Protecting Hands Against Chemical Exposures

With so many choices in hand protection, matching the right glove to a specific work environment can be confusing. These guidelines can help you make the correct choice.

Most hand injuries, exposures and skin diseases are easily preventable by wearing protective gloves. Unfortunately, sometimes they are not used because a worker may feel that, besides getting in the way of the hazard, they also get in the way of doing the job. That's why it is important to choose gloves to suit both needs: dexterity and personal protection.

How do you choose the type of protective glove that best suits a particular workplace application? Selecting the proper glove involves more than just picking the right size. Gloves should be selected on the basis of the material being handled, the particular hazard involved and their suitability for the operation being conducted.

"The ideal universal glove that protects you against every chemical there is and is nice and flexible and comfortable to wear -- that glove doesn't exist," said Fred Seebode, the director of research and development for North Safety Products and chairman of the committee that developed ANSI/ISEA 105-2000, the American National Standard for Hand Protection Selection Criteria. "In each application, you have to make trade-offs."

Before selecting the right glove, though, it is important to identify the exact environment in which the glove will be used. "That's maybe the biggest challenge -- identifying the specific solvent or chemical or solution the end user is working with," according to Larry Garner, the president of Memphis Glove. "Quite frequently, depending on the industry or application, there may be more than one chemical involved in a specific application."

There is plenty of information available about specific chemical hazards and the corresponding protective material. Most glove manufacturers and distributors publish chemical resistance guides cataloging hundreds of chemicals used in industrial and other occupational settings. Each guide lists the chemical alongside the best (and worst) gloves to protect against it. Most chemical resistance guides are available at manufacturers' Web sites or on CD-ROM.

"Chemicals are typically broken down into classes of chemicals," Seebode explained. Often a glove that performs well against one type of chemical in a particular class will also hold up against the rest of the chemicals in that class. "If you have a glove that works well against a particular acid, chances are it's probably good against other acids," he said. While this rule holds true in most instances, he stressed that there are always exceptions to the rule.

In addition to manufacturer-published chemical resistance guides, there are several general guides to choosing proper hand protection against chemical hazards.

Types of Gloves

After identifying the chemical hazards in a particular application, the next step is to match the hazards to the glove material -- or polymer -- best suited to protect against them. Different glove materials not only differ in protective properties, but also in texture, flexibility and thickness. When it comes to gloves, one type does not fit all situations. According to Jack Weiss, the national account manager for Arbill Glove & Safety, there are two key factors to consider when choosing gloves: degradation and permeation.

"Degradation is the physical change that happens to a glove after a chemical exposure," he explained. For example, hydrocarbons (or oil-based chemicals) will degrade latex extremely quickly, whereas polymer nitrile holds up well against this group of chemicals.

Permeation, on the other hand, explained Magid Glove Senior Vice President of Sales Mike Stevens, is the rate at which the gas or vapor of the chemical seeps through a glove. He likened it to the manner in which air permeates cotton. "Because certain chemicals can easily permeate certain polymers, these chemicals can get to the worker's hand or skin and be absorbed into the blood stream," according to Stevens.

While there are dozens of styles and types of gloves to protect against chemical hazards, the most common include:

Latex. Natural rubber, or latex, gloves are the least expensive and most common type of glove used in occupational settings, according to Don Groce, a research chemist for Best Manufacturing. "Latex is not very chemical-resistant. It's mainly used in the food industry and the medical industry because it does protect well against bloodborne pathogens," he said.

One concern when using latex, however, is the possibility of an allergic reaction to the powder coating in the gloves, evidenced as a skin rash. There is also the possibility of hypersensitivity reactions (e.g., contact dermatitis or asthma) to latex.

Nitrile. Nitrile gloves have a good, general chemical resistance and are generally less expensive than other gloves. As a result, they are used in a wider variety of applications than most gloves, according to North Safety's Seebode. "Nitrile is the workhorse of the chemical-resistant glove. Chemical manufacturers would use nitrile as general around-the-plant work gloves," he said. Nitrile gloves resist gasoline, kerosene and other petroleum solvents well (making it a primary component in gasoline-pump hoses). In an effort to prevent latex allergies, medical gloves are often made out of nitrile because it is also resistant to oils and fats in the body, Groce explained.

Nitrile gloves, however, are not recommended for use with ketones, strong oxidizing acids and organic chemicals containing nitrogen, according to Jim Slosser, a consultant for QRP and Guardian. "Nitrile also tends to have a rather poor flame resistance," he added.

