Commercial /Industrial Systems
2.1 Design and General Practices
This section deals with the design of refrigeration and air
conditioning systems and their components, and identifies
possible sources of refrigerant emissions of CFC/ HCFC/HFCs to
the atmosphere.
Application of established technology in both the design,
construction, proper operation, and maintenance of refrigeration
systems constitutes a good foundation for the prevention of
refrigerant leakage to the atmosphere. Improved design of systems
and use of new technologies and practices are essential for
reduction and elimination of emissions.
2.1.1 General Design Principle
Commercial/Industrial refrigeration and air conditioning
sectors are the major source of emissions. Environmentally sound
design, therefore, is an important goal in pollution prevention.
Equipment manufacturers, distributors, and associated service
industries should incorporate product stewardship into their
corporate policies, if not already present.
2.1.2 Building Owners, Operators, and Managers
Equipment owners and managers using ODS equipment should be
informed of the environmental impact of ODS emissions and use of
alternative refrigerants. The immediate need is to communicate
that planned preventative maintenance is an essential component
of preventing emissions. The second need is to improve
maintenance techniques and procedures for maintaining the
equipment to reduce or eliminate the potential for refrigerant
release.
2.1.3 Relief Devices
Effective on the date of publication of this document, all new
units containing over 10 kg (22 lb) of refrigerant should have a
self-reseating relief valve vented to the outside atmosphere in
accordance with the applicable B-52 code requirements. Also,
units with over 50 kg (110 lb) should have a monitoring system in
the compressor room, capable of detecting leakage greater than 30
ppm.
2.2 Compressors
To prevent fugitive emissions, compressors or associated
equipment fitted to them, e.g., gauge and cut-out connections,
oil return, oil drain, oil level sight glass, relief valve and
connecting pipe work, need to be inspected regularly according to
manufacturer's specifications, or at least twice a year if no
specifications exist.
2.2.1 Mechanical Seals
Damaged mechanical seals on open type compressors are a
frequent source of refrigerant leakage. Some manufacturers
indicate that a small amount of oil leakage is required to keep
dirt out of the seal and keep the seal surface lubricated.
However, damage to the seals may be caused by oil contamination
or lubrication breakdown.
A clean, dry system is essential for prolonged mechanical seal
effectiveness to eliminate emissions. Compressor oils used for
HCFCs and HFCs will absorb moisture readily and must be kept dry
to prevent refrigerant decomposition.
Straining and filtration of refrigerant and compressor oil
should be provided on new equipment to minimize mechanical seal
wear and thereby reduce the possibility of having leaks. Existing
equipment should be modified to include these features.
Gland housing should be designed to prevent oil draining away
from the mechanical seal during shutdown, which may cause leakage
due to seal face damage on startup.
2.2.2 Seal Lubrication
During shutdown the mechanical seals on large open compressor
systems should be lubricated weekly before the compressor is
started. A film of oil maintained on the shaft and seal surface,
helps to prevent refrigerant from escaping.
2.2.3 Vibration
Compressors should be mounted on a solid foundation and/or
with vibration eliminators to prevent leaks due to vibration and
failures.
Gauges and Cutouts. Snubber valves should be used to
protect gauges and cutouts. They are also required to permit
removal of these devices for repair.
Isolating Valves and Access Valves. All commercial and
industrial compressors should have isolating and access valves on
both the suction and discharge sides. New units/systems
immediately or from the date of publication of this document
should have "refrigerant recovery access valves" sized
to allow 0.64 cm (1/4") of free area for flow of refrigerant
on units/systems having up to 4 kg (8.8 lb) of refrigerant charge
and 0.95 cm (3/8") I.D. for systems containing over 4 kg
(8.8 lb) of refrigerant to permit recovery of refrigerant before
the system is opened.
2.3 Condensers and
Evaporators
Effective on the date of publication of this document, the
refrigerant should not be used as a holding charge for storage or
shipping; use dry nitrogen or dry air that meets ASHRAE
standards.
2.3.1 Condenser and Evaporator Vibration
Excessive vibration from compressors or other equipment can
cause evaporator and condenser tube failure. Antivibration
mountings and vibration eliminators should be used where
feasible. Piping should have flexible connectors and be solidly
anchored. Equipment should be inspected periodically to identify
and remediate any excessive vibrations.
2.3.2 Excessive Water Velocity
Excessive water velocity through the tubes of shell and tube
units should be avoided. On larger units (e.g., greater than 50
tR), eddy current testing of tubes every three years and water
flow measurements will help minimize refrigerant losses due to
tube failure. Adequate protection against water hammer is also
recommended to reduce failure.
2.3.3 Water Quality
Water treatment and filtration should be used where needed to
avoid corrosion or erosion failure. Careful selection of tube
materials can also help to minimize corrosion.
For non-ferrous tubes, sacrificial anodes should be used to
reduce corrosion pitting.
Reduced or suspended water flow can lead to serious corrosion
problems. Flushing and a regular inspections should be done.
Sacrificial anodes are ineffective unless there is water
flowing through the tubes. Tube sheets should also have a tube
sheet vent valve to avoid trapped gases. These should be purged
at least once a month.
