Regulations, Glove Types, Miscellaneous Glove Information
OSHA 29 CFR 1910.138 - This regulation of the U.S. Occupational Safety and Health Administration (OSHA) requires appropriate protection when hands are exposed to various hazards. Hazards cited include those that can cause skin absorption of harmful substances, severe cuts, lacerations or abrasions, punctures, chemical burns or injuries from temperature extremes. Employers must base selection of hand-protection products on "an evaluation of the performance characteristics of hand protection in relation to the task performed, duration of use, and hazards present." (www.osha.gov)
ANSI/ISEA 105-2005 - The Hand Protection Group of the International Safety Equipment Association (ISEA) has updated this standard to assist employers and users in the appropriate selection of gloves for specific workplace exposures. This document references appropriate test methods for specified criteria and provides classification criteria that allow users to interpret test results and determine if certain products meet their needs. Performance and classification criteria are included for the following characteristics: cut resistance, puncture resistance, abrasion resistance, protection from cold, chemical permeation and degradation, detection of holes, heat degradation and flame resistance. (www.safetyequipment.org)
Many US glove users are becoming aware of markings and symbols on their gloves that relate to European regulatory standards. These markings are not required in the US, but they offer some useful information for US users once they are understood. Hand protection in Europe is closely regulated and subject to the requirements of a series of standards or "Norms". Regulation starts with European Norm EN420 - General Requirements for Gloves, which must be met by all protective gloves. It specifies the basic requirements for a glove, such as ergonomics, construction, sizing, marking and user information and guidance.
Protective gloves are separated into three categories according to the risks they are designed to protect against and each category has different marking requirements:
- Category 1 - Minimum Risk - Gloves that meet the requirements of EN420 and are intended to provide basic protection. They are required to be clearly marked with a declaration of conformity to EN420 (indicated by the pictogram shown below) and must include user information on use, storage, disposal etc. They must also be marked with the CE mark, glove size, item number and manufacturer. Category 1 gloves include gardening gloves and washing-up gloves.
- Category 2 - Medium Risk - Gloves offer a greater level of protection. As well as meeting EN420, they are tested against the requirements of an additional EN that is appropriate to their intended use. For example, general purpose gloves will be independently tested and certified against the requirements of EN388 for mechanical hazards (abrasion, cut, tear and puncture resistance). Compliance to an additional EN is indicated by marking with an appropriate pictogram.
- Category 3 - High Risk - Gloves offer protection from irreversible injuries and mortal danger (such as chemical burns, high or low temperatures). Category 3 gloves may be tested and certified against the requirements of several European Norms, according to their intended use. For example, chemical resistant gloves will be tested for mechanical properties (EN388) as well as chemical permeation (EN374) and will be marked with more than one EN pictogram.
BASIC GLOVE TYPES
Disposables - These are thin (4 to 6 mil) unsupported gloves, usually made from nitrile or natural rubber (commonly known as latex). Disposable gloves provide limited protection against liquids, oils, chemicals and mechanical hazards, but are an excellent choice for contamination protection. They can be used to protect the wearer from the product, or the product from the wearer. They are ideal for tasks requiring short term protection from minor hazards. Typical applications include maintenance, inspection, food preparation, etc. They are usually discarded after a single use.
Liquid & Chemical Resistant - Liquid & chemical resistant gloves provide a continuous membrane that protects the hands from hazardous and non-hazardous substances. They are available in many different types and materials. Choice is dependent upon the hazard being faced. Most gloves in this category are un-supported, but supported types are also available (with an integral liner for wearer comfort). Many liquid & chemical resistant gloves can also be used for protection against abrasion, cuts, tears and punctures. Their applications vary depending on the material used.
General Purpose - This broad category of gloves encompasses many different designs and materials. For the most part, they are intended to provide protection from dirt and
mechanical hazards (such as sharp or abrasive objects) or to enhance the wearer's grip. Some types are also liquid proof, but generally offer low levels of chemical protection.
Cut Resistant - Cut resistant gloves are specifically designed to provide protection against sharp objects such as blades, glass and metals. Gloves in this category offer enhanced protection compared to similar looking general purpose gloves, because they are made from materials that offer superior performance against mechanical hazards. Typical materials include Kevlar, Dyneema® and stainless steel mesh.
Controlled Environment - Controlled environment hand protection products range from finger cots to clean room gloves to glovebox and isolator box gloves. Finger cots are generally worn to protect an item or product from the wearer (for example, static dissipative cots protect sensitive electronic components on a PCB). Cleanroom gloves prevent contamination of critically clean products, such as silicon chips and protect the wearer from hazardous chemicals. Glovebox and isolator box gloves allow a worker to safely handle toxic or radioactive substances within the box, or protect the product in the box from contamination from the environment outside the box. Controlled environments are found in the electronic, nuclear and pharmaceutical industries.
