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Industrial Hand Protection

Published: 10th Jan 2012

Car buyers tend to purchase a vehicle to meet their application and set a specification for a suitable car to meet their needs, whether that’s farming, urban road or rally driving - this ensures the car stands up their particular requirements.

When deciding on a suitable glove we follow a similar procedure: assess the risk, and then simply purchase to meet those needs - or that’s the theory. If only it was that easy in reality.

Probably the first thing we should be clear about is why we provide protection to staff at all.

Why provide protection?

In Europe and many other territories it is a legal requirement. In Europe the use of personal protective equipment (PPE) is governed by the Directive 89/656/EEC.

  • Article 3 requires a basic assessment of the risk
  • Article 4 requires the employer to advise the worker of the risk and to supply appropriate fitting PPE, which complies with EU standards, is correctly fitted and used by trained staff
  • Article 5 requires the employer to monitor the work area to ensure the correct PPE is being used and that it complies with the relevant standards, further to keep records of the assessment and reasons for selecting a particular product

Employers need to be compliant with current legislation to ensure their employees are sufficiently protected. So how does an employer ensure the correct glove is in use? This is by using a glove which meets the appropriate standards.

Categories of gloves

• Category 1- gloves of simple design - for minimal risk only

• Category 2 - gloves of intermediate design; gloves in this category are not considered to have a risk which is not irreversible. In this category are general handling gloves requiring puncture and abrasion resistance. This category is subject to independent testing by a notified body

• Category 3 - gloves of complex design, for irreversible or mortal risk. Gloves in this category are also tested independently by a notified body

Standards of glove

EN 420 This standard defines the general requirements of a glove - its size and construction or pH levels. Leather gloves should have a chromium V1 level of less than 3mg/kg. The gloves should meet the agreed size specifications and length. EN 388 Mechanical protection a) Resistance to abrasion - based on the number of cycles of abrasion of sandpaper on the material under a stipulated pressure. b) Blade cut resistance based on the number of cycles of a blade required to cut through a material at constant speed. c) Tear resistance based on the force required to tear a material. d) Puncture resistance based on the force required to pierce a material with a standard size point. EN 374 Protection from chemicals and microorganisms

This is based on the flow of microorganisms through a glove material, seams, small holes or other defects in the glove. A statistical evaluation of pin holing in gloves provides an indication of the gloves’ tightness - represented as AQL (acceptable quality level) 4, 1.5, 0.65 where 0.65 indicates the highest level of tightness.

Protection from chemicals

Throughout the world there are more than 1500 chemicals and chemical mixtures in use. It is necessary to use a glove which will provide protection - the evaluation is not only the chemical involved but also the contact time required. These criteria can then be compared with freely available chemical databases. Chemical resistant gloves are tested against a range of chemicals:

  • Methanol
  • Acetone
  • Acetonitrile
  • Dichloromethane
  • Carbon disulphide
  • Toluene
  • Diethylamine
  • Tetrahydrofuran
  • Ethyl Acetate
  • n-Heptane
  • Sodium hydroxide 40%
  • Sulphuric Acid 96%

The chemical resistant pictogram must be accompanied by a three digit code, which refers to three chemicals from the above list for which a breakthrough time of at least 30 minutes has been achieved.

Use of the alternative pictogram for chemical gloves is for liquid proof gloves which do not meet the above requirement or offer protection from chemicals not on the list.

EN 421 Protection from radioactive contamination

This pictogram is used for gloves protection against particulate radioactive contamination. EN 407 Heat protection

The nature and degree of protection is shown by a pictogram followed by a series of performance levels relating to specific protective qualities - the higher the number the better the test result. 1) Resistance to burning - the glove material is stretched and lit with a flame - the material is held against the flame for 15 seconds - after the flame is extinguished the length of time is measured for how long the material burns or glows. 2) Resistance to contact heat - the glove material is exposed to 100° C and then 500° C, the time is then measured for the inside of the glove to rise by 10° C. 3) Resistance to convective heat - the time taken for the inside of the glove to rise 24° C from a gas flame 80Kw/kvm. 4) Resistance to radiant heat. 5) Resistance to small splashes of molten metal - the number of small drops of molten metal to increase the temperature inside the glove by 40° C. 6) Resistance to large splashes of molten metal - molten metal is poured over the glove; the total weight of metal to damage simulated skin on the inside of the glove.

EN 511 Gloves giving protection from cold Protection from cold is measured in two ways - convective cold and contact cold and finally, water penetration after 30 minutes.

EN 10819 Gloves giving protection from vibration

Gloves should show a reduction in the level of vibration by 40% over a moderately strong vibration 31.5-200Hz and at high frequency 200-1250Hz.

Risk assessment

The choice of the correct glove becomes easier with the knowledge of the above standards - gloves are marked with the appropriate CE mark so there should be no difficulty ensuring the correct glove is in use once the appropriate evaluation is made.

