Cal. Code Regs. tit. 25, § 4533 – Mechanical.

(a) Except as provided in Subsections (b) and (c), the provisions of Article 3, Subarticle 4 of this subchapter, shall apply to mechanical equipment and installations of all special purpose commercial modulars.
(b) Make-up air shall be provided at the rate of that exhausted and may be accomplished from screened service openings, screened vents in the ceiling, or mechanically through an air-conditioning system, but not through open doors or operable windows.
(c) Ducts shall be securely fastened in place and supported at least every four (4) feet.

Note: Authority cited: Section 18015, Health and Safety Code. Reference: Sections 18025 and 18028, Health and Safety Code.

1. Amendment of section and new Note filed 9-19-2011; operative 10-19-2011 (Register 2011, No. 38).