3.1.1 Standards for Safety and Reliability

Much has been learned about how to create effective standards for safety and reliability since the early efforts. Even the codes for protection from fire have evolved and expanded. Much of Baltimore burned in 1904 because fire crews sent from other cities to help found that their hoses could not be connected to the Baltimore fire hydrants. This lesson was learned again in 1991 in Oakland, California, when thousands of houses were burned, in part because fire departments from neighboring jurisdictions found themselves unable to connect with the hydrants in that city (Note that in neither of these two cases was this a failure of standards due to lack of conformity assessment. In each case the city had selected a product that happened not to be compatible with tools available in other jurisdictions.). Standards for interchangeability thus play a significant role as safety standards.

The National Fire Protection Association (NFPA) has developed several hundred standards to enhance safety. Some of these are aimed directly at preventing fires, but these standards have evolved to serve other purposes as well. The National Electric Code (NEC) was developed by the NFPA because of the large number of home fires caused by arcing and overheating due to overloaded wiring and unsafe installations. It has evolved, however, to include other aspects of safety, such as requirements for ground fault circuit interrupters to reduce the risk of electrocution. With adoption by most jurisdictions in the United States, it has become the accepted standard guiding the design, installation, and inspection of practically all home and commercial electrical installations in the country. While the primary purpose of the NEC was originally increased safety, this standard now has the added benefits of reducing the costs of construction and insurance, and increasing the confidence of home purchasers.

Another organization that has developed a large number of standards (∼600 as of this writing) is the American Society of Mechanical Engineers (ASME). In 1883, an ASME committee on standards and gauges was created, and in 1884 the ASME published its first standard to provide uniform test requirements for boilers. ASME is perhaps most known for the Boiler and Pressure Vessel Code (BPVC), first published in 1914, but it also has standards for materials, fasteners, cranes and other lifting devices, and more. Since that time the BPVC has grown from 114 pages to comprise 28 volumes, including 12 volumes on nuclear components. The ASME B31 piping codes perform a similar role for piping systems in many applications from gas distribution to industrial refrigeration to chemical plants and petroleum refineries.

The BPVC is effective in enhancing safety because it provides a structured way of designing and constructing pressure vessels, including standard materials and designs, standard design processes, limitations on material stress, as well as nomenclature and symbology, and its use involves a rigorous conformity assessment process. Among its standards are those for materials and materials testing, ensuring predictability of material properties. These lead to greater understanding and confidence on the part of engineers using these standards, as well as ensuring designs that effectively serve their intended functions.

The BPVC volumes on welding and nondestructive evaluation help round out the BPVC, ensuring that implementation of a quality design is performed with proper process control and inspection, resulting in a product that effectively meets and safely performs its intended function.

All volumes of the BPVC are quite prescriptive, and while many choices are still made by the designer, once a design approach and materials are selected, there are many specific requirements that must be met.

Standards from the American Institute of Aeronautics and Astronautics (AIAA), reflecting the more recent development of the aerospace industry and the continued evolution in products used, tend to be less developed, and therefore more performance based, but they still aim to provide for a safe and reliable product. Because weight is of critical importance, aerospace standards provide for increased use of composites and new design concepts, but they still specify safety factors on stress and on life, as well as stringent control of quality. When new challenges are recognized, such as the previously unknown time-dependent failure mode referred to as stress rupture, standards developing committees move to update the standards in order to address them.

Finally, a simple standard of uniformity for the purposes of safety, which most of society takes for granted, is the PRNDL (Park-Reverse-Neutral-Drive-Low). This is the federally mandated order for features in an automobile automatic transmission. Because of the PRNDL we can get in a car, start the engine, and drive away, confident that we will not accidentally shift into Reverse when we intend to put the car in Low or Drive.