LIQUID & CHEMICAL RESISTANT GLOVE MATERIALS
Silver Shield® (PE and EVOH Laminate film) - Silver Shield is exclusive to North Safety Products. Silver Shield gloves and accessories resist permeation and breakthrough against a wider range of toxic chemicals than any other material. They are ideal against aromatics, esters, ketones and chlorines. Silver Shield products are an excellent choice for chemical and petrochemical laboratories, spill cleanups, hazmat control operations, photo finishing, medical laboratories and a host of other hazardous applications.
Butyl - Butyl is a man-made rubber that exhibits the highest permeation resistance to gas or water vapor of any glove polymer available today. It has many applications in industry, and is also the glove of choice for military, disaster preparedness and hazmat applications the world over. It is ideal for use in ketones (MEK, MIBK, acetone), esters (tricresyl phosphate, amyl acetate, ethyl acetate) and highly corrosive acids.
Viton® - Viton gloves are made specifically for handling chlorinated and aromatic solvents. They exhibit a high degree of impermeability to these solvents and can be used in or around water and water-based solutions. Viton also has superior resistance to PCBs. Viton gloves are used for applications in the automotive and chemical industries as well as aircraft maintenance and degreasing operations.
Nitrile (NBR) - Nitrile can be used for both supported and un-supported gloves. It offers excellent protection against acids, bases, oils, solvents, esters, grease and animal fats. Nitrile is more resistant to snags, punctures, abrasions and cuts than neoprene or PVC gloves, and unlike natural rubber gloves, contains no natural rubber proteins which can cause allergic reactions. Because nitrile gloves are so versatile, they are ideal for use in many applications, including laboratories, automotive and aircraft part-handling and assembly, plant cleaning, chemical processing, food processing, petroleum refining, dip tank operations, acid etching, painting, graphic arts, battery manufacturing, degreasing, electronics and pesticide handling.
Natural Rubber (Latex) - Natural rubber is widely used for gloves because it is relatively inexpensive, and yet offers good resistance to certain groups of chemicals (such as acids). It also has good resistance to abrasion, cuts, tears and punctures. It's also very comfortable and permits excellent dexterity. Natural rubber can be an economical alternative to nitrile or neoprene. A negative aspect of natural rubber is that it contains proteins that can cause allergic reactions, so it is not recommended for everyone. Natural rubber also will swell and degrade in contact with various animal fats, oils and solvents.
Neoprene - Neoprene offers protection from acids, alcohols, oils, solvents, esters, grease and animal fats. It has been largely eclipsed by nitrile, but still has a niche in certain industries, notably the petrochemical industry.
Poly Vinyl Chloride (PVC) - PVC provides resistance to most fats, oils, acids, caustics and petroleum hydrocarbons, but PVC gloves are mostly sold as general purpose gloves, intended for numerous applications involving incidental exposure to a variety of low level chemical hazards. They are mostly supported gloves (dipped on a liner) which means that the PVC layer is of variable thickness, which it turn means that the glove's chemical resistance varies from one part of the glove to another. PVC is a very versatile and inexpensive polymer and supported PVC gloves are available in a wide range of styles, finishes and colors. They have applications in many industries, including petrochemical, construction, fishing industry, cold storage etc.
GENERAL PURPOSE & CUT RESISTANT GLOVE MATERIALS
Dyneema® - Dyneema was developed by DSM as a multipurpose high performance polyethylene fiber. It has excellent abrasion and cut resistance, being up to 15 times stronger than steel (weight for weight). It is cool to the touch and comfortable to wear and also launders well.
Spectra® - Spectra was developed by Honeywell Corporation. It is a high performance polyethylene with many industrial and defense related applications, including cut resistant gloves for the food industry.
Kevlar® - Kevlar is a fiber developed by the DuPont company for use in high performance applications. The par-aramid fiber has a high resistance to cuts which makes it ideal for use in cut resistant gloves for applications where sharp objects are being handled. The high tensile strength and low weight of Kevlar makes it durable yet lightweight to wear. Kevlar is flame resistant, self-extinguishing and can be used at elevated temperatures.
Blended Kevlar/Cotton/Polyester - Kevlar can be mechanically blended with cotton and polyester to provide cut protection. Blending and knitting are done in such a way as to leave the Kevlar (for cut protection) on the outside of the glove and the poly/cotton (for comfort) on the inside. This is a cost effective way of enhancing cut protection on a poly/cotton glove.
Polyester/Cotton - Poly/cotton blends are commonly used in string knit gloves because of their comfort, durability and excellent laundering characteristics. By mixing polyester with cotton, shrinkage can be minimized.
Nylon - Certain nylons have a high resistance to abrasion and provide a synthetic string-knit glove that is lint free. Shrinkage in nylon gloves is minimal and more uniform than in cotton, so nylon launders very well. Nylon is the material of choice for finer 13 and 15 gauge knitted gloves.
Stainless Steel Mesh - A mesh of individually welded stainless steel rings provides the best cut protection of any glove material.
