California Code
ARTICLE 4 - Structural Steel Framed Buildings
Section 7253.

7253. There shall be a tight and substantial temporary floor within two floors below and directly under that portion of each tier of beams on which erection, riveting, bolting, welding or painting is being done. For operations of short duration of exposure to falling, safety belts shall be required as set forth in Section 7265.

(Added by Stats. 1970, Ch. 1498.)