The component Specifications, which define the availability of components for particular types of use, are held in the SPWLD (Specification World) Elements of the Catalogue DB. These elements, which are at the same hierarchic level as the CATA elements, can own the simple hierarchy of elements shown in Figure 11:2.: The structure of a SPWLD element.

A SPEC is equivalent to an engineering specification for a given class of piping or structural component. It may contain all components of a given material, for example carbon steel, or all components for a given class of use, for example all piping components with a particular pressure rating. Such a SPEC comprises tabulated data of the type illustrated in Figure 11:3.: Part of a typical Specification for piping components, where each headed ‘question’ column represents a SELEC and each horizontal row represents an SPCOM.

It is possible to allocate a default value to most SELEC options, to be used if that particular attribute is not defined during the selection process. The default setting is shown in the tabulated SPEC immediately below the corresponding column heading (the SELEC element) for that attribute.

It is also possible to define overall specification pointers and settings which apply to the whole SPEC, not just to individual SPCOMs. These are shown at the top of the SPEC listing, before the Heading, as shown by the entries MATREF, FLUREF, RATING and LINETYPE in Figure 11:3.: Part of a typical Specification for piping components.

The meanings of the various parts of the Specification, and lists of valid attributes (corresponding to the column headings) which apply to particular types of component specification, are detailed in Typical Specifications.