2.4 Piping Fittings and
Practices
2.4.1 Piping and Fittings
Vibration eliminators should be included in the suction and
discharge lines near the compressor to prevent and eliminate
leaks and vibration transmission.
Adequate support of pipeline connections to the compressor
should be provided to avoid unacceptable stresses that could lead
to leakage.
All pipelines should be designed so that the number of joints
is minimized. Swedged joints should be used by both manufacturing
process and the service person in the field. Welding or brazing
is the preferred method of attachment on all refrigerant lines.
The use of back seating access valves for attaching control and
safety devices or gauges is preferred. Capillary lines on these
devices must be positioned to ensure they can absorb vibration
without rubbing together or against another object.
Gasket Material Compatibility. Ensure that gaskets are
compatible with the refrigerant/refrigerant oil mixture where
flanged joints are used, especially when the system is converted
to an alternative refrigerant or oil. Equipment manufacturers
should always be consulted before any retrofitting to help avoid
leakage.
Welded or Brazed Flanges. To eliminate potential leaks
in new systems, welding or brazing should be used to join flanges
to the pipeline, instead of threaded connections. Where threaded
connections must be used, fluoropolymer film is the preferred
pipe lubricant. On existing systems back-weld screwed flanges
should be used where possible.
Back Seating Valves. Use valves designed for tightening
or replacement of the gland packing/diaphragm under line pressure
except when ball valves are involved. Be sure to check valves
carefully before servicing. Leak test the gland-packing nut
regularly.
Capped Valves. Capped valves which can retain any
leakage from the spindle gland should be used for all service
stop valves. Regular operating valves in the system should be
leak tested regularly.
Welded, Brazed Valves. Valves with welded, brazed, or
flanged connections should be used instead of a flared or screwed
type, for sizes greater than 19 mm (3/4") outside diameter
(O.D.). For small sizes use compression fittings instead of
flared fittings.
Bolt-on Valves. Bolt-on valves should not be used on
smaller applications. Saddle valves can be used as a tool but
must be replaced by weld-in access valves or welded shut before
the service person leaves the site. One exception is for recovery
of refrigerant when a bolt-on valve can be used during
decommissioning of smaller equipment.
Isolation and Access Valves. Valves allowing isolation
of all vessels and equipment are required to minimize the risk of
refrigerant loss during servicing. Access valves for recovery of
residual refrigerant in isolated components are also required.
Any piping or segment between two shut-off valves must be
protected by a pressure-relief, in accordance with the B52-M1995
Mechanical Refrigeration Code (as amended from time to time).
Isolation valves should be added, if not present, when vessels
or equipment have to be shut down and evacuated for service.
2.4.2 Piping Practices
Pipelines should always be supported against vibration
stresses, which cause leaks, by being adequately clamped to solid
fixtures. Use insulated hangers for non-ferrous pipe. Vibration
eliminators and expansion bends should be used. Use trombone
bends or sprung hangers for lines too large for vibration
eliminators. Gauges, high pressure and low pressure shut-off, and
oil safety switches should be connected to the main system via
flexible connections so that vibrations are absorbed.
Filter Driers. To prevent leakage, filter driers in the
range of 5 to 20 µm should be used to reduce particulate matter
and avoid damage to the mechanical seal faces and other working
parts of compressors. Similar damage can also be caused to motor
windings and compressor parts of hermetic and semi-hermetic
compressors. A moisture indicating sight glass is strongly
recommended. New systems should have a liquid line filter drier
of sufficient size welded into place at the time of manufacture,
to protect the equipment. Replaceable filter drier cores are
available for larger systems to avoid emissions.
The drier should have isolation and refrigerant recovery
connections. A new filter/drier should be installed, complete
with required valves in the case of a system that is opened to
replace a component that has no filter/drier.
Welding Blanket. Refrigerant should not be used as
welding blanket. Dry nitrogen should be used during welding or
brazing.
Relief Devices. A nonfragmenting rupture disc in
conjunction with a self-reseating type relief valve is
recommended for low pressure refrigerant systems. All relief
devices must be vented to the outdoors.
Three-way Refrigerant Valves. A three-way refrigerant
valve is required to accommodate dual-relief valves on all high
pressure refrigerant machines with a charge of over 50 kg (110
lb), to facilitate repair or replacement. To eliminate emissions
the relief valve setting shall be in accordance with the B52-M1995
Mechanical Refrigeration Code. (As amended from time to
time).
2.5 Air Purge and Pump-down
Systems
2.5.1 Air Purgers
Air purge systems should vent outdoors. When purge systems
operate, some refrigerant is emitted with air and frequent
purging indicates a system leak. High-efficiency purgers will
help to significantly reduce refrigerant purge emissions. In
conjunction with adsorption technology, a 100% capture rate of
normal purge emissions is possible. To correct the problem,
trained qualified service persons must inspect and repair all
leaks in the system. Regular leak testing is essential.
High-efficiency Purgers. Effective on the date of
publication of this document, all new low pressure centrifugal
units using refrigerants such as CFC-11, CFC-113, or HCFC-123
should be fitted with high-efficiency air purgers or other
devices designed to emit less than 0.1 parts of refrigerant per
part of air during usual operation, according to manufacturer's
specifications.
