(a) For each new, reconstructed, or existing large solvent mixer at your friction materials manufacturing facility, you must limit HAP solvent emissions to the atmosphere to no more than 30 percent of that which would otherwise be emitted in the absence of solvent recovery and/or solvent substitution, based on a 7-day block average.

(b) For each new, reconstructed, or existing small solvent mixer at your friction materials manufacturing facility, you must limit HAP solvent emissions to the atmosphere to no more than 15 percent of that which would otherwise be emitted in the absence of solvent recovery and/or solvent substitution, based on a 7-day block average.