US lawWashingtonRegulationsTitle 51 — ENTERPRISE SERVICES, DEPARTMENT OF (BUILDING CODE COUNCIL)Chapter 51-11C — STATE BUILDING CODE ADOPTION AND AMENDMENT OF THE 2021 EDITION OF THE INTERNATIONAL ENERGY CONSERVATION CODE, COMMERCIAL51-11C-40240WAC 51-11C-40240WAC 51-11C-40240. Section C402.5 — Air leakage-thermal envelopeLast amended: 2020Year: 2026Length: 16 wordsOfficial source C402.5 Air leakage-thermal envelope. The thermal envelope of buildings shall comply with Sections C402.5.1 through C402.5.8.PreviousWAC 51-11C-40234NextWAC 51-11C-40241