Hand selected for the job

As the largest source of particle and bacterial contamination in the cleanroom, it is human operators that form the greatest threat to products and yield rates. Should failures in contamination procedures occur, the results could include anything from product failure in cleanroom-based electronics manufacturing, through to bacterial hazards for patients receiving contaminated pharmaceuticals.

Almost all the bacterial contamination found in a cleanroom comes from the people working within it, as do many of the inert particles. Therefore, it is necessary to ensure that the people working within a cleanroom generate the minimum contamination possible.

Technology continues to play an increasing role in reducing the threat of contamination but it has yet to master the dexterity of the human hand. While this technology gap remains people – and perhaps more importantly their hands – will continue to play an invaluable and central role in the cleanroom manufacturing process.

Human culprits

Research has shown that each individual operator working within a cleanroom environment can shed millions of skin flakes and clothing fibres every minute. The following statistics put the size of this contamination threat into perspective:

•A person, motionless, sitting or standing can generate approximately 100,000 particles per minute

•A person with their arms, head and body in motion can generate approximately 1,000,000 particles per minute

•A person walking at two miles per hour can generate approximately 5,000,000 particles per minute.

As the hands are the tools via which many products in the cleanroom are manufactured, they pose one of the main threats to products, making it essential that the right glove for the cleanroom job is chosen and employees must be provided with the best quality products available.

But the glove selection process requires a diverse range of considerations to be taken into account to identify the best glove for the job. Typically these considerations should include:

• What is the Class designation(s) that needs to be adhered to?

• Is particulate protection or sterile protection required?

• Which glove material best suits the product being manufactured?

•Does product protection need to be continued in post manufacture?

• Does the glove need to have resistance against abrasion, cuts, tearing and punctures?

• How important is grip - does the manufacturing process require wet and dry grip?

• How important is user sensitivity during manufacture?

• Is the glove to be worn for long periods requiring higher level of wearer comfort?

Companies need to ensure the gloves conform to legislated standards. While, there are some variations between American and International standards essentially they are the same, merely expressed in different ways (see table 1).

Getting the glove selection process right is a cost-effective insurance policy, one that protects both the products, people and thus the bottom-line.

Worker compliance

Ensuring high worker glove compliance is a key element in reducing the threat of contamination. As with other sectors, the reality is that wearing gloves is viewed by workers as one of the least popular aspects of working within a controlled environment. Despite understanding the need for wearing protective gloves, there remains a natural aversion to gloves, the perception being that they interfere with the hand's desire to directly touch and work with materials.

When hands feel constricted, damp, clumsy or generally uncomfortable, or when, as a result of the glove, the operators lose the sense of feeling and dexterity during the production process, the result is a loss in productivity and efficiency.

While workers in critical environments must wear hand protection, a well-chosen glove will reduce the feeling of discomfort, having a positive effect on production output.

When it comes to selecting the right glove for the job, making the correct choice will depend on suitability to the task being undertaken, performance, quality construction and cost pressures.

Sterile gloves
Any gloves selected need to be sterile. Marigold Industrial achieves this through gamma irradiation, a physical means of sterilisation or decontamination for gloves that is known as a “cold process” because the temperature of the processed product doesn't significantly increase.

The gamma irradiation kills bacteria by breaking down bacterial DNA and inhibiting bacterial division. By exposing products or substances to gamma rays — electromagnetic radiation of very short wave lengths (similar to UV) — the energy passes through the treated product disrupting the organic processes that cause contamination.

The most common source of gamma rays for irradiation processing comes from the radioactive isotope Cobalt 60, which is manufactured specifically for the gamma irradiation process.

First the hermetically sealed gloves are packed in standard corrugated cardboard cartons. These boxes are loaded in carriers, each having five shelves. Each carrier travels at a controlled speed, on an overhead monorail. It then enters the irradiation cell through a labyrinth. Five such passes through the cell ensures the exposure of the products to a minimum dose of 25 kilo Gray which makes the gloves sterile, this is indicated by a red dot on the label of the outer packaging.

In addition to traditional latex gloves, a range of other glove materials can be used in cleanroom environments, including:

• Polyisoprene - synthetic latex
• Nitrile - natural butyl
• Neoprene – chloroprene with good chemical protection
• Vinyl – PVC with anti-static properties

While most cleanroom operatives understand what they need their gloves for, selecting the right gloves to meet those requirements is not always a straightforward task. Seeking the advice and input from a leading and reputable glove manufacturer is one of the most effective weapons in the fight against contamination.

Leading glove manufacturers have amassed a great deal of glove knowho and are able to bring experience, reliable facts and glove-selecting expertise to hand-protection protocols. Their input can be invaluable.

Gloves have an essential role to play in reducing the threat of contamination within the cleanroom sector, protecting both the worker from the product and the product from the worker. But choosing the right glove for the job is not a straightforward process and takes time and research. Put the work in and it is an investment that will make positive in-roads into contamination levels, which ultimately will be reflected in the bottom line.