The maximum wear duration of a chemical protective glove cannot be stated easily. Several factors are relevant. These include the mechanical stress and also the degradation (destruction of the material by chemicals). Provided the glove is used properly, however, it is possible to estimate how long its barrier action will be retained. Studies (PDF, 456 kB) conducted at the IFA have shown that the glove temperature rises to approximately 33 °C when the glove is worn, with the result that the actual duration of the protective action may be as little as one-quarter of that determined in accordance with the standard. The safest approach is therefore to use the glove for no longer than one-quarter of the wear duration stated by the manufacturer once it has come into contact with the chemical.
Polanz, O.; Paszkiewicz, P.: Praxisnahe Auswahl von Chemikalien-Schutzhandschuhen – ein neuer Ansatz (PDF, 456 kB). Gefahrstoffe – Reinhalt. Luft 63 (2003) No. 10, pp. 410-412 (in German)