Radioactivity in Consumer Products
Historically, radioactive material has been found in several products available to the consumer. Modern thinking on justification of the use of radioactive materials and ionising radiation has greatly reduced the practice of using such materials, but some products are still available, including thoriated welding rods and lamps containing tritium. The most common consumer product currently utilising ionising radiation is the household smoke alarm – in 2022 it was estimated that these were installed in 94 % of UK households. Additionally, some historic products such as Vaseline glass, which contains uranium, or luminous watches and dials containing radium or tritium, may still be available on the second hand market. The sections below provide some information on smoke detectors and a few other products of interest. impact background radiation levels in the home. Old smoke alarms can safely be disposed of in household rubbish, however the radiation sources within them should not be tampered with. The sealed sources can only be broken by the deliberate use of force, which would require significant destruction. In a fire, the sources would release less than 0.1 percent of their radioactivity.
Ionisation Chamber Smoke Detectors If you turn a smoke detector upside down or open the cover, you will probably see the radiation warning symbol. This indicates the presence of radioactive material, typically Americium-241. This radioactive source is sandwiched between two layers of metal and rolled into a thin " foil ", which is enclosed inside an ionisation chamber. The radiation emitted from the Am-241 source is very low( 0.02 µ Sv per year) and therefore does not
Lamps containing radioactivity Gaseous tritium light devices( GTLDs) have been widely used for many years as selfilluminating items that require no external power, such as exit signs. They consist of a phosphor-coated sealed glass tube containing tritium and emit light because electrons released from the decay of tritium cause the phosphor layer to phosphoresce. All GTLDs originally required registration under radioactive substances regulations, but since 1985 certain categories of GTLD can be used and disposed of without a permit, although specialist disposal is now required. Although some uses of GLTDs have declined, they are still widely used by the military and a range of civilian applications such as selfluminous signage, fishing floats, prismatic compasses and camping equipment.
Old smoke detectors
About 2 % of other types of lamp also contain low levels of tritium, Krypton-85 and isotopes of thorium, which aid starting the lamp or are used as a component of the electrode. They
22 Radiation Protection Today www. srp-rpt. uk