Texas Air Control Board Austin Texas Memorandum To: Permit Engineers, Regional Directors From: Lawrence E. Pewitt, P.E., Director, Permits Program Date: June 17, 1991, Updated April 11, 1996 Subject: Use of Standard Exemptions at Permitted Facilities It is often necessary to decide what Regulation VI requirements may be triggered when standard exemptions are used at existing grandfather or permitted facilities. To assist in evaluating these situations please use the following guidance: Use of exemptions at grandfathered facilities would trigger a permit review for the grandfathered unit via Regulation VI, Rule 116.1 now 116.110, only if the addition of the exempted facility will cause emissions from the existing unit to significantly increase without consideration of abatement system changes. If, for example, an exempted tank can be added at a grandfathered refinery and the addition of the tank will not cause existing emissions to increase, then the exemption may be appropriate and a permit will not be required for the existing facilities. Otherwise, construction of the exempted facility may be allowed but a permit must be obtained for the grandfathered unit before the emissions increase from the grandfathered unit unless the emissions increase qualifies under an exemption. Please see Regulation 30 TAC 116.116(e) for additional information. If the exempted facility is to be added at a permit unit, then consideration must be given to Regulation VI, Rule 116.5 now 116.116(a) which states, in part, that "It shall be unlawful for any person to vary from such representation in an application for a permit or in an exemption request if the change will cause a change in method of control of emissions, the character of emissions or will result in an increase in the discharge of the various emissions unless he first makes application to amend his permit." Therefore, if the exempted facility will cause the permit unit to change method of control, change character of the emissions or increase emissions, then it will be necessary to roll this exemption into the permit at a later date when the permit is either amended or renewed under Rule 116.116(c). However, construction and operation of the exempted facility may be commenced pursuant to Rule 116.6 now 116.211. Please be advised that future permits of special concern will include special conditions which prohibit the use of standard exemptions at the facility if Rule 116.5 now 116.116(a) will be triggered. Thank you for your ongoing cooperation in implementing these guidelines.