A weld map is a version of the drawing used to number each of the welds or joints contained within it. The process of numbering or annotating each weld’s location is what turns the standard drawing into a map. See the weld map example below; this example includes nine welds and two segments or piping spools. You can find these nine welds documented on the weld log in the example later in the article.
The weld map is the foundational document for creating a weld log. The numbered joints on a weld map correspond to the numbered rows of the weld log. Using both documents in tandem provides the most value. The benefit of the weld map is that it creates the weld’s visual position on the map. The advantage of the weld log is that it documents the who, what, when, and how of the weld.
In some limited cases, weld details are included on the map, and no separate log is generated. In these situations, the project requirements are minimal and may only require one or two properties to be associated with the weld. In these cases, there may be a small table applied directly to the weld map, often in the area of the bill of materials. Embedding the log on the map can create a confusing situation for terminology, but this is still referred to as the weld map. This situation primarily exists in pipe spool fab shops or some structural shops. The disadvantage of this convenience is the ability to effectively track the progress of welds and maintain the cleanliness of documentation used to turnover to the client. In most cases, many data fields must be documented, which requires the standard two document, “map + log” approach.
The styles of annotations used for the weld numbering can vary between companies. Most situations involving manual mapping utilize common shapes found on drawing stencils, the hexagon, circle, or square being the most common. The weld number annotation style must also consider what shapes have already been utilized by the drawing to communicate item numbers and other such things. It is advisable to follow a company standard that helps the project team distinguish between weld numbers and item numbers. Welding codes do not specify the shape of the annotation used in weld mapping. In some cases, a company's past practices, quality manuals, or client specifications may designate what is used.
A weld log is a table style document that contains data in rows and columns used to document weld details.
Weld log rows correspond to the numbered joints on the weld map. Weld log columns correspond to the required documentation fields of the weld.
Weld log columns typically include
Weld maps & weld logs are standard where the product produced will be placed into service where there is an elevated level of risk; as risk increases, so do the inspections and documentation level. Each welding code, client, and company will have a standard practice to address the requirements applicable to the scope of your project.
These factors create a situation where there is no single standard used for a weld log. Many weld logs will have common elements as there are substantial overlaps from different codes, clients, specifications, and company practices. The lack of standardization, to some extent, causes some confusion in the industry as to what is “right” or “wrong” to include on the weld log. What is most important to remember is that the fields included on the weld log satisfy the contractual requirements and can be used to benefit business needs.
The documents must be created by a competent person that can deliver the work in an organized and tidy manner. As such, the author can vary due to project team sizes, a mixture of staff talents, individual responsibilities, and a company’s organizational supporting structure. Where specialization exists amongst larger project teams, it is common for a staff person from the quality department to perform the creation of the weld maps and logs. On small teams, such as on a maintenance crew, the foreman will likely create the map and may, in very limited situations create the weld log. In both cases, the inspector still performs the required inspections.
Weld maps & weld logs provide the following benefits
Depending on the industry, client, specifications, codes, and company quality program, other forms of mapping may be used or required on a project. These different types of mapping may include heat number mapping, thickness mapping, or welding procedure specification (WPS) mapping.
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