Using standard abbreviations, line types, dimensions, title blocks and symbols ensures that engineering drawings are readily understood. The American Society of Mechanical Engineers (ASME), International Standards Organization (ISO) and British Standards Institute (BSI) have issued standard engineering drawing practice guidelines. The BSI standards are based upon International Standards Organization (ISO) standards. American drawing standards and practices are separate from other international standards.
ASME 14.100 is the standard for engineering drawing and practices. ASME Y14.1 defines standard sheet sites and formats, while ASME Y14.1M defines metric sheet sizes. ASME Y14.2 gives American line conventions and lettering. ASME Y 14.5 defines geometric dimensioning and tolerancing for American units. American drafting standards allow dimensions to be given with a maximum and minimum accepted value or with the centre value with a plus and minus tolerance. ASME Y 14.41 is the American standard for 3-D computer models. ASME Y14.38 lists the approved standard abbreviations to be used on drawings. According to "Drawing and Detailing with SolidWorks 2010" by David and Marie Planchard, "the ASME Y14 practices supersede the American National Standards Institute ANSI standards." ANSI has directly adopted ASME geometric tolerancing and drawing size standards.
British Standards are identified by the BS in front of the standard number. According to "Engineering Fundamentals" by Roger Leslie Timings, "in the UK, we use the British Standard for Engineering Drawing Practices as published by the British Standards Institute (BSI)." British Standards defined by the ISO can be referenced as BS ISO. BS ISO 128-21, which is also ISO 128-21, is the standard for general presentation of technical drawings. BS ISO 128-22 defines the basic conventions and use of leader and reference lines. BS 888 is the British Standard for technical product specifications. It also gives recommended engineering drawing practices.
ISO 7200 gives the standards for title blocks and document headers. ISO 7273 defines item lists and what should be included in a Bill of Material. ISO 5455 gives the standard scales for technical drawings. ISO 129-1 gives general standards for dimensioning of technical drawings. ISO 5457 gives the standard sizes and layouts of drawing sheets. ISO 888 defines geometric dimensioning and tolerancing standards. Surface textures are defined by ISO 1302. ISO 16792 is the management and presentation of digital production data. This refers to 3-D computer-aided drafting models.
Other International Standards
The Bureau of Indian Standards (BIS) sets engineering drawing standards for India. BIS has adopted ISO standards. Japanese Industrial Standards (JIS) sets standards for Japan when the ISO standards are not used.