Section 63.8590 - When must I conduct subsequent performance tests?(a) For each affected source that is subject to the emission limits specified in Table 1 to this subpart, you must conduct a performance test before renewing your 40 CFR part 70 operating permit or at least every 5 years following the initial performance test.(b) You must conduct a performance test when you want to change the parameter value for any operating limit specified in your OM&M plan.