A high rise building has a 4″ vent stack and a 4″ waste stack that extends 14 stories above the 4″ plumbing drain. A relief yoke vent would be needed. What size would this relief yoke vent be?

A high rise building has a 4″ vent stack and a 4″ waste stack that extends 14 stories above the 4″ plumbing drain. A relief yoke vent would be needed. What size would this relief yoke vent be?