The use of shielding to protect people, as well as equipment, from the harmful effects of radiation is not a new concept. The use of radiation shielding materials can range from wearable items, such as aprons and shielding sheets or bibs, through to solid lead items like bricks, sheet or plate.
Setting Standards for Protection
The choice of the correct type of radiation shielding is essential. There are many different agencies providing information. In general, the International Committee on Radiation Protection and the International Commission on Radiation Units and Measurements are seen as the resources for information on protecting humans from exposure to radiation.
However, there are also professional, regional, industry, safety and international safety standards to consider. Specific types of construction also have to meet all national standards as well as regional standards based on the specific type of application.
When standards are developed, and materials are selected to provide radiation shielding, several different types of exposure have to be considered. The most common type of exposure is the planned exposure or the occupational exposure.
This exposure type is based on the equipment in use, the duration of the use of radiation as well as the level of radiation exposure. Some types of radiation, such as dental x-rays, pose limited planned exposure while other types of radiation exposure are much more significant.
The emergency exposure is most common in nuclear facilities or where radiation is used in a process. This type of exposure has to be considered when selecting radiation protection, often including additional shielding in the structure of the room or facility.
There is also a factor known as existing exposure. This is the radiation that occurs naturally in an environment. As the risk of damage from exposure to radiation is cumulative over time, this existing exposure is critical to consider to provide the correct protection level for the planned exposure requirements.