A specification is an explicit set of requirements to be satisfied by a material, product, or service. ^[1] Should a material, product or service fail to meet one or more of the applicable specifications, it may be referred to as being out of specification;^[2] the abbreviation OOS may also be used.^[3]

A technical specification may be developed privately, for example by a corporation, regulatory body, military, etc: It is usually under the umbrella of a quality management system ^[4]. They can also be developed by standards organizations which often have more diverse input and usually develop voluntary standards: these might become mandatory if adopted by a government, business contract, etc.

Contents 1 Use 2 Guidance and content 3 Process capability considerations 4 Construction specifications in North America 5 Food and drug specifications 6 Information technology 6.1 Formal specification 6.2 Program specification 6.3 Functional specification 6.4 Web service specification 6.5 Document specification 7 Notes & References 8 Further reading 9 See also 10 References

[edit] Use

In engineering, manufacturing, and business, it is vital for suppliers, purchasers, and users of materials, products, or services to understand and agree upon all requirements. A specification is a type of a standard which is often referenced by a contract or procurement document. It provides the necessary details about the specific requirements.

Specifications may be written by government agencies, standards organizations (ASTM, ISO, CEN, etc), trade associations, corporations, and others.

A product specification does not necessarily prove a product to be correct. An item might be verified to comply with a specification or stamped with a specification number: This does not, by itself, indicate that the item is fit for any particular use. The people who use the item (engineers, trade unions, etc) or specify the item (building codes, government, industry, etc) have the responsibility to consider the choice of available specifications, specify the correct one, enforce compliance, and use the item correctly. Validation of suitability is necessary.

[edit] Guidance and content

Sometimes a guide or a standing operating procedure is available to help write and format a good specification.^{[5], [6], [7]}. A specification might include:

• Descriptive title, number, identifier, etc. of the specification
• Date of last effective revision and revision designation
• A logo (trademark recommended) to declare the document copyright, ownership and origin ^[8]
• Table of Contents (TOC), if the document is long
• Person, office, or agency responsible for questions on the specification, updates, and deviations.
• The significance, scope or importance of the specification and its intended use.
• Terminology, definitions and abbreviations to clarify the meanings of the specification ^{[9], [10]}
• Test methods for measuring all specified characteristics
• Material requirements: physical, mechanical, electrical, chemical, etc. Targets and tolerances.
• Performance testing requirements. Targets and tolerances.
• Drawings, photographs, or technical illustrations
• Workmanship
• Certifications required.
• Safety considerations and requirements
• Environmental considerations and requirements
• Quality control requirements, Sampling (statistics), inspections, acceptance criteria
• Person, office, or agency responsible for enforcement of the specification.
• Completion and delivery.
• Provisions for rejection, reinspection, rehearing, corrective measures
• References and citations for which any instructions in the content maybe required to fulfill the traceability and clarity of the document ^{[11], [12], [10]}
• Signatures of approval, if necessary ^[13]
• Change record to summarize the chronological development, revision and completion if the document is to be circulated internally ^[14]
• Annexes and Appendices that are expand details, add clarification, or offer options. ^[14].

[edit] Process capability considerations

A good engineering specification, by itself, does not necessarily imply that all products sold to that specification actually meet the listed targets and tolerances. Actual production of any material, product, or service involves inherent variation of output. With a normal distribution, the tails of production may extend well beyond plus and minus three standard deviations from the process average.

The process capability of materials and products needs to be compatible with the specified engineering tolerances. Process controls must be in place and an effective Quality management system, such as Total Quality Management, needs to keep actual production within the desired tolerances.

Effective enforcement of a specification is necessary for it to be useful.

[edit] Construction specifications in North America

Specifications in North America form part of the contract documents that accompany and govern the construction of a building. The guiding master document is the National MasterFormat. It is a consensus document that is jointly sponsored by two professional organisations: Construction Specifications Canada and Construction Specifications Institute.

While there is a tendency to believe that "Specs overrule Drawings" in the event of discrepancies between the text document and the drawings. The actual intent is for drawings and specifications to be complimentary with neither taking precedence over the other.

The Specifications fall into 50 "Divisions", or broad categories of work involved in construction. The "Divisions" are subdivided into "Sections", that address specific workscopes. For instance, firestopping is addressed in Section 078400 - Firestopping. It forms part of the Division 7, which is Thermal and Moisture Protection. Division 7 also addresses building envelope and fireproofing work. Each Section is subdivided into three distinct areas: "General", "Products" and "Execution". The National MasterFormat system has been uniformly applied to residential, commercial and much though not all industrial work.

Specifications can be another "performance-based", whereby the specifier restricts the text to stating the performance that must be achieved in each Section of work, or "prescriptive", whereby the specifier indicates specific products, vendors and even contractors that are acceptable for each workscope.

