National Hockey League rules While the National Hockey League ( NHL ) follows the general rules of Ice hockey , it differs slightly from those used in international games organized by the International Ice Hockey Federation such as the Olympics . Game timing . In the National Hockey League , between stoppages of play , teams have 18 seconds ( 5 seconds for the visiting team , 8 seconds for the home team , 5 seconds to line up at the faceoff location ) to substitute their players , except during TV timeouts . TV timeouts are two minutes long , and occur three times per period : during normal game stoppages after the 6 , 10 , and 14 minute marks of the period , unless there is a power play or a goal has just been scored . Each team may also take one 30 second time - out which may only be taken during a normal stoppage of play . Hockey rink . The hockey rink is an ice rink which is rectangular with rounded corners and surrounded by a wall , usually called the " boards " . It measures 25 . 91 by 60 . 92 metres ( 85 by 200 feet ) in the NHL , while international standards call for a rink measuring 60 - 61 meters long by 29 - 30 meters wide ( 196 . 85 - 200 . 13 feet by 95 . 14 - 98 . 43 feet ) . The centre line divides the ice in half lengthwise . The centre line is used to judge icing violations . There are two blue lines that divide the rink roughly into thirds . They divide the ice into zones . Near each end of the rink , there is a thin red " goal line " spanning the width of the ice . It is used to judge goal s and icing calls . New in the 2005 - 06 season , after testing in the American Hockey League , is a trapezoid behind each goalie net . The goalie can only play the puck within that area or in front of the goal line . If he plays the puck behind the goal line and not in the trapezoid , a 2 minute minor penalty for delay of game will be assessed by the referees . This rule is widely referred to as the " Brodeur rule " , after New Jersey Devils goalie Martin Brodeur , whose puckhandling behind the net is believed to be the cause for the rule . Scoring and winning . A goal is scored when the puck completely crosses the goal line and enters the net . A goal may be disallowed under the following circumstances : The team with more goals at the end of regulation time wins the game . If a regular - season game is tied at the end of regulation , the game enters a five - minute , 4 - on - 4 sudden - death overtime period ; any team that scores during overtime immediately ends the game with a victory . If neither team scores during this time , a shootout takes place . Three players from each team are picked by their respective coaches and alternate chances to score on the opposing goaltender , in a method functionally identical to penalty shots . This sequence ends when one team mathematically has to have more shootout goals than the other , thus winning the game . If neither team emerges victorious , the shootout continues one frame at a time until one team scores and the other does not , in which case the team who scores , wins . No player may shoot twice until everyone on the bench has taken a shot . A team that loses a game in overtime or the shootout will receive one point in the standings ; the awarding of game points to losing teams is a point of debate among fans and the media . Shootouts are not implemented in the playoffs . If a playoff game is tied at the end of the regulation , the game instead enters a twenty - minute 5 - on - 5 sudden - death overtime . The game continues indefinitely in this format until a goal is scored ; the team that scores this goal immediately wins the game . Additional 20 - minute overtime periods are played as necessary until the winning goal is scored . Offside . In ice hockey , play is said to be " offside " if a player on the attacking team enters the attacking zone before the puck ( unless the defensive team brings the puck into their own zone ) . When an offside violation occurs , the linesman blows the play dead , and a faceoff is conducted in the neutral zone . During the ' 04 - ' 05 lockout , the league removed the offside pass or two - line pass rule , which required a stoppage in play if a pass originating from inside a team ' s defending zone was completed on the offensive side of the centre line , unless the puck crossed the line before the player . The removal of the two - line offside was one of several rule changes intended to increase overall scoring , which had been in decline since the early 1990 ' s . Icing . Icing occurs when a player shoots the puck across both the centre line and the opposing team ' s goal line without the puck going into the net . When icing occurs , a linesman stops play if a defending player ( other than the goaltender ) touches the puck before an attacking player is able to . Play is resumed with a faceoff in the defending zone of the team that committed the infraction . Icing is not enforced for a team that is short - handed . If the goaltender makes a move from his net to play the puck , the icing is immediately waved off ( In contrast to Minor and International Hockey , where the goaltender must play the puck for it to be waved off ) . Icing can also be waved off if , in the officials ' opinion , the defending team had a viable opportunity to play the puck before crossing the goal line . Under the rules following the 2004 - 2005 lockout if a team is guilty of icing the puck they are not allowed to make a line change before the following faceoff . Penalties . A penalty is a punishment for infractions of the rules . A referee makes all penalty calls while the linesmen may call only obvious technical infractions such as " too many men on the ice " . In the NHL , the linesman may also call major intent - to - injure penalties that the referee may have missed . During a penalty , the player who committed the infraction is sent to the penalty box . Small infractions are deemed minor penalties , and the player is kept off the ice for two minutes of gameplay . More dangerous infractions , such as fighting , are deemed major penalties and have a duration of five minutes . The penalized team cannot replace the player on the ice and is thus shorthanded for the duration of the penalty . Normally , hockey teams have five skaters on the ice ( excluding the goaltender ) , so if a minor or major penalty is called , play becomes five - on - four . This situation is called a power play for the non - offending team and a penalty kill for the offending team . A team is far more likely to score on a power play than during normal play . If the penalized team is scored on during a minor penalty , the penalty immediately terminates . Unlike minor penalties , major penalties must be served to their full completion , regardless of number of goals scored during the power play . There are exceptions to the rule where a team cannot replace a player on the ice after a penalty : mutual majors for fighting , where there are two participants in a fight , will result in each person receiving five minutes , but the penalties will not affect the on - ice strength of either team ( play remains five - on - five ) , unless if a player is deemed to be the instigator of the fight , that player will receive a two minute minor . There are also " coincidental " minors in which the penalties called against both teams are simultaneous and equal in length , so that neither team receives a power play . The players are let out of the penalty box at the stoppage of play There also exist game - and 10 - minute - misconducts which are reserved for infractions such as continued disputing of a call with an official or for intent to injure penalties . Misconducts do not affect the on - ice strength of the offending team , though they are usually accompanied with a minor , double minor , or five - minute major . Various combinations of penalties may also result in match - ups such as 5 - on - 4 , 5 - on - 3 , 4 - on - 3 , 4 - on - 4 or ( rarely ) 3 - on - 3 .