal operations.5 Process flow diagram (PFD) A schematic drawing of the refrigeration process The primary purpose of this drawing is to show the heat and material balance of the process Main valves, pressures, temperatures, and flows may be shown to enhance understanding of the refrigeration system Drawings of utilities, including chilled water, glycol, compressed air, lube oil, condenser water, cooling tower water, etc., may be shown for clarity Pump and vessel capacities may also be shown for an understanding of the system.5 Process safety Protection of people and property from episodic and catastrophic incidents that may result from unplanned or unexpected deviations in process conditions.5 Process safety management (PSM) Application of management programs to the identification, understanding, and control of process hazards to prevent process-related incidents and injuries.5 Process safety management (PSM) elements Comprehensive sets of policies, procedures, and practices designed to ensure that barriers to episodic incidents are in place, in use, and effective These elements are required by OSHA’s PSM Standard and by the EPA’s final RM Program Rule.5 Process safety management (PSM) program Program established under 29CFR1910.119 that contains requirements for preventing or minimizing the consequences of catastrophic releases of toxic, reactive, flammable, or explosive chemicals These releases may result in toxic, fire, or explosion hazards Proof (1) Design confirmation by testing a production sample to verify that it will not fail when exposed to a predetermined pressure that exceeds its rated design pressure.10,11 (2) Test to indicate that a material or structure is suitable for the purpose intended.2 Property insurance underwriter An insurance company licensed to write insurance for the property in question in the jurisdiction concerned.7,12 50.7 Public Any person except employees or contractors at the stationary source.4,5 Public receptor Off-site residences; institutions (e.g., schools, hospitals); industrial, commercial, and office buildings; parks; or recreational areas inhabited or occupied by the public at any time without restriction by the stationary source where members of the public could be exposed to toxic concentrations, radiant heat, or overpressure, as a result of an accidental release.4,5 Pumpdown A procedure for removing refrigerant liquid from a piece of equipment prior to a prolonged shutdown or for maintenance or repair It involves emptying the piece of equipment or subsystem of liquid by the refrigerant flows occurring during normal operation The lowest pressure to which the piece of equipment can be reduced is that of the suction of the compressor network to which it is connected.5 Pumpdown charge The quantity of refrigerant stored at some point in the refrigeration system for operational, service, or standby purposes.1 Pumpout A procedure for removing refrigerant from a piece of equipment or subsystem whereby all liquid refrigerant is removed and the pressure within the piece of equipment or subsystem is reduced to subatmospheric level so that, upon opening of the equipment or subsystem, little or no refrigerant escapes to atmosphere The procedure requires the availability of a separate pumping means connected in such a way as to be capable of producing subatmospheric pressures in the parts of the refrigerating system in question.5 Qualified individual An individual qualified through adequate training and experience to service, maintain, and operate a familiar refrigerating system.6 Qualified welding procedure A welding procedure that meets qualification requirements for weldments made in accordance with the welding procedure specification (WPS) and recorded on a procedure qualification record (PQR) Qualified welding procedures are of two types: (1) procedures independently qualified by an employer for in-house use, and (2) standard procedures allowed for use without further qualification.16 Readily accessible Capable of being reached safely and quickly for operation, repair, and inspection without requiring those who need access to climb over or remove obstacles or to resort to the use of portable access equipment.2,10,12 Receiver A pressure vessel in a closed-circuit refrigerating system designed to hold the varying volume of liquid refrigerant resulting from changes in system operating conditions See also Controlled-pressure receiver; Pressure vessel.10 Reclaimed refrigerants Refrigerants reprocessed to the same specifications as new refrigerants by any means, including distillation Such refrigerants have been chemically analyzed to verify that those specifications have been met.1 Record of welder or welding