Sorry - I've been away for the holidays. A156.19 does include a requirement for signage when a low-energy operator is used:
6.1 Doors shall be equipped with signage visible from either side of the door, instructing the user as to the operation and function of the door. The signs shall be mounted 50” +/- 12” (1270 mm +/- 305 mm) from the floor to the center line of the sign. The letters shall be 5/8 inch (16 mm) high minimum.
6.2 Consistent with section 2.2.1 of ANSI Z535.4 - 2002 the "signage and warnings" guidelines of A156.19 are recognized, industry-specific standards that predate the adoption of Z535.4 and are not replaced by the standards set forth therein.
6.4.1 All low energy doors shall be marked with signage visible from both sides of the door, with the words "AUTOMATIC CAUTION DOOR" (See Figure 1). The sign shall be a minimum of 6 inches (152 mm) in diameter with black lettering on a yellow background. Additional information may be included. Additionally one or both of the following knowing act signs shall be applied:
6.4.2 When a Knowing Act Switch is used to initiate the operation of the door operator, the doors shall be provided with signs on each side of the door where the switch is located, with the message “ACTIVATE SWITCH TO OPERATE”. The lettering shall be white and the background shall be blue.
6.4.3 When push/pull is used to initiate the operation of the door operator, the doors shall be provided with the message “PUSH TO OPERATE” on the push side of the door and “PULL TO OPERATE” on the pull side of the door. The lettering shall be white and the background shall be blue.