ASHRAE 15: Safety Code for Mechanical Refrigeration

32 Pages·3.5 MB·English

by  American Society of Heating, Refrigerating and Air Conditioning Engineers

By Authority Of
THE UNITED STATES OF AMERICA
Legally Binding Document
By the Authority Vested By Part 5 of the United States Code § 552(a) and
Part 1 of the Code of Regulations § 51 the attached document has been duly
INCORPORATED BY REFERENCE and shall be considered legally
binding upon all citizens and residents of the United States of America.
HEED THIS NOTICE: Criminal penalties may apply for noncompliance.
e
Document Name:
CFR Section(s):
Standards Body:
Official Incorporator:
THE EXECUTIVE DIRECTOR
OFFICE OF THE FEDERAL REGISTER
WASHINGTON, D.C.

ASHRAE 15 94 .. 0759650 0507529 62T ..
ANSI/ASHRAE 15-1994
Supersedes ANSIIASHRAE 15-1992
®
ASHRAE Logo
Removed
lARD
AN AMERICAN NATIONAL STANDARD
Safety Code for
Mechanical
Refrigeration
Approved bV the ASHRAE Standards Committee June
29, 1994; by the ASHRAE Board of Directors June 30,
1994; and by the American National Standards Institute
August 23, 1994.
ASH RAE Standards are updated on a five-year cycle; the
date following the Standard number is the year of ASH
RAE Board of Directors approval. The latest copies may
be purchased from ASH RAE Customer Service, 1791
Tullie Circle, NE, Atlanta, GA 30329.
©1994 American SOCIety of Heating. Refrigerating and Air-Cond~ionong Engineers.
ISSN 1041-2336
AMERICAN SOCIETY OF HEATING,
REFRIGERATING AND
AIR-CONDITIONING ENGINEERS, INC.
1791 Tullie Circle, NE • Atlanta, GA 30329
Sold to:PUBlIC.RESQURCE.ORG, W1269038
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ANSVASHRAE STANDARD PROJECT COMMITTEE 15
Cognizant TCs: TC 10.1, Custom Engineered Refrigeration Systems,
and TC 9.1, Large Building Air-Conditioning Systems
Project Committee Liaison: Allen J. Hanley
Thomas E. Watson, Chair Richard Krause
Donald P Grob, Secretary Leonard V. Micek
George C. Briley Thomas K. O'Donnell
Lee W. Burgett Norman W. Panabaker
James M. Calm Joseph W. Pillis
Gordon F. Clyde William V. Richards
Dennis R. Dorman Philip R. Schaefer
Milton W. Garland Kenneth M. Schoonover
Jay Kohler Philip A. Squair
William L. Kopko Rudolph Stegmann
Daniel E. Kramer Michael H. Tavares
ASHRAE STANDARDS COMMrrTEE 1993-94
Lee W. Burgett, Chair Daniel E. Kramer
Harry J. Sauer, Jr., Vice-Chair James A. Ranfone
M. Kent Anderson John M. Talbott
Herman F. Behls Michael W. Woodford
Larry O. Degelman James E. Woods
Allen J. Hanley Thomas P. Wutka
John K. Hodge George S. Yamamoto
Peter J. Hoey Grenville K. Yuill
Sally A. Hooks John S. Blossom, CO
Ronald H. Howell Michael E. Dillon. ExO.
Jim L. Heldenbrand, Manager of Standards
SPECIAL NOTE
This National Voluntary Consensus Standard was developed under the auspices of the American Society of
Heating, Refrigerating and Air-Conditioning Engineers (ASH RAE). Consensus is defined as ·substantial
agreement reached by concemed interests according to the judgment of a duly appointed authority, after a
concerted attempt at resolving objections. Consensus implies much more than the concept of a single majority
but not necessarily unanimity." This definition is according to the American National Standards Institute (ANSI)
of which ASH RAE is a member.
ASH RAE obtains consensus through participation of its national and intemational members, associated
societies, and public review.
ASHRAE Standards are prepared by a Project Committee appointed specifically for the purpose of writing
the Standard. The Project Committee Chairman and Vice-Chairman must be members of ASHRAE; while
other committee members mayor may not be ASHRAE members, all must be technically qualified in the
subject area of the Standard. Every effort is made to balance the concerned interests on all Project
Committees.
