California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4 - Division of Industrial Safety
Subchapter 2 - Boiler and Fired Pressure Vessel Safety Orders
Article 7 - Repairs
Section 788 - Repair of Corroded Surfaces

(a) Corroded surfaces in stayed sheets including tube sheets of fire-tube boilers, provided the remaining thickness is at least fifty percent (50%) of the original thickness and further provided the affected areas are not sufficiently extensive to seriously impair the safety of the object; the qualified inspector shall decide when such areas shall be repaired by other means.

(b) Corroded surfaces in plate around handholes or manholes in unstayed sheets within three inches (6") of the opening, provided the remaining thickness is not less than fifty percent (50%) of the original thickness.

(c) Calking edges of girth seams, provided the metal remaining between the rivet and calking edge to be built up is at least fifty percent (50%) of the original thickness and also provided the length of calking edge to be built up does not exceed a length equal to the diameter of the boiler. Before any welding is done, all rivets in the affected area and six inches (6") beyond each portion to be built up shall be removed. After the welded repair has been completed the rivet holes shall be reamed and new rivets driven.

(d) The building up or repair by welding of rivet heads, staybolts, braces, or attachments to braces, or grooved areas is not permitted.

(e) Scattered pits and corrosion in unstayed shells may be built up by welding, provided the largest dimension of such corroded area does not exceed the diameter of an unreinforced opening in paragraph PG-32 of the Code and providing such areas are not so located that they form a ligament in the longitudinal direction.