New York Codes, Rules and Regulations › Title 12 - DEPARTMENT OF LABOR › Chapter I - Industrial Board Of Appeals › Subchapter A - The Industrial Code › Part 14 - Construction, Installation, Inspection And Maintenance Of High Pressure Boilers; Construction Of Unfired Pressure Vessels › Subpart 14-3 - Repairs, Alterations And Miscellaneous Requirements › Welded Repairs and Alterations › Section 14-3.16 - Welded patches

Current through Register Vol. 46, No. 28, July 10, 2024
(a) Flush
						patches. The weld around a flush patch shall be a full penetration weld and the
						accessible surfaces shall be ground flush where required by the applicable
						section of the ASME Code. The welds shall be subjected to the nondestructive
						examination method used in the original construction or an acceptable
						alternate. Flush welded patches shall be applied as specified in Figure
						14-3.17-1 or by other equivalent methods.
(b) Tube patches. In some situations, it is
						necessary to weld a flush patch on a tube, such as replacement of tube sections
						resulting in the restriction of accessibility around the complete circumference
						of the tube, or when it is necessary to repair a small bulge. This is referred
						to as a window patch. Window patches shall be applied as specified in Figure
						14-3.17-2 or by other equivalent methods.
(c) Lapped and fillet welded patches. Lapped
						and fillet welded patches may be applied provided they are not exposed to
						radiant heat. Lapped and fillet welded patches shall be applied on the pressure
						side of the sheet. Lapped and fillet welded patches shall have a minimum lap of
						1/2 inch. If the area to be patched includes a riveted seam, rivets shall be
						removed before the patch is applied and new rivets driven before the patch is
						welded at the edges. New staybolts shall be installed in the patched area, and
						the heads of the staybolts shall be covered by welding.
FIGURE 14-3.17(1)
FLUSH PATCHES
Image
Before installing a flush patch, the defective metal
						  shall be removed until sound metal is reached. The patch shall be rolled or
						  pressed to the proper shape or curvature. The edges shall align without
						  overlap.
In stayed areas, the weld seams shall come between
						  staybolt rows and riveted seams.
Patches shall be made from material that is at least
						  equal in quality and thickness to the original material.
Patches may be of any shape or size. Corners of patches
						  shall have a radius of such size as is necessary to avoid creating a stress
						  point.
FIGURE 14-3.17(2)
TUBE WINDOW PATCHING METHOD
Image
It may be necessary to weld a flush patch on a tube,
						  since in some situations, accessibility around the complete circumference of
						  the tube is restricted. Window patches shall be applied as follows:
a. The patch shall be made from tube material
						of the same type, diameter and thickness as the one being repaired.
b. Fitup of the patch is important to weld
						integrity. The root opening shall be uniform around the patch.
c. The gas tungsten arc welding process shall
						be used for the initial pass on the inside of the tube and for the initial pass
						joining the patch to the tube.
d.
						The balance of the weld may be completed by any appropriate welding
						process.