DUBAI MUNICIPALITY

ENVIRONMENT DEPARTMENT

ENVIRONMENT PROTECTION & SAFETY SECTION

إرشادات فنيــةTechnical Guideline

بلدية دبي إدارة البيــــئة

قسم محاية البيئة و السالمة

Technical Guideline No. 55

Replacement of CFCs in Degreasing and Cleaning

Introduction: CFC-113(Chlorofluorocarbons), carbon tetrachloride and methyl chloroform are used extensively in general metal part cleaning in a wide range of manufacturing and maintenance processes throughout the industry. Solvent use is integral to many production processes, removing organic compounds such as grease and oils, particulate matter and inorganic contaminants from metal surfaces and preparing parts for subsequent operations such as assembly, coating, electroplating, inspection and packing. 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 instruments and surfaces. Carbon tetrachloride and methyl chloroform is widely used in general metal part cleaning. 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. 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 containing CFC-113, 111- Trichloroethane(also known as methyl

chloroform), and carbon tetrachloride that are classified as ozone depleting substances shall not be used from January 01, 1996.

2. 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 solvent degreasing and cleaning systems.

3. Alternative substances which have low ozone depleting potential including but not limited to those listed in the Table below shall be used in cleaning and degreasing activities.

Fluorocarbon Compounds Non-Fluorocarbon Compounds Substances ODP Substances ODP

HCFC - 225ca HCFC - 225cb HCFC-141b/HCFC-123/ Methanol Blend

0.025 0.033

0.08 - 0.13

Isopropanol Methylene Chloride Pentafluoropropanol(5FP) Perchloroethylene trichloroethylene

0 0 0 0 0

Non-Aqueous Solvents 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 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 Alcohol 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 Sytems In aqueous cleaning, water is the primary solvent. Surfactants, synthetic detergents, and other additives enhance the cleaning process. 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. 4. Industries 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 Protection and Safety Section for documentation .

For further information contact Environment Protection and Safety Section

Tel : 2064244 / 2064245 Fax : 2270160