<simpleType name="ElementClassEnumType">
  <restriction base="string">
    <enumeration value="trial">
      <annotation>
        <documentation>An element installed before production begins, to prove the installation method or calibrate the design. Normally not part of the permanent works. Constructed independently of any rigid inclusion system by definition - diggs:RIColumnType/samplingFeatureRef is correspondingly irrelevant for a trial element, not merely omitted, since there is no parent system for it to cite.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="test">
      <annotation>
        <documentation>A production element selected for verification testing. Distinct from a trial element (which precedes and is independent of production) and from a sacrificial element (which is destroyed by the test): a test element is a permanent, in-service element that also happens to be tested, and is expected to remain in service afterward.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="production">
      <annotation>
        <documentation>An element that carries permanent load and is not tested destructively. The default, unremarkable case - most elements in a rigid inclusion system are production elements.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="sacrificial">
      <annotation>
        <documentation>An element installed specifically to be tested to failure, and not relied on to carry permanent load either during or after the test.</documentation>
      </annotation>
    </enumeration>
  </restriction>
</simpleType>