Neoprene. Neoprene gloves provide excellent chemical resistance to a broad range of hazardous chemicals including acids, alcohols, oils and inks, according to Art Schell, Arbill's chief operating officer. In fact, Best's Groce touts neoprene as the "acid glove" for its superior protection against acids and bases, and many organic chemicals. Another characteristic of this polymer, according to Memphis Glove's Garner, is its flexibility and dexterity. "Neoprene is great in situations needing good sensitivity and grip."

Neoprene gloves are not recommended for use with inorganic oxidizing agents, however, such as concentrated nitric or chromic acids.

PVC (polyvinylchloride). PVC (also known as plastic or vinyl) gloves are used frequently in the petrochemical industry, according to Groce. "The main reason they're used is that they're inexpensive, and you can almost use them as a disposable glove." In addition to being inexpensive, PVC gloves are durable with good snag and cut resistance, he said.

Slosser added that PVC gloves have better chemical resistance than other polymers to diluted oxidizing agents such as nitric, chromic, hydrochloric and phosphoric acids. They also resist aging.

Slosser did not recommend using PVC gloves with acetone, ketones, ether and aromatic or chlorinated solvents. "Some concentrated acids and solvents actually extract the plasticizer and harden PVC gloves, making them rigid," he explained.

PVA (polyvinylalcohol). PVA gloves are excellent when dealing with aromatics and chlorinated chemicals, according to Arbill's Weiss. "PVA will hold up to some really nasty stuff," he said, "but water will dissolve it."

PVA gloves are water soluble because they are made out of a water solution, Slosser explained. "While they are tremendous against almost any chemical, if you have them out on a humid day, they begin to draw moisture out of the air and literally dissolve in front of your eyes."

Butyl. A major use for butyl gloves is for working with gases -- chlorine gas or hydrogen cyanide, for example, according to Groce. "The reason is because butyl has very low permeability with gases. It's used for inner tubes in tires because it has such a tight molecular structure." Butyl is also used by the military for chemical warfare suits because chemical warfare agents can't penetrate it, Groce said. He recommended it when using methyl ethyl ketone, acetone or other similar cleaning agents. "It's the gas glove and the ketone glove," he said.

One of the drawbacks of using butyl gloves, however, is its price. "Butyl is one of the more expensive glove materials," Schell explained.

Viton. Viton is the most expensive polymer to produce, but it is also the most effective. "We call it the last resort polymer," Groce said, "not only because it's so expensive, but because it works where some other things don't work."

Viton was developed for use in the aerospace industry due to its extreme resistance to chemicals and heat. "Viton is the same thing used in o-rings on the Challenger Space Shuttle," Groce offered.

Viton gloves are used when dealing with aromatic hydrocarbons such as benzene, toluene and xylene. "In the case of benzene, which has been shown to cause liver cancer in workers, you want to be protected against it," Groce explained. "You'd use viton."

Physical Considerations

There are other factors to keep in mind when choosing the proper glove, namely, the physical environment in which the glove will be used. "Cuts, snags, punctures, abrasions -- what types of physical hazards will the worker be exposed to? These things all need to be considered," Magid's Stevens said. "You can have the right material, but if a worker can't bend his fingers or grasp a tool to do the job, then that glove is not appropriate."

Some physical considerations include:

  • Glove length
  • Slip protection
  • Puncture, cut or abrasion resistance
  • Heat and flame resistance
  • Cold protection
  • Dexterity.

A final consideration is whether to choose a supported glove (a glove with a cotton lining that provides support) or an unsupported glove (a "dishwasher style" of glove). "Unsupported gloves are good for dexterity," Groce explained. "Supported gloves, though, are often good for cut resistance and tear resistance, and the liner makes them a lot more durable."

Field Testing

One thing to keep in mind when choosing the proper glove for a specific work environment is that the data provided on chemical resistance charts is based on laboratory conditions, North's Seebode emphasized. "What happens in the laboratory and what happens in the field is always different. When you start using a new glove or different glove, things like temperature and other conditions will vary. You have to test the glove under your own conditions."

Another good rule of thumb, according to Weiss, is to remember that each chemical resistance chart applies to a single manufacturer's gloves. "Just because a glove manufacturer rates its particular glove 'good' against a specific chemical, you can't assume that all glove manufacturers with the same polymer (have gloves that provide) the same resistance." Each manufacturer has proprietary ways of making gloves that can affect the density and, ultimately, the permeation resistance. Bottom line: "Until you test a glove under your specific conditions, you won't know if it's the right glove for the job."

TAGS: Archive
Hide comments

Comments

  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Publish