Inform personnel, Identify directional flow for pipes carrying hazardous contents by applying a short arrow. Pipe markers should be placed at frequent intervals along piping systems, and should be clearly legible at a distance. Visible colors and bold lettering on the pipe marker are designed to meet or exceed ASME (ANSI) A13.1-2007 recommendations for size, color and visibility for flammable fluids. Available in Self Stick adhesive Vinyl, or a pre-coiled wrap made of heavy-gauge 20-mil rigid vinyl plastic.