The concentration of welding fume was measured by 221 welders themselves in chassis frame workplace of the manufactory from February, 1, 1996 to May, 31, 1997. Welding parameters were the welding current and the distance between helmet and arc. Those two optimum conditions were proposed by excess probability analysis using logistic regression, so the best position in the workplace was proposed considering two factors to control the welding fume. The results are as followings;
1) The excess probability of welding fume TLV was over 99% in above 260 Amperes of welding current and also in below 30㎝ of distanced between helmet and arc.
2) The equation from logistic regression analysis using SPSS/PC+5.02 had the welding current as a independent variable and the excess of welding fume TLV as a dependent variable (p$lt;0.05). Logit(welding fume TLV) = 0.1296 × welding current - 28.8750.
3) The equation from logistic regression analysis using SPSS/PC+5.02 had the distance between helmet and arc as a independent variable and the excess of welding fume threshold limit value as a dependent variable (p$lt;0.05). Logit (welding fume TLV) = -0.6809 × distance between helmet and arc+25.1665.
4) Considering both cases of 2) and 3), the result equation is following. (p$lt;0.05). Logit (welding fume TLV) = 0.1346 × welding current -0.3859 × distance between helmet and arc-15.7382.
5) The excess probability of welding fume threshold limit value was 100% in above 240 Ampere of welding current. Thus, below 220 Ampere can be suggested to reduce the 40% number of welders who have a excess welding fume threshold limit value.
6) The excess probability of welding fume TLV was l00% in below 34㎝ of distance between helmet and arc. Thus, over 38㎝ can be suggested to reduce the 33% number of welders who have a excess welding fume TLV.
7) Considering both 5) and 6) cases, first of all, the best welding current can be 200 Ampere to have a below l5% of welding fume excess probability for the welders who works in distance of 34-37㎝. Secondly, to have a below 30% excess probability of welding fume TLV, the working distance must be over 38㎝ in 220 Ampere and 32㎝ in 200 Ampere.
8) To reduce the average exposure concentration of welding fume (8.21±5.83㎎/㎥), the movable local exhaust system equipped with flexible hoods can be used.
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