operator qualification tests (performance qualification test record) Tests that qualify a welder to perform manual or semiautomatic welding, or machine or automatic welding The welder or welding operator performs the test with a specific welding procedure specification (WPS) The record includes guided bend test results, radiographic results, and fillet weld test results, where applicable.16 Recover To remove refrigerant in any condition from a system and to store it in an external container without necessarily testing or processing it in any way.2 Recovered refrigerants Refrigerants removed from a system in any condition without necessarily testing or processing them.1 Recycle To clean refrigerant for reuse by oil separation and single or multiple passes through moisture absorption devices, such as filter-driers with replaceable cores This procedure is usually implemented at the field site or at a local service shop.2 Recycled refrigerants Refrigerants for which contaminants have been reduced by oil separation, removal of noncondensable This file is licensed to Abdual Hadi Nema (ahaddi58@yahoo.com) License Date: 6/1/2010 Licensed for single user © 2010 ASHRAE, Inc 50.8 gases, and single or multiple passes through filter-driers or other devices that reduce moisture, acidity, and particulate matter.1 Refrigerant (1) Ammonia used for heat transfer in a closedcircuit ammonia refrigerating system applying the vapor-compression cycle.10,12 (2) Fluid used for heat transfer in a refrigeration system The refrigerant absorbs heat and transfers it at a higher temperature and pressure, usually with a change of state.1,5 (3) In a refrigerating system, the medium of heat transfer that picks up heat by evaporating at a low temperature and pressure, and gives up heat on condensing at a higher temperature and pressure (4) Fluid used for heat transfer in a refrigerating system that absorbs heat at a low temperature and pressure of the fluid and transfers heat at a higher temperature and a higher pressure of the fluid, usually involving changes of state of the fluid.2 (5) A substance used to produce refrigeration by its expansion or vaporization.7 Refrigerant detector A device that is capable of sensing the presence of refrigerant vapor.1 Refrigerant pump A mechanical device for moving liquid ammonia refrigerant within a closed-circuit ammonia refrigerating system.7,10,12 Refrigerant receiver A vessel in a refrigerating system designed to ensure the availability of adequate liquid refrigerant for proper functioning of the system, and to store liquid refrigerant when the system is pumped down.2 Refrigerating system (1) A combination of interconnected refrigerant-containing parts constituting one closed refrigerant circuit in which a refrigerant is circulated for the purpose of extracting heat.1,5,7,12 (2) System that, in operation between a heat source (evaporator), and a heat sink (condenser), at two different temperatures, is able to absorb heat from the heat source at the lower temperature and reject heat to the heat sink at the higher temperature.2 Refrigerating system classification Indicates the degree of probability (low or high) that leaked refrigerant from a failed connection, seal, or component could enter an occupied area The distinction is based on the basic design or location of the components.1 Refrigerating system—direct System in which the refrigerant evaporator or condenser is in direct contact with the air or substance to be cooled or heated.2 Refrigerating system—indirect System in which a secondary coolant, cooled or heated by the refrigerating system, is circulated to the air or substance to be cooled or heated.2 Refrigeration flow diagrams Schematic that shows major pieces of ammonia refrigeration equipment (vessels, compressors, condensers, etc.) and interconnected refrigeration piping It may also contain crucial emergency isolation valves such as the main liquid shutoff valve (king valve), labels for main piping headers that indicate direction and type of service (e.g., “HPL” for high-pressure liquid), utility tie-in points such as cooling water lines to the evaporative condensers, and a legend of the symbols and abbreviations used.5 Regulated substance A material listed in Table of § 68.130 (e.g., ammonia inventory in excess of 4536 kg).5 Regulations Government orders that have the force of law behind them, with penalties for failure to comply Regulations may be issued by federal, state, or local governments.5 Relief valve Safety valve actuated by inlet pressure that opens in proportion to the increase in pressure above the opening pressure.2,15 Relieving pressure Set pressure plus overpressure.15 Replacement in kind A replacement that