How high above the floor must a primary barrier contain the minimum lead thickness?

The correct answer is that a primary barrier must contain the minimum lead thickness at a height of 210 cm (7 feet) above the floor. This requirement is crucial for ensuring adequate radiation protection in medical and industrial settings where radiation exposure could pose health risks to personnel and the public.

The choice of 210 cm as the appropriate height is based on radiological safety standards, which take into account the typical positions of patients and operators in environments where X-ray equipment is used, such as in diagnostic imaging rooms. This height is sufficient to shield against scattered radiation that may occur during procedures, effectively reducing the exposure risk to individuals who may be standing or working nearby.

Having established this height is particularly important also due to the understanding that a significant portion of exposure can happen at standing height, making it critical to implement effective barriers at this level. Such standards help ensure comprehensive safety protocols are in place, enhancing the protective measures against radiation.