# Vault and pit sealing, venting, and ventilation

- **operation:** document
- **citation:** Mich. Admin. Code R 460.20303
- **title:** Vault and pit sealing, venting, and ventilation
- **source type:** regulation
- **agency:** Michigan Public Service Commission
- **status:** current
- **official:** true
- **published on:** Not available
- **effective on:** 2026-05-04
- **summary:** Rule 303. In addition to the requirements contained in 49 C.F.R.§192.187(a)(3), which is adopted by reference in R 460.20606, an operator shall ensure that the outside end of the ventilation ducts of an underground vault or closed top pit is equipped with a suitable weatherproof fitting or vent head
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/mi-admin-code-r-460-20303.json
- **markdown:** https://regulus.evalyn.ai/document/mi-admin-code-r-460-20303.md
- **app url:** https://regulus.evalyn.ai/document/mi-admin-code-r-460-20303
- **source url:** https://ars.apps.lara.state.mi.us/AdminCode/DownloadAdminCodeFile?FileName=R%20460.20101%20to%20R%20460.20606.pdf
**body:**

Rule 303. In addition to the requirements contained in 49 C.F.R.§192.187(a)(3), which is adopted by reference in R 460.20606, an operator shall ensure that the outside end of the ventilation ducts of an underground vault or closed top pit is equipped with a suitable weatherproof fitting or vent head designed to prevent foreign matter from entering or obstructing the duct.

History: 1998-2000 AACS.
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- **body characters:** 400