While North American specifications are usually restricted to broad descriptions of the work, European ones can include actual work quantities, including such things as area of drywall to be built in square metres, like a bill of materials. This type of specification is a collaborative effort between a specwriter and a quantity surveyor. This approach is unusual in North America, where each bidder performs his or her own quantity survey on the basis of both drawings and specifications.

Although specifications are usually issued by the architect's office, specwriting itself is undertaken by the architect and the various engineers or by specialist specwriters. Specwriting is often a distinct professional trade, with professional designations such as "Certified Construction Specifier" (CCS) available. Specwriters are either employees of or sub-contractors to architects. Specwriters frequently meet with manufacturers of building materials who seek to have their products "specified" on upcoming construction projects so that contractors can include their products in the estimates leading to their proposals.

[edit] Food and drug specifications

Pharmaceutical products can usually be tested and qualified by various Pharmacopoeia. Current existing pronounced standards include:

• British Pharmacopoeia
• European Pharmacopoeia
• Japanese Pharmacopoeia
• The International Pharmacopoeia
• United States Pharmacopoeia

If any pharmaceutical product is not covered by the above standards, it can be evaluated by the additional source of Pharmacopoeia from other nations, from industrial specifications. or from standardized formulary such as

• British National Formulary for Children
• British National Formulary
• National Formulary

A similar approach is adopted by the food manufacturing, of which Codex Alimentarius ranks the hightest standards, followed by regional and national standards. ^[15]

The coverage of food and drug standards by ISO is currently less fruitful and not yet put forward as an urgent agenda due to the tight restrictions of regional or national constitution ^{[16], [17]}

Specifications and other standards can be externally imposed as discussed above, but also intenal manufacturing and quality specifications. These exist not only for the food or pharmaceutical product but also for the processing machinery, quality processes, packaging, logistics (cold chain), etc and are examplified by ISO 14134 and ISO 15609 ^{[18], [19]}

The converse of explicit statement of specifications is a process for dealing with observations that are out-of-specification. The United States Food and Drug Administration has published a non-binding recommendation that addresses just this point.^[3]

[edit] Information technology

[edit] Formal specification

A formal specification is a mathematical description of software or hardware that may be used to develop an implementation. It describes what the system should do, not (necessarily) how the system should do it. Given such a specification, it is possible to use formal verification techniques to demonstrate that a candidate system design is correct with respect to the specification. This has the advantage that incorrect candidate system designs can be revised before a major investment has been made in actually implementing the design. An alternative approach is to use provably correct refinement steps to transform a specification into a design, and ultimately into an actual implementation, that is correct by construction.

[edit] Program specification

A program specification is the definition of what a computer program is expected to do. It can be informal, in which case it can be considered as a blueprint or user manual from a developer point of view, or formal, in which case it has a definite meaning defined in mathematical or programmatic terms. In practice, most successful specifications are written to understand and fine-tune applications that were already well-developed, although safety-critical software systems are often carefully specified prior to application development. Specifications are most important for external interfaces that must remain stable.

[edit] Functional specification

In software development, a functional specification (also, functional spec or specs or functional specifications document (FSD)) is the set of documentation that describes the behavior of a computer program or larger software system. The documentation typically describes various inputs that can be provided to the software system and how the system responds to those inputs.

[edit] Web service specification

[edit] Document specification

This type of documents defines how a specific document should be written, which may include, but not limit to, the systems of a document naming, version, layout, referencing, structuring, appearance, language, copyright, hierarchy or format etc ^{[20], [21]}. Very often, this kind of specifications is complemented by a designated template ^{[22], [23], [24]}.

[edit] Notes & References

[edit] Further reading

• Pyzdek, T, "Quality Engineering Handbook", 2003, ISBN 0824746147
• Godfrey, A. B., "Juran's Quality Handbook", 1999, ISBN 007034003
• "Specifications for the Chemical And Process Industries", 1996, ASQ Quality Press, ISBN 0-87389-351-4
• ASTM E29-06b Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• Journal of Chemical Information and Modeling
• Journal of Documentation, ISSN: 0022-0418, ^[1]

[edit] See also

Change control Construction Specifications Institute Defense Standard Design specification Diagnostic design specification Documentation Document management system Formal specification Functional specification List of ISO standards List of Air Ministry specifications MasterFormat Manufacturing test requirement design specification Open standard

Performance testing Process specification Product design specification Publicly Available Specification Revision control Requirements analysis Submittals (construction) Shop drawing Specification and Description Language Specification tree Statistical interference Technical documentation Tolerance (engineering) Verification and Validation‎

[edit] References

1. ^ Emerald Group Publishing. "Journal of Documentation". http://info.emeraldinsight.com/products/journals/journals.htm?PHPSESSID=18na5lljuj9hjamf6te5i99r21&id=jd. Retrieved 12 June 2009.