Radiation and Contamination
In talking about radiation is is important to differentate between the two risks:
- Radiation exposure
- Radioactive contamination
Radiation exposure can be prevented or minimised only by
- Keeping a distance to the radiation source
- Shielding the source with for example concrete or water
- Minimise the time of exposure
Radioactive contamination can be prevented or minimised by:
- Using respiratory protection
- Protective clothing which are certified to EN 1073
EN 1073 - "Protective clothing against radioactive contamination"
EN 1073 has two parts, describing two different type of clothing:
Part 1 - Freeflow suits i.e. suit which are used with airline
Part 2 - Non-freeflow suits i.e. for example gastight chemical protective suits used with SCBA (self-contained breathing apparatus).
The standard stipulates testing of the material, joins and assemblages as well as a practical performance test where at the same time an Inward leakage test is made. Using the test results from the Inward leakage test, one can also determine the Nominal Protection Factor for the suit.
Inward leakage and Protection Factor
When performing the Inward leakage test according to EN 1073-2, a person wearing a suit is placed in a test chamber which contains an aerosol. The person is fitted with three (3) test probes on the body, to measure any aerosol coming into the suit. Test duration is 20 minutes and during this time the person is doing a set of exercises.
The Inward leakage (IL) is calculated as the concentration inside the suit (Ci) divided by the concentration outside the suit (Co) and is presented in percentage.
IL = Ci / Co
Example: IL= 5/100 = 0.05 i.e. 5%
The Nominal Protection Factor (PF) is the inverted IL i.e.
PF=1 / IL
Example: 1/0.05 = 20
The inward leakage is classified as follows:
according to EN 1073-2