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| Chemical Compatibility
Glove Material: NITRILE |
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| Challenge Chemical | Degradation | Breakthrough Time | Permeation Rate |
| Isopropanol | E | >480 min. | .001 |
| Breakthrough Time: The elapsed time between initial contact of the chemical on the glove surface and the analytical detection on the inside of the glove. Typically expressed as a greater than symbol (>), the example shows the test was run for 480 minutes and then stopped. Also may be expressed as "ND" for none detected Degradation: A change in one or more of the physical properties of a glove due to contact with a chemical. Can appear as a swelling, softening, shrinkage or cracking of the material. Rating example is "E" for excellent, meaning the glove has little or no signs of degradation when exposed to the challenge chemical. A good degradation rating does not guarantee an acceptable breakthrough time. Permeation Rate: The rate at which a chemical passes through a glove material. This process involves absorption on the glove surface, the diffusion of the chemical through the material, and the desorption on the glove's inside surface. This is a complex measurement: µg/cm2/MIN (micrograms per square centimeter per minute). This measurement is also limited to the "LDL" or Lower Detection Limit of the equipment used. The example given is .001, but is sometimes expressed as "E" or "P" for excellent or poor. | |||
Another factor to consider is chemical combinations. Glove permeation guides generally list test data for pure chemicals only-not mixtures-because combining chemicals can change their physical properties and permeation rates. In the non-mandatory Appendix B to the personal protective equipment rule, OSHA recommends the following:
(c) For mixtures and formulated products, (unless specific test data are available), a glove should be selected on the basis of the chemical component with the shortest breakthrough time, since it is possible for solvents to carry active ingredients through polymeric materials.
ANSI/ISEA 105-2005
ANSI/ISEA 105-2005, American National Standard for Hand Protection Selection Criteria, provides a consistent, numeric-scale method for manufacturers to rate their products against certain contaminants and exposures. With classifications based on this scale users can make better-informed decisions about which gloves are best suited for their application.
Glove performance and pass/fail criteria are included for cut, puncture and abrasion resistance; chemical permeation and degradation; detection of holes; heat and flame resistance; and vibration reduction and dexterity.
The standard also includes a recommended hand protection selection procedure, and reference information on special considerations such as biological protection, extreme temperature applications, cleanroom applications, hazardous materials response applications, electrical protection and radiation hazards.
A section on human factors describes how fit, function and comfort are incorporated into glove selection.
Thickness and Length
Other choices you must make in selecting chemical protective gloves include thickness and length. Thicker gauge gloves are heavier and have better chemical resistance than thinner gauge gloves. Thinner, lighter gloves offer better touch sensitivity and flexibility, chemical resistance is sacrificed. Glove manufacturers generally state that doubling the thickness of a glove quadruples the breakthrough time of the chemical.
Glove thickness is stated in either mils or gauge. A 10-gauge glove equals 10 mils, or 0.010 inches. When choosing your glove, look for the stated thickness on the manufacturer's test data.
When assessing the job, also take into account the length of glove needed. Extra splash or immersion protection is provided by gloves longer than 14 inches. For deep tank cleaning or glove box applications, gloves can be as long as 31 inches. Generally longer gloves are made with thicker materials.
Finishes and Linings
Gloves also have a variety of finishes and linings. Textured finishes are applied to gloves to give a better grip. Flock and knit linings are offered on many styles of gloves. Cotton flock linings are applied for basic perspiration absorption. Knit linings do this too, as well as offering a small amount of temperature protection.
Inspection and Care
Even the best chemically resistant glove will break down after repeated chemical exposures. Before each use gloves must be inspected for signs of chemical degradation such as swelling, cracking, shrinking or discoloration of the material. If detected, it means the glove material has undergone a physical change due to chemical contact and will no longer provide chemical protection. Also during inspection, look for any signs of holes or punctures and remove the gloves from service if any are found. For complete care and maintenance instructions, refer to the glove manufacturer's information.
Commonly Asked Questions
| Q. | Can I get a thin surgical glove that offers chemical resistance? |
| A. | Thinner glove materials sacrifice chemical resistance to offer the best touch sensitivity and dexterity. Because surgical gloves are so thin, the material is easily stretched over the hand, allowing better sensitivity. But this stretching also leaves bigger spaces in the glove material at a molecular level. These larger spaces allow a chemical to permeate through very quickly, limiting the amount of time it can be worn. Some surgical nitrile gloves offer limited splash protection from chemicals. These gloves are not intended for complete immersion in chemicals, and should only be used for a very limited time period. |
| Q. | Can I decontaminate and reuse gloves? |
| A. | Decontaminating gloves is possible, but generally not practical. The decontamination procedures would probably cost more than replacing the gloves, so glove manufacturers do not recommend it. Gloves are a limited-use item that need replacement after time and chemical exposures. |
| Q. | Is there a standardized test used to test the chemical compatibility of glove materials? |
| A. | The manufacturer runs permeation and degradation tests in accordance with standards established by the American Society for Testing and Materials (ASTM F739). |
| Glove Material | Applications |
| Butyl | A synthetic rubber material that offers the highest permeation resistance to gas and water vapors. Especially suited for use with esters and ketones. |
| Neoprene | A synthetic rubber material that provides excellent tensile strength and heat resistance. Neoprene is compatible with some acids and caustics. It has moderate abrasion resistance. |
| Nitrile | A synthetic rubber material that offers chemical and abrasion resistance-a very good general-duty glove. Nitrile also provides protection from oils, greases, petroleum products and some acids and caustics. |
| PVC
(polyvinyl chloride) |
A synthetic thermoplastic polymer that provides excellent resistance to most acids, fats and petroleum hydrocarbons. Good abrasion resistance. |
| PVA
(polyvinyl alcohol) |
A water-soluble synthetic material that is highly impermeable to gases. Excellent chemical resistance to aromatic and chlorinated solvents. This glove cannot be used in water or water-based solutions. |
| Viton® | A fluoroelastomer material that provides exceptional chemical resistance to chlorinated and aromatic solvents. Viton is very flexible, but has minimal resistance to cuts and abrasions. |
| SilverShield®/4H | A lightweight, flexible laminated material that resists permeation from a wide range of toxic and hazardous chemicals. It offers the highest level of overall chemical resistance, but has virtually no cut resistance. |
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