Classification Systems
=======================

Classification is important for facilitating uniform recording and use of construction products.

.. graphviz:: conceptual-model-classification.dot
    :caption: Schematic overview of conceptual model zoomed at classification systems
    :name: conceptual-model-schematic-classification-systems


Field of application
###############################################
Field of Application currently encompasses “Civil and Utility Construction” and “Ground, Road, and Water Construction.”


Classification System
###############################################

There are various systems available to classify construction products. Currently, the NMD employs four classification systems:

1. NL/SfB (for :index:`"Civil and Utility Construction"` (:index:`Burgelijke en Utiliteitsbouw`, :index:`B&U`)),
2. RAW (for :index:`"Ground, Road and Water Construction"` (:index:`Grond-, Weg- en Waterbouw`, :index:`GWW`))
3. Processes (for processes in both fields),
4. Energy

Each of these systems has its own set of :ref:`Elements <element>` and :ref:`Components <component>`, which can be
found in the document `Functional Descriptions <https://milieudatabase.nl/en/downloads/download/18/>`_.


Element
############################################
An Element is a classification of a construction function. The GWW uses a different name for Element, though,
called ‘Chapter’ (Hoofdstuk). But for consistency, the database  uses the term Element in both cases.


Component
############################################
An `Element`_ is composed of various Components that work together to fulfill the functions and characteristics of
the given element. For instance, a "wall opening filled with windows" is an element built up by components such
as window frames, glass, and ventilation grilles.