It is recommended that by January 1, 1999, existing chillers
be retrofitted with a new high-efficiency purge or other device
that is designed to reduce emissions below 0.1 kg of
refrigerant/kg of air.
After January 1, 2000, all purge systems should have zero
refrigerant emissions.
Pre-vacuum systems are available to prevent low pressure
systems from going into a vacuum during idle periods. Potential
refrigerant loss or leakage will be reduced; however, leaks
should still be eliminated through proper leak testing and
maintenance.
Residual refrigerant should also be recovered from the purge
exhaust port using the best available technology. Systems to be
shut down more than four months should have the refrigerant
removed and transferred to approved storage vessels or
containers.
2.5.2 Pump-down Equipment
Effective on the date of publication of this document, all new
high pressure refrigeration and air conditioning units with a
refrigeration capacity of 35.2 kW (10 tR) or greater, should
incorporate a fully protected and isolatable liquid receiver to
facilitate pump down during servicing, repairs, or winter lay
ups. A condenser and receiver combination of sufficient capacity
to hold the complete refrigerant charge is also acceptable.
Auxiliary Receivers. If manufactured before the date of
publication of this document, units containing a refrigerant
charge of over 10 kg (22 lb) should be installed with auxiliary
receivers, if required, to hold the complete refrigerant charge
during winter and summer. Units using capillary expansion
control, however, need not necessarily be fitted with an
isolatable liquid receiver. For smaller systems approved
containers can be used.
Shell and Tube Condenser. The previous paragraph on
auxiliary receivers does not necessarily apply to systems
containing a shell and tube condenser if the condenser shell is
on the refrigerant side; is large enough to contain the entire
refrigerant charge; is fully isolatable and is protected by a
pressure-relief device.
Evaporator and Accumulator. The paragraph on auxiliary
receivers does not necessarily apply when the evaporator and/or
liquid accumulator separator can contain the entire refrigerant
charge and is fully isolatable and protected by a pressure-relief
device.
Pump-down Attachments. Large systems may incorporate a
separate pump-down condensing unit and receiver. Compressors and
major equipment should be fitted with suitable refrigerant access
valves to allow connection of a recovery unit for the removal of
refrigerant before service or repair operations or any section of
the system.
2.5.3 Oil Draining
Since refrigerants are soluble or miscible in compressor
lubricating oils, compressor crankcases should be designed for
pumped-down to below atmospheric pressure, before the oil is
removed. High pressure systems should have discharge oil
separators.
2.5.4 Leak Detection and Alarms
Refrigerant analyzers and warning alarms should be
incorporated into the mechanical room design in accordance with
the B52-(latest edition) Mechanical Refrigeration Code, to
detect refrigerant emission.
Refrigerant alarms are not a substitute for actual leak
testing on the system itself. Alarms should always give warnings
before the TLV level for a particular refrigerant is reached.
A regular leak testing program (minimum twice a year) for all
systems is essential. Use industry recognized leak detection
equipment and methods. High refrigerant levels, i.e., greater
than 10 ppm in the compressor room is an indication that one or
more systems are leaking. All compressor rooms should have
refrigerant detectors and alarms.
2.6 Manufacturing
Operations, Refrigerant, and Equipment
2.6.1 Product Stewardship
Refrigerant manufacturers and suppliers should incorporate
product stewardship ("Responsible Care®")
as a part of the corporate ethic, to ensure that their product is
used safely and in an environmentally sound manner.
The Canadian Chemical Producers' Association (CCPA)
"Responsible Care®" program states that:
"A Total Commitment" signifies commitment to the
responsible management of the total life cycle of our products;
from the very beginning in the laboratory to the very end at
ultimate disposal or destruction". This should be adopted
throughout the refrigeration and air conditioning industry.
There are many stakeholders that have a role and
responsibility for the disposal or transformation of surplus
stock of ODS. Leadership from the chemical industry (i.e., the
refrigerant manufacturers) that is consistent with Responsible
Care® should be forthcoming to prevent future
problems. It should be the same type of leadership that industry
initiated for development of new alternatives.
A responsible corporate environmental ethic should not
tolerate leaks of ODS and should incorporate and implement the
best available design, maintenance, and operational practices to
eliminate and prevent leaks.
Components of this program should also include:
- the phaseout of use of CFCs;
- maintaining on-going records of sources and quantities of
emissions;
- a preventive leak detection and maintenance repair
program;
- routine (such as annual) progress and performance
reporting that is readily available to the public; and
- management systems to audit progress and ensure that
programs are in place and working.
2.6.2 Refrigerant Manufacturers
Sources of emissions during the refrigerant manufacturing
process should be eliminated.
The main sources include:
- chemical processing and fugitive emissions;
- bulk loading;
- storage and cylinder filling; and
- laboratory analysis.
The best available technology should be applied in monitoring
and processing refrigerant to prevent emissions.
Emissions of chemicals at the plant level are monitored by
Federal or Provincial Environment Officers with the goal of
pollution prevention.
