The standard specification for face brick, ASTM C216, contains a required minimum compressive strength of 3000 psi. Shouldn't the engineer of record on the job be defining what compressive strength is needed for a wall? Why is this default value given in the specification?
The purpose of the minimum compressive strength in ASTM C216 is to establish minimum durability requirements for units. Units with very low compressive strengths generally are not durable. In ASTM C216, severe weathering bricks have a higher required minimum average compressive strength than do moderate weathering bricks. The minimum requirement for compressive strength is just one of the durability requirements in ASTM C216; refer to the specification for the other requirements. It is the responsibility of the engineer of record or architect to specify the required compressive strength in structural masonry walls. The ACI 530.1 Specification contains a table that correlates the minimum compressive strength of masonry units with the required compressive strength of the wall when used with a specific type of mortar.