Personal protective equipment (PPE) serves as a barrier between the wearer and a hazardous environment. Gloves are a primary form of this equipment, shielding hands from external threats like physical trauma, chemical contact, extreme temperatures, and biological agents. Selecting the correct glove material and design requires precisely identifying the specific hazard present. A glove designed for one type of danger may offer no protection against another.
Protection Against Physical Damage
Gloves engineered for protection against mechanical injury are categorized by their resistance to three forces: cuts, abrasions, and punctures. Cut resistance measures the material’s ability to resist a shearing force, such as a blade or glass edge, and is measured using standards like ANSI/ISEA 105 or EN 388. High-Performance Polyethylene (HPPE) and para-aramid fibers, such as Kevlar, are often woven into composite yarns to create a strong barrier against slicing injuries. Steel mesh gloves offer the highest level of cut protection, commonly used in applications like meat processing, but they typically reduce dexterity.
Abrasion resistance measures the glove’s ability to withstand repeated friction against rough surfaces without wearing through. Materials like heavy-duty cowhide leather or thick, coated nitrile are used in construction and material handling to delay wear.
Puncture resistance is the material’s ability to prevent penetration by a sharp, pointed object like a needle, wire, or shard. It is important to note that a glove with high cut resistance, such as a tightly woven aramid fiber, may offer relatively poor puncture resistance against a fine, sharp point.
The distinction between cut and puncture resistance is important because the forces involved are different; cut protection guards against a moving blade, while puncture protection guards against a straight-on impact from an object’s tip. Heavy-duty nitrile gloves offer superior puncture protection compared to thinner materials, making them suitable for handling small, sharp debris or metal shavings. Selecting the appropriate glove requires evaluating the work task to determine whether the hazard is primarily slicing, rubbing, or piercing.
Shielding from Chemical Exposure
Gloves protecting against chemical exposure must manage two mechanisms: permeation and degradation. Permeation is the process where a chemical moves through the glove material at a molecular level, eventually reaching the skin even if the glove remains visibly intact. Protection is measured by the “breakthrough time,” the duration from initial contact to detection on the inside surface.
Degradation involves the physical deterioration of the glove material itself, manifesting as swelling, shrinking, hardening, or cracking upon chemical contact. The choice of material depends entirely on the chemical class being handled, as no single glove material protects against all hazards.
Butyl rubber provides exceptional resistance to highly corrosive materials like strong acids and ketones due to its tight molecular structure. Nitrile is a popular, general-purpose choice, offering good protection against petroleum-based solvents, oils, and greases.
European Standard EN 374 classifies chemical gloves based on their performance against common test chemicals. Gloves are rated Type A, B, or C, depending on the number of chemicals they resist for a specified breakthrough time. A Type A rating signifies the glove resists at least six defined chemicals for a minimum of 30 minutes.
Guarding Against Thermal and Electrical Hazards
Thermal Hazards
Protection from thermal hazards spans both extremes of the temperature spectrum, requiring specialized materials to insulate the hand effectively. For extreme heat, gloves must guard against contact heat, radiant heat, and molten metal splash, often using specialized leather, aramid fibers, and aluminized fabrics. Aluminized gloves reflect radiant heat energy, allowing them to withstand exposure to temperatures up to 3000°F (1650°C) for brief periods near furnaces or molten metal.
Cryogenic gloves protect against ultra-cold conditions, such as handling materials stored in liquid nitrogen at -196°C (-320°F). These multi-layered gloves use insulating materials to prevent cold burns, but they are intended only for splash protection and should not be immersed in the cryogenic liquid.
Electrical Hazards
For electrical hazards, gloves must provide dielectric insulation to prevent the passage of current through the wearer. These specialized safety devices are made from non-conductive rubber and classified by their maximum use voltage, according to standards like ASTM D120. Classes range from Class 00 (protecting up to 500 volts AC) to Class 4 (rated for 36,000 volts AC).
A non-conductive glove must always be worn with a leather protector to prevent mechanical damage, such as cuts or punctures, which would compromise the rubber’s electrical integrity. High-voltage gloves must be regularly tested in an accredited laboratory, typically every six months, to ensure they maintain their rated insulating properties.
Mitigating Biological Risks and Contamination
Gloves used in medical, laboratory, and food service settings primarily mitigate biological risks and prevent the transfer of infectious agents, such as bacteria, viruses, and bodily fluids. The effectiveness of a glove as a biological barrier is quantified by its Acceptable Quality Level (AQL), a measure of pinholes or defects per batch determined by water leak testing.
Medical-grade examination gloves are held to an AQL of 1.5, while surgical gloves, used in sensitive sterile environments, are held to a stricter AQL of 0.65.
Disposable gloves made from latex, nitrile, or vinyl are the standard choice, as they are discarded after a single use to prevent cross-contamination. Nitrile is favored over natural rubber latex due to its superior puncture resistance and lack of allergy risk. Prevention of cross-contamination also depends on the user’s technique, particularly the process of removing the gloves, known as doffing. Proper doffing involves turning the gloves inside out to contain external contamination, ensuring the wearer’s skin does not contact the soiled outer surface.