Who is responsible for deciding the correct glove?

Ultimately this is the responsibility of the Health and Safety Manager who may take advice from:

• An outside consultant who will bring a wealth of experience and even may show how the process can be managed more effectively (even without gloves)

• A manufacturer’s representative who in most cases will be more than willing to conduct a glove survey and provide recommendations

• It may be that the operator or line manager is competent to provide the correct assessment in view of their detailed knowledge of the risk

So, having identified the risk, how long is the exposure? With the standards in mind it is possible now to seek a suitably protective glove. There is a wide range of glove offering very similar protection, however - so how do we decide which best meets our needs?

We need to consider the construction of the glove - the material it is made from and finally the coating.

Glove types

• Seamless knitted glove - loom woven into a single piece

• Cut and sewn knitted glove - a glove made from pieces of material sewn together

• Supported glove - this is where a textile glove is dipped into a coating to provide specific protection properties

• Non-supported glove - a glove that is formed by dipping a ceramic former into a protective liquid material which coagulates to produce a seamless glove

• Other - leather, metal fibre and injection moulded glove, multilayer laminates

Glove materials

• Cotton - Natural cellulose fibre, flexible, soft and non irritating. Cotton protects against mechanical impact, absorbs perspiration and gives excellent comfort when wearing dipped gloves for extended periods. Cotton fibres may be mixed with polyester to provide extra strength and elasticity

• Nylon - a lightweight elastic polyamide which is lint free, washable and has excellent drying characteristics and is resistant to abrasion

• Aramid - (Kevlar®) excellent cut protection, protects from convective heat, durability and performance exceeds leather by five times and cotton by three times. Sensitivity to UV rays and bleach

• High Performance Polyethylene - (Spectra®, Dyneema®) the material is flexible, lightweight and durable, is as resistant to cutting as para-aramid but has far greater resistance to abrasion

• Elastane - (Lycra®) excellent elasticity, extends 600% before breaking, perspiration and detergent resistant

• Leather - a traditional glove material, multidirectional fibres make for excellent puncture resistance, good mechanical resistance. In wet conditions the gloves’ performance is poor. Caution, tanning may leave a residue of hexavalent Chromium, which is a carcinogen - purchase from a reputable source

Coating materials

• Nitrile - a synthetic elastomer, the material has excellent puncture resistance (three times greater than latex), good abrasion resistance, good resistance to oils and greases and solvents. Good grip in both dry and wet conditions. Relatively rigid - can affect comfort - poor resistance to ketones and chlorinated hydrocarbons

• Natural rubber latex - elastomer from a natural source the (Hevea Brasiliensis) rubber tree. Latex has excellent elasticity, elongation and flexibility. The material is waterproof and has good grip characteristics. Latex will protect against aqueous chemicals and provides good bacterial and virus protection.

Latex has poor chemical resistance against oils and greases. Latex proteins may cause problems to wearers

• Polyurethane - a microporous elastomer which is a very flexible and elastic. The material is clean and does not shed particulates. Polyurethane allows perspiration to flow as a result of the material’s microporous nature. The material has good oil resistance and will not harden in the cold or soften when heated. Polyurethane has poor resistance to both chemicals and hot water

• Polyvinyl chloride (PVC) - an impermeable plastic exhibiting good flexibility even down to -20° C. PVC has good mechanical characteristics - good grip in wet and dry and oily conditions. PVC has low resistance to cuts, puncturing and heat, and also to solvents

Polychlorprene - (Neoprene®) a synthetic elastomer, good resistance to tearing and abrasion, has flexibility and elongation similar to latex. Very good resistance to a wide range of chemicals: aqueous oil based products, greases and petrochemicals. Poor grip in wet conditions - no resistance to chlorinated hydrocarbons

• Butyl Rubber - a synthetic elastomer, very elastic even at low temperatures, excellent chemical protection against ethers, ketones and acids. Very impermeable to gases, resistant to aging and corrosive chemicals. Butyl rubber has poor grip and mechanical resistance. The material has poor resistance to aliphatic hydrocarbons (hexane diesel gasoline) aromatic hydrocarbons (benzene toluene, xylene) and halogenated hydrocarbons (chloroform and chlorobenzene)

• Fluoroelastomer - (Viton®) a synthetic elastomer, excellent resistance to heat can be used in the range - 10° C to 250° C. Protects against PCBs, provides excellent protection against chlorinated aliphatic and aromatic hydrocarbons. Limited grip and dexterity. Not suitable for ketones, esters and nitro compounds

Chemical protection

We have mentioned coatings and their relative performance with chemicals. There are several sources of data which will provide specific information on which glove to use with particular chemicals. The easiest to use are chemical databases. Ones worthy of looking at include:

• www.chemrest.com - This database developed by Showa Best is easy to use and pretty comprehensive

•www.ansell.eu/industrial - This database readily provides access to Ansell information on gloves and standards

• www.ansellpro.com/specware/ - One of my favourite databases, very easy to use and very comprehensive

• www.marigold-industrial.com - Click on ‘Chemical Recommendation Guide’ on the home page, ideal for identifying the best glove from their range

Note: Where use is limited (maximum four hours), a multilayer glove can provide outstanding protection from the widest range of chemicals. Ansell manufactures the Barrier® glove and Honeywell Silvershield®. These gloves should be included in any emergency clean up team’s protection equipment - you do not have to know the spill, just that the gloves will provide protection. Clearly these gloves have a place in the glove armoury - they may not be the most comfortable in use but they can be relied upon to provide protection where not available from other products.