Chemical Processing. Emissions from chemical processing
can be eliminated or minimized by using technologies or
techniques that include, but are not limited to:
- vapour recovery;
- minimum volume fittings;
- systems using welded piping and fittings, or if not
possible, a minimum number of screwed mechanical joints;
- gaskets specifically designed for the process materials
to prevent leaks;
- transfer hoses/tubing of high integrity and chemical
resistance which are regularly inspected and/or replaced;
- routine inspections and testing for leaks in systems
- online monitors and/or analyzers strategically located in
the operations areas and compressor rooms to detect leaks
and sound alarms should a leak occur;
- maintenance and repair program to respond rapidly to a
detected leak; and
- records maintained and analyzed on leaks and emissions to
determine where improvements can be made.
Some specific examples are:
- ensuring that sample valves do not leak (leak test
regularly);
- do not vent equipment and piping to atmosphere - recover
to low vacuum levels;
- evacuate hoses before disconnecting temporary equipment;
e.g. service equipment or temporary replacement equipment
- check relief valves to ensure they are not leaking;
- ensure process refrigeration systems are leak tight;
systems should not require regular topping up;
- practice recovery and recycling when recharging dryers
and filters; and
- repair the leak before top up.
Storage and Filling Operations. Emissions from storage
and filling operations should be eliminated or minimized by:
- checking storage tank relief valves to ensure they are
not leaking;
- checking pump seals for leaks regularly;
- not venting overfilled cylinders to the atmosphere;
- ensuring that charging hoses for cylinders are
self-sealing when disconnected; and
- totally evacuating cylinders before opening for
inspection.
Bulk Loading. Emissions from bulk loading operations
should be eliminated or minimized by:
- not venting loading hoses from trailers and railcars to
the atmosphere at the plant or customer site; and by
using recovery and recycling equipment;
- customers should have recovery equipment available at the
loading station;
- when switching trailers from one product to another, all
residual refrigerant should be recovered;
- leak checking trailer valves and pumps regularly; and
- all customer bulk installations should be leak tested
once a year minimum.
Laboratory Analysis. Emissions due to laboratory and
analysis should be eliminated or minimized by:
- ensuring sample hoses are self-sealing;
- recovering all unused portions of samples in the
laboratory;
- venting Goetz bulb analysis for volatile compounds to a
chilled vacuum container;
- passing vapour from boiling point analysis through resin
adsorption;
- sealing and keeping samples of liquid refrigerants
sealed; and
- evacuating sample containers and recovering refrigerant
after use.
2.6.3 Manufacturers of Equipment
Deep vacuum evacuation, as per the manufacturers'
specifications should be the only method used to evacuate and
dehydrate refrigerating and air conditioning systems during the
manufacturing process. Systems should be evacuated to 75 µm of
Hg or less.
2.6.4 Holding Charges
Dry nitrogen or dry air (-40 °C dew point) meeting ASHRAE
guidelines should be used as a holding charge, when shipping
equipment.
2.6.5 Cleanliness of Systems
Irrespective of the type of compressor being used, the system
should be absolutely clean to reduce the risk of contamination of
refrigerant and the need for subsequent recharging. All key
personnel involved should be conversant with refrigerant
technology and familiar with the need for zero emission.
2.6.6 Leak Testing
Ozone-depleting substances should not be used as a trace gases
and class one substances (CFCs) cannot be used for leak testing
without recovering all of the leak test refrigerant using the
best available technology. If a leak is found, the system should
be evacuated and repaired before top-up.
Leak Testing Methods. Consideration should also be
given to bubble testing with soap for larger leaks, or by water
immersion. An electronic leak detection device, which will detect
very small leaks, can also be used. Some of the major methods of
leak detection include:
- bubble testing with soap for larger leaks;
- water immersion;
- electronic leak detection; and
- fluorescent dye.
Various electronic leak detectors are
available, most new leak detectors can detect less than
14 g (0.5 oz) per year. Ensure that the detector is
sensitive to the refrigerant to be detected.
If the fluorescent dye method is used, make sure there
is no equipment warranty problem. Sulphur hexaflouride
should not be used for leak testing as it has a high
global-warming potential.
2.6.7 Access Valves
Discharge and evacuation valves should be fitted to
compressors to assist in servicing and maintaining the
installation, with removal of refrigerants to approved
recovery containers.
Control Devices. When a low pressure control is
used as a cycling control, it should be hooked up to a
separate low side access port and not to the normal
access suction service port where practicable.
2.7 Installation and
Servicing
Installation and servicing is the single largest
source of ODS emissions. Principle causes are:
- improper leak testing of new installations;
- venting during installation and servicing;
- failure to repair leaks before recharging; and
- inadequate design and/or improper installation.
2.7.1 Installation of Equipment
Recommendations on the design of pipework and on the
methods of connection can be found in Section 2.1. All
facets of the B52-1995 Mechanical Refrigeration Code
(as amended/updated from time to time) should be followed
and any other applicable codes, dealing with design of
mechanical rooms and ventilation requirements and space
monitoring, adhered to during the siting and installation
of the major components. Special attention should be paid
to access for recovery and recycling.
