A partial determination must be requested for all property that is in the figure in § 18.26 of this title (relating to Expedited Review List) or that is not wholly used for pollution control, except for property that is on the Tier I Table located in § 18.25(a) of this title (relating to Tier I Eligible Equipment) at a specified partial use percentage. It is the responsibility of the applicant to propose a reasonable method for calculating a partial determination. The calculation must be documented and included with the application. It is the responsibility of the executive director to review the appropriateness of the proposed method and make the final determination.
30 Tex. Admin. Code § 18.30