GE 497 Senior Design

Engineering Standards

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Engineering Standards

• Standards are detailed documents that may be rules, testing methods, definitions, recommended practices, or specifications that promote uniformity for engineering design, industrial practices, and terminology.

• Engineering standards are developed by experts within each technical field.

• They are usually developed in consultation with professional societies such as IEEE and ASME.

• There is usually ample opportunity for input by a broad constituent group of professionals and academics.

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Reasons to Use Engineering Standards

• Standards promote safety.The Uniform Principle of Safety

• Standards promote technological development.Concurrent development of hardware and software

• Standards promote ease of interfacing.Standardized parts

• Standards promote uniform performance.Predictable behavior

• Standards promote fairness.

• Standards promote professional development.

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Standards Organizations

• National Institute of Standards and Technology (NIST)Standardized weights and measurements,

technological standards.

• Underwriters’ Laboratory (UL)Safety standards, especially for electrical appliances

• National Electric Code (NEC)Safety standards, especially for electrical utilities

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More Standards Organizations

• American National Standards Institute (ANSI) Variety of standards ranging from ASCII codes to nuts

and bolts

• International Standards Organization (ISO) International standards, usually in quality (ISO-9000)

and sustainability (ISO-14000)

• Occupational Safety and Health Administration (OSHA)Safety standards, especially in the workplace

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Professional Societies and Standards

• American Society of Mechanical Engineers (ASME)Safety standards, especially for pressure vessels

• Institute of Electrical and Electronics Engineers (IEEE)Electronic standards, especially for computer and

communication hardware and software

• Society of Automotive Engineers (SAE)Automotive standards, especially safety and

performance

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Standards Promote Safety

• Standards ensure both quality and specifications

• Guidelines for use can become standardized into codes

• Safety is promoted through vast deployment

• Lowers liability for companies

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Standards Promote Technology Development

• When a standard is developed for a product, many competitors can design for that product

• This increases choice, drives down cost, and improves quality

• This open-architecture can drive an entire market

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Standards Promote Ease of Interface

• Many systems are integrated from several manufacturers

• Standards allow pieces to fit together, and design to be independent

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Standards Lower Cost

• A standard part gives rise to economies of scale

• Standardization reduces cost through lowering of inventories and simplification of supply chains

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Standards Promote Ease of Maintainence

• If parts are standardized, tools can be standardized as well

• Ease of inventory allows swapping of parts

• Standardization of parts allows a more intimate knowledge of each system.

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Ethics of Standards

• Standards promote safetyhold paramount the safety, health and welfare of

the public

• Lowers Cost to Consumerserving with fidelity the public

• Builds on expertiseperform services only in areas of their competence

Standards exist for Ethics, too!

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Corporate Standards

• In addition to industry-wide, national, and international standards, some companies have their own standards for safety and performance that may exceed required standards.

• It is very important to learn and follow these standards when you work for such a company.

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Programming Standards

• Many organizations require standard programming procedures. For example:

Maximum line length of 80 characters

Variables start with a lowercase letter. 

All word breaks should start with a capital with no delimiter between them.   

All variables should have names that represent their function.

Class names shall start with a capital letter

All functions shall be preceded with a comment listing usage of function, arguments, and return types. 

Comment block shall have a 60 character "***" line on top and bottom.

Function names shall be verbs, and class names shall be nouns

Constants shall be in all CAPS with underbars separating word breaks

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Standards Are Expensive!

• It costs a great deal of money to develop standards.

• Companies and organizations recuperate that cost by selling the standards to companies and individuals, usually at a discount to their own members.

• Several hundred dollars is a small price to pay for a large company, but it is a lot of money to an individual.

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Standards Can Be Complicated

• Most standards are hundreds of pages long, because they must fully specify the exact specifications and behavior of each element of the system described.

• It takes a great deal of time to thoroughly understand even one standards document.

• Doing so will make you very valuable to your employer!

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A “Short List” of Electrical and Mechanical Standards for GE 497/8

In this class, you must comply with the eight standards to be described in this lecture along with any other applicable standards specific to your project.

1. All devices using 120-V AC power shall use copper wire of at least 14AWG to carry up to 20A, 12AWG to carry up to 25A, and 10AWG to carry up to 30A. (National Electrical Code Table 310.16)

2. All devices using 120-V AC power shall be grounded and shall use a grounded plug. (National Electrical Code 250.20(B))

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A “Short List” of Electrical and Mechanical Standards for GE 497/8

3. All grounding connections shall be made using wire sized to match the over-current protection device of the outlet: 15A protection uses 14AWG, 20A uses 12AWG, and 30 A uses 10 AWG. (National Electrical Code Table 250.122)

4. Standard 22 AWG hook-up wire can carry a maximum of 7A in unbundled applications and 0.92A in bundled applications. 30AWG “Wire-wrap wire” can carry 0.86A in unbundled applications and 0.142A in bundled applications. (Handbook of Electronic Tables and Formulas)

5. No exposed conductors shall be at more than 14V DC above ground or above any other exposed conductors. (Underwriters’ laboratory standard 1446)

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A “Short List” of Electrical and Mechanical Standards for GE 497/8

6. All systems containing compressed gases or liquids shall comply with the ASME Boiler and Pressure Vessel Code (BPVC).

7. All devices with exposed surfaces exceeding 140°F shall be clearly marked with warning labels. (Occupational Safety and Health Administration)

8. All lasers used in this class shall be limited to less than 5mW, and appropriate signage must be used. (ANSI standard Z136.1)

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Key Take-Aways

• Engineering standards promote the success of engineers in every field of study.

• They make people’s lives safer, more productive, and more efficient.

• You will need to follow corporate, industry, national, and international standards in your career.

• In this class, you need to follow the eight standards in this lecture as well as any other standards directly applicable to your project.