The Manager of Standards of ASH RAE should be contacted for.
a. interpretation of the contents of this Standard,
b. participation in the next review of the Standard,
c. offering constructive criticism for improving the Standard,
d. permiSSion to reprint portions of the Standard.
ASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDS
ASH RAE Standards and Guidelines are established to assist industry and the public by offering a
uniform method of testing for rating purposes, by suggesting safe practices in deSigning and installing
equipment, by providing proper definitions of this equipment, and by providing other information that
may serve to guide the industry. The creation of ASHRAE Standards and Guidelines is determined by
the need for them, and conformance to them is completely VOluntary.
In referring to this Standard or Guideline and in marking of equipment and in advertising, no claim
shall be made, either stated or implied, that the product has been approved by ASHRAE.
DISCLAIMER
ASHRAE uses its best efforts to promulgate Standards and Guidelines for the benefit of the public in
light of available information and accepted industry practices. However, ASH RAE does not guarantee,
certify, or assure the safety or performance of any products, components, or systems tested, installed,
or operated in accordance with ASH RAE's Standards or Guidelines or that any tests conducted under
its Standards or Guidelines will be nonhazardous or free from risk.
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ASHRAE 15 94 II 0759650 0507531 288 ..
TABLE OF CONTENTS
Section Page
Foreword ...................................................................................................................................................................................... 1
1. Purpose ................................................................................................................................................................................ 2
2. Scope ................................................................................................................................................................................... 2
3. Definitions ........................................................................................................................................................................... 2
4. Occupancy Classification .................................................................................................................................................... 4
5. Refrigerating System Classification .................................................................................................................................... 5
6. Refrigerant Classification .................................................................................................................................................... 7
7. Restrictions on Refrigerant Use .......................................................................................................................................... 7
8. Installation Restrictions ....................................................................................................................................................... 9
9. Design and Construction of Equipment and Systems ....................................................................................................... 11
10. Operation and Testing ..................................................................................................................................................... 18
11. General Requirements ..................................................................................................................................................... 19
Appendix A ................................................................................................................................................................................ 20
Appendix B ................................................................................................................................................................................ 20
Appendix C ................................................................................................................................................................................ 21
Appendix D ................................................................................................................................................................................ 21
Appendix E ................................................................................................................................................................................. 23
Appendix F ................................................................................................................................................................................. 24
Appendix G ................................................................................................................................................................................ 25
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ASHRAE 15 94 .. 0759650 0507532 114 ..
(This foreword is not part of this standard but is included The principal changes in this version are:
for information purposes only.)
Section 2-Revisions to the Scope for refrigerant
changes after adoption and for parts replacement
FOREWORD
after adoption.
A new version of one ofA SHRAE's oldest standards, "Safety Section 4-wrge Mercantile Occupancy added.
Code for Mechanical Refrigeration, " has been issued in the Section 5-Clarification of indirect open spray system.
Society's Centennial year. Rapid introduction of alternative Section 7-Rules rewritten for clarity and for applica-
refrigerants is necessary to make a timely response to envi tions of 100 horsepower or less.
ronmental issues that challenge the air-conditioning and Section 8-Air ducts through machinery rooms added
refrigeration industry. This edition of the "Safety Code for and leak detector requirements revised.
Mechanical Refrigeration" is written in code (nonpermis Section 9-Added ASME code stamping, revised pres
sive) language to reduce the time for its implementation. sure test factor, added pilot-operated relief valves,
ANSIIASHRAE 15-J992 was used as the starting point for added note for other heat sources to pressure-relief
this edition. formula, added exception for hydrostatic relief
This standard is directed toward the safety of persons valves, reworded section on ammonia discharge,
and property on or near the premises where refrigeration revised rules for positive displacement compressor
facilities are located. It includes specifications for fabrica relief, and eliminated rule for mounting of stop
tion oft ight systems but does not address the effects of refrig valves under O.875-inch diameter.
erant emissions on the environment. For information on the Section ll-Added lubrication identity and amount and
environmental effects of refrigerant emissions see ASHRAE revised requirements for storage of refrigerants in
Guideline 3-1990 and Addendum 3a-J992, "Reducing Emis machinery rooms.
sion of Fully Halogenated Chlorofluorocarbon (CFC) Table 1-Revised the quantities and footnotes.