satisfies the design specification.5 Room temperature Temperature of the surrounding air, or air in the enclosure under consideration, held between 15.6 and 37.8°C.11 Rupture disk Valve or rupture member designed to relieve excessive pressure by mechanical failure of the disk.2 2010 ASHRAE Handbook—Refrigeration (SI) Rupture disk device A nonreclosing pressure relief device actuated by inlet static pressure and designed to function by bursting a rupture disk.15 Rupture member A device that will rupture at a predetermined pressure differential.1,7,10,12 Safety relief valve (SRV) A pressure relief valve characterized by rapid opening or pop action, or by opening in proportion to the increase in pressure over the opening pressure, depending on application.15 Safety systems/devices Systems and/or equipment used to warn of hazardous conditions or prevent them from occurring Examples include alarms, interlocks, detection devices, and suppression systems.5 Safety valve A pressure relief valve actuated by inlet static pressure and characterized by rapid opening or pop action.15 Saturation pressure The pressure at which vapor and liquid can exist in equilibrium at a given temperature.1,7,10 Saturated vapor Vapor at the saturation temperature corresponding to the existing pressure and without any liquid phase.2 Seal cap Generic term for pressure-containing or non-pressurecontaining enclosure that attaches to the valve and fully encloses a stem (spindle) and associated stem seal packing nut.11 Sealed ammonia/water absorption system (1) Unit system in which all refrigerant-containing parts are made permanently tight by welding or brazing.2 (2) An absorption system where ammonia (R-717) is the refrigerant and water is the absorbent and all refrigerant-containing parts are made permanently tight by welding or brazing.1 Secondary coolant (1) Any liquid used for transmission of heat, without vaporization.1 (2) Liquid used for the transmission of heat without a change of state, having no flash point, or a flash point about 65.6°C.2 Seep Nuisance loss of refrigerant from a relief valve that can occur when the vessel pressure approaches the relief pressure setting, or after the valve discharges if the valve does not fully reseat.10 Self-closing valve A manually operated stop valve that automatically returns to the closed position by means of a spring or other device when the operating handle is released.10 Self-contained system A complete factory-assembled and factory-tested closed-circuit refrigerating system that is shipped in one or more sections and has no refrigerant-containing parts that are joined in the field by other than companion or block valves.1,7,10 Self-contained refrigerating system (single-packaged) Unit assembly comprising a compressor, evaporator, condenser, and expansion device, used for refrigerating and for extracting heat.2 Set pressure (1) The pressure at which a pressure relief device or pressure control is set to operate.1 (2) The pressure stamped on a pressure relief valve name plate.15 (3) Pressure level at which a pressure relief device is set to operate; the value marked on the valve or indicated on the switch.2 Set pressure tolerance Plus or minus 3% of set pressure for safety relief valve settings higher than 483 kPa (gage).15 Shall (shall not;11 “it is required”) Term used where the provision is mandatory.1,2, 6,10,11,12 Shell-and-tube condenser (1) A type of condenser with tubes secured into a tube sheet at one or both ends of an enclosing shell See also Air-cooled condenser; Condenser; Desuperheater; Double-pipe (tube-in-tube) condenser; Evaporative condenser.10,12 (2) A refrigerant condenser with tubes secured into a tube sheet at one end or both ends of an enclosing shell.7 Shell-and-tube evaporator A type of evaporator where tubes are enclosed in a shell Refrigerant can be either in the shell or tubes See also Evaporator.7,10,12 Shell-and-tube heat exchanger Nest of tubes or pipes, or a coil of tube or pipe, contained in a shell or container The pipes carry a fluid through the shell, which is also provided with an inlet and outlet for flow of another fluid.2 This file is licensed to Abdual Hadi Nema (ahaddi58@yahoo.com) License Date: 6/1/2010 Licensed for single user © 2010 ASHRAE, Inc Terminology of Refrigeration Should (should not; “it is recommended”) Used in codes and standards where the provisions are not mandatory but are (are not) recommended good practice under most but not all conditions.2,6,10,12 Shutoff valve Externally actuated valve solely designed to stop flow for the purpose of isolating a subsection of the system Also referred to as a block, hand, service, or stop valve.10,11 Slugging (1) The phenomenon