Abstract: A service shut off device which is a selected length of a composite body adapted to be formed into a shape to fit in use around a service line. The composite body has a flexible casing (20) and a body of intumescent material (28) received in the casing. The body of intumescent material (28) may be continuous. The composite body has means (32) associated with the casing to contain the intumescent material within the casing and means (36) to retain the collar in a selected shape around the service line. Mounting brackets (36) can clip onto the body or be part of the body.