Okla. Admin. Code § 748:20-16-13
Chapter 8 of the Oklahoma adopted IPC® 2018 is adopted with the following modification: Section 802.1 Where required. This section has been modified to address errata published by the ICC® to correct a section reference specified in the section from "802.1.1 through 802.1.8" to "802.1.1 through 802.1.7." This section has been modified to read: 802.1 Where required. Food-handling equipment, in other than dwelling units, clear-water waste, humidifiers, dishwashing machines and utensils, pots, pans and dishwashing sinks shall discharge through an indirect waste pipe as specified in Sections 802.1.1 through 802.1.7. Fixtures not required to be indirectly connected by this section and the exception to Section 301.6 shall be directly connected to the plumbing system in accordance with Chapter 7.
Okla. Admin. Code § 748:20-16-13