A head wall apparatus includes a support configured to be coupled to a wall, and a front panel coupled to the support to define an interior region of the head wall. The front panel includes an elongated opening. The apparatus also includes a gas block having an inlet and an outlet, and a shield configured to extend over the opening. The shield defines a track for slidably coupling the gas block to the head wall. The shield is configured to block access to the interior region of the head wall. A gas supply line located in the interior region of the head wall is coupled to the inlet of the gas block.