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BSR/ASHRAE Standard 147-2002R
Public Review Draft
_____________________________________
ASHRAE Standard
Proposed Revision of Standard 147-2002, Reducing the Release of
Halogenated Refrigerants from Air-Conditioning Equipment and
Systems Second Public Review (May 2011) (Complete Draft for Full
Review) This draft has been recommended for public review by the
responsible project committee. To submit a comment on this proposed
addendum, go to the ASHRAE website at
http://www.ashrae.org/technology/page/331 and access the online
comment database. The draft is subject to modification until it is
approved for publication by the ASHRAE Board of Directors and ANSI.
The current edition of any standard may be purchased from the
ASHRAE Bookstore @ http://www/ashrae.org or by calling 404-636-8400
or 1-800-527-4723 (for orders in the U.S. or Canada). The
appearance of any technical data or editorial material in this
public review document does not constitute endorsement, warranty,
or guaranty by ASHRAE of any product, service, process, procedure,
or design, and ASHRAE expressly disclaims such. May 13, 2011. This
draft is covered under ASHRAE copyright. Permission to reproduce or
redistribute all or any part of this document must be obtained from
the ASHRAE Manager of Standards, 1791 Tullie Circle, NE, Atlanta,
GA 30329. Phone: 404-636-8400, Ext. 1125. Fax: 404-321-5478.
E-mail: [email protected]. AMERICAN SOCIETY OF HEATING,
REFRIGERATING AND AIR-CONDITIONING ENGINEERS, INC. 1791 Tullie
Circle, NE Atlanta GA 30329-2305
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BSR/ASHRAE Standard 147-2002R, Reducing the Release of
Halogenated Refrigerants from Refrigerating and Air-Conditioning
Equipment and Systems (Second Public Review Draft)
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BSR/ASHRAE Standard 147-2002R Reducing the Release of
Halogenated Refrigerants
from Refrigerating and Air-Conditioning Equipment and
Systems
CONTENTS SECTION PAGE
Foreword.........................................................................................................................................
3 1
Purpose....................................................................................................................................
4 2 Scope
..........................................................................................................................................
4 3
Definitions....................................................................................................................................
4 4
Design.........................................................................................................................................
7 5 Product
Development.................................................................................................................
9 6
Manufacture.............................................................................................................................
10 7
Installation...................................................................................................................................
11 8
Service/Operation/Maintenance/Decommissioning..................................................................
12 9 Refrigerant Recovery, Reuse, and
Disposal................................................................................
14 10 Handling and Storage of Refrigerants
.......................................................................................
15 11 Normative
References..............................................................................................................
16 Annex A: Recommended Procedures and
Practices......................................................................
17 Annex B: Training of
Personnel....................................................................................................
34 Annex C: Informative References
................................................................................................
34 Annex D:
Bibliography..................................................................................................................
35
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BSR/ASHRAE Standard 147-2002R, Reducing the Release of
Halogenated Refrigerants from Refrigerating and Air-Conditioning
Equipment and Systems (Second Public Review Draft)
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(This foreword is not part of this standard. It is merely
informative and does not contain requirements necessary for
conformance to the standard. It has not been processed according to
the ANSI requirements for a standard and may contain material that
has not been subject to public review or a consensus process.
Unresolved objectors on informative material are not offered the
right to appeal at ASHRAE or ANSI.)
FOREWORD When the potential link between release of
chlorofluorocarbons (CFCs) and depletion of stratospheric ozone was
first discovered, ASHRAE appointed a task group to study the issue
and to develop appropriate policy and program recommendations to
the Board of Directors. In response, a comprehensive action program
was initiated. It included research, education, communication, and
training directed toward the various aspects of the CFC issue. A
part of this program was the development of a guideline for
reducing CFC refrigerant release. This was published as ASHRAE
Guideline 3-1990, Reducing Emission of Fully Halogenated
Chlorofluorocarbon (CFC) Refrigerants in Refrigeration and Air
Conditioning Equipment and Applications. Since that date, it has
been determined that all releases of chlorine containing
refrigerants, hydrochlorofluorocarbons (HCFCs) as well as CFCs,
contribute to depletion of the stratospheric ozone layer. Not long
after, it was also determined that the release of CFCs, HCFCs, and
hydrofluorocarbons (HFCs) contributes to global warming, adding new
urgency to controlling their release. At this time, in 1996,
Guideline 3 was revised to reflect this need for a more stringent
policy, and in 2002 ASHRAE published Standard 147, Reducing the
Release of Halogenated Refrigerants from Refrigerating and
Air-Conditioning Equipment and Systems. Standard 147 took many of
the recommended practices of Guideline 3 and made them mandatory
requirements, thus further increasing the stringency of the
guideline, which was then withdrawn. However, some of the material
from Guideline 3 was preserved in the standard in informative
annexes that provide recommended practices that are not required by
the standard. This revision of Standard 147 updates the 2002
edition by expanding the number of equipment types and systems
covered, by providing significant requirements for field-erected
systems, by adding more sections on leak checking, by adding
requirements for systems with larger charges, by addressing the
shipping and handling of containers for refrigerants, and by making
many formerly recommended practices mandatory.
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BSR/ASHRAE Standard 147-2002R, Reducing the Release of
Halogenated Refrigerants from Refrigerating and Air-Conditioning
Equipment and Systems (Second Public Review Draft)
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1. PURPOSE This standard establishes practices and procedures
that will reduce inadvertent release of halogenated
refrigerants.
2. SCOPE The practices and procedures in this standard cover
release reduction of halogenated hydrocarbon and halogenated ether
refrigerants in the following circumstances:
(a) from stationary refrigerating, air-conditioning, and
heat-pump equipment and systems; (b) during manufacture,
installation, testing, operation, maintenance, repair, and disposal
of such equipment and
systems.
3. DEFINITIONS Although the following terms may have broader
interpretations elsewhere in the industry, their specific meanings
as used in this standard are as follows. CFC (chlorofluorocarbon):
a fully halogenated (no hydrogen remaining) halocarbon containing
chlorine, fluorine, and carbon atoms. equipment type: a
classification used to distinguish between the different kinds of
refrigerant-containing systems and equipment covered by this
standard.
type 1 component: single refrigerant containing piece of a
refrigeration system, (Examples: thermostatic expansion valve [TXV]
body, TXV power head, valves, receiver; controls, tube.) type 2 -
small assembly: the extension of the refrigerant volume by brazing/
welding/ mechanical connection of components and can include other
hardware. Internal volume is less than 61 in3 (1 liter). type 3
large assembly: a further extension of the refrigerant volume by
brazing/welding/mechanical connection of multiple components.
Internal volume is equal to or greater than 61 in3 (1 liter). type
4 - appliance: A very small packaged piece of refrigeration
equipment that is installed by the consumer and has a design
refrigerant operating charge of less than 5 lb (2.3kg) of
refrigerant. type 5 - small packaged equipment: A small piece of
refrigeration equipment manufactured, assembled in its entirety and
which is typically installed by a contractor and with a refrigerant
design operating charge of less than 50 pounds (23kg) per circuit.
type 6 - small assembled equipment: small refrigeration equipment
that is assembled and installed by a professional and contains a
refrigerant design operating charge of less than 50 lb (23kg) per
circuit. These are typically two assemblies, a condensing unit and
an evaporator/air handler but may have as many as 3
AHU/evaporators. type 7 - large packaged equipment: a large piece
of refrigeration equipment manufactured and assembled in its
entirety in a manufacturing facility and which is installed by a
professional, and contains a refrigerant design operationg charge
of 50 lb (23kg) or more per circuit. type 8 - large assembled
equipment: large refrigeration equipment that is assembled and
installed by a professional and contains a refrigerant design
operating charge of 50 lb (23kg) or more per circuit. These are
typically two or three pieces being a compressor(s), evaporator(s),
and condenser(s) type 9 small field erected system: a system that
is professionally and specifically designed, and erected for a
particular application. With a refrigerant design operating charge
of less than 50 lb (23kg), a system of this type may contain
multiple compressors, evaporators, and condensers. type 10 large
field-erected system: a system that is professionally and
specifically designed, and erected for a particular application.
With a refrigerant design operating charge of 50 lb (23kg) or more
of refrigerant, a system of this type often contains multiple
compressors (rack), evaporators, and condensers as well as heat
recovery.
halocarbon: any of a class of compounds containing carbon, one
or more halogens, such as fluorine, and sometimes hydrogen.
HCFC(hydrochlorofluorocarbon): a halocarbon that contains fluorine,
chlorine, carbon, and hydrogen. hermetically sealed system: a
factory-charged refrigerating system that is welded, brazed,
soldered, or otherwise joined together in such a manner as to
create a completely sealed system. HFC(hydrofluorocarbon): a
halocarbon that contains only fluorine, carbon, and hydrogen.
holding charge: an inert gas used to temporarily create a positive
pressure and thereby avoid the ingress of air or moisture during
shipment or storage.
