Most all of our boilers lines are being offered in Lo Nox verisons. Our Vertical Tubeless design is pre approved for SCAQMD rule 1146.2 up to 47.5 BHP, meeting 30 ppm and 20 ppm measurements. The Scotch marine line can meet requirements as low as 9 ppm measurements. Using Coen Burners, Gordon-Piatt, Powerflame and Webster Burners.