# 63.1435 Heat exchanger provisions.
(a) The owner or operator of each affected source shall comply with the requirements of § 63.104 for heat exchange systems, with the exceptions noted in paragraphs (b) through (e) of this section and, beginning March 18, 2026, in paragraphs (f) through (i) of this section.
(b) When the term “chemical manufacturing process unit” is used in § 63.104, the term “polyether polyols manufacturing process unit” shall apply for the purposes of this subpart. Further, when the phrase “a chemical manufacturing process unit meeting the conditions of § 63.100(b)(1) through (3) of this subpart, except for chemical manufacturing process units meeting the condition specified in § 63.100(c) of this subpart” is used in § 63.104(a), the term “PMPU, except for PMPU meeting the conditions specified in § 63.1420(b)” shall apply for the purposes of this subpart.
(c) When the HON heat exchange system requirements in § 63.104(c)(3) specify the monitoring plan retention requirements, and when § 63.104(f)(1) refers to the record retention requirements in § 63.103(c)(1), the provisions of the general recordkeeping and reporting requirements in § 63.1439(a) and the applicable provisions of the General Provisions in 40 CFR part 63, subpart A, as specified in Table 1 of this subpart, shall apply for the purposes of this subpart.
(d) When the HON heat exchange system requirements in § 63.104(f)(2) require information to be reported in the Periodic Reports required by the HON general reporting provisions in § 63.152(c), the owner or operator shall instead report the information specified in § 63.104(f)(2) in the Periodic Reports required by the general reporting requirements in § 63.1439(e)(6), for the purposes of this subpart.
(e) When the HON heat exchange system requirements in § 63.104 refer to Table 4 of 40 CFR part 63, subpart F or Table 9 of 40 CFR part 63, subpart G, the owner or operator is only required to consider organic HAP listed in Table 4 of 40 CFR part 63, subpart F or 40 CFR part 63, Table 9 of subpart G that are also listed on Table 4 of this subpart, for the purposes of this subpart.
(f) Substitute “For each source as defined in § 63.101,” with “For each affected source as described in § 63.1420(a),”.
(g) Substitute “beginning no later than the compliance dates specified in § 63.100(k)(10)” with “beginning no later than the compliance dates specified in § 63.1422(h).
(h) If an owner or operator complies with § 63.104(g), then § 63.104(b) through (e) no longer apply.
(i) For heat exchange systems in ethylene oxide service:
(1) Substitute “in ethylene oxide service, as defined in § 63.101” with “in ethylene oxide service, as defined in § 63.1423”.
(2) § 63.104(g)(6) does not apply. Instead, for heat exchange systems in ethylene oxide service, the monitoring frequency is monthly.
(3) § 63.104(h)(6) does not apply. Instead, for heat exchange systems in ethylene oxide service, owners and operators must repair the leak to reduce the concentration or mass emissions rate to below the applicable leak action level as soon as practicable, but no later than 45 days after the sample was collected.
(4) Section 63.104(k) does not apply. Instead for each source as described in § 63.1420(a), beginning no later than the compliance dates specified in § 63.1422(h), owners and operators must not inject water into or dispose of water through any heat exchange system in a PMPU if the water contains any amount of ethylene oxide, has been in contact with any process stream containing ethylene oxide, or is considered wastewater as defined in § 63.1423.
[64 FR 29439, June 1, 1999, as amended at 65 FR 26501, May 8, 2000; 91 FR 13175, Mar. 18, 2026]