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, 2015, 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, symposium dates and locations will be delivered to your inbox on January 5th. If you're not, subscribe 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, a lot of the new language falls into their purview.
620-3.3 - Surface Preparation
1) Surface Preparation Methods
- What Changed - Expanded guidance to include the following language: "Surface preparation methods shall be selected by the engineer from the following choices or combination of methods: [waterblasting], [shotblasting], [grinding], or [sandblasting] to remove any contaminants that would reduce the bond of the new marking material to the pavement or to existing markings. After cleaning of the markings, sweeping, blowing, or rinsing with pressurized water shall be performed to ensure that the surface is clean and free of grit or other debris left from the cleaning process".
- The Intent - Expanded the previous surface preparation definition to include mechanical methods required to adequately prepare surfaces to be marked.
- What It Means To You - It means your project (new construction and maintenance) has a better chance of being properly cleaned prior to painting - and it's great news to airport striping projects everywhere.
2) Existing Markings
- What Changed - Expanded guidance to include the following language: "At least 24 hours prior to remarking existing markings, the existing markings must be removed such that [ 75% ][ 90% ] of the existing markings are removed with low (3,500-10,000psi) waterblaster. After waterblasting, the surface shall be cleaned of all residue or debris either with sweeping or blowing with compressed air or both".
- What Changed Again - The recent errata sheet clarified the now optional language: "[At least 24 hours prior to remarking existing markings, [loose] existing markings must be removed such that [75%][90%][100%]of the [loose] existing markings are removed. After removal, the surface shall be cleaned of all residue or debris either with sweeping or blowing with compressed air or both.]".
- The Intent - After discussing this particular change with the authors and reading the recent errata sheet addressing this paragraph, the intent was to make it clear loose markings (e.g. flaking paint) should be removed and most importantly, not painted over.
- What It Means To You - Despite the choices you're given, the industry's goal should always be to remove 100% of loose paint when present. However, I would prefer to see this paragraph under the paint removal item; surface preparation (cleaning) and paint removal are different. If you have an existing condition like loose and poorly bonded paint, do not expect surface preparation alone to be adequate.
3) Contractor Certifications
- What Changed - New guidance includes: "Prior to the initial application of markings, the Contractor shall certify in writing that the surface has been prepared in accordance with the paint manufacturer's requirements, that the application equipment is appropriate for the type of marking paint and that environmental conditions are appropriate for the material being applied. This certification along with a copy of the paint manufacturer's surface preparation and application requirements must be submitted and approved by the Engineer prior to the initial application of markings."
- The Intent - To hold the contractor responsible for proper surface preparation, equipment, weather conditions and materials prior to application.
- What It Means To You - It means that someone needs to make sure the contractor has done what they were supposed to do. It also means that to be sure you're getting what you're paying for, you still need to know what you're looking for or have an inspector on-site to know for you. Do not assume your resident/consulting engineer does. Also, I warn that "a copy of the paint manufacturer's surface preparation and application requirements" will likely have been written for highways, and may not pertain to airports at all... and the answer is "No - They're not the same thing."
4) Engineer Notes
- What Changed - Additional notes for the Engineer (the stuff in bold between the lines of asterisks) were included in the document.
- The Intent - The additional notes are an attempt to get the Engineer to think critically about what will be required in the way of surface preparation when it's time to paint.
- What It Means To You - Traditionally, the aviation industry has been careless about surface preparation (cleaning). The FAA would like to see more attention given to marking project specifications in the future. As an aside, it is my opinion the second and fourth notes pertain to paint removal rather than cleaning.
5) Shotblasting
- What Changed - The third note for the Engineer states: "Shotblasting is not recommended on grooved surfaces".
- The Intent - Certain methods for surface preparation are not recommended on grooved surfaces due to potential damage to grooves.
- What It Means To You - This is a good recommendation. Of the surface preparation methods listed, I would generally only recommend waterblasting and sandblasting on grooved surfaces.
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, designed to "ramp" you up quickly.