Refrigerants in Refrigeration and Air-Conditioning Equip Table 2-Removed rules 6 and 8 from Industrial Occu
ment and Applications. " pancy; revised use of rules 1 and 2 for high-proba
An additional objective of the committee was to make bility systems.
the document easier to use by grouping topics to assist the
A table with a paragraph number comparison of ASHRAE
reader: The numbered paragraphs are separated into the fol
lowing major topics: 15-1992 with this edition is in an informative appendix at
the end of this document.
General
Restrictions The hazards of refrigerants are related to their physical
Design and Construction and chemical characteristics as well as to the pressures and
Operation and Testing temperatures occurring in refrigerating and air-conditioning
systems. Personal injury and property damage from inade
While the user must be familiar with the entire docu
quate precautions may occur from:
ment, this major topic grouping allows quicker location of
information. The subtopics included in these major group
Rupture of a part or an explosion with risk from flying
ings are:
debris or from structural collapse.
GENERAL: Purpose, Scope, Definitions, Occupancy Release of refrigerant from a fracture, due to a leaking
Classification, Refrigerating System Classification, seal, or from incorrect operation.
Refrigerant Classification. Fire resulting from or intensified by burning or defla
RESTRICTIONS: Restrictions on Refrigerant Use, In gratton of escaping lubricant or refrigerant.
stallation Restrictions.
Personal injury from accidental release of refrigerants
DESIGN AND CONSTRUCTION: Materials; System
may also occur from:
Design Pressure; Refrigerant-Containing Pressure
Vessels; Pressure-Relief Protection; Setting of Pres Suffocation from heavier-than-air refrigerants in inade
sure-Relief Devices; Marking of Relief Devices and quately ventilated spaces.
Fusible Plugs; Pressure Vessel Protection; Positive Narcotic and cardiac sensitization effects.
Displacement Compressor Protection; Pressure Toxic effects of vapor or the decomposition products due
Limiting Devices; Refrigerant Piping, Valves, Fit to vapor contact with flames or hot surfaces.
tings, and Related Parts; Components Other than Corrosive attack on the eyes, skin, or other tissue.
Pressure Vessels and Piping; Service Provisions; Freezing of tissue by contact with liquid.
Fabrication; Factory Tests; and Nameplate.
Table 1 shows the amount of refrigerant in a given space
OPERATION AND TESTING: Field Tests, General
that, when exceeded, requires a machinery room. When a
Requirements.
refrigerant is not classified in ASHRAE 34-1992 or addenda
In the text of the standard, superscripts indicate the refer or shown in Table 1, it is the responsibility of the owner of a
ences included in Appendices D and E. Also, the notes refrigerating system to make this judgment. For blends,
included in the body of the standard are informative in Appendix A is offered to aid in determining allowable con
nature and are not mandatory. centrations.
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Care should be taken to avoid stagnant pockets of 2.3 This code does not apply where water is the primary
refrigerant vapors by proper location of ventilation inlet and refrigerant.
exhaust openings (all commonly used refrigerants except
2.4 Equipment listed by an approved, nationally recog
ammonia [R-717] are heavier than air). All machinery
nized testing laboratory is deemed to meet the design, manu
rooms are now required to have detectors that will activate
facture, and factory test requirements section of this code for
an alarm and mechanical ventilation at a value not greater
the refrigerant or refrigerants for which the equipment was
than the corresponding TLV-TWA (or toxicity measure con
designed.
sistent therewith).
During public review of this standard, extensive com 2.5 The authority having jurisdiction has the authority to
ments were received from those interested in the use of grant exceptions from the requirements of this code or allow,
ammonia as a refrigerant. The Society has established an for local jurisdictional purposes, the use of other devices,
ASHRAE Position Statement, "Ammonia as a Refrigerant, " materials, or methods when evidence is provided to demon
to which the reader is referred for positions in this regard. strate equivalent protection and performance.
