From the AHSAA

Guidelines for the proper administration of football games during the 2013 season have been have been finalized by the AHSAA, including mandatory heat timeouts during early season games.
Heat Timeouts: According to Rule 3-5-7g in the National Federation Rules Book, an official may grant a heat timeout anytime during the contest when it is warranted. As a matter of procedure, the AHSAA has instructed the Referee at each game to make this decision.
The AHSAA will mandate the heat timeouts being called during the first dead ball period after the six-minute mark in each of the four quarters. These mandated timeouts will be used during the first three weeks of the season that begins Aug. 29 or 30.
25-Second Clock: The use of a 25-second clock as supplemental equipment has been approved by the AHSAA. The home team will have sole authority whether to use it or not. The 25-second clock operator must be registered with the AHSAA as an official or an Electric Clock Operator (ECO).
After a game has begun, the Referee will have the authority by rule to make any adjustments to timing issues and competency of the operator. This clock will be used for the “Super Six” championship games in Tuscaloosa Dec. 5-6.
All varsity games must have a registered official operating the game clock. All non-varsity games must have a registered official or an AHSAA-approved Electric Clock Operator (ECO) running the game clock.
Chain Crews: Each host school should use three competent adults on the chain crew for each home game.
Halftimes: According to Rule 3, Section 1, Table 3-1 Note 2, the AHSAA has set a mandatory length for halftimes of all member school contests. Varsity game halftimes will be 20 minutes in length while all sub-varsity halftimes will be 15 minutes in length. By rule, 20 minutes is the maximum length allowed.
By mutual agreement of opposing coaches, the intermission may be reduced to the minimum length of 10 minutes for all levels of play.
Warm-up Periods: All players, including team captains, shall have the opportunity to warm up during the mandatory three-minute warm-up period prior to the second half of play. This mandatory period will begin at the conclusion of the scheduled halftime. If the bands are late leaving the field and other appropriate areas are not provided for the teams to warm up, then the three-minute warm up will begin as soon as the bands exit the field. The home school will be penalized for such a delay.
If the bands clear the field prior to the conclusion of the scheduled halftime and opposing coaches agree to shorten the halftime, the mandatory three-minute warm up period may begin at that time.