Internally Coated Pipe Spool
All piping with an internal diameter of less than 2.0”Ø (ie: schedule 80, XS, schedule 160) shall be ground flush to allow for proper access of sandblasting, coating and inspection equipment. Olets should have full penetration at the olet-to-pipe interface. There shall be no pinholes, skips, splatter, undercut, mig wires, high or sharp areas. Welds not meeting these criteria usually require grinding to allow for blast cleaning to acceptable grade of cleanliness and to obtain a holiday-free coating. Epoxy grouts can be used to fix defective areas such as pinholes, undercuts and skips, however this is not nearly as desirable as good welding. MIG or TIG roots are preferred. Stick welds are acceptable provided they are within the prescribed guidelines. If welds are not, it is recommended they be ground to within acceptable parameters as assembly progresses. We recommend this be achieved by the use of die grinders fitted with suitable abrasive stones, flapper wheels, burr bits, and/or extensions as required. Not all weld defects may be visible prior to abrasive blasting. For an hourly fee, Brother’s can perform grinding as required in spooling 2” I.D. and larger on most welds within 6’ of an access. This will result in additional turn-around time on the project. Socket fit welds are not acceptable unless the I.D. at the socket has been fully seal welded and ground flush.
Spooled piping with elbows should not have lengths in excess of approximately 3’-4’ on 2”Ø and 6’-8’ on 3”Ø and up to prevent washout of elbows during blast cleaning operations and for ease of access for inspection and equipment. There shall be no run length when rise length exceeds 10’ This is to allow for access to rise welds if required. Double elbows are not acceptable. The basic rule of thumb is “line of sight” – if you can look in the pipe and see it, it can be coated. If double elbows are a necessity, elbolets are required. Maximum pipe length between double elbows is 36” center to center. Elbolets must be a minimum of 1” for 2”Ø pipe and 1.5” for 3”Ø pipe and larger. This is to allow for proper access for blasting, coating, and inspection. Alternatives are to install break flanges between the two elbows or replace one elbow (90º elbows) with a tee and blind flange. Exceptions are large diameter pipe (6”+) welded fitting or with short pups of 12” length or less in 6”Ø and larger piping.