Section 63.7821 - [Effective until 6/3/2024] When must I conduct subsequent performance tests?(a) You must conduct subsequent performance tests to demonstrate compliance with all applicable emission and opacity limits in Table 1 to this subpart at the frequencies specified in paragraphs (b) through (e) of this section.(b) For each sinter cooler at an existing sinter plant and each emissions unit equipped with a control device other than a baghouse, you must conduct subsequent performance tests no less frequently than twice (at mid-term and renewal) during each term of your title V operating permit.(c) For each emissions unit equipped with a baghouse, you must conduct subsequent performance tests no less frequently than once during each term of your title V operating permit.(d) For sources without a title V operating permit, you must conduct subsequent performance tests every 2.5 years.(e) For each BOPF Group, if demonstrating compliance with the mercury emission limit in Table 1 to this subpart through performance testing under §§ 63.7825 and 63.7833 , you must conduct subsequent performance tests twice per permit cycle (i.e., mid-term and initial/final) for sources with title V operating permits, and every 2.5 years for sources without a title V operating permit, at the outlet of the control devices for the BOPF Group.71 FR 39586, July 13, 2006, as amended at 85 FR 42116, July 13, 2020