Replacement of Chlorinated Solvents (CFCs, CTCs, MCFs)

ﻲـــــﻨﻓ دﺎــــﺷرإ
TECHNICAL GUIDELINE
Number
( 12)
لﺎﻤﻋأ ﻲﻓ ﺔﻣﺪﺨﺘﺴﻤﻟا ( CFCs, CTCs, MCFs ) ةرﻮﻠﻜﻤﻟا تﺎﺒﻳﺬﻤﻟا لاﺪﺒﺘﺳا
مﻮﺤﺸﻟا ﺔﻟازإو ﻒﻴﻈﻨﺘﻟا
Replacement of Chlorinated Solvents (CFCs, CTCs, MCFs)
for Degreasing and Cleaning
April
2011
ﻢﻗر
ﻞﻳﺮﺑأ
ﺔﺌــــﻴﺒﻟا ةرادإ -ﻲﺌﻴﺒﻟا
ﻂﻴﻄﺨﺘﻟاو تﺎﺳارﺪﻟا
ﻢﺴﻗ
Environmental Planning and Studies Section (EPSS)
Environment Department

Introduction:
The Montreal Protocol on substances that deplete the Ozone Layer that is
adopted in 1987, establishes specific limits on production and consumption
levels and deadlines for reduction and elimination of these substances for
cleaning and degreasing activites.
The solvents controlled by the Montreal Protocol are: chlorofluorocarbons (i.e.
CFC-113, trichlorotrifluoroethane), carbon tetrachloride (CTC), methyl
chloroform (MCF-only 1,1,1-trichloroethane) and hydrochlorofluorocarbons
(i.e. HCFC-225, HCFC-123, HCFC 141b). These chemicals have high ozone
depleting potential(ODP) which have contributed to the depletion of ozone
level in the upper atmosphere. The ozone layer protects us from the harmful
effects of ultraviolet(UV) radiation from the sun.
The CFC-113, CTC and MCF are used extensively in general parts cleaning
in a wide range of manufacturing and maintenance processes throughout the
metal or plastic industry. Solvent use is integral to many production
processes, removing organic compounds such as grease and oils, particulate
matter and inorganic contaminants from metal or plastic surfaces and
preparing parts for subsequent operations such as assembly, coating,
electroplating, inspection and packing.
The CFC - 113 due to its low toxicity, non-flammability and stability make it
attractive for use as solvent. It is widely used in the electronics and other
similar industries to clean delicate surfaces and precision instruments. Carbon
tetrachloride and methyl chloroform is widely used in general metal part
cleaning.
This guideline sets out the general requirements in the replacements of ozone
depleting CFCs and solvents in degreasing and cleaning industries.
Guidelines:
1. All substances that are classified as high ozone depleting substances such
as CFC-113, 111-Trichloroethane(also known as methyl chloroform), and
carbon tetrachloride that are used in cleaning and degreasing shall not be
used from the dates stated below.
Date
Table 1: Chlorinated Solvent Phaseout
Controlled Substances
CFCs and Carbon Tetrachloride (CTC) phased
January 01,2010 out
January 01,2015
Methyl Chloroform (MCF) phased out
HCFC reduction by 10%
January 01,2020 HCFC reduction by 35%
January 01,2030 HCFCs phase out
2. Any industry using the controlled substances should prepare an inventory
and phase-out program in order to comply with the latest phase out