Visual Inspections. Before installation all
pipework and fittings should be thoroughly examined both
for cleanliness and to ensure that they meet approved
standards.
Metal Filings. No metal filings are to be left
inside the cut pipework since these can cause damage to
shaft seals, compressor bearings, and other internal
components of compressors, leading to serious leaking and
emission.
Flared Tube Connections. Compression type
fittings should be used in preference to flared fittings.
A suitable lubricant should be used between the back of
the flare and the nut to avoid tearing the flare and
allowing the flare nut to be tightened more securely.
Ensure the correct grade of copper tubing is being used
for the pressure and bending requirements of the
installation. This will help prevent future leaks.
Flanged Connections. Only the correct type and
grade of gasket material compatible for use with CFCs,
HCFCs, HFCs and/or other refrigerant products and their
lubricants should be used. Flanges should be tightened
evenly to avoid leaks.
Nitrogen Welding Blanket. Before welding or
brazing pipe joints, dry nitrogen should be allowed to
bleed continuously through the system to eliminate
oxidation. All mechanical joints should be visually
inspected and double checked for tightness before a
nitrogen pressure test is performed.
2.7.2 General Items
Refrigerants should not be vented into the atmosphere
or used in place of compressed air for any purpose. Valve
stem gland caps that cover gauge points and service valve
caps must always be replaced and thoroughly leak tested
after service. Gland packing nuts should not be tightened
unless they are leaking.
Shortage of Refrigerant. A leak test should
always be done upon finding a system which appears to be
short of refrigerant. Some commons points where leaks
appear are:
™B7 flare joints;
- brazed joints;
- compressor gaskets;
- control bellows;
- shaft seals; and
- where there are traces of oil.
The low pressure side of a system should be given a
positive pressure before leak testing the evaporator,
heat exchanger, thermostatic expansion valve, or solenoid
valve. This can be achieved by reversing the cycle if the
system is of the hot gas type.
In a normal application, high and low sides of the
unit equalize on shut down. The static pressure is more
than enough to locate leaks.
On sub-atmospheric applications, the evaporator water
temperature can be raised a few degrees to facilitate
leak testing, taking care not to exceed pressure of the
relief devices.
Belt Drives. The belts on open belt driven
compressors should be thoroughly checked for wear,
damage, and tension. Worn or damaged belts, misalignment,
or over-tensioning can cause compressor shaft seal and
front end bearing failure, resulting in leaks.
Component Isolation. When a leak has been
located, that part of the system must be isolated and
pumped down, using recovery/recycling equipment. If
isolation is not possible, the charge should be pumped
back into the system receiver or into a suitable approved
storage container(s).
Purging Manifold Gauge Sets. Hoses with back
check or isolation refrigerant valves located within 15
to 30 cm (6 to 12") from their end should be used to
minimize emissions. Purge gas must be collected using
appropriate technologies. Non-condensables such as air
from the lines can be recovered using conventional or
adsorption technology.
2.7.3 Cleaning and Flushing
Contaminated systems require cleaning and flushing
after a hermetic or semihermetic compressor failure or
motor burn out:
- cleaning or flushing fluid should be contained within the
confines of the system; and
- procedure must include:
- - recovery of refrigerant,
- - circulation of flushing fluid,
- - recovery of flushing fluid,
- - installation of a new compressor,
- - new suction line filter drier,
- - a leak test, and
- - evacuation and dehydration of the system.
New, recovered, recycled, or reclaimed refrigerant is
then charged back into the system for circulation and
final cleanup to remove trace contaminants.
Cleaning and Flushing of Large Systems. On
large systems, isolate as many sections of the system as
possible. Remove contaminated refrigerant to approved
recovery containers. Clean each section separately, or
when the system is empty, the component parts should be
removed, capped off and taken off site for cleaning. The
cleaning should be carried out using a non- ODS as a
cleaning agent.
Passive Recovery. Passive recovery on small
systems using the unit compressor and a bucket of ice is
no longer an acceptable practice.
Recovery Equipment Standard. All recovery
equipment should, as a minimum, meet the ARI 740-93
standard or other standards or guidelines recommended by
federal/provincial agencies as amended or updated from
time to time, for extraction efficiency (see Appendix A).
System Dehydration. After the cleaning
operation is complete, the major component parts should
be reassembled into the system with the new compressor.
The system should be drawn into a deep evacuation of 500
µm of Hg or less and the discharge from the vacuum pump
recovered using the best available technologies.
2.7.4 Service Records
An up-to-date service record should be kept close to
the equipment or with the owner and should be made
available for inspection by the proper authorities. This
should include details on leak testing and quantities
charged or recovered.
2.8 Conversion of
Systems to an Alternate Refrigerant
2.8.1 Alternate Refrigerant
System or equipment conversion to a refrigerant with a
significantly lower, or zero ODP is one of the best ways
to reduce ODS emissions. It is cheaper than equipment
replacement. Ultimately all CFC equipment will have to be
converted or replaced.
Owners of a large number of systems should develop a
long-term strategic plan. This applies to both high
pressure and low pressure equipment. Selection of
suitable alternative refrigerant should be made by a
qualified person. Consult refrigerant manufacturers
and/or a consulting engineer.
