The effectiveness of guardrail system improvement for metal sheet roof installation to reduce working at hight: case study in construction workers building a factory in Chonburi province
Abstract:
The studys objectives are as follows: it is to study the effectiveness of the improvements of the
guardrail system for the installations of metal sheet roofs, by comparing the risks of incidents of workers, and to
assess the satisfaction of the improvements, both before and after use. The improvements conducted to comply
with the standards from the US Occupational Safety & Health Administration on the issue of the installations of
guardrail system of OSHA (2015). The research is divided into two parts. The first one is the study of the
design and strength test of the improvements of the guardrail system for the installations of metal sheet roofs. It
consists of the study of basic information, the design, defining the way to strengthen the structure by adding
side shores and equal angles in the shores, which are made according to the JIS SS400 standard. The second
part studies the risk and the satisfaction of construction workers on the metal sheet roofs. The population
sample is 20 workers who work on metal sheet roofs. Information is gathered from the satisfaction evaluation
survey and the safety assessment survey in using the guardrail system both before and after the improvements.
Results from the tensile tests of the guardrail system are as follows: the comparison reveals that
before the improvements, the average tensile strength is 80 kilograms. While after the improvements, the
average is 140 kilograms minimum which is higher than the requirement for guardrail system of OSHA (2015)
which is 90.718 kilograms. Concerning the satisfaction results of the construction tools and the strength of the
installations, the satisfaction of workers increased after the improvements. P-value equals to 0.025, which
means a significant difference from statistics point of view. In terms of safety checks for dangerous incidents
and near miss, neither incidents nor near miss were found after the improvements. Results from the risk
assessment according the standards of the Department of Industrial Works are as follows: it was 12 before the
improvements, which is defined as high-risk and it is 4 after the improvements, which is defined as acceptable
risk. The level of risk decreased.