A directional fire exit sign is a green rectangle carrying the running figure and an arrow. It is a safe condition sign, which means it tells a person where to go rather than warning them about anything. Its whole value lies in being part of a consistent run, because a person following signage is making a series of decisions and a single wrong arrow ends the sequence.
How the sign is constructed
The running figure faces the direction of travel and the arrow points the same way. Where the route goes down, the arrow points down; where it goes up, it points up. A sign directly over a final exit door carries no arrow, because there is no further decision to make. These conventions exist so that a person can read the sign without thinking about it.
Placement along a route
A sign is needed at every point where the route is not obvious: junctions, changes of direction, doors that are not the obvious way out, and any point where a person would otherwise have to choose. Between those points the run has to be continuous enough that the next sign is visible from the last, which is the test that catches long corridors.
The failure modes
An arrow left in place after a layout change, pointing at a route that no longer exists. A run that stops halfway because refurbishment removed a section. Two signs at a junction pointing in different directions. A sign mounted so high it is in the smoke layer. Each of these is a defect the fire risk assessment should find and a walk of the route will find faster.
Signage does not replace lighting
A sign is only readable if it can be seen. That is why escape routes need emergency lighting, and why signs on routes that are not lit are made of photoluminescent material. A correct sign in the dark has done nothing.
Questions people ask about fire exit left
Which way should the running figure face?
In the direction of travel, matching the arrow. A figure running away from the arrow is a manufacturing or installation error and should be replaced.
Do signs need to be visible from each other?
Along a route, effectively yes. A person should not reach a point where no sign is in view and a choice has to be made.
Should the word exit appear on the sign?
Supplementary text is common and is there to reinforce the pictogram. The pictogram and the shape carry the meaning, and text alone is not a compliant sign.