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joint, brazed: a gas-tight joint obtained by joining metal parts
with alloys that melt at temperatures higher than 800F (426C) but
less than the melting temperatures of the joined parts. joint,
mechanical: a gas-tight joint obtained by joining metal parts
through a positive-holding mechanical construction. joint,
soldered: a gas-tight joint obtained by joining metal parts with
metallic mixtures or alloys that melt at temperatures above 400F
(204C) but not exceeding 800F (426C). joint, welded: a gas-tight
joint obtained by the joining of metal parts in the plastic or
molten state or through the use of filler metals that melt at
temperatures 800F (426C) and above. maintenance: the upkeep of
property or equipment in order to keep it in an existing state (as
of repair, efficiency, or validity) and to preserve it from failure
or decline. maintenance, corrective: a type of maintenance program
where failures are corrected or repaired as they occur. Corrective
action is always performed after failure occurs. maintenance,
planned: a type of maintenance program in which resources are
invested in prudently selected functions at specified intervals. In
this type of program, all functions and resources are planned,
budgeted, and scheduled. maintenance, predictive: a type of
maintenance program in which statistically supported objective
judgment is used. Non-destructive testing, chemical analysis,
vibration and noise monitoring, as well as visual inspection and
logging are all used to predict when a particular part or system
might fail so its useful life can be extended and maximized.
maintenance, preventive: a type of maintenance program in which
inspections, checks, servicing, and replacements are performed
according to either a predetermined schedule or condition based
monitoring indicators. Durability, reliability, efficiency, and
safety are the principle objectives. Preventive maintenance
embodies two concepts: planned and predictive maintenance.
maintenance, program: a systematic approach to maintenance in terms
of time and resource allocation. It documents the objectives and
establishes the criteria for evaluation and commits the maintenance
department to basic areas of performance such as prompt response to
mechanical failure, maintenance, and attention to planned functions
that protect the capital investment and minimize downtime or
failure response. pressure, design: the maximum allowable working
pressure for which a specific part of a system is designed to
operate under normal or abnormal conditions, as defined in a
relevant standard, such as UL 1995. 16 pressure, high: as this term
applies to refrigerations systems, it refers to gage pressure at
room temperature (74F [23.3C]) that is typically more that 100 psig
(689 kPa). Common high-pressure refrigerants include R-22, R-502,
R-404A, R-407A, R-407C, R-410A and R-507A. pressure, low: a as this
term applies to refrigerations systems, it refers to absolute
pressure at room temperature (74F [23.3C]) that is below ambient
pressure absolute. Low-pressure refrigerants include R-11, R-113,
and R-123. pressure, maximum working: (see pressure, design).
pressure, medium: as this term applies to refrigerations systems,
it refers to gage pressure at room temperature (74F [23.3C]) that
is greater than atmospheric pressure but typically less that 100
psig (689 kPa). Common medium-pressure refrigerants include R-12,
R-500, R-134a, and R-245fa. pressure, operating: the pressure
occurring at a reference point in a refrigerating system when the
system is in operation. pressure-relief device: a valve or rupture
member designed to relieve excessive pressure automatically.
prevention-of-vacuum system: a refrigerant pressure control system
that prevents refrigerant loss and infiltration into idle
low-pressure chillers and is also used to pressurize for leak
testing without the use of non-condensables. purging: removing
non-condensable gases from the system. purging device: an
automatic, semiautomatic, or handoperated device that removes
non-condensable gases introduced into a system during charging,
servicing, or normal operation. receiver: a vessel in the
refrigerating system designed to ensure the availability of
adequate liquid refrigerant for proper functioning of the system
and to store the liquid refrigerant when the system is pumped down.
reclaim: to process used refrigerant so that it meets new product
specifications. recover: to remove refrigerant in any condition
from a system and store it in an external container. recycle: to
reduce contaminants in used refrigerants by separating oil,
removing non-condensables, and using devices such as filter driers
to reduce moisture, acidity, and particulate matter. refrigerant
charge: the mass of refrigerant in a closed system. refrigerant,
design operating charge: the mass of the refrigerant required for
proper functioning of a closed system refrigerant circuit: an
assembly of refrigerant containing parts connected to allow the
flow of refrigerant in the refrigerating cycle. The
refrigerant-containing parts are considered part of the circuit
even if isolated by a valve. A system or equipment may be
considered to have multiple circuits only if there is no intended
path for the refrigerant to cross over from circuit to circuit.
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refrigerant release: any movement of refrigerant out of its
containment and into the atmosphere, including, but not limited to,
movement by a leak, by an action of filling or testing, or by
failure. rupture disc: a safety device that is designed to rupture
at a predetermined pressure. seasonal adjustment: the adding of
refrigerant to a refrigeration or air conditioning system due to
change in ambient conditions caused by a change in season, followed
by the subsequent removal of refrigerant in the corresponding
change in season where both the addition and removal occurs within
one consecutive 12 month period. topping off: adding refrigerant to
a refrigeration or air conditioning system in order to bring the
system to its normal operating charge. trace gas: a gas that is
detectable by a leak detector and can be mixed with an inert gas.
Typical trace gases are helium, hydrogen, and most refrigerants.
vacuum, deep (high vacuum): a vacuum of 1000 m Hg (micron) (130 Pa)
or less of absolute pressure. valve, pressure-relief: a
pressure-actuated valve held closed by a spring or other means and
designed to automatically relieve pressure in excess of its
setting. valve, purge: a device to allow non-condensable gases to
flow out of the system.
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BSR/ASHRAE Standard 147-2002R, Reducing the Release of
Halogenated Refrigerants from Refrigerating and Air-Conditioning
Equipment and Systems (Second Public Review Draft)
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4. DESIGN This section covers the compliance requirements for
designers of air-conditioning and refrigerating systems and
components. For all equipment and systems described in this
section, the following requirements shall be met: Informative Note:
The understanding and application of established techniques in both
the design and construction of refrigerating systems provide a good
foundation for the prevention of refrigerant release to the
atmosphere. Examples of recommended design practices and techniques
to minimize refrigerant leakage are given in Annex A. 4.1 Safety.
All equipment and systems shall be designed in accordance with a
recognized national standard, such as ANSI/ASHRAE Standard 15,
Safety Standard for Refrigeration Systems1 or UL Standard 1995. 16
4.2 Documentation. Documentation to instruct field personnel how to
install, operate, and service refrigerating equipment to minimize
refrigerant release shall be provided for factory-built equipment
and for field-erected systems. 4.3 Compressors Leaks associated
with compressors may be related to the design of the compressor
(e.g., oil pan, motor bell, oil pump) or to the associated
equipment fitted to it (e.g., gauge and cutout connections, relief
valves, and connected piping). Compressors shall meet the following
requirements to minimize the possibility of leaks. 4.3.1 Shaft
Seals. Seals shall be designed with materials compatible with the
refrigerant and oil to be used in the compressor. Informative Note:
Shaft seals used in open-style compressors can be a source of
refrigerant leakage. 4.3.2 Vibration. To minimize leakage due to
vibration, compressors, compressor mountings, and piping
connections shall be evaluated to see that vibration-induced
stresses do not exceed material endurance limits. If the equipment
is not evaluated for material endurance testing, then all copper
tubing that is of an outside diameter of 3/8 in.[9.5mm] or smaller
(excluding suction and discharge) and are connected to compressors
or assemblies that are not isolated from compressor vibrations
shall be constructed with vibration loops to minimize fatigue at
connections. 4.3.3 Semi-Hermetic Compressors. Materials used for
gaskets and O-rings shall be compatible with the refrigerant and
lubricant used. All bolts shall be torqued to the required level as
set by the compressor manufacturer. 4.4 Condensers and Evaporators.
Connections shall be designed so that vibrational stresses from the
suction, discharge, and liquid line loads at the condenser and
evaporator joint(s) do not exceed material endurance limits. All
electrical power and control wiring greater than 100V shall be
routed and tethered in a way where an energized, severed wire
cannot come into contact with any refrigerant tubing. Thermal
expansion valve (TXV) equalizer tubes shall be routed and secured
to support the weight of the tube. 4.4.1 Air-to-Refrigerant
Condensers and Evaporators. These components shall be designed for
the ability to withstand stress, vibration, and corrosion under
normal operation and during transport. Tubing supports shall be
designed to minimize vibration, to provide protection against
abrasion due to movement, and to allow for thermal expansion.
