Rule 3 – Section 2 – Article 4 – Timing Devices

a. Game clock.
Playing time shall be kept with a game clock that may be
either a stop watch operated by the line judge, back judge, field judge or side judge, or a
game clock operated by an assistant under the direction of the appropriate judge. The
type of game clock shall be determined by the game management.

b. 40-Second Clock.

1. When an official signals that the ball is dead, the play clock shall begin a 40-second
   count.
2. If the 40-second clock does not start or the count is interrupted for reasons beyond the
   control of the officials or the play-clock operator (e.g. clock malfunction), the referee
   shall stop the game clock and signal (both palms open in an over-the-head pumping
   motion) that the play clock should be reset at 40 seconds and started immediately.
3. In the event that the 40-second clock is running and reads 20 before the ball is ready
   to be snapped, the referee shall signal that the play clock be set at 25 seconds. If there
   is a delay in doing this, the referee shall declare a timeout and signal that the play
   clock be set at 25 seconds. When play is to be resumed, the referee will give the
   ready-for-play signal [S1] and the play clock shall begin the 25-second count. The
   game clock will start on the snap unless it had been running when the referee declared
   a timeout; in that case, it will start on the referee’s signal (Rule 3-3-2-f). (A.R.
   3-2-4:I and II)
   

c. 25-Second Clock.
If the officials signal the game clock to be stopped for any of the
following reasons, the referee shall signal (one open palm in an over-the-head pumping
motion) that the clock should be set at 25 seconds:

1. Penalty administration.
2. Charged team timeout.
3. Media timeout.
4. Injury timeout for a player of the offensive team only. The play clock is set to 40
   seconds for an injury to a player of the defensive team.
5. Measurement.
6. Team B is awarded a first down.
7. After a kick down other than a free kick where Team B will next snap the ball.
8. Scores other than a touchdown (not the try).
9. Start of each period.
10. Start of a team’s possession series in an extra period.
11. Video review.
12. Other administrative stoppage.
13. An offensive team player’s helmet comes completely off through play. The play
    clock is set to 40 seconds if the helmet comes completely off a player of the defensive
    team.
    When play is to be resumed, the referee will give the ready-for-play signal [S1] and the
    play clock will begin its count.
    

d. Device malfunction.
If a visual 40/25-second timing device becomes inoperative, both
coaches shall be notified by the referee immediately and both clocks shall be turned off.