§ 63.2253 What are the general requirements for lumber kilns?
(a) Lumber kiln O&M plan. The lumber kiln O&M plan must include the elements specified in paragraphs (a)(1) through (3) of this section and be maintained according to paragraph (a)(4) of this section.
(1) Procedures for maintaining the integrity of lumber kiln internal air flow and heat distribution components (such as, baffles, fans, vents, heating coils, or temperature sensors) to provide as uniform a temperature and air flow as reasonably possible.
(2) Charge optimization practices to reduce over drying.
(3) At least annually, you must inspect lumber kiln integrity and review the charge optimization practices used. You must implement corrective actions as needed and maintain records of the inspections and corrective actions taken.
(i) The initial inspection of kiln integrity must be completed by the compliance date specified in § 63.2233(e). After the initial inspection, each annual inspection is required to be completed no more than 13 months after the previous inspection.
(ii) Corrective actions must be initiated within 30 days after the inspection and completed within 180 days following the inspection identifying the need for the corrective action. If the corrective action cannot be completed within 180 days, a written request for an extension may be submitted to the delegated authority, who may grant an extension if they determine additional time is necessary.
(4) After the compliance date in § 63.2233(e), any updates made to the O&M plan maintained onsite must be described in the semiannual compliance report. Delegated authorities may require modification of the O&M plan, as needed, upon review.
(b) Lumber kiln site-specific plan approval. If you choose to comply with the work practice option in § 63.2241(e)(3)(iii) using a site-specific plan for temperature and lumber moisture monitoring, the requirements in paragraphs (b)(1) through (5) of this section apply.
(1) The site-specific plan must be developed and submitted to the delegated authority by January 6, 2028.
(2) The written site-specific plan must be maintained onsite at the facility and is enforceable upon the compliance date specified in § 63.2233.
(3) After the compliance date, you must report deviations from the site-specific plan according to § 63.2281.
(4) Once the site-specific plan is approved by the delegated authority, the site-specific limits from the plan must be incorporated into the facility's title V permit when the title V permit is next reopened for cause or renewed, as applicable.
(5) After the compliance date in § 63.2233(e), any updates made to the site-specific plan must be approved by the delegated authority, and any updates to the site-specific limits from the plan must be incorporated into the facility's title V permit when the title V permit is next reopened for cause or renewed, as applicable.
[91 FR 41436, July 6, 2026]