Full Description

Many process plants such as refineries, chemical plants and power plants have undergone the operation as long as more than forty years not only in Japan but also in other industrial countries. It means that the equipment maintenance of these plants has emerged as a key technology for ensuring the safe and reliable operation of plants. Consequently, the role of repair welding has increased to a larger extent, causing a great demand for the development of recommended systematic and practical practices of repair welding.

The Chemical Plant Welding Research Committee, hereafter called the Committee, issued "Guideline for Repair Welding Procedure" in 1983 and revised it in 1993, as one of the main activities of the Committee. Since it has been more than 10 years after the last revision, the renewal of the Guideline is strongly requested by the industries waiting for an advanced issue including practical know-hows.

With this background, the Working Group for Repair Welding of Pressure Equipment was launched in 2001 in the Committee, and advanced to the Subcommittee on Repair Welding for Pressure Equipment (Chaired by E. Yamamoto) in 2004. The Sub-committee was set up with 35 members of qualified engineers including end users, material suppliers, equipment fabricators, engineering constructors, maintenance and inspection coordinators to make "Examples of repair welding" and 'Technical data sheets related to repair welding" which can be used in the study and performance of repair welding of pressure equipment.

In Phase I of the activity, the Sub-committee formed a basis for technical database of repair welding by surveying more than 100 literatures. In addition, it reviewed the latest status of regulations, codes and standards related to repair welding of pressure equipment in Japan and other countries including ASME and API.

In Phase II of the activity which started in 2004, ?Guidelines for repair welding? was made as an engineering reference including the analysis of the state and cause of damage, the diagnosis of equipment by fitness-for-service (FFS) assessment, the study on the necessity and availability of repair welding, the practice of repair welding and post-repair maintenance. The product of the activity has been released at the National Symposium year by year, and also presented at the international conferences such as ASME-PVP with remarkable attentions.

In 2009, the activities were compiled into one handbook, Committee issue CP-0902, 'Guidelines for Repair Welding of Pressure Equipment in Refineries and Chemical Plants" as the first practical repair welding guideline. The contents of CP-0902 were presented in six papers at ASME-PVP Conference, Baltimore, ML in 2011, and a part of them was announced at ICPVT-13 Conference, London, UK in 2012. Furthermore, the summary of the PVP conference papers was published in ASME Journal of Pressure Vessel Technology in 2013.

Oil refinery and petrochemical industries have strongly called for the standardization of repair welding practices of pressure equipment in service. In compliance with these needs, the Committee has played an important role in the standardization of repair welding for post-construction maintenance. The product was published in July 2012 as the Japan Welding Engineering Society Standard, WES 7700 "Repair Welding of Pressure Equipment." WES 7700 consists of 4 Parts: Part 1 General, Part 2 Flaw excavation and repair welding, Part 3 Butt-welded insert plates and Part 4 External fillet welded patches. The follow-up works are under progress to promote WES 7700 in the industries and related regulatory bodies

The maintenance standards for plant equipment primarily consist of three specifications for inspection, assessment and repair. Although the procedures for fitness-for-service (FFS) assessment and risk-based inspection (RBI) have been standardized in advance, the standardization of flaw repair methods has not been well developed. The issue of this guideline will form a substantial contribution to the safe operation of plant equipment in the world.

The Committee has published an English version of the handbook, CP-0902E, "Guidelines for Repair Welding of Pressure Equipment in Refineries and Chemical Plants" for the maintenance of pressure equipment in process plants.

The Committee, which exerts efforts to develop and improve the repair welding technologies for pressure equipment, appreciates the cooperation and cordial support for our activities from the engineers in various industries worldwide.

Product Details

Published: 2016 Number of Pages: 164 File Size: 1 file , 11 MB