N.Y. Comp. Codes R. & Regs. Tit. 12 §§ 14-3.16

Current through Register Vol. 46, No. 45, November 2, 2024

Section 14-3.16 - Welded patches

(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

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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

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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.

N.Y. Comp. Codes R. & Regs. Tit. 12 §§ 14-3.16