IN THE PREVIOUS COLUMN we discussed the overwhelming scope of standards. While the process, product, chemical, or materials of construction meet certain required and/or agreed upon standards, the ultimate goal is rugged, reliable product performance.
Questions to Ask About Standards
Standards take on a life of their own, moving from one set of build instructions to the next. The number of standards multiplies with each generation of product. In the interest of lean manufacturing and contamination control, it is helpful to periodically step back from a given set of process instructions and critically evaluate the profusion of standards. We suggest you do the same. Some questionsto ask are:
- What is the source of the standard?
- Is it required?
- Should it be required? Is it superfluous? Can you eliminate it?
- Does the standard reflect current technology?
- Is it currently relevant to my product?
- Are there newer standards that are more geared to my application?
- Is the standard sufficient to achieve the required performance?
- Is it realistic?
- Is the safety or environmental standard sufficient to meet the requirements of your local geographical area?
- Does the standard have a potential negative effect on the product? If so, should the standard be negotiated?
- Should additional standards and controls be adopted?
Once a standard is adopted, it tends to stay. Forever! This is not necessarily beneficial. For example, chlorinated solvents can break down in the presence of water. Free chlorine is very reactive and it can compromise both the cleaning equipment and the product; therefore chlorinated solvents are routinely analyzedto assure that free chlorine stays below a specified level.
At one point we worked with a group that had used chlorinated solvents for decades; they then switched to an alternative solvent that contained no chlorine and did not even use chlorine as a feedstock.
Nevertheless, the notion of testing for free chlorine content was so ingrained, that this manufacturing group insisted on determining the free chlorine content of the non-chlorinated solvent. In vain we explained the lack of relevance, but they insisted. Why? Because they were doing a critical process, and they knew that the process worked if they tested for free chlorine. This is an example of where a previouslyvalid standard had turned into a non-functional superstition.
There are several problems with continuing to test to the free chlorine standard. For one thing, analyses are not free; unwarranted standards add to the production costs. In addition, the group would be left with a false sense of security, because the new product would always conform to the standard. In this instance, the most tactful and expeditious approach was to continue to test for free chlorine while gradually introducing standards that were more relevant to the non-chlorinated material. With relevant standards in place, it is easier to suggest the elimination of archaic ones.
Sometimes the bar is set too low. For example, cleanliness standards are particularly challenging to set because, typically, we really do not know how clean is clean enough. A percentage of soil removal, a nonvolatile residue level, or an extractable particulate level that is suitable for most programs may not be suitable for new ones. It is often helpful to set internal standardsslightly above those of the customer to assist in process control.
Occasionally, the bar is set so high that meeting the standard becomes a process in itself. If the level of contamination is at the low end of the sensitivity range, test variability will account for a high failure rate. Such standardsmay have been set arbitrarily.
Coping with Standards
Standards are productively thought of as tools to achieve the goal of superior performance. If standards are not achievable, sufficient, or relevant, reassessmentsand negotiations are in order.
Next month we will cover the importance of controls.
Barbara Kanegsberg and Ed Kanegsberg are independent consultants in critical and precision cleaning,surface preparation,and contamination control.They are the editors of “Handbook for Critical Cleaning,”CRC Press.Contact them at BFK Solutions LLC., 310-459-3614;firstname.lastname@example.org;www.bfksolutions.com.