(a) Except as provided in § 1915.51(c)(3) of this part, whenever an employee is working alone, such as in a confined space or isolated location, the employer shall account for each employee:
(1) Throughout each workshift at regular intervals appropriate to the job assignment to ensure the employee's safety and health; and
(2) At the end of the job assignment or at the end of the workshift, whichever occurs first.
(b) The employer shall account for each employee by sight or verbal communication.