A specification, colloquially spec, often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard.
There are different types of technical or engineering specifications (specs), and the term is used differently in different technical contexts. They often refer to particular documents, and/or particular information within them. The word specification is broadly defined as "to state explicitly or in detail" or "to be specific".
A requirement specification is a documented requirement, or set of documented requirements, to be satisfied by a given material, design, product, service, etc. It is a common early part of engineering design and product development processes in many fields.
A functional specification is a kind of 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 either a designed solution or final produced solution. It is often used to guide fabrication/production. Sometimes the term specification is here used in connection with a data sheet (or spec sheet), which may be confusing. A data sheet describes the technical characteristics of an item or product, often published by a manufacturer to help people choose or use the products. A data sheet is not a technical specification in the sense of informing how to produce.
An "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 are a type of technical standard that may be developed by any of various kinds of organizations, in both the public and private sectors. 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 different public entities, 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.Gary Blake and Robert W. Bly, The Elements of Technical Writing, pg. 108. New York: Macmillan Publishers, 1993.
A specification may refer to a standard which is often referenced by a contract or procurement document, or an otherwise agreed upon set of requirements (though still often used in the singular). In any case, it provides the necessary details about the specific requirements.
Standards for specifications may be provided by government agencies, standards organizations (SAE, AWS, NIST, ASTM, ISO / IEC, CEN / CENELEC, DoD, etc.), trade associations, corporations, and others. A memorandum published by William J. Perry, U.S. Defense Secretary, on 29 June 1994 announced that a move to "greater use of performance and commercial specifications and standards" was to be introduced, which Perry saw as "one of the most important actions that [the Department of Defense] should take" at that time.Perry, W. J., Specifications & Standards - A New Way of Doing Business: A memorandum by William J. Perry, published 29 June 1994 (republished by the Society of Automotive Engineers, 7 January 2001), accessed 14 September 2022 The following British standards apply to specifications: BS 7373-1:2001 Guide to the preparation of specifications BS 7373-2:2001 Product specifications. Guide to identifying criteria for a product specification and to declaring product conformity BS 7373-3:2005, Product specifications. Guide to identifying criteria for specifying a service offering
A design/product specification does not necessarily prove a product to be correct or useful in every context. 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 other, non-validated uses. 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.
Public sector procurement rules in the European Union and United Kingdom require non-discriminatory technical specifications to be used to identify the purchasing organisation's requirements. The rules relating to public works contracts initially prohibited "technical specifications having a discriminatory effect" from 1971;Council of the European Communities, Council Directive 71/305/EEC of 26 July 1971 concerning the co-ordination of procedures for the award of public works contracts, preamble, published on 26 July 1971, accessed on 4 June 2025 this principle was extended to public supply contracts by the then European Communities' Directive 77/62/EEC coordinating procedures for the award of public supply contracts, adopted in 1976.Publications Office of the European Union, Council Directive 77/62/EEC of 21 December 1976 coordinating procedures for the award of public supply contracts, accessed 14 September 2022 Some organisations provide guidance on specification-writing for their staff and partners.Suffolk County Council, General Guide to Writing Specifications, Version 4, September 2017, accessed September 2022Crown Commercial Service, How to write a specification – Procurement Essentials, published 16 November 2021, accessed 26 September 2022 In addition to identifying the specific attributes required of the goods or services being purchased, specifications in the public sector may also make reference to the organisation's current corporate objectives or priorities.
Guidance and content Sometimes a guide or a standard operating procedure is available to help write and format a good specification. 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 Table of Contents (TOC), if the document is long Person, office, or agency responsible for questions on the specification, updates, and deviations. The philosophical significance, scope or importance of the specification and its intended use. Terminology, definitions and abbreviations to clarify the meanings of the specification 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 Security considerations and requirements (where appropriate: e.g. for products and services to be provided to government or military agencies, information technology firms, etc.) Environmental considerations and requirements Quality control requirements, acceptance sampling, inspections, acceptance criteria; or, where a quality management system is operating, quality assurance requirements set forth to regulate business processes involved in the delivery of the product/service which is in the scope of the specification. Person, office, or agency responsible for enforcement of the specification (which could include the arrangement and execution of audits for verifying compliance with the requirements set forth in the specification). Completion and delivery conditions (often referring to standardized INCOTERMS). 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 documentISO 690 Signatures of approval, if necessary;Title 21 CFR Part 11 sometimes specific procedures apply to sign-off / buy-off events. Change record to summarize the chronological development, revision and completion if the document is to be circulated internally Annexes and Appendices that expand on details, add clarification, or offer options.
Construction North America Specifications in North America form part of the contract documents that accompany and govern the drawings for construction of building and infrastructure projects. Specifications describe the quality and performance of building materials, using code citations and published standards, whereas the drawings or building information model (BIM) illustrates quantity and location of materials. The guiding master document of names and numbers is the latest edition of MasterFormat. This is a consensus document that is jointly sponsored by two professional organizations: Construction Specifications Canada and Construction Specifications Institute based in the United States and updated every two years.
While there is a tendency to believe that "specifications overrule drawings" in the event of discrepancies between the text document and the drawings, the actual intent must be made explicit in the contract between the Owner and the Contractor. The standard AIA (American Institute of Architects) and EJCDC (Engineering Joint Contract Documents Committee) states that the drawings and specifications are complementary, together providing the information required for a complete facility. Many public agencies, such as the Naval Facilities Command (NAVFAC) state that the specifications overrule the drawings. This is based on the idea that words are easier for a jury (or mediator) to interpret than drawings in case of a dispute.
The standard listing of construction specifications falls into 50 Divisions, or broad categories of work types and work results involved in construction. The divisions are subdivided into sections, each one addressing a specific material type (concrete) or a work product (steel door) of the construction work. A specific material may be covered in several locations, depending on the work result: stainless steel (for example) can be covered as a sheet material used in flashing and sheet Metal in division 07; it can be part of a finished product, such as a handrail, covered in division 05; or it can be a component of building hardware, covered in division 08. The original listing of specification divisions was based on the time sequence of construction, working from exterior to interior, and this logic is still somewhat followed as new materials and systems make their way into the construction process.
Each section is subdivided into three distinct parts: "general", "products" and "execution". The MasterFormat and SectionFormatConstruction Specifications Institute systems 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). Master specification systems are available from multiple vendors such as Arcom, Visispec, BSD, and Spectext. These systems were created to standardize language across the United States and are usually subscription based.