The thickness of the ice used in NHL games is very important for the safety of the players and the quality of the game. The standard thickness of the ice used in the NHL is 3/4 of an inch, which is tested and regulated by the NHL to ensure it is up to the necessary standard. The ice must be properly chilled and treated with a resin solution to ensure that it is thick enough and that the surface is smooth. The ice must also be protected from any external elements such as sunlight and humidity. Finally, the Zamboni machine is used to maintain the ice and keep it in good condition for the duration of the game.