resulting from liquid entering a compressor suction flow stream; the compressor’s inability to compress liquid results in various degrees of mechanical damage to the compressor.5 (2) Effect produced by droplets of liquid refrigerant or oil, or a mixture of both, that reach the cylinder of a compressor.2 Soldered joint A gastight joint formed by joining metal parts with alloys that melt at temperatures not exceeding 426.5°C and above 204.5°C.1,2 Solenoid valve (1) Control valve actuated by an electrically charged coil, designed to functionally stop flow.10 (2) A valve that is opened or closed by the magnetic action of an electrically energized coil The opposite action is accomplished by gravity, pressure, or spring action.7,12 (3) Valve that is closed by gravity, pressure, or spring action and opened by the magnetic action of an electrically energized coil, or vice versa.2 Source of ignition A source of ignition is a flame, tool spark, static electric charge, or electric spark that could cause a fire or explosion Examples include the following: • Welding, burning, brazing, soldering, or any use of an open flame • Metal removing operations such as drilling, chipping, abrasive cutting, milling, grinding, etc • Internal combustion engines • Explosive-actuated fastening tools • Cutting or chipping concrete with or without reinforcements • Operating equipment and tools (including those that are battery operated) in a hazardous area • Operating any cleaning device utilizing metal or any other metal contacts that can produce sparks • Work on live electrical circuits of any voltage in hazardous locations5 Specified Explicitly stated in detail Specified limits or prescriptions are mandatory.1 SRV Safety relief valve, also commonly referred to as a pressure safety valve (PSV), a pressure relief valve (PRV), or simply relief valve (RV).5 Standards (1) Practices that are recommended by either an internal (company generated) or outside organization Standards are prepared to record best practices to be used by design, operations, and maintenance personnel so that a level of safety and consistency is established and maintained.5 (2) A document that defines properties, processes, dimensions, materials, relationships, concepts, nomenclature, or test methods for rating purposes.2 Start-up (1) A procedure, following the installation of a refrigerating system, that confirms the proper operation of all the equipment and interconnecting piping and electrical switchgear and controls.12 (2) Procedure to start a prime mover and supporting auxiliaries, including synchronizing and loading the generator.2 Stationary source The facility; any buildings, structures, equipment, or installations that (a) belong to the same industrial group, (b) are located on one or more contiguous properties, (c) are under the control of the same person or persons, and (d) could be the source of an accidental release.5 Stem Rotating or linear sliding component that extends through the pressure-containing envelope for the purpose of actuating an internal element (e.g., disk) of the valve Also called a spindle.11 Stop valve (1) A device used to shut off the flow of refrigerant.1,7 (2) Shutoff valve of any type, as distinguished from a flow control valve.2 50.9 Strainer (1) Pressure-containing component through which ammonia flows for the purpose of separating particulate matter from the flow stream.10,11 (2) Device used to separate solids from the liquid containing them.2 Strength test pressure Pressure applied to test the strength of a refrigerating system or any part of it.7 Subcooling (1) Cooling a substance below its saturated condition or its freezing temperature.2 (2) Reduc[ing a substance] to a temperature below the saturation temperature for the existing pressure.10 Sudden liquid deceleration The rapid decrease of liquid flow in a line or pipe, as a result of the sudden closing of a valve; also called hydraulic shock or liquid hammer.9 Superheat Extra heat in a vapor that is at a higher temperature than the saturation temperature corresponding to its pressure.2,10,12 Superimposed back pressure The static pressure existing at the outlet of a pressure relief device at the time the device is required to operate.15 Supplier The individual or organization from whom title for equipment or material passes to the purchaser.7,12 System components Any part that contains refrigerant and is not part of the piping system; includes compressors and compressor units, condensers, receivers, thermosiphon vessels, recirculators, intercoolers, accumulators, transfer vessels, heat exchangers, oil pots, etc.8 Technical operating specifications (TOS) Documentation that provides a complete description of each