Building workers lose beneficiary status at 60 or after 90 days non-engagement; three years' continuity preserves prescribed benefits. Section 107 provides that a registered building worker ceases to be a beneficiary on attaining sixty years or on non-engagement in construction work for ninety days in a year, excluding absence due to employment-related personal injury. A worker with at least three years' continuous beneficiary status immediately before turning sixty remains eligible for prescribed benefits, and any immediately prior beneficiary registration with another Board shall be added when computing that three year continuity.