Barricade tape

Barricade tape is brightly colored tape (often incorporating a two-tone pattern of alternating yellow-black or red-white stripes or the words "Caution" or "Danger" in prominent lettering) that is used to warn or catch the attention of passersby of an area or situation containing a possible hazard. It acts as a minor impediment to prevent accidental entrance to that area or situation and as a result enhances general safety. 
Barricade tape is also known as construction tape or barrier tape or in reference to the safety hazard involved as caution tape, warning tape, danger tape or hazard tape. When used by a police force, the tape is named police tape.
The tape is often wrapped and affixed as a visual warning sign and demarcation, for instance against entering a dangerous area, such as an industrial or commercial building site, a roadworks construction site or the scene of an accident or a crime (for crime scene preservation), or against handling inoperative machinery or appliances.
Description.
Barricade tape is made with durable, resilient, tear-proof plastic materials such as polyethylene, polypropylene, or nylon. Different manufacturers offer different sizes and thicknesses of barricade tape. Barricade tape often has a bright background and pre-printed bold warning text. It is also possible to purchase plain barricade tape and write a custom message on it. However, care should be taken when using custom tape, as barricade tape designs may be required to comply with regulations, such as the Occupational Safety and Health Administration (OSHA) and American National Standards Institute (ANSI) regulations (when used for purposes subject to regulation by these organizations) in the USA.
Types.
Barricade tape is used according to the color specifications set by OSHA and ANSI. Barricade tape may be use primarily as a safety precaution for various industries and procedures.
Foreground (tape) and background colours.
The choice of colours of barricade tape depends on the contrast with its background, which in the case of the sky, can vary from black to white.
To have a reasonable chance of being visible against most backgrounds, the tape needs a light colour (white or yellow) and a darker colour.
Requirements for barricade tape.
Requirements for barricade tape vary according to the health and safety laws of the country or region it is being used in.
United States.
OSHA and ANSI provide precise specification for barricade tape colors. These are found in OSHA regulations 1910.22 and 1910.144 and ANSI Z535.5-2007, "Safety Tags and Barricade Tapes (for Temporary Hazards)". However, the dimension, thickness, and materials of the barricade tape are left to the discretion of the manufacturer.
United Kingdom.
Health and safety regulations state that markings should be placed around obstacles or dangerous locations. This includes where any of the following present a risk:
These markings should be made up of alternating red and white or yellow and black stripes of equal size at a 45 degree angle. Barricade tape can be used to satisfy this requirement as long as the tape is "commensurate with the scale of the obstacle or dangerous location in question".