4.4.1.1 The user or the users designated agent shall select
materials that will prevent corrosion failure in the installed
environment. 4.4.2 Liquid-to-Refrigerant Condensers and Evaporators
4.4.2.1 These components shall be designed to withstand stress,
vibration, and corrosion under normal operation and during
transport. Tubing supports shall be designed to minimize vibration,
to provide protection against abrasion due to movement, and to
allow for thermal expansion. 4.4.2.2 The characteristics of fluids
used in liquid chillers and liquid-cooled condensers vary widely
and can lead to premature failure of tubes, resulting in release of
the entire refrigerant charge. The user or the designated agent
shall
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BSR/ASHRAE Standard 147-2002R, Reducing the Release of
Halogenated Refrigerants from Refrigerating and Air-Conditioning
Equipment and Systems (Second Public Review Draft)
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select tube materials, tube configurations, tube-wall
thicknesses, and filtration/ treatment techniques suitable for the
fluid characteristics. 4.4.2.3 The user or the users designated
agent shall select tube and water-side materials that will prevent
corrosion failure when used with the intended fluids in the
installed environment. 4.4.2.4 To prevent freeze-up of
water-chilling machines during operation, safety controls shall be
provided by the manufacturer of the equipment. Examples include,
but are not limited to, refrigerant pressure control and/or
refrigerant temperature control. See Section 7.6 for requirements
when the system is not in operation. 4.4.2.5 When utilizing a
brazed plate heat exchanger as an evaporator, insulation of the
entire unit and attached tubing is important. This insulation
prevents the formation of frost in critical areas that may force
the plates to separate and eventually leak. Equipment and attached
tubing shall be insulated to prevent frost from forcing plates to
separate. 4.5 Piping, Tubing, and Connections 4.5.1 Minimized
Connections. Systems shall be designed in such a manner as to
minimize the number of fittings and connections. Tapered pipe
threads shall not be used for fittings in refrigerant circuits
unless the threads are back-welded or sealed by equally effective
means. Single-flare fittings shall not be used. 4.5.2 Flanged Joint
Seals. Designers shall specify flanged joint seal materials that
are compatible with both the refrigerant and refrigerant oils to be
used in the system. 4.5.3 Support. Pipe and tubing supports shall
be designed to provide protection of tubing components against
external abrasion due to movement. Tubing inside refrigerated cases
in Equipment Types 9 & 10 shall be supported by the case at
least every 36 in. (91 cm) of tube length and within 12 in. (30 cm)
from any connection or elbow. 4.5.4 Corrosion Prevention. External
protection shall be specified to prevent corrosion of metal
components that contain refrigerant or are in direct contact with
refrigerant-containing components. 4.5.5 Over Pressurization. To
prevent hydrostatic over pressurization due to thermal expansion,
liquid-containing system parts shall be protected as specified in
Section 9.4.3 of ANSI/ASHRAE Standard 15, Safety Standard for
Refrigeration Systems.1 Exemptions. Equipment Types 4, 5 and 6 that
is approved by a nationally recognized testing agency shall be
exempt from all provisions of Section 4.5 except the provisions in
Section 4.5.1 regarding single flare fittings and tapered pipe
threads. 4.6 Isolation Valves. Isolation valves shall comply with
one of the following: 4.6.1 The valve stems are sealed by internal
diaphragm. 4.6.2 The valve has a spindle, with a tethered cap .
4.6.3 The valve meets the requirements of Section 6.2.1 4.7 Access
Valves for Charging, Evacuation, or Both. Access valves or
couplings, except as noted below, shall have a tethered
metal-to-metal or metal-to-o-ring sealing surface to prevent
leaking through the cap and shall be provided for evacuation and
liquid charging of refrigerating systems. Caps shall meet the
leakage requirements of Section 6.2.1. For Equipment Types 4, 5,
and 6 using hermetically sealed compressors, an equally effective
design feature (e.g., process tube or stub) shall be considered to
meet the requirements of this section 4.8 Relief Devices System
relief devices shall conform to the requirements of ANSI/ASHRAE
Standard 15, Safety Standard for Refrigeration Systems.1 Equipment
types 7, 8, and 10 shall have an alarm that notifies personnel of
high refrigerant
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Halogenated Refrigerants from Refrigerating and Air-Conditioning
Equipment and Systems (Second Public Review Draft)
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pressure that can result in refrigerant release through the
relief device(s). Medium and high pressure refrigerant systems
shall not use a rupture disc as the sole relief device venting to
the atmosphere. Exemptions to 4.8: Equipment Types 4, 5, & 6
having sealed systems approved by a nationally recognized testing
agency shall be considered to comply with the provisions of Section
4.8. 4.9 Purging Devices 4.9.1 Sub-atmospheric Pressure. Purging
devices shall be provided for Equipment Types 7, 8 & 10 that
have any portion of the system that operates at sub-atmospheric
pressure. New equipment designs shall specify purging devices that
release less than one unit mass of refrigerant per unit mass of air
as tested by ARI Standard 580, Performance of Non-Condensable Gas
Purge Equipment for Use with Low Pressure Centrifugal Chillers.2
4.9.2 Infiltration. Systems with purges as described in Section
4.9.1 shall be designed so that air infiltration under idle storage
conditions 74F (23.3C) saturated refrigerant temperature and 14.7
psia (101.235 kPa) atmospheric pressuredoes not prevent systems
from starting and operating. To conform, the system shall include
one or more of the following: (a) A purge unit that operates while
the system is under idle storage conditions. (b) A
prevention-of-vacuum system that prevents air infiltration while
the system is under idle storage conditions. (See Section A2.9.1 in
Annex A for an explanation.) (c) A system design means that allows
a system to start and operate when air infiltration has occurred
under idle storage conditions. Any means to remove air from the
chiller shall conform to the emissions requirement of Section
4.9.1. 4.9.3 Alarm. The purge unit shall automatically indicate
purge activity and shall alarm if the amount of purging exceeds the
system manufacturer's preset limit. 4.10 Storage Capability In
large field-erected systems, such as supermarket refrigerating
systems, one or more receivers shall be provided for the system to
store the charge as necessary to service various components.
Systems shall be exempt from this requirement if the condenser is
large enough to contain the entire charge, is fully isolatable and
is protected by a pressure-relief valve in accordance with
ANSI/ASHRAE Standard 15, Safety Standard for Refrigeration
Systems.1 4.11 Shipping and Package Testing Procedures The
following testing procedures shall be used to ensure products
arrive in acceptable condition: Compression strength tests: ASTM
D6423 and ASTM D45774 Vibration tests: ASTM D9995 and ASTM D47286
Mechanical handling tests: ASTM D 60557 and ASTM D61798 Shock and
impact tests: ASTM D8809 and ASTM D527610 4.12 System Monitoring
All new Equipment Types 7, 8 & 10 with a refrigerant design
operating charge greater than 500 lb (230kg) shall be equipped with
a feature to alert the owner that the system is releasing
refrigerant or has released enough refrigerant to affect system
performance. 5. PRODUCT DEVELOPMENT This section of the standard
describes compliance requirements for products during their
development phase. 5. 1 General. When components or systems are
being tested for refrigerant leakage during development, the
practices and procedures specified in Sections 7.17.5 shall be
followed. A refrigerant charge used for operational testing during
development shall not be released to the atmosphere following
development tests or at the end of the development period. The
refrigerant shall be removed and stored in a suitable container.
5.2 Refrigerant Handling The laboratory shall be equipped with a
recovery/recycling system and storage capacity for holding charge
recovered from any individual test unit in the laboratory. When
servicing of a recovery/recycling unit is required, refrigerant in
the unit shall be recovered and recycled or reclaimed in the same
manner as that from test systems.
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Equipment and Systems (Second Public Review Draft)
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5.2.1 Recovery. Upon completion of tests, the refrigerant shall
be recovered from an experimental system. It is recognized that
sometimes the recovered refrigerant must first be put into a
container to determine or confirm charge levels, but ultimately all
refrigerant shall be recovered into appropriate storage devices as
required under Section 10. Refrigerant that is known to be
contaminated, as with a motor burnout, for example, shall be
recovered into proper containers and recycled, reclaimed, or
disposed of as described in Section 9. 5.2.2 Inventory Record. A
refrigerant inventory record shall be maintained to account for
virgin material received into the laboratory and material shipped
for reclaim or destruction. This inventory must include the types
and quantities of refrigerant received and shipped for reclamation
or destruction and the dates of receipt and shipment. 5.2.3 Test
Facility Air Conditioning Equipment. Test facilities have
conditioning equipment that provides a controlled environment for
testing. This equipment shall be constructed and installed in
accordance with this standard and checked for leaks on a regular
basis. When servicing is required, the refrigerant shall be
recovered and recycled or reclaimed in the same manner as that from
test systems.
6. MANUFACTURE This section applies to the manufacture of all
equipment types. Informative Note: Refer to Annex A for practices
and procedures that are recommended but not required for compliance
with this standard. 6.1 General. All equipment, components, and
complete systems shall be cleaned, dried, evacuated, leak-tested,
and sealed before shipment. Components or sub assemblies that will
be tested in a larger assembly further in the manufacturing process
shall be exempt from this requirement. 6.2 Factory Leak Testing
6.2.1 Leak Rate Specification. All equipment types shall be
leak-tested by either a leak rate measurement method or a leak
location method such as those described in Annex A4.3. The measured
leak rate shall not exceed the values established for the method
selected in Table 1 (when tested at the conditions prescribed in
ANSI/ASHRAE Standard 15, Safety Standard for Refrigeration Systems,
Section 9.14.1).1 The components of Equipment Types 6, 9, and 10
shall be tested as Type 1, 2 or 3 assemblies, as appropriate.
Table 1: Equipment Manufacture Leak Threshold Limits Equip.