Alternative refrigerants should be examined for effect
on efficiency and capacity as well as effect on motor
windings, gaskets, and seals. In addition, for flammable
refrigerants or blends, check the Canadian Electrical
Code, the B-52 code, CSA, and building code. Highly
flammable refrigerants may require systems to be re-wired
to meet explosion proof requirements.
2.8.2 Selection of Equipment
Generally, equipment for conversion should be less
than 20 years old to avoid early replacement cost.
The equipment and system should first have a thorough
leak test and all leaks repaired. A performance test or
check should be done on the equipment. A review of the
energy efficiency of old versus new may be part of the
equation.
2.8.3 Prevention of Emissions and Leaks by
Preplanning
Leaks can be prevented by ensuring that the system
will be tight after conversion. Existing seals and
gaskets should be checked to be sure they are compatible
with the new refrigerant and refrigerant oil. If the
system is hermetic, motor winding compatibility should
also be verified. Any other plastic or elastomeric parts,
such as tubing, should be checked for compatibility. The
type of oil to be used should be verified so that proper
system cleaning can be done before conversion.
Prevention of Emissions and Leaks During Conversion.
To prevent leaks during conversion, qualified service
persons with experience in equipment conversion should be
used. After the system has been shut down and is at room
temperature, recover all refrigerant and put it in
approved recovery containers. Use approved recovery
equipment. Oil in the crankcase should be heated to
vaporize residual refrigerant which should be recovered.
For low pressure systems the evaporator temperature can
be raised using hot water.
Evacuate the system to <75 µm of Hg by using
a vacuum pump and pass the discharge through a resin
adsorption system. If necessary, flush the system in
accordance with the refrigerant and equipment
manufacturers' recommendations.
Dismantle the system and change any gaskets or seals,
etc. as necessary. This is best done one section at a
time.
It is usually best to replace any removed gaskets with
new ones which are compatible with the new alternative
refrigerant and oil to prevent leaks.
Install recovery connections and valves where required
(one per section) and then do a second low vacuum leak
check. If the system is leaking, check all joints,
valves, and connections and tighten as required, until
the unit is leak free.
Slowly add refrigerant, to pressurize the system, one
section at a time. Leak check each section with an
electronic leak detector before proceeding to the next.
If there is a leak in any section recover all the
refrigerant and repair the leak before proceeding.
Once the system has been fully charged with the
correct amount of refrigerant and oil, run the system for
the recommended time and do another leak check. The
weight of the old refrigerant recovered should be logged.
The used refrigerant should be retained for other
systems or returned to the supplier for a credit, (see
Section 2.9). Re-label the system to indicate the amount
and type of both new refrigerant and oil. Recheck for
leaks after 24 to 48 hours operating time.
2.8.4 Equipment Replacement
Equipment replacement is available when the previous
CFC equipment is no longer serviceable or has outlived
its useful life. Suitable long-term alternative
replacement refrigerants would be the logical choice for
the new equipment.
2.9 Recovery, Reuse,
and Disposal of Refrigerants
2.9.1 Venting
Venting of any refrigerant, other than water, to the
atmosphere during manufacturing, installation, operating
or servicing should be prevented by practicing due
diligence and the recovery, recycling and reuse of
refrigerant. Owners are responsible for the maintenance,
operation, and security of their equipment - as well as
ensuring operators are adequately trained.
2.9.2 Performance Testing
When refrigerant is used in performance testing of
units or systems in both development and production
operations only Transport Canada approved recovery
cylinders can be used to capture refrigerant that would
otherwise escape to the atmosphere.
2.9.3 Installation and Servicing
Manufacturers may use auxiliary receivers or specially
approved "ton tanks" to recover larger
quantities of refrigerant from refrigeration and air
conditioning equipment to facilitate the reuse of the
refrigerant charge following servicing.
Small Self-contained Systems. In smaller
capacity equipment it is not usual to fit receivers and
provide pump-down capability. In such cases only approved
recovery cylinders, or approved refrigerant drums for low
pressure refrigerants, may be used for the temporary
storage of recovered refrigerants.
Cylinder Hazards. Hazards may arise as there
are safety issues in the use of refrigerant containers as
storage vessels. A refrigerant container is a pressure
vessel if its capacity is greater than 28.32 L (1 ft3).
All approved containers should be designed to meet the
Canadian Transport Commission (CTC) specifications. The
design maximum working pressure should not be exceeded in
any filling operation, however temporary. An approved
container should not be filled to more than 80% of its
normal refrigerant capacity, when used for recovered
refrigerant.
Cylinder Specifications Under the Transportation
of Dangerous Goods Act
(TDGA). All cylinders must meet the appropriate
specifications listed in the Transportation of
Dangerous Goods Act. All cylinders should be properly
labelled as to content and weight, as required under TDGA
with the appropriate Workplace and Health Material
Information System (WHMIS) language and labelling.
The design specifications and pressure rating should be
stamped on the cylinder.
Refrigerant/Oil Mixtures. Refrigerant/oil
mixtures have a lower density than refrigerant alone, and
so, the weight carrying capacity of refrigerant
containers will be reduced for refrigerant/oil mixtures
compared to pure refrigerants.
