Changing or upgrading cleanroom gloves requires time and due consideration. A good decision could improve employee satisfaction and product yields, but a bad decision could necessitate millions of dollars worth of rework, recalls, and rejects if the gloves don’t perform as expected. Personnel should consider various criteria to choose the best glove for their cleanroom.

A white nitrile glove. Image is courtesy of Kimberly-Clark Professional.

Glove materials
Cleanroom gloves typically are made from vinyl, natural rubber latex, or nitrile. Vinyl dissipates static and is considered clean and inexpensive. Vinyl gloves retain heat, however, and transmit moisture vapor poorly.

Natural rubber latex has the best cost–performance ratio of any material available. It is durable and easy to manufacture, but does not dissipate static. Also, some people have allergies to the proteins found in natural latex that can result in painful rashes.

Nitrile offers good puncture resistance and exhibits broader chemical resistance, especially to solvents, than natural rubber latex does. Unlike natural rubber latex, nitrile dissipates static well and does not cause allergic reactions. Nitrile gloves also are becoming more affordable.

A glove’s material can influence its comfort dramatically. Latex gloves typically are considered comfortable, but vinyl gloves tend to be uncomfortable because of their rigidity. Nitrile gloves are becoming more comfortable, and some suppliers are using new nitrile-based production technologies to combine the sensitivity of latex with the protection of nitrile.

Key performance factors
Cleanroom gloves should exhibit various performance factors (see Table I). For example, a glove’s particle and extractable counts should match the class of the cleanroom. The Institute of Environmental Sciences and Technology’s RP-CC005.3 standard provides material specifications and procedures for evaluating the cleanliness of cleanroom gloves. It also helps users choose the proper glove type and test method according to their applications.

Gloves also should comply with standards from organizations such as the American Society for Testing and Materials (ASTM) and the US Pharmacopeia. Some suppliers exceed the minimum performance standards set by these organizations.

Gloves must withstand not only tasks within the cleanroom, but also the gowning process. They must not tear so that operators do not have to leave the cleanroom to regown. Barrier integrity (i.e., freedom from pinholes) is another critical quality, especially for sterile cleanroom gloves.

If a cleanroom environment is sensitive to static electricity, gloves should be evaluated for their resistance to electrostatic discharge. Gloves also should be evaluated to ensure that they do not contain nonvolatile residue, contamination that is not easily removed from surfaces through evaporation.

Operators should examine the glove’s tack level, too. High-tack gloves sometimes are preferable because they make it easier to hold items. But a slick grip facilitates donning and double-donning, which is common in aseptic environments. Texture can be limited to a glove’s fingertips or can cover its entire surface. Beaded cuffs make gloves easier to grip and pull up during donning.

The gloves’ length also affects their applications. Cleanroom gloves are either 10 or 12 in. from the tip of the middle finger to the cuff. Less stringent environments can accept 10-in. gloves, but 12-in. gloves and gowns are used in more stringent cleanrooms. Personnel can tuck the gown sleeves into longer gloves, thus preventing the sleeves from billowing out and creating a potential contamination concern.

Finally, most cleanroom gloves are designed to protect the sensitive cleanroom environment from contamination by workers, but workers may need protection from chemicals, acids, or other hazards in the environment. Consider a glove’s protective properties during the evaluation.

Performance certification
Shutting down a cleanroom can cost manufacturers as much as $1.5 million per day, so consistently high glove performance is of utmost importance. Gloves should stay within a reasonable range of quality over time, and the glove vendor should ensure lot consistency throughout its manufacturing process.

The acceptable quality level (AQL) refers to the probability of having defective gloves within a lot. The lower the AQL, the lower the probability of defective gloves. ASTM sets an AQL of 2.5, but some glove suppliers exceed that standard to provide gloves with fewer pinholes and, thus, a higher level of barrier protection.

A glove supplier should provide certificates of analysis with particle and extractable counts for each lot of product. Suppliers of sterile gloves should provide trend data, technical specification sheets, and certificates of irradiation. This information sometimes is accessible on suppliers’ websites. Actual data are preferable to average data because they reflect consistency in quality manufacturing.

Packaging and sterility
Cleanroom gloves should be packaged in a cleanroom environment and double-bagged with an additional case liner to ensure cleanliness. The gloves also should be sterilized (e.g., through gamma irradiation) to reduce their potential bioburden. Sterile gloves also should be packaged in high-density polyethylene pouches and wallets that open up for easy aseptic donning.

The decision-making process
Many employees have a stake in selecting and qualifying new products to be used in a cleanroom. Production managers, contamination-control personnel, validation engineers, quality-assurance employees, and purchasing workers all should play a role. After a glove is chosen, employees should test three lots of the product before validating it. Once a new glove is approved, personnel should change the standards of practice for the cleanroom to reflect the new glove.

Careful consideration of materials, comfort, performance, operator protection, and industry standards can help manufacturers find the most appropriate glove for their cleanroom application. An informed choice can ensure that a facility manufactures a sterile product, as well as saving it from costly and time-consuming rework.

Carolina Krevolin is a category manager for scientific gloves at Kimberly-Clark Professional, carolina.g.krevolin@kcc.com.