operating component and subsystem, defining construction, function, capacity or size, operating alignment, operating conditions, controls and instrumentation, and safety systems It is the logical repository for much of the process safety information called for as part of the process safety management (PSM) program.5 Temporary operation Deliberate and planned operation of a piece of equipment at conditions outside of its normal operating range, including any specific steps that are to be taken so there are no safety ramifications.5 Tenant A person or organization having the legal right to occupy a premises.1 Test pressure (1) The pressure to which a piece of equipment or a system is subjected, according to pressure test or leak test procedures.7,10,12 (2) Pressure, usually higher than the design working pressure, to which a piece of equipment is subjected for testing according to specified procedures.2 Testing/inspection/preventative maintenance (T/I/PM) Any maintenance activity that is preventative or predictive in nature and is performed on a recurring basis T/I/PM tasks consist of checks, calibrations, adjustments, and other tasks that are useful or appropriate to ensure that the integrity of critical process equipment is maintained on an ongoing basis.5 Thermostatic expansion valve (1) A control valve that regulates flow of refrigerant into an evaporator of a closed-circuit ammonia refrigerating system and is actuated by changes in evaporator pressure and superheat of the refrigerant gas leaving the evaporator The basic function is to control the amount of superheat.2,7,10 Three-way (stop) valve (1) A manually operated valve with one inlet that alternately can stop flow to either of two outlets.7,10 (2) A service valve for dual mounted pressure relief valves.2,10 (3) A service valve for dual pressure relief devices that allows using one device while isolating the other from the system, maintaining one valve in operation at all times.1 (4) Valve having either a single inlet and two outlets (diverting) or two inlets and a single outlet (mixing), in which either one or the other is open.2 TLV/TWA (threshold limit value-time weighted average) The refrigerant concentration in air for a normal h workday and a 40 h workweek to which repeated exposure, day after day, will not cause an adverse effect in most persons.1 This file is licensed to Abdual Hadi Nema (ahaddi58@yahoo.com) License Date: 6/1/2010 Licensed for single user © 2010 ASHRAE, Inc 50.10 2010 ASHRAE Handbook—Refrigeration (SI) Trade secret Any confidential formula, pattern, process, device, information, or compilation of information that is used in an employer’s business, and that gives the employer an opportunity to obtain an advantage over competitors who not know or use it This definition comes from the Hazard Communication Standard (29CFR1910.1200) Appendix D of the Hazard Communication Standard sets out the criteria to be used in determining whether materials meet the definition of trade secrets.5,17 Trained start-up technician An individual having adequate training and experience that qualifies that individual to start up and operate a familiar refrigerating installation.7,12 Trained technician An individual having adequate training and experience that qualify that individual to service, maintain and operate a familiar closed-circuit ammonia refrigerating system.10 Trapped liquid The complete filling of the internal volume of a containment, such as a pressure vessel or pipe, with liquid refrigerant This is also referred to as hydrostatic lockup.9 Type E, electric-resistance-welded pipe (ERW) Pipe produced in individual lengths or in continuous lengths from coiled skelp and subsequently cut into individual lengths, having a longitudinal butt joint welded by the heat from the pipe’s resistance to the flow of electric current in a circuit of which the pipe is a part, and by the application of pressure.14 Type F, furnace-welded pipe (prohibited for ammonia service) Pipe produced in continuous lengths from coiled skelp and subsequently cut into individual lengths, having its longitudinal butt joint forge welded by the mechanical pressure developed in rolling the hot-formed skelp through a set of round welding rolls.14 Type S, wrought steel seamless pipe A tubular product made without a welded seam It is manufactured by hot-working steel and, if necessary, by subsequently cold-finishing the product to produce the desired shape, dimensions, and properties.14 Typical meteorological conditions The temperature, wind speed, cloud cover, and atmospheric stability class prevailing at the site based on data gathered at or near the site or from a local meteorological station.4,5 Ultimate strength (1) The highest stress level that the component can tolerate without rupture.7,10 (2) The stress at which rupture occurs.1 Unibody valve Valve limited to maximum 15 mm nominal bore incorporating a one-piece body with integral bonnet and without any pressure-containing assembly joint.11 Unprotected tubing Tubing that is not protected by enclosure or suitable location so that it is exposed to crushing, abrasion, puncture or similar mechanical damage under installed conditions.1, Upstream pressure regulator A controlling device that regulates the flow of refrigerant gas, liquid, or oil through the device from a section of the system to a lower-pressure section, and is actuated toward open by a pressure rising above regulator set point upstream of the regular orifice.7 Valve (1) Device to regulate or stop the flow of fluid in a pipe or duct by throttling.2 (2) A pressure-containing component that stops, allows, or controls flow See also Automatic expansion valve; Check valve; Control valve; Dual pressure relief device; Evaporator-pressure regulator; Flow regulator; High-side float valve; Hot-gas bypass regulator; Low-side float valve; Motorized valve; Oil drain float valve; Piping; Pressure relief device; Pressure relief valve; Self-closing valve; Shutoff valve; Solenoid valve; Thermostatic expansion valve; Three-way valve.10,11,12 Vapor-propelled liquid The movement of liquid refrigerant propelled at high velocity by high-pressure vapor in hot-gas and suction lines; also called hydraulic shock, liquid hammer, or surge.9 Ventilation Process of supplying or removing air by natural or mechanical means to or from any space Such air may or may not have been conditioned.2 Ventilation system The system used to circulate air in an enclosed volume.5 Vessel (1) Any reactor, rank, drum, barrel, cylinder, vat, kettle, boiler, or other container.5 (2) Container or structural envelope in which materials are processed, treated, or stored.2 Welded joint A gastight connection, created by joining metal parts in a molten state.2,7,10 Welding procedure specification (WPS) A document that delineates or references all welding variables required to provide direction for welding.16 Zeotropic Refers to blends comprising multiple components of different volatility that, when used in refrigeration cycles, change volumetric composition and saturation temperatures as they evaporate (boil) or condense at constant pressure The word is derived from the Greek words zein (to boil) and tropos (to change).1 Zeotropic refrigerant Blend of two or more component refrigerants whose equilibrium vapor-phase and liquid-phase compositions are different at a given temperature.2 Zone (1) A general term used to identify a pressure level or temperature level of a refrigeration system A zone is associated with a compressor or group of compressors and the associated vessels serving a common pressure level This usage does not pertain to individual temperature-controlled areas or rooms served by one or more compressor.10 (2) Space or group of spaces within a building with heating or cooling requirements sufficiently similar that comfort conditions can be maintained by a single controlling device.2 SOURCES ANSI/ASHRAE Standard 15-2007: Safety Standard for Refrigeration Systems ASHRAE Handbook usage ASME Standard B31.5-2006: Refrigeration Piping and Heat Transfer Components EPA’s RMP: Risk Management Plan (http://www.epa.gov/oem/ content/rmp/index.htm) IIAR’s Ammonia Refrigerant Management (ARM) Program IIAR Bulletin 109: Guidelines for IIAR Minimum Safety Criteria for a Safe Ammonia Refrigeration System IIAR Bulletin 110: Guidelines for Start-up, Inspection and Maintenance of Ammonia Mechanical Refrigerating Systems IIAR Bulletin 114: Guidelines for Identification of Ammonia Refrigeration Piping and System Components IIAR Bulletin 116: Avoiding Component Failure in Industrial Refrigeration Systems Caused by Abnormal Pressure or Shock 10 ANSI/IIAR Standard 2: American National Standard for Equipment, Design and Installation of Ammonia Mechanical Refrigerating Systems 11 IIAR Standard 3: Ammonia Refrigeration Valves 12 IIAR Standard 5: Start-up and Commissioning of Closed-Circuit Ammonia Mechanical Refrigerating Systems 13 IIAR Ammonia Refrigeration Piping Handbook 14 IIAR Ammonia Refrigeration Piping Handbook, Ch 2: Pipe Installation Procedures 15 IIAR Ammonia Refrigeration Piping Handbook, Ch 6: Piping for Pressure-Relief Devices 16 IIAR Ammonia Refrigeration Piping Handbook, Ch 8: Welding Procedures 17 OSHA’s 29CFR1910.119: Process Safety Management of Highly Hazardous Chemicals (http://www.osha.gov/pls/oshaweb/ owadisp.show_document?p_table=STANDARDS&p_id=9760) Related Commercial Resources