Type
Description Leak Rate Measurement Threshold Leak Location Method
Threshold
Type 1 Component 0.1oz / year 0.1oz / year / joint Type 2 Small
Assembly 0.5oz / year 0.1oz / year / joint Type 3 Large Assembly
1.0oz / year 0.1oz / year / joint Type 4 Appliance 1.0oz / year
0.1oz / year / joint Type 5 Small Packaged 3.0oz / year 0.1oz /
year / joint Type 7 Large Packaged Greater of 15oz / year or 0.25%
of the charge 0.1oz / year / joint Type 8 Large Assembled Greater
of 15oz / year or 0.25% of the charge 0.1oz / year / joint
6.2.2 Leak-Test Gas. CFCs are prohibited by law from use as a
leak test gas. HCFC or HFC refrigerants are prohibited by this
standard for use as leak-test gases unless they are recovered. A
mixture of a trace quantity (no more than 10% by mass) of non-CFC
halocarbon refrigerant, such as HCFC-123, with nitrogen may be used
as the leak-test gas. Leak-test gas containing halocarbon
refrigerants shall be recovered and reused. 6.3 Operating Test Gas
Recovery Refrigerant used during the manufacture and operational
testing of systems and components shall be recovered from systems
and components prior to repair or re-work.
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6.4 Evacuation Systems shall be evacuated to 1000 microns of Hg
and held long enough to remove moisture. 6.5 Holding Charge A
halogenated refrigerant shall not be used as a holding charge. 6.6
Purging Purging with inert gas is required during brazing to
prevent oxidation, which can cause plugged driers, filters,
strainers, dirty oil, and compressor failure. 7. INSTALLATION This
section specifies the installation requirements that must be met to
comply with this standard. It applies only to Equipment Types 6
through 10. Informative Note: Practices and procedures that are
recommended but not required for compliance with this standard are
described in Annex A. 7.1 Installation of Equipment Types 6, 8, 9,
and 10 7.1.1 General. All piping, tubing, and connections shall be
installed as required by Section 4.5. 7.1.2 Major Considerations
7.1.2.1 All cut piping shall be deburred and metal filings removed
to prevent damage to the compressors and refrigerating system
parts, such as shaft seal, compressor bearing, motor, and capillary
tube. 7.1.2.2 All tube and fittings shall be thoroughly cleaned
prior to assembly. Both the outside of copper tube and the inside
of fittings must be bright and clean before brazing. Braze filler
metal selection shall be consistent with the types of materials
being joined. 7.1.2.3 Except as provided for in Section 4.5.1,
tapered pipe thread connections shall not be used to join pipe or
tube to fittings, valves, and other components. 7.1.2.4 The gasket
material used on flanged connections shall be of a type and grade
that is compatible for use with refrigerants and refrigerant oils
of the types being used. 7.1.2.5 Equipment shall be checked for
tightness; moisture and non-condensables shall be removed before
charging the system with refrigerant. 7.1.2.6 Liquid line filter
driers shall be provided on all installations of equipment types 6,
9, and 10 to ensure a dry and clean system. Such filter driers
shall be chosen to ensure that the size and desiccant material are
appropriate for the equipment. 7.1.2.7 Purging with inert gas is
required during brazing to prevent oxidation, which can cause
plugged driers, filters, strainers, dirty oil, and compressor
failure. 7.2 Field Leak Testing. Equipment Types 6, 8, 9, and 10
shall be leak tested per Section 6.2.1 as an equipment type 8 to
ensure system integrity and minimize refrigerant leakage.
Informative Note: See Annex A for recommended procedures. 7.3 Field
Evacuation. After it is determined that there are no refrigerant
leaks, Equipment Types 6, 8, 9, and 10 shall be evacuated to 500
microns or less and held until long enough to remove moisture. 7.4
Field Charging
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7.4.1 Charging. After it is determined that the system does not
leak, it shall be charged with refrigerant following the procedure
specified in the equipment manufacturers instructions. If the
system uses a medium or high pressure refrigerant and is not to be
fully charged immediately after evacuation, it shall be placed
under positive pressure with a partial charge of the refrigerant to
be used in the system. 7.4.2 Backflow Prevention. When connected
for charging, refrigerant containers shall not be connected to a
system at a higher pressure or to hydraulic legs where the pressure
is sufficient to cause a backflow of refrigerant into the
container. 7.5 Refrigerant Charging Log For Equipment Types 6, 7,
8, 9, and 10, the owner shall keep a record of the following:
Identification of the installing contractor Identification of
the facility The full charge Refrigerant type and designation under
ASHRAE Standard 3417 Lubricant type and amount added. Lubricant
additives type and amount added
This information shall be recorded in a clear, legible
condition. This log shall be used to contain the records of future
maintenance actions described in Section 8.4.1. 7.6 Water-chilling
Machines: During installation, the installer or operator shall
provide and install controls to prevent fluids from freezing in
water-chilling machines when they are not in operation.
8. SERVICE/OPERATION/MAINTENANCE/DECOMMISSIONING This section
explains the requirements for operating, servicing and maintaining,
and decommissioning air-conditioning and refrigerating systems and
equipment. 8.1 Servicing. Servicing of air-conditioning and
refrigerating systems shall be undertaken only by properly trained
personnel. In the US and in some other countries, regulations
require that personnel engaged in refrigerant handling be
certified. Reference shall be made to the manufacturer's operating
and maintenance instructions for recommended service procedures.
Informative Note: Generally recommended practices and procedures
can be found in Annex A; however, they are not required for
compliance with this standard. 8.1.1 Incorrect Uses. Halogenated
refrigerants shall not be used for the purpose of cleaning debris
and dirt from air-cooled condenser coils, cooling coils, or similar
equipment. 8.1.2 When to Leak Check. Loss of capacity, loss of
efficiency, unusual operating conditions or traces of oil may be
evidence of a refrigerant leak. If a refrigerant leak is suspected,
refrigerant shall not be added without leak-checking the system.
Refer to the U.S. Code of Federal Regulations, 40 CFR, Part
82.15611 for the criteria for repairing leaks. Special attention
shall be given to all joints, gaskets, control bellows, and shaft
seals. These items shall be thoroughly leak-tested after servicing.
8.1.3 Pressurization. Equipment Types 5 10 that use a refrigerant
and that have the potential to be in a vacuum at normal room
temperatures shall be put under positive pressure before leak
testing. The low-side pressure increase could typically be from the
addition of heat to the system, or injecting another vapor into the
system. Extreme care shall be taken to prevent excessive pressure
buildup and the subsequent refrigerant release into the atmosphere.
Automatic pressurization processes shall be provided with controls
to prevent over-pressurization. Manual pressurization processes
shall be continuously monitored to prevent over pressurization. A
pressure increase shall be accomplished by the addition of dry
nitrogen only if the system employs a refrigerant recovery type
purge device. Air or oxygen shall not be
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used for pressurization. Refrigerant and oil in the presence of
pressurized air or oxygen can cause uncontrolled combustion. 8.1.4
Leak Sources. Valve stem glands, blanks over gauge ports, and
service valve seal caps shall be replaced and tightened after
removal for servicing and shall be thoroughly leak-tested after
servicing. 8.1.5 Oil Removal. Before oil is removed from a
compressor, the oil sump heater (if so equipped) shall be turned on
and the oil sump refrigerant pressure shall be repetitively reduced
by safe and correct recovery, or by pump down to 0 psig or below
until such time that the oil sump pressure does not noticeably rise
within 10 minutes of terminating the pressure reduction. 8.1.6
Repairs. For non-major repairs, refrigerant pressure shall be
reduced to less than 0 psig by safe and correct recovery or
pumpdown to prevent refrigerant loss from a system or its
components when opened to atmosphere during maintenance of
non-major repairs. Non-major repairs are those that do not involve
removing the compressor, condenser, evaporator, or auxiliary heat
exchanger coil(s). See the U.S.E.P.A. regulations at 40 CFR
82.156(a) 11 for the provisions governing major and non-major
repairs to air-conditioning and refrigerating equipment. For major
repairs, the serviced part of the system shall be isolated to
minimize the loss of refrigerant during recovery. If isolation is
not possible, the total refrigerant charge shall be pumped into the
system receiver or recovered. Refer to 40 CFR, Part 82.15, 11 for
evacuation requirements. Only then shall repair be undertaken.
Under no circumstances shall the refrigerant be discharged to the
atmosphere. 8.1.7 Charging of Systems during Service. When
connected for charging, refrigerant containers shall not be
connected to a system at a higher pressure or to hydraulic legs
where the pressure is sufficient to cause a backflow of refrigerant
into the container. 8.2 Cleaning a Refrigerant System After a
Mechanical Failure, Contamination, or Motor Burnout If the
refrigerant is to be removed from the system due to contamination,
the refrigerant shall be recycled, reclaimed, or disposed of in
accordance with EPA regulations. In no case shall the refrigerant
be vented to the atmosphere. After reassembly, the system shall be
evacuated, leak-tested, and charged in accordance with Section 7.
