I have the 60 year jopist manual too, and there are no DH joists shown. Are you sure they are not DLH?
Is this the nomenclature on the joist tag?
FYI, 24" DLH11 is not listed either as they start at 52".
A 24" LH11 is good for 768/418 at 40 feet with a safe load of 31,200#. (total load / live load)
Your nomenclature must be wrong.
Mike McCann
MMC Engineering
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