The importance of the PRNDL never fully impressed one driver until he had the opportunity to drive a Model T Ford. On a Model T, there are three pedals (just like in a current model manual shift vehicle – almost) and there are two levers on the steering column (again like a current model vehicle – almost). This familiar appearance gives the driver of cars with a stick shift immediate confidence, until a closer look reveals that the lever on the left side of the steering column does not operate the turn signal and high beams (there are none – no standard required them), and the right lever does not operate the windshield wipers and washers (none of those, either – who thought of them?) (That lever on the left is the spark advance–retard, and the one on the right is the throttle (no gas pedal!?). The right pedal is the brake, the middle pedal is forward–reverse, and the left pedal is high, neutral, and low. This particular driver found himself pushing the Model T away from his rental car after a fortunately very low speed collision.

Other more recent standards for safety and reliability include those for biomedical devices, computer hardware and software, and protection of the environment.

3.1.2 Standards to Reduce Cost

Many standards have been developed to provide predictability and dependability of design through use of standardized components and standard configurations. This provides for a simplified design process, permits development of preapproved lists of products and product standards, and avoids the need for requalification for every application.

Component standardization makes possible the specification of pipe sizes, for example, with the designer having confidence that the product will be available, that standard off-the-shelf fittings and flanges can easily be procured for it, that the pipe has a known pressure–temperature capability (given a particular material and wall thickness), and that future modifications will find compatible products as needed. Many of these standards include pressure/temperature ratings as well as the physical characteristics and material properties, eliminating the need for analysis every time that a component is used.

Similarly, standard door, latch, and lock sizes simplify the design process for architects and make it easy for homeowners to purchase hardware replacements and upgrades for their homes. Other standards for such things as wall electrical receptacles, tire sizes, bearings and bushings, and USB ports expand this benefit.

An engineer recently arrived from a less developed country was doing some design work. Her supervisor stopped by her desk one morning to check on progress, and was told that she was designing a bearing for a wind tunnel access hatch. When showed a catalog of standard bearings, she was almost overcome. “You can just order these!?” Because of lack of standards and lack of stock, she was used to designing from scratch essentially every component that she used. She was overjoyed to find that she could now look up standard components, specify them, and apply the standard dimensions to her designs.

The full benefit of the economies of scale that came with the industrial revolution could not be realized until standardization of components allowed manufacture of product components without the producer knowing the end product. While there will always be a need for specialized fasteners, the existence of standard screws, bolts, and nuts, available at the local auto parts or hardware store, has reduced costs immensely.

Relatively recent engineering standards include many related to information technology. Printers, scanners, monitors, memory devices, and other components can simply be plugged into the backs of computers, using USB or other plug configurations that are all available at electronics stores. Inkjet printers have become so inexpensive that companies now sell them at little more than the cost of an ink cartridge, just to get the business of selling the replacement cartridges (remember the safety razor?). Even the internal components of a computer have become sufficiently standardized that a novice, after minimal study, can purchase a housing, power supply, motherboard, memory, and other components, and with a reasonable investment of time and effort, produce a working computer capable of running standard operating systems, software applications, and games, often better than the products available on the open market as completed assemblies.

Motors with standard power, torque, and speed ratings are available, with standard mounting configurations, shaft sizes, and power demands. If a manufacturer finds a shortage of a drive component, or a user finds that a component has ceased to work, another can likely be substituted with no decrease in performance and essentially no downtime.

The same standard materials that enhance safety through predictable properties allow designers to work with confidence, without testing materials for themselves. Many materials, after having been subject to rigorous process control, have been tested and certified by the manufacturer (steel mill, plastic manufacturer, etc.) in accordance with accepted industry standards for material chemical and physical properties. This process is referred to as conformity assessment and is discussed in Chapter 8.

3.1.3 Standards for Increased Flexibility

Standards developed for increased flexibility and those for reduced cost are often difficult to distinguish, since their roles go hand in hand. Until the 1990s, students wishing to take the train from France to Madrid found that an unexpected drawback to taking the overnight train was that they were awakened at the border in the middle of the night, not just to show their passports, but because the train cars were lifted onto new trucks, or the gauge of the trucks on the cars was adjusted, to accommodate the different rail gauge then in use in Spain. It would be hard to say whether the inability to share rolling stock, the labor to change the trucks, the inability simply to keep the trains rolling, or the inconvenience was the greatest cost. In the early days of railroads in North America rail gauges were not standardized. Because of the economic challenges associated with varying rail gauges, Canada had converted to “standard gauge” by 1880, and by 1886 the railroads in the United States had converted as well.

