Four Types of "Specifications"

The meaning of the term "specification" varies depending on how it is used:

Product Specification:
This describes a manufacturer's product and its performance without consideration for a particular building. A manufacturer publish this information as part of its sales literature.

Project Specification:
This describes an architect's design and performance requirements for a particular building. It might contain requirements for how a product should be used for a the building. Contractors and sub-contractors submit bids and supply products to meet a project specification.

Master Specification:
This is a template an architect can use to help him or her create a Project Specification. It may contain requirements for several products to help the architect select the one or ones best suited for a particular project. Some architects have their own library of master specification sections. Other architects subscribe to commercially published libraries of specifications such as "MasterSpec" by Arcom.  A manufacturer will try to encourage an architect or publisher to include its product in a master specification, but has little or no control over the document.

Guide Specification:
This is a type of master specification that is published by a building product manufacturer to help an architect write a project specification that is based on the manufacturer's products.  There are publishers that, for a fee, will write a guide specification for a manufacturer and publish the specification on the publisher's website. Being included in the publisher's database is a form of advertising. Each publisher has its own "style" of specifying, and having your spec written in the house style will be useful to specifiers that frequent the publisher's site. These benefits must be weighed against the costs and drawbacks. I frequently find it better for a manufacturer to write its own specification section (with the help of a consultant, if necessary) and publish the guide specification on the manufacturer's own website.