Refrigerant Piping, Controls, and Accessories
ASHRAE Technical Committee 10.3

Scope of TC 10.3

TC 10.3 is concerned with the design, layout, sizing, specification, insulation, oil carrying characteristics, safety and corrosion of refrigerant piping, excluding secondary refrigerant piping.


The ASHRAE Handbook is published in a series of four volumes, one of which is revised each year, ensuring that no volume is older than four years.

This TC is responsible for the following chapters in the Refrigeration Handbook:

REFRIGERATION: Halocarbon Refrigeration Systems
This chapter focuses on systems that use halocarbons (halogenated hydrocarbons) as refrigerants. The most commonly used halogen refrigerants are chlorine (Cl) and fluorine (F).Halocarbon refrigerants are classified into four groups: chlorofluorocarbons (CFCs), which contain carbon, chlorine, and fluorine; hydrochlorofluorocarbons (HCFCs), which consist of carbon, hydro-gen, chlorine, and fluorine; hydrofluorocarbons (HFCs), which contain carbon, hydrogen, and fluorine; and hydrofluoroolefins (HFOs),which are HFC refrigerants derived from an alkene (olefin; i.e., an unsaturated compound having at least one carbon-to-carbon double bond). Examples of these refrigerants can be found in Chapter 29 of the 2013 ASHRAE Handbook—Fundamentals.

REFRIGERATION: Ammonia Refrigeration Systems
Ammonia is the refrigerant of choice for many industrial refrigeration systems. Custom-engineered ammonia (R-717) refrigeration systems often have design conditions that span a wide range of evaporating and condensing temperatures. Examples are (1) a food freezing plant operating from +50 to –50°F (10 to –45°C); (2) a candy storage requiring 60°F (15°C) db with precise humidity control; (3) a beef chill room at 28 to 30°F (–2 to –1°C) with high humidity; (4) a distribution warehouse requiring multiple temperatures for storing ice cream, frozen food, meat, and produce and for docks; and (5) a chemical process requiring multiple temperatures ranging from +60 to –60°F (15 to –50°C).

REFRIGERATION: System Practices for Carbon Dioxide Refrigerant
Carbon dioxide (R-744) is one of the naturally occurring compounds collectively known as “natural refrigerants.” It is nonflammable and nontoxic, with no known carcinogenic, mutagenic, or other toxic effects, and no dangerous products of combustion. Using carbon dioxide in refrigerating systems can be considered a form of carbon capture, with a potential beneficial effect on climate change. It has no adverse local environmental effects. In recent years, CO2 has once again become a refrigerant of great interest. However, high-pressure CO2 systems (e.g., 490.8 psia [3.4 MPa] at a saturation temperature of 30°F [–1°C], or 969.6 psia at 80°F [6.7 MPa at 26.7°C]) present some challenges for containment and safety.

REFRIGERATION: Insulation Systems for Refrigerant Piping
This chapter is a guide to specifying insulation systems for refrigeration piping, fittings, and vessels operated at temperatures ranging from 35 to –100°F (2 to –70°C). It does not deal with HVAC systems or applications such as chilled-water systems. Refer to Chapters 23, 25, 26, and 27 in the 2013 ASHRAE Handbook—Fundamentals for information about insulation and vapor barriers for these systems.

The ASHRAE HVAC REFRIGERATION HANDBOOK may be purchased from the on-line bookstore by clicking on the highlighted text.

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Technical committees develop and sponsor technical sessions at the winter and annual conferences. Information about their future technical program is discussed at each TC meeting and at the TC’s Program Subcommittee meeting

ASHRAE publishes papers and transactions from presentations at its conference events. In addition, ASHRAE records most of the seminar sessions from its conferences on DVD. These DVDs are ideal for use at chapter meetings, in university courses, or company lunch and learns. Products available from the most recent conference may be found here.


Technical Committees are responsible for identifying research topics, proposing research projects, selecting bidders, and monitoring research projects funded by ASHRAE. Information about their specific research program is discussed at each TC meeting and at the TC’s Research Subcommittee meeting.

The TC has the following active research projects:

The objective of this research project is to determine the minimum vapor velocity required to sustain vertical upward flow of liquid anhydrous ammonia when transported by vapor anhydrous ammonia in the same pipe. This velocity shall be determined for a range of pipe diameters, overfeed rates, and temperatures. The pressure drop per foot of pipe as a function of velocity, temperature, and overfeed rate will also be determined.

This computational fluid dynamic (CFD) research project is the extension of the empirical work completed in the prior laboratory study research project. The research would provide the basis for design criteria for two-phase ammonia piping and evaporator coils.


ASHRAE writes standards for the purpose of establishing consensus for: 1) methods of test for use in commerce and 2) performance criteria for use as facilitators with which to guide the industry. ASHRAE publishes the following three types of voluntary consensus standards: Method of Measurement or Test (MOT), Standard Design and Standard Practice. ASHRAE does not write rating standards unless a suitable rating standard will not otherwise be available. ASHRAE is accredited by the American National Standards Institute (ANSI) and follows ANSI's requirements for due process and standards development. Standards may be purchased at the ASHRAE Bookstore.

Other Activities

TIP: If MTG involvement add here otherwise leave blank.

Include other activities, such as MTG involvement, into this section.


ASHRAE Technical FAQs are provided as a service to ASHRAE members, users of ASHRAE publications, and the general public. While every effort has been made to ensure their accuracy and reliability, they are advisory and provided for informational purposes only, and in many cases represent only one person’s view. They are not intended and should not be relied on as an official statement of ASHRAE. Technical questions not addressed may be submitted to the ASHRAE Technical Services department at