There will be radio communication beet ween the safety watch & site safety supervisor.As supplement to radio communications an air horn or portable siren will be used by the workers inside the confined space to alert the safety watch in case of an emergency .Where possible a life line  will run from the access / egress point to the location of the workers to felicitate rescue operations.Where practical ,each worker will wear harness attached to the life line facilitate efficient rescue operations.Trained personal out side the confined space will aid an rescue operations.