I am the QA Manager of a custom fabrication shop. More and more we are seeing international jobs with ISO weld symbols. One local customer who supplies Europe has asked me to review the weld detailing of thier drawings. Aside from the obvious differences when reviewing the ISO 2553 International Standard, there are several questions I have, for which I am hoping some of the more experienced board members can provide some answers. Can multiple reference lines be used with the ISO system to specify weld operation sequence? How does one properly specify root opening with ISO weld symbols? Any help is greatly appreciated.