Engineering Fundamentals: An Introduction to Engineering, 4th ed.c

66 Chapter 3 Introduction to Engineering Design

Why Do We Need Standards and Codes?

Standards and codes have been developed over the years by various organizations to ensure

product safety and reliability in services. The standardization organizations set the authorita-

tive standards for safe food supplies, safe structures, safe water systems, safe and reliable elec-

trical systems, safe and reliable transportation systems, safe and reliable communication

systems, and so on. In addition, standards and codes ensure uniformity in the size of parts and

components that are made by various manufacturers around the world. In today’s globally

driven economy where parts for a product are made in one place and assembled somewhere

else, there exists an even greater need than ever before for uniformity and consistency in parts

and components and in the way they are made. These standards ensure that parts manufac-

tured in one place can easily be combined with parts made in other places on an assembly line.

An automobile is a good example of this concept. It has literally thousands of parts that are

manufactured by various companies in different parts of the United States and the world,

and all of these parts must fit together properly.

To shed more light on why we need standards and codes, let us consider products that we

all are familiar with, for example, shoes or shirts. In the United States, you are familiar with shoe

sizes of 9, 10, or 11 and so on, as shown in Table 3.5. In Europe, the standard shoe sizes are

43, 44, or 45 and so on. Similarly, the standard shirt sizes in the United States are 15, 15 , or 16

and so on, whereas in Europe the standard shirt sizes are 38, 39, or 41 and so on. If a shirt

manufacturer in Europe wants to sell shirts in the United States, it has to label them such that

people understand the sizes so that they can choose a shirt of the correct size. Conversely, if a shoe

manufacturer from the United States wants to sell shoes in Europe, it has to label them such that

the shoe sizes are understood by European customers. Would it not be easier if every shirt or

shoe manufacturer in the world used uniform size identifications to eliminate the need for cross

referencing? These simple examples demonstrate the need for uniformity in the size and the

way products are labeled. Now, think about all possible parts and components that are manu-

factured every day by thousands of companies around the world: parts and components such as

bolts, screws, nuts, cables, tubes, pipes, beams, gears, paints, adhesives, springs, wires, tools, lum-

ber, fasteners, and so on. You see that if every manufacturer built products using its own stan-

dards and specifications, this practice could lead to chaos and many misfit parts! Fortunately,

there are existing international standards that are followed by many manufacturers around

the world.

A good example of a product that uses international standards is your credit card or

your bankcard. It works in all the ATM machines or store credit card readers in the world.

The size of the card and the format of information on the card conform to the International

Organization of Standards (ISO), thus allowing the card to be read by ATM machines every-

where. The 35-mm camera film speed (e.g., 100, 200, 400) is another example of ISO stan-

dards being used by film manufacturers. As another example, warning and functional

symbols based on ISO standards on the instrument panel of your car have become com-

monplace. The ISO standards are being implemented by more and more companies around

the world every day.

There are many standardization organizations in the world, among them various engi-

neering organizations. Recall from our discussion in Chapter 2 that most national /interna-

tional engineering organizations create, maintain, and distribute codes and standards that deal

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