Filling Approved Recovery Cylinders. Never
store cylinders near any source of heat or where
temperatures could exceed 51.7°C (125°F). Approved
cylinders should only be filled to 80% of their fill
capacity by weight for normal ambient temperatures of
around 21°C (70°F) and should not be filled beyond 60%
if the temperatures could reach 48.9°C (120°F).
Corrosion may occur if contaminated refrigerant is
decanted into a refrigerant container.
Container Belonging to a Third Party. If a
refrigerant container belonging to a third party (e.g., a
refrigerant manufacturer), is to be used as a temporary
receiver, written permission of the owner of the
container must be obtained in advance.
Recovery Cylinders. Recovery cylinders (have a
broad yellow band and ASHRAE designated colour) must be
inspected and hydrostatically retested every five years
by the owner. Virgin cylinders usually only have a
one-way valve and cannot be used to store recovered
refrigerant, because they should not be contaminated.
2.9.4 Recovered Refrigerant, Reuse, and Disposal
Refrigerant removed from working equipment must be
recovered, reused, and recycled by the service person or
sent to the supplier for reclaim or disposal.
Alternatively, it may be sent to an independent reclaimer
or to a licensed disposal facility.
A recovery unit does not bring refrigerant to a new
level of purity. The refrigerant should only be returned
to the same refrigerant system or a similar system of the
same owner. If the refrigerant is to be used elsewhere,
only recycling equipment meeting the ARI 740-93 and ARI
700 standard, latest edition or other standards or
guidelines recommended by federal/provincial agencies is
acceptable to ensure that Original Equipment Manufacturer
(OEM) equipment warranties within the industry are valid
(see Appendix A).
A service person or equipment owner/operator who
recycles a refrigerant using his/her own equipment should
ensure that the equipment is intended for the type of
refrigerant being processed, and that it will clean the
refrigerant to meet the industry recognized standards.
Recycling machines must meet the ARI 740-93 and ARI 700,
latest edition, Purity Standard or other standards or
guidelines recommended by federal/provincial agencies if
OEM equipment warranties are to be valid.
An external agency that recycles or reclaims used
refrigerants should ensure that the equipment it uses is
functioning properly and the recycled or reclaimed
refrigerant meets at least the recognized industry
standards (ARI 700; should be verified by laboratory
analysis) (see Appendix A). If facilities are available,
refrigerant that cannot be reused should be returned to
the refrigerant manufacturer to be destroyed or reclaimed
by an approved facility.
2.10 Handling and
Storage of Refrigerants
Refrigerant can be lost to the atmosphere during the
handling and storage of refrigerant containers. Some
sources of emissions are faulty valves, pin-hole leaks,
and improper closing of bungs and valves on drums.
Refrigerant Storage. Refrigerant containers
should be stored in a cool dry place, away from risk of
fire, and sources of direct heat. Areas where large
quantities of refrigerant containers are stored should be
monitored.
Refillable Refrigerant Containers. Effective
the date of publication of this document, only refillable
refrigerant containers should be filled in Canada or
imported into Canada by those who are registered to
import refrigerants under the Canadian Environmental
Protection Act (CEPA).
Pressure Testing of Hoses and Equipment. Hoses
and gauges should be pressure tested to prevent
refrigerant emissions to the atmosphere. Dry nitrogen
should be used to pressure test the hoses and gauge
manifold for leaks at regular intervals before they are
attached to a system.
Charging Lines. Charging lines should be as
short as possible and fitted with either back check
valves or an isolation valve within 15 to 30 cm (6 to
12") of the end of the charging lines.
Refrigerant Transferred. Refrigerant
transferred to a sealed system should be metered by
either weight or volume using approved weigh scales or a
volumetric charging device. The use of quick disconnect
fittings having one-way valves is strongly recommended.
Charging Cylinders. Charging cylinders may be
used to charge or recharge air conditioning or
refrigeration systems and should not be used as storage
vessels to transport new, used, recycled, or reclaimed
refrigerant from the shop to the job site.
Refrigerant Container Handling. Containers
should be handled carefully and not dropped to prevent
mechanical damage to the container and its valve. When
not in use, container valves should be closed, and the
valve outlet cover nut or cap screwed on.
Refrigerant containers should not be manifolded
together if there is a possibility of temperature
differences existing between them, since this will result
in refrigerant transfer and the danger of overfilling the
coldest container. Where containers are manifolded
together, care should be taken that all containers are
the same height to avoid gravity transfer between
containers. These items constitute safety hazards as well
as sources of leaks.
Refrigerant Transfer Between Containers.
Refrigerant should be carried out in a way that is safe
and will prevent any chances of release or over-filling
when refrigerant is transferred from one container to
another.
A pump and weight scale should always be used.
Establish a pressure differential between the containers
using a pump or by heating of discharging container under
controlled conditions. Heating of the discharge container
must be of an indirect method (warm water or forced warm
air) to a maximum 49°C (120°F). Under no circumstances
should direct heating of any type be used, with the
exception of plug-in charging cylinders (dial-a-charge).
