P-number is a numbering system used by ASME for grouping materials of similar weldability so that Code users don’t have to qualify every material that is being welded.
Category: Pipe Welding
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This quick reference tool provides critical information on 84 safety and health topics that are specific to work performed by mechanical service technicians, including information on the newest and most frequently used refrigerants, substantive changes to NFPA 70E, and new information on how to properly administer CPR.
A contractor has liability when contracts specify meeting ASME B31 Codes. When it comes to welding procedures and welder qualification, meeting those requirements can be challenging. Those responsibilities can be met easily as members of the NCPWB by following a few simple rules that will be explained during this presentation.
When welding stainless steel and nickel alloy piping using an open root or consumable insert, the root side of the joint (i.e., the inside surface of the pipe at a weld) must be protected from the oxygen in the atmosphere, otherwise the liquid weld metal will oxidize badly creating a surface that is not only discolored but is also quite rough. This roughness and discoloration will reduce the corrosion resistance of the metal at the weld. In this webinar you will learn what is acceptable level of discoloration of the root side of the stainless-steel pipe weld and provides general guidance on the level of root surface discoloration that can be tolerated for some service conditions.
There are key aspects about pipe welding that project managers and supervisors must understand in order to be sure that welds their company makes are suitable for service and meet contract and code requirements. Despite the idea that codes are difficult to meet, when properly understood and followed, they can protect a contractor from unreasonable demands by owners and their engineers. Knowing what codes cover allows managers to identify unusual and costly requirements in customer specifications. Understanding what goes on in assembling and welding pipe joints illustrates the importance of performing inspections at critical steps. Codes impose radiography or ultrasonic examinations and customers frequently add additional requirements and knowing how to manage those requirements on a project can make or break a job.
This publication helps educate technicians and customers about ASME Code requirements for the proper installation and fabrication of welded piping systems in accordance with Welding Procedure Specifications.
Find out why NCPWB recommends the ANSI/ASME B31.9 Building Services Piping Code for quality and economy in building services piping construction.
This document explains the many tools that the National Certified Pipe Welding Bureau provides to help its members reduce the cost and risk of welding and brazing.
This article presents guidance on what to do when dissimilar metals are used in heating and air conditioning piping systems. NCPWB is grateful to ASHRAE for allowing us to reproduce this article, which was published in ASHRAE Journal, Vol. 51, April 2009.
This document explains the concept of a bend test for welds and what factors, beside poor weld quality, can cause test specimen to fail.
The document provides instruction on how to weld P91 materials and what to avoid in order to ensure a sound weld.
The document provides links to a variety of sources that offer technical Information on welding.
The document provides a guideline on how to run straight stringer beads and how to set amperages using E7018, E8018 and E9018 series electrodes.
The document is a table of suggested filler metals for SMAW process used to weld various base materials.
The document helps readers develop an understanding of the types of defects found in weldments and how they appear in a radiograph.
This document provides tips for purging various materials and pipe sizes. It also covers techniques for making purge dams and blocks.