The test for helmets visor consists of three numbers adjustable supports on which the helmet under test can be placed with its crown facing down, a Bunsen burner mounted on a suitable stand such that it can be made vertical for setting of flame height and inclined to enable the flame to strike the helmet at 45° to the vertical, and an arrangement to move the burner in a horizontal direction to change its distance from the outer surface of the helmet manually.
The height of supports on which the helmet is placed on can he adjusted to enable the helmet to be supported properly and the flame to impinge on it at the specified distance below its crown.
The burner is made of brass and ss. The height of the flame can be adjusted with the help of a built-in needle valve. This adjustment is carried out with the burner vertical.
The burner is mounted on a swayable stand. It can be made vertical for setting of the flame height. It can then be inclined for conducting the test. The burner and platform are mounted inside a sheet metal enclosure to guard the flame against air currents.
The distance between the tip of the burner and the outer surface of the helmet can be changed manually with the help of a screw arrangement so that this distance can be kept at the desired value.