Catalogues and Specifications Reference Manual
Specification Constructor : How Component Selection Works : SPCOmponent and the Component Data
SPCOmponent and the Component Data
In addition to these specifying attributes, each SPCOM contains a pointer to a COMP, which meets all the listed specifications, in a CATA element. It is this pointer, known as the Catalogue Reference (CATREF), which forms the key to correct component selection when new pipework is being designed.
Each SPCOM also contains pointers to detailing text (DETAIL points to DTEXT), material text (MATXT points to MTEXT), bolting requirements (BLTREF points to BLTAB), component properties (CMPREF points to CMPT in a Properties DB) and part requirements (PRTREF).
There are two essential links which make sure that an appropriate component is selected during the design of new pipework or a new structure, namely:
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Design Component to Specification
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Specification to Catalogue Component
Thus, when a new pipe component is to be selected for inclusion in a Design DB, the following sequence is applied:
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The design component is allocated a Specification Reference (SPREF) which is selected from the required SPEC. You usually define the Pipe Specification (PSPEC) as soon as you create a new pipe, and this is then applied to all components which the Pipe owns unless you override it.
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The SPREF points to an SPCOM (in the Catalogue DB).
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The SPCOM points to a suitable catalogue component (COMP) via the CATREF pointer.
(The SPCOM also points to a DTEXT via the DETAIL pointer, an MTEXT via the MATXT pointer, a BLTAB element via the BLTREF pointer, and a CMPT element in a Properties DB via the CMPREF pointer, as appropriate.) This is illustrated below.
Figure 11:5.
The links between Design Data, Specifications and Catalogue
EXAMPLE:
As an illustration of the principles of the selection process, consider the following question and answer sequence which might apply when choosing a valve from the /RF300 Specification represented in Figure 11:3.: Part of a typical Specification for piping components:
SELEC_1 TYPE?
Answer VALV, which leads to the next question ...
SELEC_2 PBOR0?
Answer 25.0, which leads to a choice of three STYPs
SELEC_3 STYP?
Answer GA, which in this example offers only one choice for SHOP
SELEC_4 SHOP?
Answer TRUE
The resulting combination of SELEC answers, namely a 25mm bore Gate Valve with its SHOP attribute set to TRUE, is represented in the SPEC by one, and only one, SPCOM, namely */25GA. This points to the component in the Catalogue which completely matches the specification, via the CATREF /VGAFF. The corresponding descriptive DTEXT is pointed to by the DETAIL /DGA.V.SW, and so on. Note that the CATREF is unique within this SPEC, whereas the same DETAIL applies to other components such as */20GA.
 
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