Replacement of Chlorinated Solvents (CFCs, CTCs, MCFs)

More documents

Recommendations

Info

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
Page 1: ﻲـــــﻨﻓ دﺎــــ
Page 5 and 6: cleaned parts. Using deionized proc
Page 7: Further information is available at

Replacement of Chlorinated Solvents (CFCs, CTCs, MCFs)

Create successful ePaper yourself

Delete template?

Save as template?