Product performance, grip and comfort

We have considered why we provide protection, glove standards, glove materials and coatings. The most important consideration is the user: unless they are involved in the process of glove selection they may be a reluctant user, only wearing the protection when under observation. Their input is important in ensuring they are confident in the product and are aware of the need for protection.

The factors affecting comfort are dexterity, thickness, elasticity and perspiration - if the operative experiences problems with any of these factors then they will not be inclined to use the glove. For example, if the glove provided is too thick they may not be able to operate small valves. If their hands are running with perspiration they cannot work effectively - use of a palm coated glove may just solve the problem. Simply observe the problem and there will be a solution from one of the manufacturer’s ranges.

The grip provided by a glove can have serious implications for the user and his colleagues. If an object slips it could be a chemical vat or a container of molten metal. It should be remembered that if an operative is gripping too tightly he may tire easily and lose control - with potentially disastrous consequences. Clearly the work conditions are unlikely to change but the grip characteristics of the glove can - look for a glove which has improved grip on the exterior of the glove.

Cut resistant gloves

National statistics show that in the workplace approximately 15% of all accidents are due to cuts - this will include minor to major cut injuries. It would appear that to provide the best protection for your workforce you just provide a glove with the highest cut rating.

EN388 uses the Coup test in which a rotating circular blade is dragged over a test sample under a constant weight (500gm). The test is stopped when the blade cuts through the sample and makes electrical contact with the base of the machine.

The use of high performance yarns where stainless steel is incorporated into the mix and where glass fibres are used significantly improves cut resistance; however, it can also can affect the results from the cut test machine.

Steel based engineering yarns will stop the machine due to metal to metal contact, even though the machine has not cut through the material - thus a false reading is given. On the other hand, with glass fibre yarns the blade exposes the glass surface which becomes slippery - this results in the blade skating over the yarn, so dulling its microscopic edge.

As results of glove cut testing will vary between manufacturers and test sites, probably the best way to check the product’s suitability for your application is to compare samples in the workplace.

Note: It is not recommended to use high cut resistance engineering fibre gloves when they are likely to be exposed to moving and serrated blades. The tensile strength of these fibres is very high and can pull a workers hand into machinery.

Vibration protection gloves

The hand-arm vibration syndrome causes bouts of ‘white finger’. It may also cause permanent numbness of the fingers. This is as a result of working with vibrating tools, normally for a period in excess of 10 years.

Tools that cause the syndrome include: power drills, chainsaws, pneumatic drills or other machinery that vibrates.

The condition is probably caused by slight but repeated injury to small nerves and blood vessels in the fingers. The use of a gel pad incorporated into the glove can provide effective protection from vibration injury.

Help is at hand

I started this article comparing the purchase of a car - be it a low cost utility car or a high performance racing car - to deciding on a suitable glove. An at first sight easy decision often turns out to be quite complicated.

To push the analogy a little further, even a high performance car needs attention from a mechanic. If you require assistance with your glove choices, I run a glove clinic on Twitter every Friday at 12pm (UK time). Find us on @sentinellabs or send me an email brian@Sentinel-Laboratories.com

Author

Brian Smith MRSC, Dip.M MCIM, MIEx (Grad)

Brian Smith initially trained as a chemist specialising in analytical instrumentation, when he gained five years of laboratory experience. As a direct result of this he became a product specialist in laboratory instrumentation, travelling extensively in the UK and latterly throughout the world, promoting specialist instrumentation.

At this time Smith studied marketing and export administration, gaining a diploma in marketing and graduating in export administration. This led him to the post of export administrator at a Unilever company specialising in laboratory products.

In 1988 he established Sentinel Laboratories to meet the increasing need in the pharmaceutical and laboratory market for specialist advice in skin care and hand protection. Sentinel developed several innovative products - silk glove liners, barrier products and skin washes - but is probably best known as the company which pioneered the introduction of nitrile examination gloves in the UK, a product which now dominates the UK and European markets.

When questioned about his greatest achievement he claims becoming a PADI Master Instructor as probably the greatest personal challenge. Brian remains a fanatical scuba diver, visiting wrecks around the coast every weekend.

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Published: 10th Jan 2012 in Health and Safety Middle East

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