What counts as a foul?

A foul is when any part of your body (shoes and clothing included) goes on or past the foul line and touches the lane, equipment or building during or after a delivery. The ball is in play until the next bowler is on the approach ready to deliver.

• The delivery counts, but you get zero pins for it.
• The foul line runs indefinitely, across walls, posts and ball returns.
• Not a foul: crossing the line while still holding the ball, the ball itself rolling over the line, stepping onto the adjacent approach (as long as you don't cross the line there), or a coin, pen or jewelry falling past the line.
• A wheelchair, walker or other aid crossing the line and touching the lane is a foul.
• Deliberately fouling to gain an advantage scores zero for that delivery and you get no further deliveries in that frame.

Who calls it: an automatic foul detector if the center has one. Otherwise the opposing team captains or an appointed foul judge. A foul that the detector misses still counts if it's apparent to both captains or to one or more members of each team.