In some cases, manufacturers have maintained internal standards different from each other or even from an industry standard. This is usually done in hopes of continuing to control a market. There are benefits and drawbacks of this approach. It is a difficult situation to maintain, and most companies that have tried have not been successful. In some cases, the standard is maintained as a secret, as with a large soft drink company, which has maintained a prominent position in the soft drink market for well over 100 years. A prominent computer company has been successful in maintaining its own standard, but it nearly went under because of it during the 1990s. Several manufacturers of tube fittings and other piping components have been fairly successful in maintaining unpublished internal standards due to a reputation for quality, combined in some cases with a certain amount of mystique, but the tendency is for these suppliers to be marginalized as more and more customers opt for the greater level of flexibility that is provided by common industry standards. The ability to purchase with confidence a product, sight unseen, is hard to beat.

3.1.4 Standards for Promotion of Business

The reader has probably by this time observed that the benefits of a single standard often fall into a number of areas. What makes a product safer, more reliable, less expensive, and more flexible in its application will typically promote product sales as well. Automobiles are more reliable because the materials of which they are made are well defined, the tolerances are good, and electronic components have been produced using precise process control. Customers who used to expect to have spark plugs replaced every three to five thousand miles now may not have to replace spark plugs during the life of their vehicle.

The same customer is also more willing to make other purchases because she knows how much light to expect from a light bulb, that the battery she orders online will work in her smart phone, and that the sheets she purchases will fit her bed (The standards for clothing sizes are less well defined, and thereby less effective.).

In years past, Swedish knives had a reputation for quality, although for a long time, there was little understanding of why. Now that standards for steel call out how much carbon, sulfur, molybdenum, and other alloying elements and impurities they contain, and how they are worked and heat treated, customers can purchase quality knives from many more sources.

In business, engineering, and industrial settings, similar motivations apply. Consistent expectations allowed by standards drive sales of machine tools, allow faster and easier design and production of heat exchangers, and help chemical producers sell great volumes of their products.

Many businesses, in order to be more competitive in a world market, adopt not only local standards but also international standards such as ISO to enable them to compete on the same level with other companies. Unfortunately, there are sometimes competing international standards. Thus, the international standard used in one continent, say Europe, may not be the same as that used on another continent, say Asia. This sometimes forces businesses doing international work to be familiar with multiple international standards for the same product.

3.1.5 Standards to Help Society to Function

It used to be that the use of credit cards and their billing entailed thousands of keypunch operators keying in millions of credit card numbers and dollar amounts every day. Engineering standards for credit and bank cards and the machines that accept them ensure that consumers can drive into a gas station almost anywhere, purchase a tank of gas, and drive off, usually without even the need to interact with the gas station attendant. The use of barcode scanning and a credit card swipe at a department or hardware store allows customers to purchase, and stores to sell, in much less time than used to be required, including (for better or for worse) a complete record of purchase, time, and other information.

Everyone knows what a stop light means, and the standardization of red light on top ensures that even people who suffer from red–green color blindness know when to stop. Similarly, a double yellow stripe on a pavement or highway indicates a no-passing zone.

Mobile phones can be purchased new or used, online or in person, and can be activated and used on the systems of multiple carriers, and the apps available for smart phones are endless.

The standards for these items, while also featuring one or more of the benefits noted in the previous sections, simply make life easier and more enjoyable, allow the traffic to flow, and help a modern society function. Similarly, standards give people the ability to purchase components with confidence, sight unseen. Hence a purchaser buying over the Internet a class 150 flange from Supplier A or Supplier B is assured of having the same quality and performance from either supplier.

3.1.6 Consistency

Standards help maintain consistency in a wide range of commercial and consumer products. One example is the shape and size of an electrical outlet in a given country. Many manufacturers produce electric receptacles for a given country and they all fit the appliances connected to them in that country. Of course if a single standard were used worldwide, then the receptacles and plugs would also be compatible from country to country.