For more information on equipment, design, and installation
of ammonia refrigerant systems, see ANS/lllAR-2, published 3. DEFINITIONS
by the International Institute of Ammonia Refrigeration,
accessible: easy to approach for service or use (also see
Washington, DC 20036.
readily accessible).
A short publishing history of this code traces the origins
of these safety provisions. In 19/9, the American Society of approved: acceptable to the authority having jurisdiction.
Refrigerating Engineers (ASRE) proposed a Tentative Code
approved, nationally recognized laboratory: one that is
for the Regulation of Refrigerating Machines and Refriger
acceptable to the authority having jurisdiction, which pro
ants. Over the next 11 years, representatives from the Ameri
vides uniform testing and examination procedures and stan
can Gas Association, American Institute of Electrical
dards for meeting design, manufacturing, and factory testing
Engineers, American Institute of Refrigeration, American
requirements of this code; is organized, equipped, and quali
Chemical Society, American Society of Heating and Ventilat
fied for testing; and has a follow-up inspection service of the
ing Engineers, American Society of Mechanical Engineers,
current production of the listed products.
National Electrical Refrigerator Manufacturers Association,
National Fire Protection Association, and ASRE met to blends: refrigerants consisting of mixtures of two or more
expand the code to address all of the issues raised on the use different chemical compounds, often used individually as
of refrigeration equipment. The first Safety Code for refrigerants for other applications.
Mechanical Refrigeration, recognized as American Standard brazed joint: a gas-tight joint obtained by the joining of
89 in October 1930, appeared in the first edition, 1932- metal parts with metallic mixtures or alloys that melt at tem
1933, of the ASRE Refrigerating Handbook and Catalog. peratures above lOOO°F (537.7°C) but less than the melting
ASRE revisions designated ASA 89 appeared in 1933 and temperatures of the joined parts.
1939. ASRE revisions designated ASA 89.1 appeared in
companion or block valves: pairs of mating stop valves that
1950, 1953, and 1958. After the formation of ASHRAE, edi
allow sections of a system to be joined before opening these
tions appeared as ASA 89.1-1964, ANSI 89.1-1971, ANSll
valves or separated after closing them.
ASHRAE 15-1978, ANSIIASHRAE 15-1989, and ANSII
ASHRAE 15-1992. compressor: a machine used to compress refrigerant vapor.
compressor unit: a compressor with its prime mover and
1. PURPOSE
accessories.
The purpose of this standard is to specify safe design, con condenser: that part of the refrigerating system where refrig
struction, installation, and operation of refrigerating systems.
erant is liquefied by the removal of heat.
condenser coil: a condenser constructed of pipe or tubing,
2. SCOPE
not enclosed in a pressure vessel.
2.1 This code establishes safeguards for life, limb, health,
condensing unit: a combination of one or more power
and property, and prescribes safety standards.
driven compressors, condensers, liquid receivers (when
2.2 This code applies required), and regularly furnished accessories.
(a) to mechanical refrigerating systems and heat pumps containers, refrigerant: a cylinder for the transportation of
used in the occupancies defined in Section 4 and
refrigerant.
installed subsequently to adoption of this code; and
corridor: an enclosed passageway that limits travel to a sin
(b) to parts or components added after adoption of this
gle path.
code, or a change to a refrigerant of a different number
designation (per ANSIIASHRAE Standard 34-19924) critical pressure, critical temperature, and critical volume:
after adoption of this code; and a point on the saturation curve where the refrigerant liquid
(c) to parts or components replaced after adoption of this and vapor have identical volume, density, and enthalpy, and
code only if they are not identical in function. there is no latent heat.
