FAA AC 150/5370-10G
By Donna Speidel
The most recent edition of the FAA Advisory Circular 150/5370-10 was released on July 21, 2014. As of July 13, 2016, an errata sheet was published and the current AC reflects those changes.
Needless to say, the AC 5370-10G, Item P-620 "Runway and Taxiway Painting", has undergone extensive revision to include several quality control measures for new construction projects. I'm comfortable with most of these items being included in your specifications as they're written, with some exceptions. To hear about all of the changes, consider attending an Airfield Marking Symposium in 2016. If you are already a subscriber, you'll get updates about the symposiums in your inbox. If you'd like to get updates, sign up here.
This series of articles will address each change in the guidance literature, its intent, and what the new language means to you. You may download your own
copy of Item P-620 from our website as a reference by clicking on the icon to the right.
Be sure to share this article with your Resident/Consulting Engineers so your project specifications remain relevant.
Table 1. Application Rates For Paint And Glass Beads
- What Changed - The application rates for waterborne and solvent paints have been modified to increase the thickness when Type IV glass beads are specified. If waterborne is selected, the Type III formulation should be applied at 55-60 square feet per gallon to achieve a thicker (30 mil) coating when Type IV beads are specified.
- The Intent - Paint coverage rates shall be tailored to account for the various physical sizes of glass bead types to achieve proper bead embedment.
- What It Means To You - Using Type IV beads means using Type III paint*. The old reliable standard of 115 ft2/gal and Type I and II paints won't necessarily be suitable for all of your projects. From an applicator's (and a quality control) standpoint, the level of difficulty will likely increase when attempting an application of this kind with typical marking equipment.
- * While it's not listed in Table 1, it is our opinion that Type III paint may also be used at the traditional coverage rate of 115 ft2/gal.
Additional Changes
- What Changed - [Added] It is recommended when using waterborne paints on previously unmarked asphalt or seal coat, that an initial paint coat at 50% of the permanent coverage rates be applied for white markings to reduce the discoloration that occurs.
- The Intent - Application of a "primer" coat should be considered when painting white markings on unmarked asphalt to mitigate changes to marking color.
- What It Means To You - This is a best practice particularly on new runway projects with white markings, but it should also be considered for any reflective markings irrespective of color. One suggestion would be to generally use 230 ft2/gal for an initial paint coat instead of "50% of the permanent coverage rates" as those rates can vary significantly. Further, due to the thinner coverage, glass beads are not required in these initial coats, but may be advisable in certain circumstances. In those instances, the glass beads would not properly embed and markings would [also added] "require immediate sweeping and cleanup before aircraft are allowed to use the pavement" due to potential FOD.
- What Changed - [Changed] New concrete pavements should be allowed to cure for eight to twelve weeks before removing the curing compound and installing permanent markings.
- The Intent - Concrete pavements must be allowed to "gas" and cure prior to mechanical removal of curing compound.
- What It Means To You - That's a long time to have to wait to open a new concrete project on the airfield. Be prepared and plan to paint temporary markings over the curing compound to get the pavement open, wait for the requisite cure time, remove both the temporary markings and the curing compound, and then apply the permanent markings.
- What Changed - [Added] Different bead types shall not be mixed.
- The Intent - Engineers shall not specify a mix of bead types for the any marking (e.g. 50% Type I and 50% Type III). Applicators shall not apply more than one bead type simultaneously.
- What It Means To You - The vast majority specifications and applications didn't mix bead types so this may not affect you, but it's probably a good thing that it is clearly stated this way in the AC. For what it's worth, certain approved materials, such as preformed thermoplastic, are designed and manufactured containing a mixture of Type I and Type IV beads; so this added language likely pertains to traditional paint applications.
- What Changed - [Added] Regular monitoring of glass bead embedment should be performed.
- The Intent - This is an effort to increase quality of application and the life cycle of markings in general.
- What It Means To You - Someone has to be responsible for "regular monitoring of glass bead embedment." Do not assume the contractor will inspect his/her own product for quality. In my experience, few contractors and even inspectors know to inspect the beads let alone what to look for or how to fix it when it's inadequate. Sightline's very existence is indicative of that fact!
There is a tremendous amount of new information, best practices, and technologies available relating to airport pavement markings; all of which will be incorporated into the 2016 Airfield Marking Symposiums, so mark your calendars.
Jump to another article:
Spring 2016 Newsletter | FAA AC 150/5370-10G | Life Cycle Cost Analysis | Scars & Stripes | What's New?