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How to Read a Mechanical Blueprint

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Blueprints are a set of schematic drawings of a project that contractors will use to install, maintain or troubleshoot a structure. Mechanical blueprints illustrate the characteristics and features of the intended product in explicit detail. These drawings render the subject from a number of different perspectives and levels of depth. For example, a mechanical blueprint of a home will include a view from the foundational level used for excavation and the electrical perspective used for wiring.

Recognize that blueprints represent a multidimensional view of a structure to be built. This is usually reflected in a group or collection of blueprints where each page is called a sheet and each sheet depicts a different layer or floor of the project. For example, a two-story home may have five sheets in its blueprint set. There will be one for the foundation and two others for the first and second floor.There will also be one for the electrical systems and one for the plumbing.

Understand the naming conventions. Each sheet will have a title block that provides profile information about the project, its owners, the date the plan was created and the developer of the blueprint. Sheets are individually identified with a letter and number sequence. For example, a structural or foundation page will be numbered "S-1" or electrical page "E-2."

Identify the content of each section. Architectural pages show the structure in its environment. Structural pages show the concrete, masonry, wood framing, roof and plumbing. Mechanical pages show the HVAC and electrical pages depict the wiring systems.

Learn the symbols. Draftsman use specific symbols and notations for each item or entity in the structure. Builders can acquire a listing of the common symbols from Los Alamos National Laboratory Engineering Drawing Standards, Engineering Edge, and Training Update.