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d."lln pr."ur.: the maximum pressure for which a specific lower flammability limit (LFL): the minimum concentration
part of a refrigerating system is designed. of the refrigerant that propagates a flame through a homoge
neous mixture of refrigerant and air.
dual pressure-relief device: two pressure-relief devices
mounted on a three-way valve that allows one device to lowside: the portion of a refrigerating system that is sub
remain active while the other is isolated. jected to approximate evaporator pressure.
duct: a tube or conduit used to conveyor encase: (a) air duct machinery: the refrigerating equipment forming a part of the
is a tube or conduit used to convey air (air passages in self refrigerating system including, but not limited to, any or all
contained systems are not air ducts); (b) pipe duct is a tube or of the following: compressor, condenser, liquid receiver,
conduit used to encase pipe or tubing. evaporator, and connecting piping.
evaporator: that part of the refrigerating system designed to machinery room: a space, meeting the requirements of 8.13
vaporize liquid refrigerant to produce refrigeration. or 8.14, that is designed to house compressors and pressure
vessels.
evaporator coil: an evaporator constructed of pipe or tubing,
not enclosed in a pressure vessel. manufacturer: the company or organization that evidences
its responsibility by affixing its name, trademark, or trade
fusible plug: a plug containing an alloy that will melt at a
name to refrigerating equipment.
specified temperature and relieve pressure.
means of egress: a continuous and unobstructed path of
header: a pipe or tube (extruded, cast, or fabricated) to
travel from any point in a building or structure to a public
which other pipes or tubes are connected.
way.
heat pump: a refrigerating system used to transfer heat into a
mechanical joint: a gas-tight joint obtained by joining metal
space or substance.
parts with a positive-holding mechanical construction such
highside: those portions of the refrigerating system that are as flanged, screwed, or flared joints or compression fittings.
subject to approximate condensing pressure.
nonpositive dispkzcement compressor: a compressor in
horsepower: the power delivered from the prime mover to which the increase in vapor pressure is attained without
the compression device of a refrigerating system. changing the internal volume of the compression chamber.
IDLH (immediately dangerous to life or health): the maxi normative appendix: integral parts of the mandatory
mum concentration from which unprotected persons are able requirements of the standard, which, for reasons of conve
to escape within 30 minutes without escape-impairing symp nience, are placed after all other normative elements.
toms or irreversible health effects. I
occupancy: for class of occupancy see Section 4.
informative appendix: appendix that is not part of the stan
dard but is included for information purposes only. occupied space: that portion of the premises accessible to or
occupied by people, excluding machinery rooms.
inside dimension: inside diameter, width, height, or cross
sectional diagonal. piping: the pipe or tuhe used to interconnect various parts of
a refrigerating system. Piping includes pipe, flanges, bolting,
internal gross volume: the volume as determined from inter
gaskets, valves, fittings, pipe-supporting fixtures, structural
nal dimensions of the container with no allowance for the
attachments, and the pressure-containing parts of other com
volume of internal parts.
ponents, such as expansion joints, strainers, filters, and
limited charge system: a system in which, with the compres devices that serve such purposes as mixing, separating, muf
sor idle, the design pressure will not be exceeded when the fling, snubbing, distributing, metering, or controlling flow.
refrigerant charge has completely evaporated.
positive dispkzcement compressor: a compressor in which
liquid receiver: a vessel, permanently connected to a refrig the increase in pressure is attained by changing the internal
erating system by inlet and outlet pipes, for storage of liquid volume of the compression chamber.
refrigerant.
premises: a tract of land and the buildings thereon.
listed: equipment or materials included in a list published
pressure-imposing element: any device or portion of the
by an approved, nationally recognized testing laboratory,
equipment used to increase refrigerant pressure.
inspection agency, or other organization concerned with
product evaluation that maintains periodic inspection of pro pressure-limiting device: a pressure-responsive electronic or
duction of listed equipment or materials and whose listing mechanical control designed to automatically stop the opera
states either that the equipment or material meets nationally tion of the pressure-imposing element at a predetermined
recognized standards or has been tested and found suitable pressure.
for use in a specified manner.
pressure-relief device: a pressure-, not temperature-, actu
lobby: a waiting room or large hallway serving as a waiting ated valve or rupture member designed to automatically
room. relieve pressure in excess of its setting.
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pressure-relief valve: a pressure-actuated valve held closed tenant: a person or organization having the legal right to
by a spring or other means and designed to automatically occupy a premises.
relieve pressure in excess of its setting.
three-way valve: a service valve for dual pressure-relief
pressure vessel: any refrigerant-containing receptacle in a devices that allows using one device while isolating the other
refrigerating system. This does not include evaporators from the system, maintaining one valve in operation at all
where. each separate evaporator section does not exceed 0.5 times.