Leather - Leather is a traditional material for gloves that is waning in popularity, but still has applications in general industry due to it's relative low cost, abrasion resistance, and ability to withstand high temperatures and hazards such as weld spatter. There are many different types and grades of leather available, and care is needed to ensure the desired level of performance is achieved.
GLOVE COATING MATERIALS
Nitrile (NBR) - Nitrile can be applied to knit and cut-and-sewn gloves using several methods, including screen printing, foam coating and dipping. It offers good mechanical properties (resistance to abrasion, cuts, tears and punctures) and yet is soft and flexible so that gloves do not feel stiff. Grip is also good and can be enhanced further by air-infusing (foaming) the nitrile during dipping. This creates an open surface texture and greater surface area which improves grip on wet or oily objects. Nitrile is also a good choice in high heat applications because it does not melt at high temperatures, which could create product contamination issues (for example, in an application such as auto-glass manufacture).
Polyurethane (PU) - Polyurethane is the toughest of the popular coating polymers, with the best resistance to abrasion, cuts, tears and punctures. This makes it highly suitable for cut resistant gloves, where its mechanical properties compliment those of the high performance fibers used in those kinds of gloves. Also, because it's tough, coatings can be made thinner than with other polymers, yet still provide comparable levels of protection. This makes it a good choice for applications such as fine assembly work where a high level of tactility (feel) is important.
Bi-Polymer - Bi-Polymer is a blend of nitrile and polyurethane. It combines the best properties of both polymers, offering great mechanical performance against abrasion, cuts, tears and punctures as well as a high level of grip and a soft, flexible feel.
Poly Vinyl Chloride (PVC) - PVC has been a popular choice for inexpensive dipped supported gloves for decades. In more recent years it has emerged as an attractive option for palm coated dipped gloves. Applied as an air infused (foamed) coating, it offers exceptional wet and dry grip as well as mechanical properties that rival nitrile and polyurethane. North was quick to recognize the potential of this coating, and pioneered it in the form of the popular NorthFlex Red (NF11). North now offers four general purpose gloves with PVC palm coatings.
MicroFinish® Nitrile - MicroFinish is a revolutionary, high grip glove finish. It is a two stage process that coats the glove in a liquid-proof nitrile layer, followed by a second nitrile layer that is textured with thousands of microscopic pockets that clear oil and other liquids from a surface and enable a sure and confident grip. MicroFinish outperforms foamed finishes in terms of grip, and being a nitrile, it also provides good resistance to abrasion, cuts, tears and punctures.
MicroFinish® is a registered trademark of the Towa Corporation.
Natural Rubber (Latex) - Natural rubber has been a popular glove coating material for many years. Normally supplied with a "crinkle" finish, it provides a thicker than average coating that offers good grip and mechanical protection. Natural rubber latex can cause allergic reactions in some individuals.
GLOVE DIPPING METHODS
Dipped Gloves are made by dipping a hand shaped form (with or without a liner) into a tank, or successive tanks of polymer in liquid form. There are two basic types of process:
Latex dipping - This is a water based process. The dipping polymer is in solution with water. This process is used for over 95% of all un-supported gloves produced around the world and is a fast process, done on a large scale. Latex dipped gloves (typically nitrile, natural rubber and PVC) are produced quickly and economically, and usually in a single dip.
Solvent dipping - Also known as cement dipping. The polymer is in solution with a solvent. This process involves multiple dips and is a relatively long and labor intensive process that produces a glove of exceptional quality. Multiple dips provide a multi-layer glove (like a glove within a glove, within a glove). A solvent dipped glove has better integrity than its latex dipped counterpart which results in superior mechanical and chemical protection. North uses this process for its glovebox and isolator gloves and for butyl and Viton industrial gloves. Some polymers (such as butyl, Viton and Hypalon) can only be processed in this way.
|SUPPORTED AND UN-SUPPORTED DIPPED GLOVES
Unsupported Gloves - Are made by dipping a hand form (usually made of porcelain) directly into a tank containing a polymer in liquid form. After drying, curing, stripping and washing, the glove produced is basically a layer or film of polymer with no supporting structure (an unsupported glove). To increase comfort, cotton flocking can be added to the interior of unsupported gloves. Flocking absorbs perspiration and aids in donning and doffing. Unsupported gloves are more economical than supported gloves, but may not last as long and will not provide as much protection against abrasions, cuts, punctures and snags.
Supported Gloves - Have a knitted or woven liner (usually cotton/poly). This is placed over the hand form, prior to dipping, so that it becomes an integral part of the glove.The liner gives the glove structure and increases its strength as well as providing wearer comfort. The liners in chemical resistant and general-purpose work gloves are usually jersey (which is similar to sweatshirt material) or interlock (which is similar to T-shirt material).
Palm Coated Gloves - Are a type of supported glove. Used for general purpose and cut resistant gloves, the palm coating process is a shallow dip that coats selected parts of the glove. Depending upon the depth of the dip and the shape of the special hand forms used, the coating can be limited to just the palm and finger tips or extended to the knuckles.