Another commercial product line includes standard flanges used for pipes and pressure vessels. In the United States most of these are specified to be in compliance with the ANSI B16.5 standard so they can be purchased from manufacturers anywhere and still be interchangeable.

While electrical receptacles and flanges are manufactured to dimensional standards for consistency, other aspects of consistency in standards involve design methodologies. Hence, a designer in the United States using the ASME BPVC will come up with the same required thickness for a given cylindrical shell as a designer using the same code in India. Such consistency in design helps world trade.

3.4.1 National Codes

The terms code and standard are often interchanged in conversation. However, a code is also often a body of standards grouped together for ease of reference. Technical codes cover a wide range of disciplines ranging from electrical to mechanical to structural. They form the basis for safe, consistent, and effective designs in various fields. Codes are normally specified in the design documents of a project.

There are instances where either of two well-recognized codes can be used in solving a given engineering problem and the engineer has to decide which one to use. A case in point is the National Board Inspection Code (NBIC) and the American Petroleum Institute (API) 579 code, both of which address the repairs and alterations of pressure vessels. These two codes have different requirements but the end result is close to the same for a majority of cases. An engineer repairing a pressure vessel needs to be familiar with both of these codes in order to make a rational decision on which one to use.

3.4.2 International Codes

In addition to the United States, many other countries have established codes that are used nationally and internationally. These codes are written by committees assembled by the appropriate jurisdiction. These committees operate in a manner more or less similar to those in the United States that follow the ANS process. Appendix B lists some American and international organizations that are engaged in writing standards and codes.

3.5.1 American Society of Mechanical Engineers (ASME)

ASME is one of the most prolific standards developing organizations in the United States, having developed thousands of general consensus standards, research publications, technical journals, and engineering books and pamphlets. ASME is ANSI accredited, and it relies on a large number of volunteers and numerous staff members for maintaining its activities. The background of the volunteers spans a wide range of disciplines such as engineering, metallurgy, nondestructive examination, welding, and materials. A visit to the ASME website at www.asme.org reveals a wide array of technical books and pamphlets available to the engineer. ASME also publishes, at regular intervals, over two dozen technical journals, all written by volunteers, with a small production staff that takes care of the mechanics of publishing.

A related entity, the ASME Standards Technology, LLC (stllc.asme.org), manages theoretical and experimental research related to mechanical engineering in the areas of analysis, metallurgy, welding, and nondestructive examination. Published reports of the research activities are available from ASME.

Some of the fields in which ASME develops standards:

• Boilers, pressure vessels, and nuclear components
• Elevators, escalators, and moving walkways
• Piping and pressure relief devices
• Flanges, gaskets, valves, and fittings
• Cableways, cranes, derricks, and hoists
• Screws, threads, and bolts
• Pumps.

Each of the above areas is addressed by numerous standards and codes. For example, the ASME Boiler and Pressure Vessel Code consists of the following sections:

• Section I. Rules for Construction of Power Boilers

• Section II. Materials

  Part A. Ferrous Material Specifications

  Part B. Nonferrous Material Specifications

  Part C. Specifications for Welding Rods, Electrodes, and Filler Materials

  Part D. Properties

• Section III. Rules for Construction of Nuclear Facility Components

  Subsection NCA. General Requirements for Division 1 and Division 2

  1. ο Division 1
     • Subsection NB. Class 1 Components
     • Subsection NC. Class 2 Components
     • Subsection ND. Class 3 Components
     • Subsection NE. Class MC Components
     • Subsection NF. Supports
     • Subsection NG. Core Support Structures
     • Subsection NH. Class 1 Components in Elevated Temperature Service
     • Appendices
  2. ο Division 2. Code for Concrete Containment
  3. ο Division 3. Containments for Transportation and Storage of Spent Nuclear Fuel and High Level Radioactive Material and Waste
• Section IV. Rules for Construction of Heating Boilers
• Section V. Nondestructive Examination
• Section VI. Recommended Rules for the Care and Operation of Heating Boilers
• Section VII. Recommended Guidelines for the Care of Power Boilers
• Section VIII. Rules for Construction of Pressure Vessels
  1. ο Division 1: Rules for Construction of Pressure Vessels
  2. ο  Division 2. Alternative Rules
  3. ο  Division 3. Alternative Rules for Construction of High Pressure Vessels
• Section IX. Welding and Brazing Qualifications
• Section X. Fiber-Reinforced Plastic Pressure Vessels
• Section XI. Rules for Inservice Inspection of Nuclear Power Plant Components
• Section XII. Rules for Construction and Continued Service of Transport Tanks
• Section XIII. Rules for Overpressure Protection (in course of preparation)

The above 28 volumes contain a wealth of information needed in order to design and construct boilers, pressure vessels, and nuclear components. Other examples of ASME standards include the following:

• A17.2. Guide for Inspection of Elevators, Escalators, and Moving Walks
• B16.5. Pipe Flanges and Flanged Fittings
• B30.16. Overhead Hoists (Underhung)
• B31.1. Power Piping
• B31.3. Process Piping
• Y14.100. Engineering Drawing Practices.

ASME uses a wide range of member interest categories, including the following diverse groups, as part of its consensus process in developing standards. These groups consist of local as well as international representatives.

1. Fabricators and manufacturers
2. Users and operators
3. Governmental agencies and jurisdictions (such as the Nuclear Regulatory Commission (NRC) and the Coast Guard as well as state and local jurisdictions)
4. Technical consultants
5. Research organizations ( such as Oak Ridge National Lab and various universities)
6. Insurance/Inspection agencies
7. Engineering and construction firms.

Personnel from the above seven categories are involved in writing various facets of the boiler code. Hence, standards written for boiler construction as well as standards written for nondestructive examination methods have to be approved by members representing the seven groups listed above.

ASME also performs a unique service by providing a Conformity Assessment process for use in industry (see Chapter 8). The process steps are generally as follows:

• ASME publishes boiler and pressure vessel standards used by manufacturers to fabricate equipment.
• ASME certifies users of these standards to ensure that they are capable of manufacturing products that meet those standards.
• The certification process consists of the following general steps:
  1. ο An ASME authorized team visits the manufacturer's site and audits its quality assurance procedures and implementation, which address items such as
     • material traceability
     • internal inspection procedures
     • third party inspection provisions
     • hold points
     • documentation such as design report, NDE records, and material certification.
  2. ο The team discusses its findings with an authorized representative of the manufacturer and then files its report with ASME.
  3. ο The auditing team is usually assembled by ASME or an institution authorized by ASME such as the National Board of Boiler and Pressure Vessel Inspectors.
  4. ο If the auditing team finds the manufacturer to be in compliance with all of the ASME requirements for a given standard, then ASME provides it with a Stamp. The stamp provided to the certified manufacturer is affixed onto their products to indicate the manufacturer's certification that a product was manufactured according to the particular standard.
  5. ο If the auditing team finds the manufacturer not in compliance with the ASME requirements, then it files a report with ASME identifying items that are noncompliant.
  6. ο An ASME committee (Committee on Boiler and Pressure Vessel Conformity Assessment) consisting of members from a wide sector of the industry meets to discuss the nonconformance. A representative of the manufacturer where the nonconformance occurred is given due process by being invited to the meeting to present the user's point of view. Based on its findings, the committee then decides whether or not to grant a stamp to the manufacturer.

The above conformity process has been in use by ASME for many decades and has proved very effective in the industry. ASME cannot, however, force any manufacturer, inspector, or installer to follow the ASME standards. Unless required by jurisdictional standards (laws, regulations, local building codes, etc.), their use is voluntary.

