The words qualification and certification are probably the two most misunderstood words in the vocabulary of a welder. These two terms are erroneously used interchangeably. Often the person who speaks these words has in mind a meaning that is entirely different from what the person who hears them perceives. Generally, “certified” refers to the welder who has a certificate signed by somebody and certificates can be issued by almost anyone. A welder can get a certificate of welding proficiency on graduating from a vocational training course, high school course, community college or industrial training school. However, none of these will qualify the welder for doing code welding.
Where welding codes are concerned, specific qualification tests are spelled out by the various codes.
Often the statement, “I’m a certified pipe welder” leaves unanswered questions such as:
(1) Qualified to what pipe welding code? There are several.
(2) Qualified for what procedure? For what position; what type of electrode and base material; what thickness of base material?
Another question is that of duration of the qualification. Some qualifications, such as AWS, are considered to remain in effect indefinitely unless the welder is not engaged in a given process of welding for a period of three months or more, or unless there is some specific reason to question the ability of the welder.
Code Welding
Every welding operation is intended to be carried out to assure operator performance at a stipulated level of quality for a given design, with certain built-in
safety factors. These performance features may be required by shop standards, customer specifications, or rules and regulations of a specific code.
A code is generally considered to be the most rigid of these requirements, since it carries the implication of law, and in some cases, actually is a law enacted by a government body. Standards are commonly included or referenced in the code in a municipal, state or federal government project to establish limits and controls over some features of the code. Some examples are a municipal building code, a state boiler and pressure vessel code, or a federal highway bridge code.
A properly worded code does not include explanatory matter. Since the features outlined in the code must be enforceable as a law, the code is written in mandatory language, using the imperatives “shall” and “must,” or equivalent words. Explanatory matter is relegated to other documents or to appendices.
The most frequently cited codes involving the welding industry are the ASME Boiler and Pressure Vessel Code and the AWS D1.l Structural Welding Code-Steel. Other codes and standards, such as API 1104 Standard for Welding Pipelines and Related Facilities, and ASME B31, Code for Pressure Piping, include specified qualification tests.
There may be other instances when a welder may be qualified to a code, even though the work being done is not involved with such a code. This frequently happens when shop welding personnel are qualified to the Dl.l, D1.2, D1.3, and D1.4 series of the AWS Structural Welding Codes.
Requalification- Some codes require requalification for every job. For example, even though a person may have qualified as an EXX18 welder (most qualifications are by type of electrode) on a certain building, that qualification may not be accepted at another building site, although it can be accepted at the option of the local building commission and the owners or architects. In most areas, even though a welder may still be working for the same contractor, the owners or architects of a new project will usually call for requalification of all welders involved. The same is true in most types of pressure vessel and pressure piping work. A welder will also be required to requalify when certain changes in the welding procedure are made. These changes are listed in the codes as Limitations of Welder Qualification.
A welder is qualified after passing a particular qualification test. For example, a welder might b,e qualified under the requirements of Section IX of the ASME Boiler and Pressure Vessel Code. In general, an employer is responsible for assuring that welders are given the correct qualification tests before work begins, since the employer is responsible for the work of the welders.
The welder who wants to be certified (not just qualified), should learn and practice the procedures described in AWS B2.1 latest edition, Standard for Welding Procedure and Performance Qualification Procedure, issued by the American Welding Society, as well as any particular requirements of the specific codes governing the type of work the welder wants to do.
Qualification. There are two distinct steps toward qualification. The first is qualification of the welding procedure; the second is qualification of the welder.
The procedure qualification is a common requirement of all codes and specifications governing welding. Its purpose is to test the capability of the procedure to produce a satisfactory welded joint, although this does not guarantee that all welds made under the procedure will be satisfactory. It merely serves to prove that satisfactory welds can be made by following the various steps of the procedure. Quality in welding depends on a great many interrelated factors, in which the procedure is the dominating control.
The second qualification is a test of the welder’s ability to perform the work; this is a mandatory requirement in many codes. Again, passing this test is not a guarantee; it merely proves that the welder has the ability to make satisfactory welds under given circumstances.
Procedure Qualification- Before taking the welding procedure qualification test, the welder will have to select a welding process, equipment, and materials, then design appropriate weld joints, and conduct trial welds. Each of these must be considered according to the metallurgical and mechanical properties of the materials involved, the degree of weld soundness or quality required, and cost. The step-by-step method which evolves is the welding procedure, and all codes require that it be in written form. The procedure may be expressed in broad, general terms, or it may be explicit in detail, depending on the class of work or type of product being welded, the ease or difficulty of
reproducing satisfactory welds, and the knowledge, skill and integrity of the person doing the work. The welding procedure is a written specification covering the necessary steps to be taken to produce a satisfactory weld.
Test Administration- Most codes are not specific on the point of who is to do the testing, but usually leave it to the option of the fabricator (or owner). In order to become certified under an AWS code, the welder must take the qualification test at an AWS accredited test
facility. While the architect or owner may demand control over testing, in most cases they do not, leaving it up to the contractor. The latter, however, is responsible for every weld made during construction, so the contractor must document the qualification of each procedure used and of every welder working on the job.
The qualification test record, or certification of procedure or welder, generally calls for the signature of the person conducting the test, as well as that of an individual who witnessed it. Whether they are employed by the weld fabricating company or by an independent testing laboratory, they are responsible for documenting the qualification.
Preparation of the test specimen is a key factor in the success of the mechanical tests; improper preparation of a specimen may cause it to fail.
There are five different types of codes which require weld qualification: (1) industrial (AWS, ASME, API, AWWA, and others); (2) military (NAV- SHIPS, MILSPEC; (3) governmental (local, state and federal); (4)consumer or customer specifications, and (5)manufacturers specifications on products for which weld quality is mandatory, but for which there are no existing specifications.
In many product areas, the influence of the insurance companies affects the codes. The insurers, while not code-writing bodies in themselves, have been influential in having codes written since the beginning of welded fabrication. The insurance companies got involved in metal fabrication in the early days of this century with the introduction of pressure vessels of riveted construction. This culminated in 1915 in the publication, by the American Society for Mechanical Engineers, of the first Boiler and Pressure Vessel Code, which is updated as required and is considered the bible of the industry.
Nuclear Systems Code
ASME’s responsiveness to the needs of nuclear systems development and for public safety led to the first Nuclear Systems Code. This was accomplished through a close relationship with the Atomic Energy Commission, which requested that one organization accept responsibility for codifying the pressure boundary of the entire nuclear system. As a result, Section 111 of the Boiler and Pressure Vessel Code, initially published in May. 197 1, includes rules for design, fabrication and inspection of various classes of nuclear components such as piping, vessels, pumps, valves and metal containment vessels. Previous issues had included provisions for nuclear vessels.