Section 250-RICR-120-05-9.12 - Stack HeightsA. The degree of emission limitation required for control of any air pollutant under these regulations shall not be affected in any manner by: 1. So much of a stack height, not in existence before December 31, 1970, as exceeds good engineering practice; or2. Any other dispersion technique not implemented before then.250 R.I. Code R. 250-RICR-120-05-9.12