8.3 System Operation and Maintenance. HVAC systems shall have
maintenance programs based on manufacturers recommendations,
ANSI/ACCA 4, Maintenance of Residential HVAC Systems,12
ANSI/ASHRAE/ACCA 180, Standard Practice for Inspection and
Maintenance of Commercial Building HVAC Systems,13 and industry
recognized practices followed to reduce and prevent refrigerant
releases. Informative Note: Recommended practices and procedures
may be found in Annex A6; however, they are not required for
compliance with this standard. 8.3.1. Maintenance Program.
Equipment types 7, 8, and 10 shall have a preventative maintenance
program that shall include inspections for evidence of refrigerant
leaks. The maintenance plan shall be reviewed and updated annually.
(a) The maintenance program shall be planned and predictive. (b)
This inspection shall include both a visual inspection of the
system, a review of any equipment operating logs, and verification
of the refrigerant charge containment. (c) he program shall verify
the function of the refrigerant leak monitoring and or charge
monitoring system. Informative Note: Recommended practices and
procedures may be found in Annex A6; however, they are not required
for compliance with this standard. 8.4 Actions after Refrigerant
Monitoring Alarm. Owners of HVACR systems that are equipped with
leak detection monitoring, or refrigerant charge monitoring, or
both, and that provide an alert when a potential refrigerant
release has occurred shall not add refrigerant without
leak-checking the system. The owner shall follow the criteria in
U.S. Code of Federal Regulations, 40 CFR, Part 82.156,11 for
repairing leaks. A refrigerant charging log as described in Section
7.5 shall be maintained. Informative Note: Generally, recommended
practices and procedures for system monitoring may be found in
Annex A; however, they are not required for compliance with this
standard.
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8.4.1 Refrigerant Charging Log: For Equipment Types 7, 8, and
10, the owner shall maintain the log initiated in Section 7.5 and
record of the following regarding any refrigerant leaks:
Identification of the servicing technician The date a leak was
discovered The location of the leaks to the extent determined to
date Any leak repair work that has been completed thus far and the
date the work was completed. Any measure taken to assess whether
the leak was effectively repaired, the date of such assessment, and
the results or conclusion Retrofits of the system with alternative
refrigerants, the type of alternative refrigerant used, and the
date of any such retrofit shall be recorded in the log. 8.5
Refrigerant/Lubricant Change-Out. Seals, gaskets, and valve packing
shall be replaced in accordance with manufacturers instructions
when changing from one refrigerant or lubricant to another. Reusing
these materials has a high potential to result in leaks.
9. REFRIGERANT RECOVERY, REUSE, AND DISPOSAL This section gives
the requirements for recovery, reuse, and disposal of refrigerant
from refrigerating and air-conditioning equipment and systems. 9.1
General. Refrigerant used in any type of air-conditioning or
refrigerating equipment shall be recovered and reused in the owners
equipment, or it shall be shipped in proper containers to a
reclamation or destruction facility whenever it is removed from
equipment. It shall not be released to the atmosphere. Informative
Note: Recommendations on the disposition of recovered refrigerant
may be found in Annex A; however, they are not required for
compliance with this standard. 9.2 Refrigerant Transfer, Transport,
and Storage. Refrigerant withdrawn from a system or equipment shall
be transferred to an appropriate pressure vessel for storage on
site or transport to another site. Disposable refrigerant
containers, including those identified as complying with the United
States Department of Transportation DOT Specification 39,14 shall
not be reused under any circumstances. 9.2.1 Safety. Appropriate
safety practices shall be followed when transferring refrigerant
from equipment or a system to a refrigerant container, when
transporting refrigerant from one location to another, and when
storing refrigerant (see Section 10). 9.2.1.1 Color-Coded
Containers. Refrigerant shall be transferred to a container that
has been identified by the color code for the refrigerant, as
specified in AHRI Guideline K-2009, Containers for Recovered
Fluorocarbon Refrigerants,15 and shall comply with appropriate DOT
regulations for refillable containers. 14 9.2.1.2 Overfilling
Prohibited. Refrigerant containers shall not be overfilled (see
Section 10.2.4). The design maximum working pressure of the
container shall not be exceeded, even temporarily, during any
filling operation. Informative Note: Refrigerant-oil mixtures have
a lower density than refrigerant alone; the container capacity will
therefore be reduced for a refrigerant-oil mixture. 9.2.1.3 Mixing
of Refrigerants Prohibited. Refrigerant shall not be placed in any
container that contains a different or an unknown refrigerant. In
no case shall a refrigerant already in a container be vented to the
atmosphere. 9.2.2 Transport. Refrigerant shall be transported from
one location to another in a safe manner. All requirements of
relevant laws, including registration and obtaining permits, shall
be observed. See, for example, DOT regulations in Title 49 CFR Part
178. 14 9.2.3 Storage. Refrigerant shall be stored in a safe manner
in accordance with local laws and regulations. The storage site
shall be dry and protected from weather to minimize corrosion of
refrigerant containers. Containers (except those
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designed for outside storage of refrigerant) shall not be stored
in direct sunlight (see also Section 10.2) or in close proximity to
a heat source. 9.3 Disposal. If recovered refrigerant is not
intended to be reused, recycled or reclaimed, it shall be destroyed
in an approved facility. 10. HANDLING AND STORAGE OF REFRIGERANTS
This section specifies how to comply with this standard in the
handling and storage of halogenated refrigerants. 10.1 System
Connections. Charging lines shall be made of materials that are
compatible with the refrigerant. 10.2 Storage 10.2.1 Refrigerant
Container Design. Refrigerant containers shall be constructed to
meet DOT packaging requirements as required by Title 49 CFR Part
178.14 10.2.2 Containers for Recovered Refrigerants. Pressure
cylinders for recovered non-flammable fluorocarbon refrigerants
shall be of refillable design, which includes a properly set relief
valve and a valve guard (49 CFR 178). 14 10.2.3 Non-Reusable
Containers Prohibited for Recovered Refrigerants. Previously filled
DOT Specification 3914 non-reusable (non-refillable) cylinders
shall not be used for recovery and transportation of recovered
refrigerants. Informative Note: Title 49 CFR 178.6514 describes
substantial fines and possible imprisonment for transportation of
refilled DOT 39 cylinders. 10.2.4 Maximum Mass for Medium and
High-Pressure Refrigerants. In filling high-pressure and
medium-pressure refrigerant containers, the maximum allowable gross
mass shall be equal to the sum of the cylinder tare mass plus 80%
of the water capacity mass multiplied by the specific gravity of
the refrigerant recovered at 77 F [25 C]. Informative Note:Further
recommendations on containers and proper storage of recovered
refrigerants may be found in AHRI Guideline K, Containers for
Recovered Fluorocarbon Refrigerants.15 10.2.5 Dedicated Containers.
For reasons of safety, and to avoid cross-contamination or
misidentification of refrigerants, containers shall only be filled
with the refrigerant indicated on the container. 10.2.6 Vapor Space
for Low-Pressure Refrigerants. Drums that originally contained
low-pressure refrigerants such as R-11, R-123, or refrigerant R-113
(excluding those originally used for cleaning agents), if used
again for the same recovered low pressure refrigerant, shall be
filled to allow a vapor space that is at least equal to 10% of the
drum height.
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11. NORMATIVE REFERENCES References required for compliance with
this standard are listed below. Informative references are listed
in Annex C.
1. ANSI/ASHRAE Standard 15-2010, Safety Standard for
Refrigeration Systems. 2007. American Society of Heating,
Refrigerating and Air-Conditioning Engineers, Inc., Atlanta,
Ga.
2. AHRI 580-2009, Performance of Non-Condensable Gas Purge
Equipment for Use with Low Pressure Centrifugal
Chillers.Air-Conditioning, Heating and Refrigeration Institute,
Arlington, Va.
3. ASTM D642-2000 (RA2005), Standard Test Method for Determining
Compressive Resistance of Shipping Containers, Components, and Unit
Loads. ASTM International, West Conshohcoken, Pa.
4. ASTM D4577-2005, Standard Test Method for Compression
Resistance of a Container Under Constant Load. West Conshohcoken,
Pa.
5. ASTM D999-2008, Standard Test Methods for Vibration Testing
of Shipping Containers. West Conshohcoken, Pa.
6.. ASTM D4728-2006, Standard Test Method for Random Vibration
Testing of Shipping Containers. West Conshohcoken, Pa.
7. ASTM D6055-1996 (RA 2007) Standard Test Methods for
Mechanical Handling of Unitized Loads and Large Shipping Cases and
Crates. West Conshohcoken, Pa.
8. ASTM D6179-2007, Standard Test Methods for Rough Handling of
Unitized Loads and Large Shipping Cases and Crates. West
Conshohcoken, Pa.
9. ASTM D880-1992 (RA 2008), Standard Test Method for Impact
Testing for Shipping Containers and Systems. West Conshohcoken,
Pa.
10. ASTM D5276-1998 (RA 2009), Standard Test Method for Impact
Testing for Shipping Containers and Systems. West Conshohcoken,
Pa.
11. U.S. Code of Federal Regulations, 40 CFR, Part 82, Subpart
F.
12. ANSI/ACCA 4, Maintenance of Residential HVAC Systems.
13. ANSI/ASHRAE/ACCA Standard 180-2008, Standard Practice for
Inspection and Maintenance of Commercial Building HVAC Systems.
