A rigid construction is a high-density constructing element designed from block work, masonry, or concrete, with an overall density ≥850kg/m³ and a thickness appropriate for the expected fire-resistance period. It can also be a low-density constructing element made from aerated concrete block, masonry, or lintels, with an overall density of ≥650kg/m³ and a thickness appropriate for the expected fire-resistance period.
