VOC Compliance: 450 grams/liter vs. 150 grams/liter

The choice between oil-base (alkyd) and water-base (latex) traffic paint may be made for you soon. This fall, the federal regulation mandating low VOC traffic paints will be in effect, mandating certain VOC limits for products used in certain areas.

The regulation established different VOC levels for zone marking coatings and traffic marking coatings. Zone marking coatings are defined as those used on sidewalks, driveways, parking lots, curbs and airport runways and packaged in containers of five gallons or less. The VOC limits for zone markings is set at 450 grams/liter, a level met by all our current alkyd and latex traffic paints.

Traffic marking coatings are defined as those used for streets, highways and traffic areas as well as the purposes outlined for zone markings. The VOC limit set for traffic markings is 150 grams/liter, a level met by all our latex traffic paints and a small handful of low-VOC alkyd traffic paints.

In effect, this regulation will mandate latex traffic paint for highway and street delineation.

Leaded or Lead-free

In the 1980’s, the search for environmentally friendly traffic marking materials resulted in a move away from paint with lead in it. Today, virtually all white traffic paints are lead-free, and many lead-free yellows are available as well.

Lead chromate pigment can be present in latex or alkyd paint, and is used to get the vibrant golden yellow that has been associated with highway centerlines for years. Today, there are a number of lead-free pigments that also offer excellent yellow color.

For that reason, the use of lead-free paint is fast becoming the norm. You cannot assume that all alkyd paints are leaded and all latex paints are lead-free.

Fast or Slow Dry

These days, traffic paint can be formulated to dry almost instantly. In fact, many of the fastest-drying formulations actually contain additives to slow them down so they won’t dry in the can or striping equipment.

Most striping operators automatically believe that the faster the dry time of the paint, the better. In fact, the fastest dry times should only be used when dry time is the most important consideration.

When traffic paint is formulated to dry too quickly, there may not be adequate time for the paint to wet through to the substrate. This means that in many cases the adhesion, or bond the paint forms with the substrate, may be compromised.

Wet paint needs to be protected from traffic in order to allow the formation of a good paint film, as well as to protect the public from tracking paint onto their vehicles.

To get the best performance from your traffic paint, in some conditions you may want to choose the slowest drying formula you can get away with. For highway stripers this may mean a three-minute dry product, while political subdivisions and parking lot contractors who can cone off their work may want to look at a paint that takes 30 to 40 minutes to dry.

Glass Bead Retention

The government is now considering mandating minimum retroreflectivity levels as a way of improving the brightness and effectiveness of traffic markings.

Retroreflectivity simply means the property of reflecting light back toward its source. In pavement markings, retroreflectivity is caused by putting glass beads on the paint before it dries so that the beads become a part of the cured film.

For best line visibility at night, the proper glass beads must be used. Beads must have the appropriate gradations, roundness and clarity to offer the best light-conducting properties.

These beads must also be coated with the right materials to enable them to adhere to the paint you are using, and in some cases to sink into or float on top of the paint film in order to achieve the right embedment. Beads should be embedded so that 60% of the bead is covered in the paint, with 40% exposed, to reflect the maximum amount of light back to the driver.

The beads also need to be applied at the right rate. This rate is measured in pounds of beads per gallon of paint, and varies from state to state. Bead application rate and embedment are affected by the equipment you use, and so quality equipment to apply beads and monitor bead application is critical.

Initial vs. Lifetime Cost

The most cost-effective paint is seldom the cheapest. The lowest priced traffic paints seldom hold up as well as more expensive paints. In fact, a product that costs twice as much could be more cost-effective because the installed marking may last more than twice as long, making the lifetime cost of the marking less.

Lower priced paints can also result in poor service to the driving public. If you paint only once a year, using a low-cost product that lasts only a few months does not provide the same quality of service as using a more expensive paint that will last all year.

Also, if you are using the specifications for a product formulated by another agency, you may not be getting the paint that is best for your application. You may be paying for performance you don’t need, such as rapid dry times, while sacrificing in other areas.

Many agencies are moving toward paint specifications that define performance rather than a recipe. They have freed themselves to buy the paint that will produce the best combination of initial and lifetime cost.

It is possible to formulate the best traffic paint for you, but only after you choose the paint features that are most important to you.

For more information, call EZ-Liner® at 800-373-4016.