Standards and Codes

A standard is a set of specifications for parts, materials, or processes intended to achieve uniformity, efficiency, and a specified quality. One of the important purposes of a standard is to limit the multitude of variations that can arise from the arbitrary creation of a part, material, or process. A code is a set of specifications for the analysis, design, manufacture, and construction of something. The purpose of a code is to achieve a specified degree of safety, efficiency, and performance or quality. It is important to observe that safety codes do not imply absolute safety. In fact, absolute safety is impossible to obtain. Sometimes the unexpected event really does happen. Designing a building to withstand a 120 mi/h wind does not mean that the designers think a 140 mi/h wind is impossible; it simply means that they think it is highly improbable. All of the organizations and societies listed below have established specifications for standards and safety or design codes. The name of the organization provides a clue to the nature of the standard or code. Some of the standards and codes, as well as addresses, can be obtained in most technical libraries or on the Internet. The organizations

of interest to mechanical engineers are:

Aluminum Association (AA)

American Bearing Manufacturers Association (ABMA)

American Gear Manufacturers Association (AGMA)

American Institute of Steel Construction (AISC)

American Iron and Steel Institute (AISI)

American National Standards Institute (ANSI)

American Society of Heating, Refrigerating and Air-Conditioning Engineers(ASHRAE)

American Society of Mechanical Engineers (ASME)

American Society of Testing and Materials (ASTM)

American Welding Society (AWS)

ASM International

British Standards Institution (BSI)

Industrial Fasteners Institute (IFI)

Institute of Transportation Engineers (ITE)

Institution of Mechanical Engineers (IMechE)

International Bureau of Weights and Measures (BIPM)

International Federation of Robotics (IFR)

International Standards Organization (ISO)

National Association of Power Engineers (NAPE)

National Institute for Standards and Technology (NIST)

Society of Automotive Engineers (SAE)

Economics

The consideration of cost plays such an important role in the design decision process that we could easily spend as much time in studying the cost factor as in the study of the entire subject of design. Here we introduce only a few general concepts and simple rules. First, observe that nothing can be said in an absolute sense concerning costs. Materials and labor usually show an increasing cost from year to year. But the costs of processing the materials can be expected to exhibit a decreasing trend because of the use of automated machine tools and robots. The cost of manufacturing a single product will vary from city to city and from one plant to another because of overhead, labor, taxes, and freight differentials and the inevitable slight manufacturing variations. All of the organizations and societies listed below have established specifications for standards and safety or design codes. The name of the organization provides a clue to the nature of the standard or code. Some of the standards and codes, as well as addresses, can be obtained in most technical libraries or on the Internet.