Regardless of the material to be used, most design projects are exercises in creative
problem solving. If the project is a very advanced one, pushing the boundaries of
available technical knowledge, there are few guidelines available for the designer.
In such instances, basic science, intuition, and discussions with peers are common
approaches that combine to produce an approach to solving the problem. With the
application of skill, daring, a little bit of luck, money, and patience, a workable
solution usually emerges.
However, most design projects just are not that challenging or different from what has
been done in the past. Historically, such information was carefully guarded and was
often kept secret. With the passage of time, however, these privately developed
methods of solving design problems became common knowledge, ever more firmly
established. Eventually they evolved into published standards of practice. Some
government entities, acting under their general duty to preserve general welfare and
to protect life and property from harm, added the standards to their legal bases.
The need for codes and standards
The fundamental need for codes and standards in design is based on two concepts,
interchangeability and compatibility. When manufactured articles were made by artisans
working individually, each item was unique and the craftsman made the parts to fit each
other. When a replacement part was required, it had to be made specially to fit.
However, as the economy grew and large numbers of an item were required, the
handcrafted method was grossly inefficient. Economies of scale dictated that parts
should be as nearly identical as possible, and that a usable replacement part would be
available in case it was needed. The key consideration was that the replacement part
had to be interchangeable with the original one.
Standardization of parts within a particular manufacturing company to ensure
interchangeability is only one part of the industrial production problem. The other part
is compatibility. What happens when parts from one company, working to their standards,
have to be combined with parts from another company, working to their standards?
Will parts from company A fit with parts from company B? Yes, but only if the parts
are compatible. In other words, the standards of the two companies must be the same.
Purposes and objectives of codes and standards
The protection of general welfare is one of the common reasons for the establishment
of a government agency. The purpose of codes is to assist that government agency in
meeting its obligation to protect the general welfare of the population it serves. The
objectives of codes are to prevent damage to property and injury to or loss of life by
persons. These objectives are accomplished by applying accumulated knowledge to the
avoidance, reduction, or elimination of definable hazards.
Before going any further, the reader needs to understand the differences between
"codes" and "standards". Which items are codes and which are
standards? One of the several dictionary definitions for "code" is
"any set of standards set forth and enforced by a local government for the
protection of public safety, health, etc., as in the structural safety of buildings
(building code), health requirements for plumbing, ventilation, etc. (sanitary or
health code), and the specifications for fire escapes or exits (fire code)".
"Standard" is defined as "something considered by an authority or by
general consent as a basis of comparison; an approved model".
As a practical matter, codes tell the user what to do and when and under what
circumstances to do it. Codes are often legal requirements that are adopted by local
jurisdictions that then enforce their provisions. Standards tell the user how to do it
and are usually regarded only as recommendations that do not have the force of law.
As noted in the definition for code, standards are frequently collected as reference
information when codes are being prepared. It is common for sections of a local code
to refer to nationally recognized standards. In many instances, entire sections of the
standards are adopted into the code by reference, and then become legally enforceable.
How standards develop
Whenever a new field of economic activity emerges, inventors and entrepreneurs
scramble to get into the market, using a wide variety of approaches. After a while
the chaos decreases, and a consensus begins to form as to what constitutes
"good practice" for that economic activity.
As an industry matures, more and more companies get involved as suppliers,
subcontractors, assemblers, and so forth. Establishing national trade practices is the
next step in the standards development process. This is usually done through special
institutions like the American National Standards Institute (ANSI), which provides
the necessary forum. A sponsoring trade association will request that ANSI review
its standard. A review group is then formed that includes members of many groups other
than the industry, itself. This expands the area of consensus and is an essential
feature of the ANSI process.
ANSI circulates copies of the proposed standard to all interested parties, seeking
comments. A time frame is set up for receipt of comments, after which a Board of
Standards Review considers the comments and makes what it considers necessary changes.
After more reviews, the standard is finally issued and published by ANSI, listed in
their catalog, and available to anyone who wishes to purchase a copy.
A similar process is used by the International Standards Organization (ISO), which
began to prepare an extensive set of worldwide standards in 1996.
One of the key features of the ANSI system is the unrestricted availability of its
standards. Company, trade, or other proprietary standards may not be available to anyone
outside that company or trade, but ANSI standards are available to everyone. With the
wide consensus format and easy accessibility, there is no reason for designers to
avoid the step of searching for and collecting any and all standards applicable to
their particular projects.
Types of codes
There are two broad types of codes: performance codes and specification or
prescriptive codes. Performance codes state their regulations in the form of what
the specific requirement is supposed to achieve, not what method is to be used to
achieve it. The emphasis is on the result, not on how the result is obtained.
Specification or prescriptive codes state their requirements in terms of specific
details and leave no discretion to the designer. There are many of each type in
Trade codes relate to several public welfare concerns. For example, the
plumbing, ventilation, and sanitation codes relate to health. The electrical codes
relate to property damage and personal injury. Building codes treat structural
requirements that ensure adequate resistance to applied loads. Mechanical codes are
involved with both proper component strength and avoidance of personal injury hazards.
All of these codes, and several others, provide detailed guidance to designers of
buildings and equipment that will be constructed, installed, operated, or maintained by
persons skilled in those particular trades.
Safety codes, on the other hand, treat only the safety aspects of a particular
entity. The safety codes sets forth detailed requirements for safety as it relates to
Professional society codes have been developed, and several have wide acceptance.
