Selecting chemical protective gloves

We received the following message this week

During one of the modules I remember (Mike) showed us a chart with different types of gloves for different uses. I’m not sure if it was a 3M chart.  Is it possible to please ask him he can send me the link.”

The publication I showed during the course referred to was the Chemical Resistance Guide for Ansell gloves.

Where gloves need to be worn for chemical protections its important that they are suitable for the chemical and application concerned and will provide protection for an appropriate time period. Too often inappropriate gloves are worn and even if suitable ones are used, they tend to be used long after they are capable of providing protection.

If it is necessary to use gloves then the first consideration is “what is the chemical we’re protecting against“. Once we know this data should be obtained from glove manufacturers on the breakthrough time, and the permeation rate.  The breakthrough time is the time it takes for the chemical to work its way through the glove, which is normally well before any physical degradation has occured. This will allow the most suitable glove to be selected, as breakthrough times for different gloves for a particular chemical will vary considerably. It will also usually allow the useful life of the glove to be defined – and the replacement frequency.

Degradation data should also be obtained – this is about the physical deterioration of the glove – as this can sometimes occur before breakthrough. Usability considerations are important too.  It’s no good specifying gloves that aren’t usable because they’re not compatible with the work or the user.

Each manufacturer should provide data for their own products so the Ansell guide is not applicable if you use a different supplier.

A pdf version of Ansell’s latest chemical resistance guide is available from here. They also have their information on line.

One of the other main suppliers, Marigold, also have an online guide.

Other manufacturer’s should have similar information available. If not, you can’t use their gloves for chemical protection.

See also When the “right” glove is the wrong glove

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When the “right” glove is the wrong glove

There are many situations where people at work can have direct skin contact with chemicals, particularly hand contact. It is often taken for granted that tasks such as cleaning will involve wiping down with cloths, or something similar, soaked with a solvent or other chemical which are held in the hand. Many of these chemicals can cause skin problems or can be absorbed through the skin contributing to the overall body burden. The panacea in such cases is to provide chemical protective gloves. The trouble is, this can create more problems than it solves.

With any personal protective equipment it is important to understand the limitations and know how and when the protection is likely to fail, because when it does it “fails to danger” – there is no back up. In the case of gloves, and other chemical protective clothing, failure can occur in three main ways

* penetration -where there is physical damage to the material resulting in a physical breach in the protection
* degradation – where the glove material is attacked by the chemical or is affected by other factors such as sunlight
* permeation – where the molecules of the chemical work their way through the molecules that make up the glove material

The time taken for the chemical to permeate through a particular glove or garment is known as the breakthrough time. This is dependent on both the permeation rate (the rate at which the particular chemical permeates through the material, which depends on the type of polymer used) and the thickness of the garment. The thicker the glove material the greater the chemical resistance. But thick gloves can impair grip, dexterity, and safety.

Many chemicals, particularly common solvents such as trichloroethylene, toluene and xylene pass through most common polymer materials very rapidly. Depending on the glove material and design, the breakthrough time can be as low as 10 minutes and rarely greater than two hours. If gloves have to be used, it’s important to make sure that the “right” one has been selected – one that will offer appropriate protection against the chemical of concern. The breakthrough time gives the effective usage time for the glove which should be changed on this basis.

Too often, even where appropriate gloves have been selected the maximum usage time is not specified. Workers continue to wear the gloves until they spot obvious faults. However, this presents a problem as that the user will not know that breakthrough has occurred. It’s easier to spot degradation (although this often ill only happen after breakthrough has occurred). Large tears and holes can e spotted fairly easily, but small “pinpricks” may not be noticeable.

Often workers continue to use gloves long after breakthrough has happened. In many cases I have encountered they use them for several weeks or months before replacing them – even though they are unlikely to offer proper protection after more than a few hours at best. The trouble is, people wearing gloves think they are protected and have a false sense of security – adopting practices they wouldn’t think of using if they knew that they weren’t protected. And once the chemical has permeated through the material it is in direct contact with the skin and the risk of harm can actually be increased. So in these cases, the “right” glove can be the “wrong” glove

Personal protection has to be a last resort, and this is just as relevant to gloves as other types of personal protection. Where there is a risk of skin contact with chemicals the best approach is to look to change the working method so that skin contact doesn’t occur, or is a least minimised to the lowest level practicable. For example, rather than using a solvent soaked cloth held directly in the hand, simple applicators could be used (something like a roller or “paint pad”might be options). A little imagination is all that is needed.