The goal of this exercise is to help you learn the superstructure for feasibility reports.

The Exercise

Complete the Revision Checklist for Feasibility Reports as you examine the report below.

The Report

NORTHWEST ENGINEERING CONSULTANTS
Interoffice Memorandum

Purpose

This report discusses my study of alternatives to CFC-113 (an ozone-depleting chloroflurorocarbon) for cleaning circuit boards in our lab. I have analyzed and tested five potential alternatives. The results of that work indicate that the best substitute is alcohol, which this report recommends.

Background and Problem

Our electronics assembly lab uses CFC-113 to clean flux off its circuit boards. Because of the ozone-depleting characteristics of CFCs and the anticipated legislative restrictions on their use, you asked me to investigate inexpensive, environmentally safe alternatives to CFC-113 and to recommend the one best suited for our use.

Potential Alternatives

In my research I found five candidate cleaners to replace CFC-113:

Terpenes—oily chemicals from the citrus family.

Deionized water—in solution with small amounts of alcohol.

Alcohol—a mixture of ethanol and isopropanol.

Lemon Juice—a mixture whose primary ingredient is lemon juice.

HCFC-141b—a cousin of CFC-113 but much less damaging to the ozone layer.

Discussion of Evaluation Results

I evaluated each of these alternatives in terms of effectiveness, environmental friendliness, availability, disposability, cost, and safety.

Cleaning Effectiveness—Each candidate cleaner was tested at one of our cleaning stations. In the tests we washed twenty circuit boards with each cleaner and evaluated both the wash time it took for the cleaner to bring the board to our standards of cleanliness and the consistency with which the cleaner maintained those cleanliness standards on repeated trials. Although all candidates were able to clean the boards effectively, alcohol had the shortest cleaning time and the highest consistency.

Environmental Friendliness—The only candidate that has known adverse effects on the environment is HCFC-141b. When released into the atmosphere, it is reported to contribute to the "greenhouse effect," a significant cause of global warming.

Costs—Based on our current usage data for cleaning fluids, the following annual operating costs were determined:

In addition, both HCFC-141b and terpenes require all cleaning stations to have sealed tanks, which will cost $5,000 per station to install.

Availability—Although I was unable to obtain any data on availability, I do not foresee any problem obtaining the chemicals that make up deionized water or alcohol. These chemicals are common and easily obtainable. Because the lemon-juice mixture is a relatively new invention, it may be hard to obtain if future demand is not high. Likewise, HCFC-141b and terpenes may also be hard to obtain because their high costs may cause companies to seek less expensive alternatives, thereby reducing demand and driving up prices until these cleaners are taken off the market.

Disposability—Terpenes is the only cleaner that creates problems with disposal. Because it ignites at relatively low temperatures, it cannot be put into the sewer system. Therefore, it must be treated as hazardous waste although it is not a safety hazard when used at our cleaning station.

Safety—All candidate cleaners are safe to store in our warehouse and safe to use in our cleaning station. Only alcohol requires any special monitoring procedures in storage because it has a limited shelf life. However, with minimum procedures and purchasing controls these special requirements can be easily met.

Conclusions and Recommendations

Although all candidates can effectively clean our circuit boards, some alternatives are clearly better than others. HCFC-141b contributes to the greenhouse effect, costs significantly more than other alternatives, and may not be available in the future. Terpenes is also very expensive, which makes its future availability questionable; it is also difficult to dispose of and requires special handling. Lemon juice is least expensive but so new that very few companies are using it, making future availability a question. Finally deionized water and alcohol are both inexpensive, environmentally safe, and easy to dispose of; however, alcohol proved to be much more effective in our lab tests. Although some special storage controls are required for alcohol, these are easily implemented. Therefore, I recommend that we replace CFC-113 with alcohol in our circuit-board cleaning stations.