Hazard alerting signs must be placed to alert and inform viewers from a safe viewing distance, according to ANSI Z535.2-2011, Sections 11 and 12.
• They must be legible, and must not be a distraction or create a hazard themselves.
• They must not be placed on or adjacent to moveable objects like doors, windows, etc.
• Safety and fire equipment signs must be clearly visible in the immediate vicinity of the equipment.
• Safety signs must be protected from damage caused by fading and other potential environmental conditions.
• Signs must be displayed with illumination or retro-reflectiveness as needed for adequate legibility under normal operating conditions.
• Where illumination is inadequate or colors are not recognizable, supplemental illumination must be used.
• Where illumination may be interrupted, the sign should be made with photo luminescent and/or retro-reflective materials, and/or equipped with emergency lighting.