When using pH test paper/indicator sticks you should also: 1  Make sure to only use paper/sticks that have not been previously wetted. 2  Wait for the color to stop changing (1-2 minutes maximum) before matching the paper/stick to the color key.
Red and White Regulatory Signs. Red and white regulatory signs tell you about regulations you must follow. For example, the DO NOT ENTER sign tells you there is danger ahead because vehicles will be coming toward you, usually on a freeway off-ramp or one-way street. The WRONG WAY sign may accompany the DO NOT ENTER sign.
Hazard warning signs â these signs warn you of a danger or risk to your health. made up of a yellow triangle with a black border and a black symbol. Emergency information signs â these signs show where emergency safety equipment is kept. They are made up of a green solid rectangle with a white symbol or text. Fire signs â these signs tell you the location of fire alarms and firefighting facilities. made up of a red solid rectangle with white text.