The Stairs Going Down (Left) (ZG17) safety sign has a white symbol of a man walking down stairs on the green square shaped safety sign.
 
The sign indicates where the escape route can be located and is often used in conjunction with one of the following safety signs:
General Direction
General Direction (Diagonal)
The emergency escape route safety sign is also available as a Photoluminescent (glow in the dark) sign as a single safety sign or as a combination of more than one safety sign.
Refer to the Photoluminescent section for various combination options. 
SABS standard safety sign