ASTM C1623-17a

Note 1: This specification covers only concrete masonry lintels containing reinforcement. Due to building code imposed limitations on the design of masonry lintels, all lintels must contain reinforcement. Concrete masonry lintels are not typically manufactured using shear reinforcement (stirrups or other vertical reinforcement). Therefore, this standard does not address issues related to such. For further guidance, refer to Building Code Requirements for Masonry Structures, TMS 402. Prestressed concrete lintels are not covered by this standard.