schedule as shown in Table 1. The inventory and phase out program must
be submitted to Environmental Planning and Studies Section for
documentation.
3. Industries should examine whether there is a need to clean items at all
and whether water based caustic systems can be used before considering
vapour and non-vapour solvent degreasing and cleaning systems.
4. Cleaner technologies now exist or are being developed that would reduce
or eliminate the use of ozone depleting substances for cleaning and
degreasing operations. The two main strategies are ;
a. Alternative substances or materials that have low or zero ozone
depleting potential including but not limited to those listed in the Table
2 shall be used in cleaning and degreasing activities.
b. Process changes that use different technologies for cleaning or that
eliminate the need for cleaning as described below.
Table 2: Alternative Solvents for Cleaning and Degreasing
Fluorocarbon Compounds Non-Fluorocarbon Compounds
Substances ODP Substances ODP
HCFC - 225ca
HCFC - 225cb
HCFC-141b/HCFC123/
Methanol Blend
Non-Aqueous Solvents
0.025
0.033
0.08 - 0.13
Isopropanol
Methylene Chloride
(Dichloromethane)
Pentafluoropropanol(5FP)
Perchloroethylene
(PERC)
Trichloroethylene (TCE)
Hydrocholorofuorocarbons Solvents (HCFCs)
To date, the HCFC-225ca and HCFC 225cb seem that the physical properties
are remarkably similar to those of CFC-113 in most respects. Their
ODPs have been calculated as fairly low, certainly less than 0.1,
possibly even 0,05. Other possible HCFCs include HCFC-141b
and HCFC-123. These have estimated ODPs of 0.08 - 0.15 and 0.02 -
0.05 respectively.
Fluorinated Solvents
Hydrofluorocarbons(HFCs) seem reasonable as fluorocarbons have a very
small light reactivity and hydrofluoprocarbons mostly breakdown in the
troposphere. HFCs have been proposed to dilute other solvents in order to
allow blend to approach more suitable characteristics for specific
cleaning applications to render it more inert or to artificially lower the ODP.
The pentafluoropropanol may have useful characteristics for degreasing
delicate parts.
Chlorinated Solvents
0
0
0
0
0

Perchloethylene and trichloroethylene have been both very low ODPs,
probably less than 0.01.They can be used with reasonable safety as far
as the ozone layer is concerned but they are both considered as
chronically toxic and probably carcinogenic. If they are used, the workers
should be protected to the maximum.
Chlorocarbons and Hydrocarbons
Chlorinated solvents should not be considered as general substitutes for
CFC-113. They are stronger solvents and have similar applications to
CFC-113 for degreasing most metal parts, but they are less suitable for use
on many synthetic polymers.
Hydrocarbons
Light hydrocarbons are all toxic and flammable. Heavier hydrocarbons with
higher flash and boiling points can also be quite effecient solvents if
handled correctly. Their low vapour pressure which renders them safer to
use also makes drying problematic.
Alcohol and other hydrocarbon derivatives
Alcohols are excellent solvents for many applications, including certain
defluxing operations. They do require enormous and expensive precautions to
be taken before they can be used for large scale industrial cleaning. First of
all, they are flammable with flash points between 12° and 15°. Isopropanol is
cheap, easy to obtain and not excessively toxic. A propanol/water azeotrope
is suggested for some applications. Other derivatives employed for cleaning
purposes include various ketones, esters and occasionally, ethers.
Alcohols are smog precursor that some controls may be applied to their
emissions.
Hydrocarbon/surfactant blends
If the solvent is blended with a surfactant or detergent, then it can be washed
off with water, which, in itself, is sufficiently volatile that it can be dried of. The
most important one is that the contaminated rinse water are properly disposed
of.
Aqueous Systems
In aqueous cleaning, water is the primary solvent. A combination of water
conditioners, detergents and surfactants are added to promote better cleaning
of the metal object. In addition, special additives such as builders, pH buffers,
inhibitors, saponifiers, emulsifiers and deflocculants can be added to meet the
desired cleaning requirements. Tap water is usually sufficient for the initial
stages of aqueous cleaning followed by deionized water in the rinse stages.
Advantages may include: safety; effectiveness; low cost.Disadvantages may
include: cleaning difficulty in small crevices; difficulty in rinsing; difficulty in
drying; requirement for high purity water; high energy consumption(heating);
and waste water disposal. Ions present in the water such as calcium and
magnesium can cause corrosion problems or allow deposits to form on

