Study on radon emanation from selected building materials in Malaysia

Abstract

ABSTRACT 

Radon-222 emanation from selected locally produced samples of building materials, used in Malaysia were measured using the Professional Continuous Radon Monitor Model 1027, which is a patented electronic detecting-junction photodiode sensor to measure the concentration of radon gas. Each sample was placed for 72 hours inside a 3.11 x 10^-2 m³ sealed container. It was found that the average radon concentration  Bqm^-3 of air for concrete bricks, concrete brick with cemented coatings, concrete brick with cemented coatings and paint samples were, 303.7 Bq/m³, 436.6 Bqm^-3, and 410.7 Bqm^-3, respectively. (Bqm^-3) for brown clay brick, brown clay brick with cemented coatings, brown clay brick with cemented coatings and paint were 166.5 Bqm^-3, 166.5 Bqm^-3, and 148 Bqm^-3, respectively. (Bqm^-3) for sample of compact ceramic tile was 0 Bqm^-3. The findings show that concrete brick samples are important source of radon emanation, while brown clay brick have been accepted as the recommendation of the U.S. Environmental Protection Agency (EPA), and ceramic tiles had no emanation of radon gas due to their compact surface, or the glazed layer created on the tile surface during the manufacturing process, which blocks radon emanation. A positive correlation between radon emanation and radium content has been observed for both brown clay brick and concrete brick samples whereas a negative correlation for ceramic tile has been observed. Consequently from the findings, in order to reduce radon emanation and radon exposure in house dwellings and in addition to EPA recommendation of sealed cracks and established good ventilation, we recommend concrete walls to be painted and concrete floors to be paved with ceramic tiles. 

ABSTRAK 

Pembebasan Radon-222 dari bahan binaan tempatan yang digunakan di Malaysia telah ditentukan dengan menggunakan Professional Continuous Radon Monitor Model 1027, iaitu alat pengesan elektronik-sensor fotodiod yang digunakan untuk mengukur gas radon. Setiap sampel diletakkan selama 72 jam di dalam bekas kedap udara bersaiz 3.11 x 10^-2 m³. Didapati bahawa purata kepekatan radon Bqm^-3 dalam udara bagi bata konkrit, bata konkrit disaluti simen, bata konkrit disaluti simen dan cat adalah masing-masing 303.7 Bq/m³, 436.6 Bqm^-3, dan 410.7 Bqm^-3. Nilai (Bqm^-3) bagi bata tanah liat, bata tanah liat disaluti simen, bata tanah liat disaluti simen dan cat adalah masing-masing 166.5 Bqm^-3, 166.5 Bqm^-3, dan 148 Bqm^-3. Nilai (Bqm^-3) bagi jubin seramik padat adalah 0 Bqm^-3. Hasil kajian mendapati bahawa sampel bata konkrit adalah sumber utama pembebasan radon, manakala bata tanah liat, dan jubin seramik tidak membebaskan gas radon disebabkan permukaannya yang padat, atau lapisan kilat di atas permukaan jubin yang sewaktu ia dihasilkan, di mana ia menghalang pembebasan radon. Kedua-dua sampel bata tanah liat dan bata konkrit didapati mempunyai korelasi positif antara pembebasan radon dan kandungan radium manakala jubin seramik didapati mempunyai korelasi negatif. Berdasarkan hasil kajian ini, bagi memngurangkan pembebasan radon dan dedahan terhadap radon di dalam bangunan dan berdasarkan cadangan EPA, kami mencadangkan dinding konkrit dicat dan lantai konkrit dilitupi dengan jubin seramik.