Fouls and violations

A foul is committed when a part of the player's body crosses the foul line and touches any part of the lane during their delivery. Although the ball counts as a roll, no pinfall will be credited, and the pins will be re-spotted if the player has a second roll. League and tournament authorities are allowed to use officially sanctioned automatic foul detection devices, or employ a foul line judge.

Illegal pinfall

When any of the following conditions occur, the delivery will count, but a pinfall will not be scored for the roll:

• A ball knocks down pins after leaving the lane.
• A ball rebounds off the rear cushion.
• A pin is knocked down by a human pinsetter.
• A pin rebounds after coming into contact with the body of a human pinsetter.
• A pin is touched by the mechanical pin setting equipment.
• The player commits a foul.

Dead ball

A ball will be declared dead if any of the following conditions occur:

• It is noticed that pins were missing from the rack after the ball has been delivered.
• A human pinsetter interferes with any standing pins before the ball reaches the pins.
• A downed pin is interfered with before it stops rolling.
• A player bowls in the wrong lane or out of turn.
• A player is interfered with by other players, spectators or moving objects. The player can accept the resultant pinfall or have a deadball declared.
• A delivered ball is obstructed by a foreign object.

When a dead ball is called, neither the delivery nor the resultant pinfall are recorded. The pins will be re spotted as they stood and the player will re-take the shot.