A standard consists of technical definitions and guidelines that function as instructions for designers/manufacturers and operators/users of equipment. Standards can run from a few pages to a few hundred pages and are written by professionals who serve on ASME committees. Standards are considered voluntary because they are guidelines and not enforceable by law. ASME publishes standards, accredits users of standards to ensure that they are capable of manufacturing products that meet those standards, and provides stamps that accredited manufacturers may place on their products to indicate conformance to a standard.
A code is a standard that has been adopted by one or more governmental bodies and is enforceable by law.
To be considered a valid ASME code or standard, a document should be
suitable for repetitive use. A major requirement of a code or standard is that it can be used time and again. If a set of requirements is so specialized that it cannot and will not be applied repeatedly, it is not a code or standard.
enforceable. A standard's requirements should be worded so that a person auditing its use or application can point out where it has or has not been followed.
definite. Requirements that are too general or contain vague applications instead of workable instructions are impractical and often useless. Requirements should be expressed as specific instructions and never as explanations.
realistic. Requirements that are unrelated, excessive, or more restrictive than necessary should not be included. A standard that is too restrictive or detailed imposes a burden on both the administrator and user. Increasing the severity or detail of a requirement does not automatically increase quality but will nearly always increase cost. Be ready to justify, in writing if necessary, every requirement of the standard and show the basis of each as a logical deduction from factual information about the item or practice in question.
authoritative. Requirements should be technically correct and accurate and cover only those properties that are subject to control or are of legitimate use. Requirements should be reasonably consistent with current practices and capabilities in the industry, and be attainable for the user.
complete. All areas open to question or interpretation (or misinterpretation) should be covered. If requirements are specified by reference to another standard, all areas of the referenced standard that are open to question or misinterpretation should also be covered.
clear. Express the requirements in easily understood language that is not ambiguous. Avoid common pitfalls such as run-on sentences, wordiness, redundancy, and complex sentence structures.
consistent. Requirements should not be contradictory or incompatible with one another; similarly, the requirements of related and dependent standards should also be consistent. Also, the requirements should be compatible with the requirements of the documents referenced in the standard, and the standard should reflect national or international standards whenever possible. Special (i.e., nonstandard) sizes, shapes, or tests require special attention and extra time on the part of the user and therefore increase cost; they also inhibit maintenance and repair.
focused. When too much is covered by one standard, its requirements become confusing and the standard becomes less effective; users may be left wondering which parts of the standard apply to their work. When the standard applies to a variety of users, with different requirements, it is often more desirable to provide separate standards.