We continue to hear people say that non-coal tar containing sealers are just too new or experimental or that they just don't perform up to the standards of coal tar sealers. What is the Federal Aviation Administration's (FAA) perspective on this because they have a lot more riding on their pavement than on your driveway.
Today's new commercial airplanes cost hundreds of millions of dollars. Not only are they getting more expensive, but the planes are getting bigger (unfortunately not the seats). These beasts can deliver a million pounds of weight on 250 psi tires dropping out of the sky at over 100 mph. The pavement must not crumble under this burden because if it does it can generate what the industry calls Foreign Object Debris (FOD). FOD has been know to bring down planes after being sucked into a jet engine.
These are the kind of conditions which the FAA must develop pavement standards. New ones just came out last fall.
|Foreign Object Debris (FOD) is so important that Britain's Royal Air Force periodically hides a "golden bolt" to be found by the maintenance crew. The person that finds it gets a day of leave.|
What does this have to do with coal tar sealers? Plenty. Coal Tar sealers are commonly used on asphalt pavements at airports in refueling, aprons, and parking areas. Yet they are considered an unacceptable contaminant in recycled asphalt material which could compromise the strength of the airport asphalt. NONE, zero, zilch is allowed in recycled asphalt according to the Director of Engineering for the Asphalt Institute, Mark Buncher and Item 401-3.3 Reclaimed Asphalt Pavement (RAP) in Advisory Circular 150-5370-10G, Standards for Specifying Construction of Airports. This recommendation was also made by the former president of the PCTC in a study at the University of Nevada at Reno in 2009.
Look for this to become common practice in the US in the future for all recycled pavements.
And non-coal tar sealer products are now being allowed in the following standards:
- P-608 Emulsified Asphalt Seal Coat (that includes gilsonite for all you gilsonite haters out there)
- P-626 Emulsified Asphalt Slurry Seal Surface Treatment
It also appears that the FAA is trying to distance itself from coal tar sealers a bit. The specs come with this caution:
"With growing environmental/safety regulations, more states and local authorities are prohibiting the use of coal tar products. The Engineer must verify the selected materials comply with local authority requirements."
So the FAA is good with these alternatives and the evidence is clear that coal tar sealers are a potent pollutant in our homes and environment. What then would reasonable people do?