3.5.2 American Society for Testing and Materials (ASTM)

ASTM is another organization that is accredited by ANSI for writing standards. Like ASME, it maintains a large number of standards covering a wide range of applications. However, unlike ASME, which focuses on mechanical systems, ASTM focuses more on the wide range of testing needs that affect our life. The ASTM sections are as follows:

• Section 1 – Iron and Steel products
• Section 2 – Nonferrous Metal Products
• Section 3 – Metals Test Methods and Analytical Procedures
• Section 4 – Construction
• Section 5 – Petroleum Products, Lubricants, and Fossil Fuels
• Section 6 – Paints, Related Coatings, and Aromatics
• Section 7 – Textiles
• Section 8 – Plastics
• Section 9 – Rubber
• Section 10 – Electrical Insulation and Electronics
• Section 11 – Water and Environmental Technology
• Section 12 – Nuclear, Solar, and Geothermal Energy
• Section 13 – Medical Devices and Services
• Section 14 – General Methods and Instrumentation
• Section 15 – General Products, Chemical Specialties, and End Use Products

The above 15 categories contain thousands of technical standards available to the engineer. Sections 1–3 of ASTM are referenced extensively in ASME. Accordingly, many volunteers are members of both ASME and ASTM in order to properly coordinate the activities of Sections 1–3 of ASTM with ASME material and testing needs.

3.5.3 American Petroleum Institute (API)

API publishes hundreds of standards related to the refinery industry. Many of these standards are also used at other facilities such as chemical plants, power plants, and other industrial facilities. Some standards of API are as follows:

• API 510 Pressure Vessel Inspection Code: In-Service Inspection, Rating, Repair, and Alteration
• API 579-1/ASME FFS-1. Fitness-For-Service
• API 620. Design and Construction of Large, Welded, Low-Pressure Storage Tanks
• API 650. Welded Tanks for Oil Storage
• API RP572. Inspection of Pressure Vessels.

3.5.4 UL (Formerly Underwriters Laboratory)

UL, best known for the UL listings that reassure the public of the safety of thousands of products in daily use, is able to provide these listings in part because it publishes over 1200 safety standards in diverse fields. UL is somewhat unique, being a private company that publishes standards using the ANSI process, including public review and comment.

3.5.5 National Board of Boiler and Pressure Vessel Inspectors (NBBI)

NBBI is a nonprofit organization consisting of the Chief Boiler Inspectors of most states in the United States as well as the provinces of Canada and many cities and municipalities in North America. They are the repository for all certificates of fabricated boiler and pressure vessels registered in the United States and Canada. They also audit and certify pressure vessel manufacturers, approve manufacturers for repairing pressure vessels and boilers, and certify pressure relief valves in their test laboratories. NBBI publishes many standards related to inspection and valves. Some of these standards are the following:

• NB-18. Pressure Relief Device Certification
• NB-23. National Board Inspection Code
• NB-235. Boilers and Water Heater Safety
• NB-535. Application of National Board T/O Certificate of Authorization to Test Pressure Relief Valves
• NB-550. Application of National Board VR Certificate of Authorization to Repair Pressure Relief Valves

3.5.6 American Society of Civil Engineers (ASCE)

ASCE publishes over 40 publications related to such topics as structures, hydraulics, water management, and soils. A few of their publications are listed:

• ASCE/SEI 07. Design Loads for Buildings and Other Structures
• ASCE/SEI 24. Flood-resistant Design and Construction
• ASCE/SEI 48. Design of Steel Transmission Pole Structures.

3.5.7 Institute of Electrical and Electronics Engineers (IEEE)

IEEE has over 3000 standards in such areas as

• Aerospace
• Antennas and Propagation
• Batteries
• Communications
• Computer Technology
• Consumer Electronics Electromagnetic Compatibility
• Electronics
• Green and Clean Technology
• Healthcare IT
• Industry Applications
• Instrumentation and Measurement
• Nanotechnology
• National Electrical Safety Code
• Nuclear Power
• Power and Energy
• Power Electronics
• Smart Grid
• Software and Systems Engineering
• Transportation
• Wired and Wireless.

Like many other major SDOs, IEEE sponsors research and seminars worldwide.

Appendix B lists some American and international standards developing organizations developing general consensus standards.