S5.6 Stability. When the warning device is erected on a horizontal brushed concrete surface both with and against the brush marks and subjected to a horizontal wind of 40 miles per hour in any direction for 3 minutes -
(a) No part of it shall slide more than 3 inches from its initial position;
(b) Its triangular portion shall not tilt to a position that is more than 10° from the vertical; and
(c) Its triangular position shall not turn through a horizontal angle of more than 10° in either direction from the initial position.