Section R. 408.14933 - Welded end attachment; certificate of proof testRule 4933.
(1) Welding of an end attachment, except covers to thimbles, shall be performed prior to the assembly of the sling.(2) All welded end attachments shall not be used unless proof tested by the manufacturer at twice their rated capacity prior to initial use. The employer shall retain a certificate of the proof test, and make it available for examination.Mich. Admin. Code R. 408.14933