American Society of Heating, Refrigerating and Air-Conditioning
Engineers, Inc., Atlanta, Ga
14. DOT 39, Department of Transportation, Code of Federal
Regulations, 49 CFR, Part 178, Subpart C.
15. AHRI Guideline K-2009, Containers for Recovered Fluorocarbon
Refrigerants. Air-Conditioning, Heating and Refrigeration
Institute, Arlington, Va.
16. UL 1995 (3rd Edition, 2/18/05), Heating and Cooling
Equipment. Underwriters Laboratories.
17. ANSI/ASHRAE Standard 34-2010, Designation and Safety
Classification of Refrigerants. American Society of Heating,
Refrigerating and Air-Conditioning Engineers, Inc., Atlanta,
Ga.
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(This annex is not part of this standard. It is merely
informative and does not contain requirements necessary for
conformance to the standard. It has not been processed according to
the ANSI requirements for a standard and may contain material that
has not been subject to public review or a consensus process.
Unresolved objectors on informative material are not offered the
right to appeal at ASHRAE or ANSI.) INFORMATIVE ANNEX A RECOMMENDED
PROCEDURES AND PRACTICES A1 INTRODUCTION This annex contains
practices and procedures that are recommended but not required for
compliance with this standard. A2 RECOMMENDED DESIGN PRACTICES A2.1
Compressors A2.1.1 Shaft Seals. Shaft-seal designs that do not rely
on the commonly used carbon faces are available. Double-faced seals
and single-carbon seals with improved features to keep the carbon
in a wet state have been found to be effective and may be used. The
design and installation of the shaft-seal assembly should minimize
external oil loss and prevent direct refrigerant loss. Lack of
lubrication during shutdown periods can cause the mating faces of
the seal to dry out and adhere together. On large systems, a
separate oil pump to lubricate the seal prior to starting the
compressor is recommended. Open compressors typically have
carbon-face seals that require positive pressure in order to
function properly. Since these are not two-way seals, leakage may
occur during evacuation. To prevent leakage, temporary sealing
measures such as shaft caps or clay-like weather stripping around
the protrusion of the shaft should be used. The motor-compressor
alignment is critical in limiting refrigerant leakage and is
affected by the style of the coupling and the speed and power of
the motor. Refrigeration machinery requires stringent alignment to
accommodate thermal growth over the load and temperature ranges. It
is recommended that a tool utilizing laser alignment technology be
used. If the motor or compressor is removed and replaced in the
field, it is best practice to utilize this type of alignment tool.
At a minimum, it is recommended that a tool utilizing laser
alignment technology be used. If the motor or compressor is removed
and replaced in the field, it is best practice to utilize this type
of alignment tool. Shutdown and start-up procedures should ensure
that oil is present to wet the seal faces. It may be necessary to
run the oil pump and rotate the shaft periodically during long
shutdown periods. If this is not possible, the seals should be
inspected and lubricated before starting the system. A2.1.2
Vibration. Vibrations from gas pulses are best handled by a muffler
placed as close to the compressor as possible. For those
compressors that are spring-mounted, vibration elimination should
be provided in the suction and discharge lines. When piping
vibration eliminators are used, they should be rated for the design
pressure used and they should be parallel with the shaft of the
compressor and anchored firmly at the upstream end in the suction
line and the downstream end in the discharge line. A2.2 Condensers
and Evaporators A2.2.1 Air-Cooled Condensers and Evaporators
A2.2.1.1 Excessive vibration from compressors or other equipment
can cause tube failure. These effects should be considered.
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A2.2.1.2 Construction materials and methods of design should be
selected to preclude emissions of refrigerant as a result of
release during normal operation. For known corrosive environments
(e.g; a service deli case where food items are being refrigerated
or a coastal environment where corrosion is eminent) the coil must
have an adequate tubing thickness or coating or other fin material
to ensure adequate life of the heat exchanger. A2.2.1.3 Condensers
and evaporators should be designed to keep the refrigerant volume
(charge) as small as possible. A2.2.1.4 Air-cooled condensers and
evaporators should be constructed with the fewest practicable
number of joints and return bends. Brazing is the preferred method
of joining (see also Section 4.5.1). A2.2.2 Liquid-Cooled
Condensers and Evaporators A2.2.2.1 Excessive vibration can cause
failure of shell-and-tube heat exchangers. Vibration from any of
several sources can cause tube failure: (a) The boiling action in
flooded evaporators can cause vibration at the natural frequency of
the tubes, creating excessive wear at tube supports and possible
failure. This problem can be avoided with tube supports that are
properly spaced and sized. (b) Excessive fluid velocity in
condensers and evaporators can set up vibrations that will cause
premature tube failure. Precautions similar to those described
above can minimize the problem. A2.2.2.2 Excessive fluid velocity
in water-cooled condensers and evaporators can lead to premature
failure by erosion. As velocities increase, the potential for
premature failure increases as the square of the velocity. Care
must be taken that design fluid velocities are within good practice
for the material selected. Tube blockage, can result in increased
velocities above design for normal flow through the heat exchanger.
The potential for damage will be reduced by limiting velocities.
A2.2.2.3 In applications where condenser fluid flows inside the
tubing, fouling can lead to premature tube failure. Proper
filtration can reduce erosion caused by foreign particles in the
fluid. Proper chemical treatment can minimize the effects of
corrosive elements in the fluid. A2.2.2.4 Seawater-cooled systems
are especially susceptible to corrosion, as are some systems using
waters containing traces of ammonia or microbiological organisms.
These contaminants will attack the tubes and may also attack tube
sheets and heat-exchanger heads leading to leakage. Facilities for
routine flushing and inspection are advisable. Special linings and
special tube materials may be required to minimize attack on these
surfaces. A2.2.3 Evaporative Condensers A2.2.3.1 Proper water
treatment can minimize the effects of corrosive elements in the
evaporative fluid. A2.3 Piping, Tubing, and Connections Strainers,
filters, and driers should be utilized to control moisture and
capture solid contaminants, which will minimize damage to moving
parts and avoid plugging of refrigerant circuits caused by
contaminants in the system. These components should be isolated
with valves (or pump-out capability provided) to permit quick
recovery of refrigerant before component servicing and to reduce
the potential for excessive refrigerant loss. Supports and bimetal
transition joints should be designed to guard against electrolytic
corrosion. A2.4 Access and Isolation Valves Access valves should be
located where pressure readings will be taken. Adequate isolation
of system components such as gauges, operating controls, and major
components (compressors, heat exchangers, expansion devices,
receivers, and accumulators) should be provided to minimize
refrigerant loss during servicing or replacement in accordance with
ANSI/ASHRAE Standard 15-2010, Safety Standard forRefrigeration
Systems. Valves not having an internal stem diaphragm should be
provided with seal caps to fit over the stem (if so equipped) in
order to minimize leak sources. Seal caps should be tightened
metal-to-metal seal type or should have equally effective long term
sealing capability and should be attached to the valve body by a
strap or chain to avoid losing them in service. A2.5 Relief
Devices
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A2.5.1 separate relief devices may be provided for the high and
low sides; however, high-side, pressure-relief devices may be piped
so as to discharge into the low side of the system provided that
(a) they are of a type not appreciably affected by back pressure
and that (b) the low side is equipped with a pressure-relief device
of sufficient capacity as specified in ANSI/ASHRAE Standard
15-2007, Safety Standard for Refrigeration Systems, to protect all
connected vessels, compressors, and pumps subjected to excess
pressure simultaneously. In centrifugal systems where the condenser
cannot be isolated from the evaporator, a single pressure-relief
device will suffice to protect the system in accordance with
ANSI/ASHRAE Standard 15-2007, Safety Standard for Refrigeration
Systems. A2.5.2 Where a relief valve is used, a rupture disc should
be installed upstream of the valve to protect the valve from
corrosion or inadvertent release. An indicator should be installed
between the rupture disc and the relief valve to indicate that the
disc has ruptured. The rupture disc should be a non-fragmenting
type. Once the rupture disc has burst, it should be replaced as
soon as possible. It may be necessary to remove the remaining
refrigerant charge before replacing the disc. Where a rupture disk
is used as the sole relief device, a relief valve is not required
downstream, and the use of a non-fragmenting rupture disk is not
required. Note: When pressure-relief devices are installed in
series, provisions of Section VIII of the ASME Unfired Pressure
Vessel Code should be observed. A2.6 Marking and Instruction The
manufacturer should document for the user the refrigerant name,
charging quantity, and needed instructions of equipment
installation, testing, operation, maintenance, repair, and
disposal. A2.7 Type 4 -Specific Topics: For factory-sealed systems,
soldering, epoxy joining, and any other method demonstrated to
maintain the hermetic nature of the system is acceptable as an
alternative to brazing. A2.8 Type 5, 6, 7 -Systems-Specific Topics
A2.8.1 Compressors. Suction and discharge fittings, whether
mechanical or brazed joints, should be easily accessible for the
service person. This will help to ensure a leak-free installation
if the compressor fails and must be replaced. A2.8.2 Air-Cooled
Condensers and Evaporators. Some commercially available silicone
marine sealants have proven effective for protecting
copper-aluminum joints from electrolytic corrosion. A2.8.3 Piping
and Connections A2.8.3.1 Brazing is the preferred method of joining
pipe to fittings, valves, and other components. A2.8.3.2 It is
recommended that driers have a hermetic shell and braze fittings;
however, the shell and fittings, whether brazed or mechanical,
should be easily accessible for the service person if the drier
needs to be replaced. A2.8.3.3 Pre-charged line sets are the
preferred method of connecting HFC-based split systems. EPA
regulations prohibit the sale of line sets pre-charged with
HCFC-22. Field-installed lines requiring brazing, evacuation, and
charging introduce more risk of release. If pre-charged line sets
are provided for connecting the indoor and outdoor units of split
systems, an adequate array of choices is recommended in order to
allow proper line selection. This will facilitate better control of
cleanliness, minimize use of fittings, and help ensure proper line
sizing for oil return and charge control. A2.8.4 Valves A2.8.4.1
Due to temperature excursions while in heating-cycle duty and
cooling-cycle duty, nonmetallic O-ring or gasket seals beneath a
thumb-tightened cap tend to vulcanize or set with time and
temperature, allowing refrigerant that seeps past the self-closing
stems to escape the system. Metal-to-metal-type seal caps will help
minimize this leakage. Adequate instructions for proper tightening
of the access valve caps should be provided.
