Specification (technical standard)

There are different types of specifications, which generally are mostly types of documents, forms or orders or relates to information in databases. The word specification is defined as "to state explicitly or in detail" or "to be specific". A specification may refer to a type of technical standard (the main topic of this page).

Using a word "specification" without additional information to what kind of specification you refer to is confusing and considered bad practice within systems engineering.

A requirement specification is a set of documented requirements to be satisfied by a material, design, product, or service.^[1]

A functional specification is closely related to the requirement specification and may show functional block diagrams.

A design or product specification describes the features of the solutions for the Requirement Specification, referring to the designed solution or final produced solution. Sometimes the term specification is here used in connection with a data sheet (or spec sheet). This may be confusing. A data sheet describes the technical characteristics of an item or product as designed and/or produced. It can be published by a manufacturer to help people choose products or to help use the products. A data sheet is not a technical specification as described in this article.

A "in-service" or "maintained as" specification, specifies the conditions of a system or object after years of operation, including the effects of wear and maintenance (configuration changes).

Specifications may also refer to technical standards, which may be developed by any of various kinds of organizations, both public and private. Example organization types include a corporation, a consortium (a small group of corporations), a trade association (an industry-wide group of corporations), a national government (including its military, regulatory agencies, and national laboratories and institutes), a professional association (society), a purpose-made standards organization such as ISO, or vendor-neutral developed generic requirements. It is common for one organization to refer to (reference, call out, cite) the standards of another. Voluntary standards may become mandatory if adopted by a government or business contract.

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.^[2] 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, DoD, etc.), trade associations, corporations, and others.

A product specification does not necessarily prove a product to be correct or useful. 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.

Guidance and content

Sometimes a guide or a standard operating procedure is available to help write and format a good specification.^[3][4][5] A specification might include:

• Descriptive title, number, identifier, etc. of the specification
• Date of last effective revision and revision designation
• A logo or trademark to indicate the document copyright, ownership and origin^[6]
• 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^[7][8]
• Test methods for measuring all specified characteristics
• Material requirements: physical, mechanical, electrical, chemical, etc. Targets and tolerances.
• Acceptance testing, including 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, acceptance sampling, 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^[8][9][10]
• Signatures of approval, if necessary^[11]
• Change record to summarize the chronological development, revision and completion if the document is to be circulated internally^[12]
• Annexes and Appendices that are expand details, add clarification, or offer options.^[12]

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 latest edition of 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—made explicit in the contract between the Owner and the Contractor—is for the drawings and specifications to be complementary, together providing the information required for a complete facility.

The specifications fall into 50 Divisions, or broad categories of work results involved in construction. The divisions are subdivided into sections, each one addressing a narrow scope of the construction work. For instance, firestopping is addressed in Section 078400 - Firestopping. It forms part of Division 07, which is Thermal and Moisture Protection. Division 07 also addresses building envelope and fireproofing work.

Each Section is subdivided into three distinct Parts: "General", "Products" and "Execution". The MasterFormat system can be successfully applied to residential, commercial, civil, and industrial construction. Although many Architects find the rather voluminous commercial style of specifications too lengthy for most residential projects and therefore either produce more abbreviated specifications of their own or use ArCHspec (which was specifically created for residential projects).

Specifications can be either "performance-based", whereby the specifier restricts the text to stating the performance that must be achieved by the completed work, or "prescriptive", whereby the specifier indicates specific products, vendors and even contractors that are acceptable for each workscope. Most construction specifications are a combination of performance-based and prescriptive types, naming acceptable manufacturers and products while also specifying certain standards and design criteria that must be met.

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 a 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 certifications such as "Certified Construction Specifier" (CCS) through the professional organizations noted above. Specwriters are either employees of or sub-contractors to architects, engineers, or construction management companies. 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.

In February 2015, ArCHspec went live, from ArCH (Architects Creating Homes), a nationwide American professional society of Architects whose purpose is to improve residential architecture. ArCHspec was created specifically for use by Licensed Architects while designing SFR (Single Family Residential) architectural projects. Unlike the more commercial CSI (50+ division commercial specifications), ArCHspec utilizes the more recognizable 16 traditional Divisions, plus a Division 0 (Scope & Bid Forms) and Division 17 (low voltage). Many Architects, up to this point, did not provide specifications for residential designs, which is one of the reasons ArCHspec was created: to fill a void in the industry with more compact specifications for residential use.

