Wearing gloves over a prolonged period of time will cause swelling of the skin whch is then less resistant against chemicals. Furthermore the warm and humid atmosphere in the glove favours formation of pathogens which may cause skin disorders. If the skin is exposed permanently to the atmosphere in a glove it will degenerate (eczema). According to the "Verordnung zur Arbeitsmedizinischen Vorsorge" in Germany an occupational-medical health examination has to be offered if gloves are worn more than 2 hours per day. If gloves are worn 4 or more hours per day this examination is obligarory.
Unproper usage of gloves may be more harmful than working without gloves!
Hints about safety gloves are found in safety data sheets oder in the GESTIS-Data base. Since there are usually lots of different chemicals in a lab it could be unreasonable to have safety gloves made of more than 2 different kinds of materials. Since as a rule only a protection from splashes is needed it should be a good idea to use cheap gloves, where it is easy to replace them even after a short time of usage.
If the risk assessment gives the result that there are no gloves with proper resistance the protection could be very enhanced if a second pair of gloves is pulled over the first ones. Use a disposable glove as the first one. It might be a little fiddly to pull over the second glove, but since both gloves are only partially in contact much more time is needed for chemicals to pass both gloves and reach the skin. You may use gloves made of different materials to further enhance the protection.
Suppliers of safety gloves offer information about the resistance of their products. Since the suppliers have the liability about their data you may trust the information.
This term might look scaring but it has the simple meaning that it is the job of the group head that by the risk assessment he has also to specify the skin protection measures. This includes:
Examples for skin care and skin cleaning:
The complete set of measures is called skin protection plan.
The lifetime of protection gloves is limited. There is no universal protection glove but every material used for gloves has its own resistance characteristics instead. Following facts have influence to the lifetime:
Values for breakthrough times are given in minutes. Following levels are in use:
480 Minutes are one workday. For use in a lab usually no gloves with a lifetime of one workday are needed, since the contact with chemicals is only for short periods of time. A splash protection should be sufficient.
As a rule in reality the breaktrough time is shorter than specified, because the glove material is streched when in use and is warmed to the skin temperature. Therefore the wearing period should be not more than 50 % of the specified time. In a batch of gloves deviations of more than 30 % are possible. Furthermore the processing of the material has a high relevance which is why a specified lifetime of a supplier may not be used to predict the lifetime of the "same" glove offered by another supplier.
Safety gloves have to be selected according to the specific needs. According to DIN EN 374 a glove may be called a "chemical safety glove" if it has a resistance of at least level 2 for at least 3 of a set of 12 standardized chemicals. Often gloves made of nitril are recommended, but nitril has no resistance against solvents like acetone and dichoromethane (Level 0).