3
ft3 (0.014 m ) of refrigerant-containing volume regardless of
TLV-TWA (threshold limit value-time weighted average):
the maximum inside dimension. This also does not include
the refrigerant concentration in air for a normal 8-hour work
evaporator coils, compressors, condenser coils, controls,
day and a 40-hour workweek to which repeated exposure,
headers, pumps, and piping.
day after day, will not cause an adverse effect in most per
pumpdown charge: the quantity of refrigerant stored at sons.3
some point in the refrigeration system for operational, ser
ultimate strength: the stress at which rupture occurs.
vice, or standby purposes.
unit system: (see self-contained system).
readily accessible: capable of being reached safely and
quickly for operation, repair, and inspection without requir unprotected tubing: tubing that is unenclosed and therefore
ing those to whom ready access is required to climb over or exposed to crushing, abrasion, puncture, or similar damage
remove obstacles or to resort to the use of portable access after installation.
equipment.
zeotropic: refers to blends comprising multiple components
refrigerant: the fluid used for heat transfer in a refrigerating of different volatility that, when used in refrigeration cycles,
system; the refrigerant absorbs heat and transfers it at a change volumetric composition and saturation temperatures
higher temperature and a higher pressure, usually with a as they evaporate (boil) or condense at constant pressure.
change of state. The word is derived from the Greek words zein (to boil) and
tropos (to change).
refrigerating system: a combination of interconnected parts
forming a closed circuit in which refrigerant is circulated for
4. OCCUPANCY CLASSIFICATION
the purpose of extracting, then rejecting, heat. (See Section 5
for classification of refrigerating systems by type.) 4.1 Locations of refrigerating systems are described by
occupancy classifications that consider the ability of people
refrigerating system, direct: (see 5.1.1).
to respond to potential exposure to refrigerant as follows:
refrigerating system, indirect: (see 5.1.2).
4.1.1 Institutional occupancy is a premise or that portion
rupture member: a device that will rupture and release of a premise from which, because they are disabled, debili
refrigerant to relieve pressure. tated, or confined, occupants cannot readily leave without
the assistance of others. Institutional occupancies include,
saturation pressure: the pressure at which vapor and liquid
among others, hospitals. nursing homes. asylums. and spaces
exist in equilibrium at a given temperature.
containing locked cells.
sealed absorption system: an absorption system in which all
4.1.2 Public assembly occupancy is a premise or that
refrigerant-containing parts are made permanently tight by
portion of a premise where large numbers of people con
welding or brazing.
gregate and from which occupants cannot quickly vacate the
secondary coolant: any liquid used for the transmission of space. Public assembly occupancies include, among others,
heat. without a change of state. and having no flash point or a auditoriums, ballrooms, classrooms, passenger depots, res
flash point above lS00P (6SSC) as determined by ASTM
taurants, and theaters.
D93.2
4.1.3 Residential occupancy is a premise or that portion
self-contained system: a complete, factory-assembled and of a premise that provides the occupants with complete inde
factory-tested system that is shipped in one or more sections pendent living facilities including permanent provisions for
and has no refrigerant-containing parts that are joined in the living, sleeping, eating, cooking, and sanitation. Residential
field by other than companion or block valves.
occupancies include, among others, dormitories. hotels.
set pressure: the pressure at which a pressure-relief device multi-unit apartments, and private residences.
or pressure control is set to operate. 4.1.4 Commercial occupancy is a premise or that portion
shan (shall not): used when a provision is mandatory. of a premise where people transact business, receive personal
service, or purchase food and other goods. Commercial occu
soldered joint: a gas-tight joint formed by joining metal
pancies include, among others, office and professional
parts with alloys that melt at temperatures not exceeding
buildings, markets (but not large mercantile occupancies),
8000P (426.5°C) and above 4000P (204.5"C).
and work or storage areas that do not qualify as industrial
specified: explicitly stated in detail. Specified limits or pre occupancies.
scriptions are mandatory.
4.1.5 Large mercantile occupancy is a premise or that
stop valve: a device used to shut off the flow of refrigerant. portion of a premise where more than 100 persons congre-
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