Assertion: trench | /r/HasProperty | 20 feet deep
Facets:
Source sentences:
text: A registered professional engineer must design protective systems for trenches that are at least 20 feet deep or approve tabulated data prepared for the system.
text: If trenches are more than 20 feet deep, education should be given to employees about the inherent risks of trench boxes, and designs that attempt to hold back earth in the trench.
text: A registered professional engineer must design protective systems for trenches that are at least 20 feet deep or approve tabulated data prepared for the system.