cleaned parts. Using deionized process water, incorporating the use of
thorough drying stages, and applying appropriate rust and corrosion inhibitors
Semi-Aqueous Systems
Semi-aqueous cleaning products have demonstrated their efficiency to
remove waxes, heavy greases, tar and baked on organic materials. Generally
semi-aqueous cleaners are effective at room temperature and they possess a
very low evaporation rate which infers low use cost and low VOC emissions.
The most common semi-aqueous cleaners include terpenes and petroleum
based hydrocarbons. Terpenes are compounds derived from the natural
extracts of a variety of plants, such as certain tree barks and citrus fruit skins.
Generally terpenes are biodegradable and noncorrosive. These
characteristics make them attractive alternative cleaners. A terpene cleaner is
used typically in a cold cleaning tank. The part is immersed in the tank with
agitation and then usually placed in a hot solution and dried.
Several disadvantages are associated with some semi-aqueous cleaning
products. The biggest concern is flammability. Several semi-aqueous
cleaners have low flash points and become extremely volatile when sprayed.
Health effects associated with the use of terpenes are still unclear. Several
terpenes have been found to be a carcinogen among certain laboratory
animals, but results are inconclusive for humans.
Dry Ice Blasting
This technology uses solid pellets of carbon dioxide as a blasting medium for
cleaning metal parts. This process uses dry ice pellets which return to their
gaseous state on impact, reduces harmful air emissions and enhances worker
safety. The process relies upon thermal shock, velocity and the lateral
delivery of kinetic energy. When the dry ice pellets impact the surface, the
drop in surface temperature helps to pierce the contaminant or residue. Once
contact is made with the base the kinetic energy acts laterally along the base
surface lifting the residue away. The system's cleaning performance is
optimized by controlling the pellet size, hardness, and quantity. In addition,
the speed or flow can be controlled to tailor the system to a specific cleaning
medium. In-process machinery, welding equipment, and turbines can now be
cleaned on-line. This means less down-time for relocation, disassembly and
masking
The carbon dioxide pellets disintegrate upon impact and dissipate to the
atmosphere. As a result, spent solvent does not need to be disposed.
Hazardous wastes such as leaded paints, PCBs and asbestos can be more
easily encapsulated and disposed. Because there are no liquid solvent
residues left behind, the process is considered dry, making it versatile for
many applications. Also, there is generally no addition to the volume of the
produced waste stream for the cleaning process. For example, if solid carbon
dioxide blasting is used for paint removal, the pellets sublime leaving the
removed paint behind. The paint residues alone can then be collected,
resulting in the smallest amount of waste. Since waste volumes are
minimized, so are the costs associated with waste removal and disposal

Vacuum De-Oiling
A new process on the market is vacuum de-oiling, an operation that removes
surface oils from parts without using ozone-depleting or hazardous chemicals,
water or detergents. Thermal and vacuum technology remove the oil residue
on parts through vaporization. Once the parts have been loaded the heater
and pump are actuated to warm and evacuate the unit's chamber. The oil's
boiling point falls with pressure so heating it in a slight vacuum dries the part
quickly. The system is not designed to clean materials that do not evaporate
quickly such as a solid lubricant. In most cases parts can be cleaned through
this one-step process in about 20 minutes or less. The vapors are condensed
and collected for reprocessing or recycling. Hazardous waste disposal costs
are reduced or eliminated in this process
5. The use of solvents in cleaning and degreasing operations produce high or
low emissions of volatile organic compounds (VOCs) that requires to be
controlled for the safety of the workers as well as protection of the air
environment. The following shall be done to minimize the emission of
VOCs;
a. For non-vapor degreasers using volatile solvent, or solvent that is
agitated, the cover should be a sliding, rolling or guillotine (bi-parting)
type which can be opened and closed easily with one hand.
b. For open-top vapor degreasers, the cover should be a sliding, rolling or
guillotine (bi-parting) type which can be opened and closed easily
without disturbing the vapor zone.
c. For conveyorized degreasers, a cover shall be provided for closing off
the entrance and exit during shutdown hours.
6. In order to determine the best cleaning and degreasing alternative(s), the
four general areas are to be investigated;
a) Governmental regulations – emission control and limit of discharges
b) Technical feasibility – new process to meet required production, ease of
installation, operation and maintainance.
c) Process economics - compare the economics of various cleaning
alternatives costs associated with initial capital equipment; process operation;
permit applications; and waste treatment, storage, and disposal. Process
operation should include material, labor, maintenance, and utility costs
d) Environmental, Health, and Safety - compatibility with regulatory trends,
public perception about cleaning chemicals and associated risks, global
warming potential of alternatives, energy efficiency, toxicity and worker
safety, flammability, and emissions, effluents, and wastes generated

Further information is available at
Environmental Planning and Studies Section
℡ 04-6066809 / 6066814; Fax: 04-7033565
Or
Visit the Dubai Municipality Website at:
www.dm.gov.ae