Section 78.47-53 - Automatic ventilation dampers(a) The manual operating positions for automatic fire dampers in ventilation ducts passing through main vertical zone bulkheads shall be identified by red day light-reflecting letters at least 1/2 inch high "VENTILATION FIRE DAMPER." In addition, the open and closed positions shall be similarly marked.CGFR 65-50, 30 FR 16955, Dec. 30, 1965, as amended by CGD 67-87, 32 FR 19181, Dec. 20, 1967