The maximum carrying capacity, when filling
refrigerant containers, is a function of the internal
volume of the container and the liquid density of the
refrigerant at a reference temperature.
Service personnel removing refrigerant for recovery
have no practical way of determining the density of a
given refrigerant charge. (Under ideal room conditions
(21°C or 72°F).) A good rule of thumb is to not exceed
80% of the maximum net weight capacity as stamped on the
upper portion of the cylinder. The receiving container
should be on a portable scale to ensure over-filling does
not occur.
2.11 Records
Up-to-date records should be kept detailing the
transfer refrigerants by type and quantity, between
various containers and refrigeration systems.
Accurate records of the contents of refrigerant
storage containers (type, quantity, transfer in, transfer
out) should also be kept. Be sure cylinders are properly
labelled as to the content and weight.
It is prudent to practice due diligence by keeping
proper records and getting the best information available
in handling refrigerants. Some provinces require that
annual records be maintained and consumptions reported.
Some provinces also require that emissions or spills over
a certain weight, usually 10 kg (22 lb) be reported to
the local authorities.
Recommendation: It is recommended that annual
consumption records of all refrigerants [including
spillage of 10 kg (22 lb) or more] be maintained for a
minimum of three years. Corrective actions taken as a
result of spills should be documented. All releases or
spills of 10 kg (22 lb) or more should be reported to the
authority having jurisdiction.
2.12 Disposal
of Equipment
As soon as the decision to retire equipment containing
a refrigerant has been taken, the owner should arrange
for full pump down of both refrigerant and oil. The
equipment should then be labelled as containing no
refrigerant, by a certified service technician.
2.12.1 Decommissioning
Decommissioning of working equipment or mothballing of
equipment that may be required for future use should
include:
- removal of all refrigerant into approved recovery
approved containers for retention, or returned to
the supplier or manufacturer for reclaiming;
- charging of the closed loop with dry nitrogen to
help prevent contamination of the system; and
- inspection of the equipment at regular intervals
to ensure that adequate pressures are maintained,
to prevent contamination.
2.12.2 Decommissioning of Smaller
Equipment
Equipment or systems should be properly labelled to
indicate they are empty. In some provinces, a 5-cm green
or yellow label is attached to decommissioned equipment
with the service person's certification number on it.
This policy should be adopted across Canada by January 1,
1997.
Smaller air conditioning and refrigeration equipment
should be stored inside heated building, be certified
leak free and inspected annually by a properly trained,
certified person. The equipment owner should have the
refrigerant removed and stored in approved cylinders if
the owner intends to keep the unit in a decommissioned
state for more than four months.
2.12.3 Receiver Condenser
The refrigerant charge on larger equipment should be
pumped down and isolated in the receiver or receiver
condenser storage, providing valves are holding and there
is a pressure relief device to protect the vessel in
accordance with the appropriate code requirements.
2.12.4 Equipment Disposal
Refrigerant and oil must be recovered from equipment
before disposal. The owner or a representative should be
able to show proof that the guideline or provincial
regulation has been satisfied by presenting a copy of the
completed work order to the metal shredder or the land
fill operator before the equipment is removed for
disposal . Appendix B shows a sample of a label that can
be used to identify equipment that is refrigerant free.
Oil must also be recovered and properly disposed of.
Building Demolition. The owner (or
representative) of a building containing equipment which
used refrigerants for its operation should show proof
that the appropriate guideline or provincial regulation
has been followed before demolition. In some cases, the
local "permit for destruction" or demolition
may already ask if the building contains refrigeration or
air conditioning equipment. Only those persons who have
been properly trained in the safe handling of
refrigerants may recover the refrigerant. Residual oil
must also be recovered for disposal or recycling.
2.13 Environmental
Awareness Training
Environment Canada, provincial, and territorial
authorities have recognized two environmental awareness
training courses. The Environment Canada course was
developed to provide consistent understanding of the
environmental issues of ozone depletion and pollution
prevention as it pertains to the Air Conditioning and
Refrigeration Industry.
2.13.1 Training of Individuals
Handling CFCs, HCFCs and HFCs
There is a general need for continuing the delivery of
environmental awareness training programs. To provide
consistent training nationally, large companies, trade
associations, labour organizations, community colleges,
and other provincially recognized learning institutions
across Canada have developed curricula which include
environmental awareness training programs.
2.13.2 Environmental Awareness
Card and Certification
The Provincial Ministers of Labour and Ministers of
Education are responsible for TRADE QUALIFICATIONS. The
Ministers of the Environment are concerned about
pollution prevention and refrigerant emissions to the
atmosphere.
The Environmental Awareness Card is issued on behalf
of Provincial Ministers of the Environment to all service
persons who have taken an environmental awareness course
in accordance with the applicable provincial regulations.
This card should be carried at all times and is required
in order to purchase refrigerant in most provinces.
The Environmental Awareness card is not a Trade
Qualification Certificate (or permit) and does not allow
those persons, not permitted by other regulations, to
work in the refrigeration or air conditioning trade.
2.13.3 Standardized Training of
(Apprentice) Service and Repair Persons
A number of provinces have adopted the environmental
awareness training program as a course component of their
provincial trade school training programs.
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