PRINCIPLES OF NAVAL ENGINEERING 



must be locked or wired shut and must be tagged 

 so that they will not be opened accidentally. 



2. Be sure that the line is completely 

 drained. 



3. In breaking a flanged joint, leave two 

 diametrically opposite securing nuts in place 

 while loosening the others. Then slack off on 

 the last two nuts. When you are sure beyond 

 the slightest doubt that the line is clear, remove 

 the nuts and break the joint. 



4. Take all appropriate precautions to pre- 

 vent fire and explosion when cutting into lines 



or breaking joints in systems that have contained 

 flammable fluids. 



5. Observe all safety precautions required 

 in connection with welding, brazing, or other 

 processes used in repairing the piping. 



6. Before repaired piping is put back into 

 service, various tests and inspections may be 

 required. Specific requirements for tests and 

 inspections may be given along with instructions 

 for the repair job; or you may find test and 

 inspection requirements indicated on the plans 

 or blueprints. If specific instructions are not 

 given, consult chapter 9480 of the Naval Ships 

 Technical Manual. 



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