Can women uncover some area above their wrists in public while for e.g. working with chemicals in a chemistry lab, or during a surgery(as a surgeon)?

This question only pertains to the specific cases mentioned above as we all know that a woman has to cover her arms till her wrists as these areas are the part of sitr. The question has been asked since the Muslimah got no choice as the chemicals interfering with the sleeves may cause her harm ,and during the surgery, sleeves might be quite a big risk when operating on a human body. Plus, the Muslimah covers her arms till her wrists as soon as her work is done.(Answers as per the Hanafi Fiqh would be highly appreciated)