Maximum acceptable weight of lift in adolescence aged 15 to less than 18 years old

Abstract

By Convention No. 138 specifies the minimum age for working children which it must not be lower than the age of completing compulsory education and lower than 15 years old. The allowable work for working children must not be harmful to children’s health, must be safe and not against good morals. Manual material handling is common tasks can be found in many conditions of working children aged 15 to less than 18 years old, especially lifting tasks. The lifting tasks may exceed the children’s capacity and may lead them to problems of accumulative fatigue, musculoskeletal disorders and other health effects in the future. This study was conducted not only to determine what maximum weight is accepted by the children but also to compare its’ results with NIOSH lifting equation whether suitable for working children or not. This research experiment get permission and approval from Thammasat University Research Ethics Subcommittee 3. The study of lifting tasks by simulating works in laboratory and applying psychophysical criteria shows that the maximum acceptable weight is significantly different between boys and girls. Increasing lifting frequency can significantly affect to the MAWL. The MAWL based on psychophysical criterion seems not to be different when lifting frequencies more than 1 lift/minute. The RWL (at origin) calculated from NISOH lifting equation based on the load constant recommended by ISO11295:2014 are higher than the MAWL of this study. It is possible using NIOSH lifting equation to assess risk of manual lifting at origin may be underestimate when applying to working children situation.