38 صفحه pdfASME B30.6:2015DerricksSafety Standard for Cableways, Cranes, Derricks, Hoists, Hooks, Jacks and Slings
ASME B30.6:2015-Derricks
38 صفحه pdfASME B30.6:2015DerricksSafety Standard for Cableways, Cranes, Derricks, Hoists, Hooks, Jacks and Slings