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A2.8.4.2 Expansion valves, if used in a unitary system, should
be of the type that has superheat preset at the factory, thus
eliminating mechanical joint s that accommodate a superheat stem.
The body and element should be hermetic with brazed fittings.
A2.8.4.3 Where possible, check valves, reversing valves, and
solenoid valves should be brazed into the system at the factory.
A2.9 Type 7 and 8 Equipment-Specific Topics A2.9.2
Prevention-of-Vacuum Systems and Leak-Test Pressurization Systems.
Low-pressure systems can develop a vacuum during idle periods,
causing non-condensable infiltration into the system. A
prevention-of-vacuum system controls refrigerant pressure by
applying heat to the evaporator. This results in maintenance of a
pressure equilibrium between the chiller and atmosphere when idle.
As a result, neither air can infiltrate nor refrigerant escape
through possible leak paths. Prevention-of-vacuum systems may also
be used to pressurize low-pressure chillers for the purpose of leak
testing. A3 PRODUCT DEVELOPMENT A3.1 Refrigerant Handling
Refrigerant recovery/recycling systems are recommended in
laboratories employing refrigerant. Laboratory recovery/recycling
systems should be examined for leaks on a frequent (at least
monthly) basis. A3.2 Vibration Tests Vibration testing should be
done to identify packaging or tubing weaknesses that could cause
leaks during shipment. A3.3 Storage Temporary and prototype systems
should not be stored for more than six months while containing
refrigerant. Temporary and prototype systems stored for more than
six months should contain positive-pressure inert gas. A4
MANUFACTURE A4.1 Evacuation To remove moisture during the
manufacture of new air-conditioning or refrigerating equipment, the
unit should be purged with heated dry air (40F [40C] dew point).
After purging, a deep vacuum evacuation, which involves a single
extended evacuation of the unit, should be performed. Air and other
noncondensable gases may be removed by deep evacuation. A4.2
Internal Cleanliness: Every effort should be made to ensure
internal cleanliness of components and equipment. A4.3 Factory Leak
Test A4.3.1 Leak Test Methods All factory leak test methods fall
into one of two catagories: the leak rate measurement method
(reveals the presence of a leak) or the leak location method
(reveals the location of a known leak). Some common examples of
these two methods being used in the HVAC industry are as
follows:
A4.3.1.1 Leak Rate Measurement Methods A4.3.1.1.1 Pressure Decay
A4.3.1.1.2 Vacuum Decay A4.3.1.1.3 Helium Inside-Out Vacuum Chamber
Test (ASTM E493) A4.3.1.1.4 Helium Accumulation Test (Method B of
ASTM E499) A4.3.1.1.5 Helium Hood Test (ASTM 1603)
A4.3.1.2 Leak Location Methods
A4.3.1.2.1 Bubble Test Immersion
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A4.3.1.2.2 Bubble Test Application of Liquid Film A4.3.1.2.3
Detector Probe Test (Method A of ASTM E499) A4.3.1.2.4 Tracer Probe
Test (Method A of ASTM E498)
Leak rate measurement methods do not provide information on the
number and location of individual leaks. Leak location methods
alone can not give reliable assurance that no leaks exist or that
tests have revealed all leaks that exist. Without prior assurance
that leaks do exist, leak location test methods become arbitrary in
application. Multiple sources for this often overlooked conclusion
and resulting misapplication of leak location methods can be cited
in the literature including:
ASTM E432, Paragraph 6.1. ASME Boiler & Pressure Vessel
Code, Section V - Nondestructive Examination, Article 10 Leak
Testing, Paragraphs III-1010, IV-1010, and V-1010(a). ASNT
Nondestructive Testing Handbook, Volume 1 Leak Testing, 3rd
Edition, pages 20, 320, 345, 346,
348. In practice, preliminary leak testing is usually done first
by a less sensitive means to permit the identification, location,
and repair of gross leaks. Next the system or component is
subjected to an overall leak rate measurement test to determine if
it meets the leakage acceptance criterion. When the system or
component fails to meet the leakage acceptance criterion,
individual leak sites are identified through the use of a sensitive
leak location test method and repaired. For final assurance that
the system or component meets the leakage acceptance criterion, it
is necessary to repeat the leak rate measurement test at the
conclusion of the location and repair process. A4.3.2 Selection and
Sensitivity of Leak Testing Methods (Note that statements below are
based largely on ASTM E432 Standard Guide for Selection of a Leak
Testing Method) The correct choice of a leak test methods optimizes
sensitivity, cost, and reliability of the test. It is important to
recognize that leak location should be attempted after the presence
of a leak has been verified by a leakage measurement test. One
approach to choosing a leak measurement method is to rank the
various methods according to test system sensitivity. The various
testing methods must be individually examined to determine their
suitability for the particular system being tested. Only then can
the appropriate method be chosen. It is important to distinguish
between the sensitivity associated with the instrument employed to
measure leakage and the sensitivity of the test methodology
followed using the instrument. Test methods that are based on
pressure change (pressure decay and vacuum decay) do not typically
have sufficient sensitivity to meet the needs of components and
systems used in HVAC applications (see Section 8.3.1 of Zero Leaks
Limiting Emissions of Refrigerants published by ASHRAE).. The
pressure change test methods are useful to verify that a component
or system is free from gross leaks. In general, leakage measurement
procedures suited to HVAC components and systems involve covering
the whole of the suspected region with tracer gas, while
establishing a pressure differential across the system by either
pressurizing with a tracer gas or by evacuating the opposite side.
The presence and concentration of tracer gas on the lower pressure
side of the system are determined and then measured. A dynamic test
method (like the vacuum chamber test) can be performed in a
relatively short time. Static techniques (involving accumulation)
can be employed to increase the test sensitivity while also
increasing the time required for testing. Leakage measurement
methods that evacuate the internals of the component or system
(like the hood test) are not suitable for HVAC applications where
the component or system is subjected to a positive pressure in
operation. Leaks may temporarily plug due to moisture, lubricants,
flux, etc. and go undetected when tested at the low differential
pressure conditions typical of testing evacuated components or
systems. Optimum leakage measurement methods suited to HVAC
components and systems are vacuum chamber testing (as described in
ASTM E493) and accumulation testing (as described in Method B of
ASTM E499). These two methods are used in practice with a number of
different tracer gases including Helium (pure or mixed with
Nitrogen), refrigerant
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(pure or mixed with Nitrogen) and 5% Hydrogen / 95% Nitrogen.
The resulting sensitivity of the leakage measurement test will
depend on a number of design factors and operating parameters. For
small components and systems (nominally 1m3 external volume) these
two methods are capable of readily and realistically detecting
tracer gas leakage equivalent to R-410A leakage of less than 1
oz/yr from 250 psig into atmosphere. For larger components and
systems, the sensitivity that is readily and realistically
attainable will be somewhat higher. A4.3.3 Leak Rate Measurement
Methods
A4.3.3.1 Pressure Decay Typically this test consists of charging
the system or component with a gas, closing a valve to isolate the
gas supply, and monitoring the pressure inside the system or
component. A decrease in pressure over time is indicative of a
leak. If the internal free volume of the pressurized unit under
test is known, the leak rate can be calculated by using the
following formula:
Q = P V
t
where: Q = Leak Rate (atm-cc/sec) P = Pressure Change Inside the
Part Under Test (atm) V = Internal Free Volume (cc) t = Time over
which the P occurred (sec) The ultimate sensitivity of a pressure
decay test is limited by the effects of temperature because changes
in temperature result in corresponding changes in pressure.
