The CSWD require the categorisation of the elements that are contained within each file. This chapter contains details of the CSWD coding system that is to be used for categorising elements.

What are elements?

Elements are defined as: "The physical parts of construction and related works." In addition, areas and spaces can be categorised as elements.

Why code elements?

One of the main objectives of the CSWD is to add intelligence to CAD data. In simple terms this means that lines that are drawn should be identifiable as the element that they represent, rather then just being lines. By being able to identify each element, then CAD data can be: 

Where is element coding used?

Element coding is used in the naming of: It can also be used as part of the file ID reference of model files.

The CSWD Elemtent Coding System

The CSWD Element Coding System is based on the international CI/SfB coding system. This coding system is already in use in Hong Kong by the Architectural Services Department and by the Housing Authority. The original SfB system has been modified for use in the CSWD by expanding the categories relating to infrastructure works. The coding system can be broken down into:
 

How to use the Element Coding System

The CSWD Element Coding Tables are divided down to the 1,000 Classes of the system. Users are required to code elements at the Class level, i.e. to use a minimum of 3 digits. For example:

Coding will normally be by Class

Automatic Smoke Detection and Alarm Systems would be coded as 674_
Highway centre-lines would be coded as 811_
Straight stairs would be coded as 241_

The use of Grouped Classes is acceptable

It would be acceptable to code these three elements under their grouped category of:
 
Fire Services 670_
Highways 810_
Stairs 240_

The decision whether to group or identify separately is left to the user and will depend on the amount of information being produced and the need for future manipulation.

The use of Sub Classes is at the user's direction

An underscore is placed in the fourth digit position when only three digits are used, as specified in the Standards. If required, Classes can be further sub-divided, at the user's discretion into Sub Classes. In this case the fourth digit would be used. For example, users may wish to identify different types of seawall (956_) thus:

9561 Blockwork Seawalls
9562 Wave Absorbing Seawalls
9563 Rock-faced sloping seawalls

Those classes that may require further sub-division into subclasses are shown with an asterisk * in the CSWD Element Coding Tables.

The CSWD Element Coding system therefore provides flexibility as to the level of detail that is used.