Stability Time of Gloves
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:
Protection gloves must not have even micro-fine fissures where liquids may seep through.
Within the lifetime chemicals must not change the properties of the material used for the glove (Swelling, tear resistance, hardening, formation of wholes)
Permeation is the diffusion of chemicals through the glove. This may happen without degradation of the glove.
Higher thickness gives a better protection. The lifetime of disposable gloves against solvents is usually only a few seconds.
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).