The American Society of Mechanical Engineers (ASME) publishes the Boiler and Pressure
Vessel Code, which have been used as a design standard for many decades. The Institute
of Electrical and Electronic Engineers (IEEE) publishes a series of books that codify
recommended good practices in various areas of their discipline. The Society of
Automotive Engineers (SAE) publishes hundreds of standards relating to the design and
safety requirements for vehicles and their appurtenances. The American Society for
Testing and Materials (ASTM) publishes thousands of standards relating to materials
and the methods of testing to ensure compliance with the requirements of the
Statutory codes are those prepared and adopted by some governmental agency,
local, stale, or federal. They have the force of law and contain enforcement provisions,
complete with license requirements and penalties for violations. There are literally
thousands of these, each applicable within its geographical area of jurisdiction.
Regulations. Laws passed by legislatures are written in general and often vague
language. To implement the collective wisdom of the lawmakers, the agency staff then
comes in to write the regulations that spell out the details.
Types of standards
Proprietary (in-house) standards
are prepared by individual companies for
their own use. They usually establish tolerances for various physical factors such as
dimensions, fits, forms, and finishes for in-house production. When outsourcing is
used, the purchasing department will usually use the in-house standards in the terms
and conditions of the order.
Quality assurance provisions are often in-house standards, but currently many are
being based on the requirements of ISO 9000. Operating procedures for material review
boards are commonly based on in-house standards. It is assumed that designers, as a
function of their jobs, are intimately familiar with their own
Government specification standards for federal, state, and local entities involve
literally thousands of documents. Because government purchases involve such a huge
portion of the national economy, it is important that designers become familiar with
standards applicable to this enormous market segment. To make certain that the
purchasing agency gets precisely the product it wants, the specifications are drawn
up in elaborate detail. Failure to comply with the specifications is cause for rejection
of the seller’s offer, and there are often stringent inspection, certification, and
documentation requirements included.
It is important for designers to note that government specifications, particularly
Federal specifications, contain a section that sets forth other documents that are
incorporated by reference into the body of the primary document. These other documents
are usually federal specifications, federal and military standards, and applicable
industrial or commercial standards. The MIL standards and Handbooks for a particular
product line should be a basic pan of the library of any designers working in the
government supply area.
Product definition standards are published by the National Institute of
Standards and Technology under procedures of the Department of Commerce. It establishes
the grading rules, names of specific varieties of soft wood, and sets the uniform
lumber sizes for this very commonly used material.
Commercial standards (denoted by the letters CS) are published by the Commerce
Department for articles considered to be commodities. Commingling of such items is
commonplace, and products of several suppliers may be mixed together by vendors. The
result can be substantial variations in quality. To provide a uniform basis for fair
competition, the Commercial Standards set forth test methods, ratings, certifications,
and labeling requirements. Testing and certification standards are developed for use by
designers, quality assurance agencies, industries, and testing laboratories.
International standards have been proliferating rapidly for the past two
decades. This has been in response to the demands of an increasingly global economy
for uniformity, compatibility, and inter-changeability demands for which standards are
Beginning in 1987, the International Standards Organization (ISO) attacked one of the
most serious international standardization problems, that of quality assurance and
control. These efforts resulted in the publication of the ISO 9000 Standard for
Quality Management. This has been followed by ISO 14000 for Environmental Management
Standards, which is directed at international environmental problems.
The ISO has several Technical Committees (TC) that publish handbooks and standards in
their particular fields. Examples are the ISO Standards Handbooks on Mechanical
Vibration and Shock, Statistical Methods for Quality Control, and Acoustics. All of
these provide valuable information for designers of products intended for the
Codes and standards preparation organizations
U.S. Government Documents
. For Federal government procurement items, other
than for the Department of Defense, the Office of Federal Supply Services of the
General Services Administration issues the Index of Federal Specifications, Standards
and Commercial Item Descriptions every April.
The American National Standards Institute also publishes a catalog of all their
publications and distributes catalogs of standards published by 38 other ISO member
organizations. They also distribute ASTM and ISO standards and English language
editions of Japanese Standards, Handbooks, and Materials Data Books. ANSI does not
handle publications of the British Standards Institute or the standards organizations
in Germany and France.
As mentioned previously, there are many organizations that act as sponsors for the
standards that ANSI prepares under their consensus format. The sponsors are good sources
for information on forthcoming changes in standards and should be consulted by designers
wishing to avoid last-minute surprises. Listings in the ANSI catalog will have the
acronym for the sponsor given after the ANSI symbol. The field of interest of each
sponsor is usually obvious from the name of the organization.
As soon as a designer has been able to establish a solid definition of the problem
at hand, and to formulate a promising solution to it, the next logical step is to begin
the collection of available reference materials such as codes and standards. This is a
key part of the background phase of the design effort. Awareness of the existence and
applicability of codes and standards is a major responsibility of the designer.
One of the designer’s responsibilities in the background phase is to make
certain that the collection of reference codes and standards is both complete and
comprehensive. Considering the enormous amount of information available, and the ease
of access to it, this can be a formidable task. However, a designer’s failure to
acquire a complete and comprehensive collection of applicable standards is ill
advised in today’s litigious environment. In addition, failure of the designer to
meet the requirements set forth in the standards can be considered professional