The U stamp is applied to all Unfired Pressure Vessels. The U stamp requires that an Authorized Inspector be present to witness the Hydrostatic testing. An Authorized Inspector must sign the Manufacturer's Data Report (MDR).

A UM Vessel must be: 5.0 cubic feet in volume with a pressure less than 250 psig; 3.0 cubic feet in volume with a pressure less than 350 psig; 1.5 cubic feet in volume with a pressure less than 600 psig. Almost all Jackets are considered UM acceptable. The UM stamp removes the need for an outside inspection by an Authorized Inspector.

Sharpsville Container has an certified individual that signs the Data Reports and Witnesses the Hydro Test. The Certified Individual must pass an exam issued by the National Board.

The R stamp is used for the Repair or Alteration of any U or UM Stamped pressure vessel. Repairs and Alterations can be done at SCC or in the field. An Authorized Inspector must be present to witness the work done and sign the report. Hydro Tests must be performed on the vessel after the repairs and/or alterations are complete.