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Subchapter 2. Boiler and Fired Pressure Vessel Safety Orders
Article 7. Repairs

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§789. Permissible Repair by Seal Welding.

(a) The ends of all tubes, suspension tubes, and nipples of water-tube boilers and superheaters may be seal-welded in accordance with the provisions of paragraph PWT-11 of the Code.

(b) Seal-welding of circumferential joints is permissible, provided the seam is calked first and made tight under hydrostatic pressure equal to the working pressure.

(c) The ends of fire tubes may be seal-welded provided the thickness of the tube is at least seventy-five percent (75%) of its original thickness, and the tubes are first rolled and beaded and found tight under hydrostatic pressure at least equal to the working pressure. The throat of the weld shall not exceed three-sixteenths inch (3/16").


1. Amendment filed 11-2-66; effective thirtieth day thereafter (Register 66, No. 38). Approved by State Building Standards Commission.

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