Industry safety standards require duct tape to be nonflammable and safe to use in temperatures up to 200 degrees Fahrenheit. Adhesive endurance is reduced in temperatures over 180 degrees Fahrenheit.
According to the Lawrence Berkeley National Laboratory, duct tape samples baked in an oven set to temperatures between 140 to 180 degrees Fahrenheit showed that the rubber adhesive changed properties and that the tape delaminated. After 30 days, duct tape degraded, and seals showed increasing leakage.
Duct tape has many effective uses but does not perform well in high temperatures. Despite industry standards, duct tape is not a durable choice for any situation in which temperatures range above 180 degrees Fahrenheit.