This study was performed to evaluate the exposure levels of worker exposed to welding fume and metals in confined spaces of a shipyard.
The airborne concentration of welding fumes and metal elements in confined spaces were compared with those in open working areas.
Results of the study were as follows.
1. The geometric mean of welding fume concentration in a confined space was 16.6㎎/㎥, which contained 3.9㎎/㎥ Fe, 1.2㎎/㎥, Mg, 0.8㎎/㎥ Zn, 0.008㎎/㎥ Cu, 0.008㎎/㎥ Pb, 0.005㎎/㎥ Ni, 0.003㎎/㎥ Cr, 0.0003㎎/㎥ Cd.
The geometric mean of welding fume concentration in open working areas was 5.2㎎/㎥, which contained 1.1㎎/㎥ Fe, 0.3㎎/㎥ Mg, 0.3㎎/㎥ Zn, 0.004㎎/㎥ Cu, 0.008㎎/㎥ Pb, 0.005㎎/㎥ Ni, 0.003㎎/㎥ Cr, 0.0003㎎/㎥ Cd.
The geometric mean of welding fume concentration in confined spaces was 3,2 times higher than that in open working areas.
The geometric mean concentrations of such metals as Fe, Mg, Zn, or Cu within fume in confined spaces were 2-4 times higher than those in open working areas, while little difference made such metals as Pb, Ni, Cr, Cd.
2. In 32 samples out of a total of 39 samples (82.1%) collected in confined spaces, the concentrations of welding fume exceeded TLV. while so did 19 samples out of 33 samples (57.6%) in open working areas.
As for the concentrations of metals in welding flame from confined spaces, Fe exceeded TLV in 14 out of a fatal of 38 samples (36.8%), Mn exceeded TLV in 23 out of a total of 38 samples (60.5%).
As for the concentration of metals in welding fume froth open working areas, Fe exceeded TLV in 3 out of a total of 34 samples (8.8%), Mn exceeded TLV in 6 out of a total of 34 samples (17.6%). Considering additive effect among metals, in 31 out of a total of 39 samples (79.5%) collected in confined spaces, the concentrations of welding fume exceeded TLV, while so did 14 out of 38 samples (55.6%p) in open working areas.
3. In respect of base metal and welding type the concentration of total welding fume by CO₂ gas W./mild steel was the highest, followed by semiauto MMA/mild steel, then followed by TIG or CO₂ gas W./stainless steel. ; as for concentration of metal within fume, a decreasing order was Fe, Zn, Mn, and Pb in CO₂ gas W./mild steel and semiauto MMA/mild steel, but Fe, Mn, Cr, and Ni in T1G or CO₂ gas W./stainless steel.
4. In case of welding base metal covered by paint, contents of Zn within red paint chip and within gray paint chip were 14.0% and 0.08% respectively, which showed a little difference, while the airborne concentrations of Zn within fume during welding base metal covered red paint and gray paint were 1.351 ㎎/㎥ and 1.018 ㎎/㎥ respectively, which showed little difference.
As for Pb, contents of red paint chip and gray paint chip were 0.14% and 0.08% respectively, and the airborne concentrations within fume during welding base metal covered red paint and gray paint were 0.009 ㎎/㎥ and 0.007 ㎎/㎥ respectively, both of which showed little difference.
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