Texas Natural Resource Conservation Commission Interoffice Memorandum To: Coatings Group Date: May 12, 1997 From: Allen Zolondek Subject: Evaluating Off-Property Concentrations of Inorganic Fluorides Since inorganic fluorides have been removed from 30 TAC 113, the following method will now be used for evaluating off-property concentrations of inorganic fluoride emissions. Water Soluble Inorganic Fluorides (1), Hydrogen Fluoride, & Hydrofluoric Acid: The individual concentrations from each of these three categories are summed together to obtain a Total Hydrogen Fluoride (Total HF) concentration. The Total HF concentration is compared with a 3-hour ESL of 4.9 micrograms/m3 and a long-term ESL of 0.5 micrograms/m3. (1) Before summing, the concentration of each water soluble inorganic fluoride compound must first be converted to an equivalent Hydrogen Fluoride concentration as follows: Concentration (HF Equivalent) = No. Fluoride Atoms (Compound) x ((M.W. HF)/(M.W. Compound)) x Concentration (Compound) Non-Water Soluble Inorganic Fluorides: The concentrations of these compounds are individually compared with a short-term ESL.