Calculations in the literature show that in regards to HVAC systems
and components, pressure decay testing is suitable to insure that
gross leaks do not exist. Pressure decay testing sensitivity is
typically insufficient for HVAC systems and components (see Section
8.3.1 of Zero Leaks Limiting Emissions of Refrigerants published by
ASHRAE). Advantages of the pressure decay test are
tests the system or component under positive pressure (most HVAC
systems and components operate under positive pressure
conditions)
requires relatively inexpensive hardware can be done at high
pressure to simultaneously satisfy any proof pressure test
requirements on the
assembly line easily automated simple to understand, requires
minimal training of personnel also can serves as a simultaneous
leak location test
Disadvantages of the pressure decay test are
internal free volume is often unknown and must be measured to
get a quantifiable result tests at high pressure can pose a safety
hazard to personnel suitable only for gross leak testing in most
HVAC applications unacceptable leaks may take excessive amounts of
time. this test procedure should not be used as a final test to
ensure a leak free joint or assembly.
4.3.3.2 Vacuum Decay
Typically this test consists of evacuating the system or
component with a vacuum pump, closing a valve to isolate the pump,
and monitoring the pressure inside the system or component. An
increase in pressure over time is indicative of a leak. If the
internal free volume of the evacuated unit under test is know, the
leak rate can be calculated by using the following formula:
Q = P V
t
where: Q = Leak Rate (atm-cc/sec) P = Pressure Change Inside the
Part Under Test (atm)
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V = Internal Free Volume (cc) t = Time over which the P occurred
(sec) The ultimate sensitivity of a vacuum decay test is limited by
the effects of outgassing. Outgassing in the system or component
causes the pressure to rise for reasons other than leakage and this
inherent P can lead to false failures. (There are a number of
sources of outgassing in HVAC systems and residual water is almost
always present to some degree.) Calculations in the literature show
that in regards to HVAC systems and components, vacuum decay
testing is suitable to insure that gross leaks do not exist. Vacuum
decay testing sensitivity is typically insufficient for HVAC
systems and components (see Section 8.3.2 of Zero Leaks Limiting
Emissions of Refrigerants published by ASHRAE). Advantages of the
vacuum decay test are
requires relatively inexpensive hardware vacuum assists in
sealing to the unit under test easily automated simple to
understand, requires minimal training of personnel
Disadvantages of the vacuum decay test are
internal free volume is often unknown and must be measured to
get a quantifiable result tests the system or component under
vacuum (most HVAC systems and components operate under
positive pressure conditions) leaks may temporarily plug due to
moisture, lubricants, flux, etc. and go undetected when tested
at
low differential pressure conditions suitable only for gross
leak testing in most HVAC applications leak location on the system
or component while it is under vacuum can be problematic and often
a
separate positive pressure test is required to locate the site
of a gross leak
4.3.3.3 Helium Inside-Out Vacuum Chamber Test (ASTM E493) This
test is referred to as an Inside-Out test because the tracer gas
(Helium) is inside the system or component under test and it is
detected on the outside of the unit under test when a leak is
present. The test is performed with the unit under test inside a
vacuum chamber which is coupled to a mass spectrometer leak
detector. The unit under test can be filled with tracer gas prior
to loading it into the chamber (referred to as a pre-charged test)
or the unit can be filled with tracer gas while it is inside the
chamber via a line that is connected to it through the chamber wall
(referred to as a charge-in-chamber test). The output of the leak
detector during the inside-out test of the unit is compared to the
output registered by a calibrated leak at the same test conditions
to determine if the unit satisfies the leakage acceptance
criterion. Analogous inside-out vacuum chamber test methods can be
employed with tracer gases other than Helium. Advantages of the
inside-out vacuum chamber test are
tests the system or component under positive pressure (most HVAC
systems and components operate under positive pressure
conditions)
sufficient sensitivity to meet the leak testing needs of most
all HVAC systems and components chamber can serve as a safety guard
for personnel when the charge-in-chamber technique is utilized
easily automated
Disadvantages of the inside-out vacuum chamber test are
hardware is expensive relative to other leak rate measurement
methods requires trained personnel for maintenance and
troubleshooting presence of tracer gas in the ambient air
(background) can be problematic
4.3.3.4 Helium Accumulation Test (Method B of ASTM E499)
In this test the system or component is pressurized with tracer
gas (Helium) and it is held in a sealed enclosure. The air in the
enclosure is well mixed with a fan over a period of time allowing
any leakage to accumulate.
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When the necessary dwell time has elapsed, the air inside the
enclosure is sampled with a mass spectrometer leak detector. By
introducing a calibrated leak into the same volume for the same
elapsed time, the leak detector output with the unit under test can
be compared to the output registered by the calibrated leak to
determine if the unit satisfies the leakage acceptance criterion.
Analogous accumulation test methods can be employed with tracer
gases other than Helium. Advantages of the Helium accumulation test
are
tests the system or component under positive pressure (most HVAC
systems and components operate under positive pressure
conditions)
sufficient sensitivity to meet the leak testing needs of most
all HVAC systems and components can be attained
hardware cost is lower than chamber test easily automated
Disadvantages of the Helium accumulation test are
requires trained personnel for maintenance and troubleshooting
presence of tracer gas in the ambient air (background) can be
problematic dwell time necessary to accumulate sufficient tracer
gas for reliable go-no-go test may be
unacceptable in a production line setting
4.3.3.5 Helium Hood Test (ASTM 1603) The test is performed with
the unit under test inside a hood which is filled with Helium. The
unit under test is evacuated and coupled to a mass spectrometer
leak detector. This test is sometimes referred to as an Outside-In
test because the tracer gas (Helium) is outside the system or
component under test and it is detected on the inside of the unit
under test when a leak is present. The output of the leak detector
during the test of the unit is compared to the output registered by
a calibrated leak at the same test conditions to determine if the
unit satisfies the leakage acceptance criterion. Analogous hood
test methods can be employed with tracer gases other than Helium.
Advantages of the hood test are
sufficient sensitivity to meet the leak testing needs of most
all HVAC systems and components hardware cost is lower than chamber
test easily automated
Disadvantages of the hood test are
tests the system or component under vacuum (most HVAC systems
and components operate under positive pressure conditions)
leaks may temporarily plug due to moisture, lubricants, flux,
etc. and go undetected when tested at low differential pressure
conditions
requires trained personnel for maintenance and troubleshooting
presence of tracer gas in the ambient air (background) can be
problematic
A4.3.4 Leak Location Methods
A4.3.4.1 Bubble Test Immersion In this simple test, the system
or component is pressurized with tracer gas (typically air) and
then immersed in a liquid bath (typically water) and an operator
looks for bubbles. Bubbles may emerge from the unit under test at
such a rapid rate that there is no question of the existence and
location of a leak. When small leaks are to be located the unit
under test must remain submerged long enough for any bubbles coming
from crevices to have a chance to collect and rise. Although longer
waiting periods theoretically should result in higher sensitivity,
the sensitivity is limited when the rate of bubble evolution
approaches the rate at which the gas is dissolving in the liquid.
In addition to dwell time, test sensitivity is influenced by
clarity of the liquid, lighting, proximity of the leak site to the
operator, and a number of human factors.
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Advantages of the bubble immersion test are requires relatively
inexpensive hardware tests the system or component under pressure
(most HVAC systems and components operate under
positive pressure conditions) with proper safety guarding,
testing can be done at high pressure to simultaneously satisfy any
proof
pressure test requirements on the assembly line the entire
pressurized component can often be examined simultaneously simple
to understand, requires minimal training of personnel leaks at test
fittings and can be effectively ignored by the operator and will
not influence test
sensitivity Disadvantages of the bubble immersion test are
introduces water into the manufacturing process which can be
problematic for subsequent dehydration operations in the HVAC
industry
there are often housekeeping and safety issues associated with
the immersion tank and dripping wet parts
human factors have a strong influence on test results,
especially in the location of small leaks
4.3.4.2 Bubble Test Application of Liquid Film The liquid film
application test technique can be used to locate leaks on any
system or component on which a positive pressure differential
exists across the wall. The test liquid is applied to the exterior
surface (application by spray or brush is common) and the joint is
examined for bubbles in the solution film. The area to be inspected
should be positioned to allow the liquid to lie on the surface
without dripping off.
Advantages of the liquid film application bubble test are
requires relatively inexpensive hardware tests the system or
component under pressure (most HVAC systems and components operate
under
positive pressure conditions) simple to understand, requires
minimal training of personnel leaks at test fittings and can be
effectively ignored by the operator and will not influence test
sensitivity Disadvantages of the liquid film application bubble
test are
introduces water and soap into the manufacturing process which
can be problematic for subsequent dehydration operations in the
HVAC industry
human factors have a strong influence on test results,
especially in the location of small leaks
4.3.4.3 Detector Probe Test (Method A of ASTM E499) In this test
the system or component is pressurized with tracer gas and the
detector is used to probe the external surfaces of the unit under
test to locate leak sites. This test technique is commonly referred
to as Helium sniffing or refrigerant sniffing where reference is
made to the specific tracer gas in use. Factors that influence the
sensitivity of the detector probe test include the speed at which
the probe is moved, the distance between the surface of the part
and the probe, and the orientation of the probe relative to the
direction of the gas exiting the defect. When Helium is