Construction specifications in the UK

Specifications in the UK are part of the contract documents that accompany and govern the construction of a building. They are prepared by construction professionals such as architects, architectural technologists, structural engineers, landscape architects and building services engineers. They are created from previous project specifications, in-house documents or master specifications such as the National Building Specification (NBS). The National Building Specification is owned by the Royal Institute of British Architects (RIBA) through their commercial group RIBA Enterprises (RIBAe). NBS master specifications provide content that is broad and comprehensive, and delivered using software functionality that enables specifiers to customize the content to suit the needs of the project and to keep up to date. UK project specification types fall into two main categories prescriptive and performance. Prescriptive specifications define the requirements using generic or proprietary descriptions of what is required, whereas performance specifications focus on the outcomes rather than the characteristics of the components. Specifications are an integral part of Building Information Modeling and cover the non-geometric requirements.

Construction specifications in other countries

Egypt : Specifications are part of contract documents. The Housing and Building National Research Center "HBRC" is responsible for developing construction specifications and codes. The HBRC had published more than 15 books which cover building activities like (Earthworks - Plastering - etc.)

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 Pharmacopeia

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 a 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 highest standards, followed by regional and national standards.^[13]

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^[14][15]

Specifications and other standards can be externally imposed as discussed above, but also internal 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 exemplified by ISO 14134 and ISO 15609^[16][17]

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.^[18]

At the present time, much of the information and regulations concerning food and food products remain in a form which makes it difficult to apply automated information processing, storage and transmission methods and techniques.

Data systems that can process, store and transfer information about food and food products need formal specifications for the representations of data about food and food products in order to operate effectively and efficiently.

Development of formal specifications for food and drug data with the necessary and sufficient clarity and precision for use specifically by digital computing systems have begun to emerge from government agencies and standards organizations.

The United States Food and Drug Administration has published specifications for a "Structured Product Label" which drug manufacturers must by mandate use to submit electronically the information on a drug label.^[19]

Recently, ISO has made some progress in the area of food and drug standards and formal specifications for data about regulated substances through the publication of ISO 11238^[20]

Information technology

Specification need

Specifications are needed to avoid errors due to lack of compatibility, for instance, in interoperability issues.

For instance, when two applications share Unicode data, but use different normal forms or use them incorrectly, in an incompatible way or without sharing a minimum set of interoperability specification, errors and data loss can result. For example, Mac OS X has many components that prefer or require only decomposed characters (thus decomposed-only Unicode encoded with UTF-8 is also known as "UTF8-MAC"). In one specific instance, the combination of OS X errors handling composed characters, and the samba file- and printer-sharing software (which replaces decomposed letters with composed ones when copying file names), has led to confusing and data-destroying interoperability problems.^[21][22]

Applications may avoid such errors by preserving input code points, and only normalizing them to the application's preferred normal form for internal use.

Such errors may also be avoided with algorithms normalizing both strings before any binary comparison.

However errors due to file name encoding incompatibilities have always existed, due to a lack of minimum set of common specification between software hoped to be inter-operable between various file system drivers, operating systems, network protocols, and thousands of software packages.

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 that 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.

Architectural specification

In (hardware, software, or enterprise) systems development, an architectural specification is the set of documentation that describes the structure, behavior, and more views of that system.

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 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, many 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.

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.

Web service specification

Web services specifications are often under the umbrella of a quality management system.^[23]

Document specification

These types of documents define how a specific document should be written, which may include, but is not limited to, the systems of a document naming, version, layout, referencing, structuring, appearance, language, copyright, hierarchy or format, etc.^[24][25] Very often, this kind of specifications is complemented by a designated template.^[26][27][28]

See also

Notes and references

Further reading

• Pyzdek, T, "Quality Engineering Handbook", 2003, ISBN 0-8247-4614-7
• Godfrey, A. B., "Juran's Quality Handbook", 1999, ISBN 007034003X
• "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, Emerald Group Publishing, ISSN 0022-0418