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Chemical Protective Gloves

Document Number: 191
Introduction
On October 5, 1994, OSHA's personal protective equipment standards for
general industry (29 CFR 1910.132-1910.138) went into effect. One of these
new standards (29
CFR 1910.138) specifically addresses the need for hand protection:
(a) Appropriate hand protection must be worn when hands are exposed to
hazards such as skin absorption of harmful substances, severe cuts, lacerations
or abrasions, punctures, chemical or thermal burns, and harmful temperature
extremes. (b) Employers must base the selection of appropriate
hand protection on an evaluation of the performance characteristics of
the hand protection relative to the task(s) to be performed, conditions
present, duration of use, and the hazards and potential hazards identified.
This rule makes it mandatory to match the right glove material with each
application or task. This includes assessing the job for chemical exposures,
and then selecting the appropriate glove based on material, thickness,
length and other traits.
Hazard
Assessment
An industrial
hygienist or other safety professional familiar with the task can perform
a hazard assessment. The hazard assessment begins with knowing what chemicals
or combination of chemicals the task or job requires. The next step is
to determine the chemicals' toxic properties by reviewing the Material
Safety Data Sheets (MSDSs). Attention should be focused on potential local
skin effects, as well as potential absorption through the skin and resultant
systemic effects. When reviewing the job requirements, the degree
of dexterity required for each task must be taken into account. Tasks
that require fine motor skills, such as laboratory work, may require a
thinner glove material, while operations such as industrial parts cleaning
may not. Also, the length of exposure to the chemicals must be
considered. Some tasks may require only splash protection or include intermittent
contact, while others may involve complete immersion or continual contact
with the chemicals. Other factors to consider are chemical concentration
and temperature. The higher the concentration and temperature of a chemical,
the shorter the breakthrough time. The hazard assessment must also take
into account other hazards of the job, such as cut or abrasion hazards.
It's important to remember that although the number of glove choices
can be staggering, no one glove can possibly address all types of hand
hazards. Gloves are never a substitute for safe work practices or proper
engineering controls.
Choosing a Glove Material Because
different glove materials resist different chemicals, no one glove is
suited for all chemical exposures. A glove that is well suited well for
one application may may not be well suited for another. Base glove material
selection on the manufacturer’s chemical resistance guide. From the guide,
choose a glove that is most resistant to the chemicals being used. Remember,
the actual chemical compatibility of a given glove material can vary from
manufacturer to manufacturer. Selections must be based on the particular
manufacturer's test data. To read a chemical resistance guide, it is important
to become with the terminology used:
Chemical Compatibility
Glove Material: NITRILE |
| 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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Please Note: The information contained in this publication
is intended for general information purposes only. This publication is not
a substitute for review of the applicable government regulations and standards,
and should not be construed as legal advice or opinion. Readers with specific
questions should refer to the cited regulation or consult with an attorney.
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