Jim, I have several problems with your explanations: 1. A design approved in 1992 does not constitute an approval for all time. Standards evolve over time. 2. The specification for requirements on grate inlets is clearly stated in the FAA Circulars. Here are a couple links for you: a. http://www.faa.gov/airports/resources/advisory_circulars/media/150-5370-10D/150_5370_10d_d751.doc b. http://www.faa.gov/airports/engineering/construction_standards/ 3. I believe I have stated this before, but this is an airport not a bridge. The letter for the certification mentions several vehicle loads, which is great for a bridge project. However, I question its ability to support aircraft, especially with all of the after market welding. The letter only states that they do not know what these loads are. Perhaps additional research should have been completed before a grate was specified that may or may not meet the load requirements for aircraft. We have discussed this issue on several occasions and I fail to see what additional meetings would accomplish. The inlet must be repaired this week in accordance with the FAA Circulars. Thanks, Clay Barnett, P.E. Town Engineer Town of Addison 16801 Westgrove Drive Addison, TX 75001-2818 Office: (972) 450-2857 P Please consider the environment before printing this email. -----Original Message----- From: Jim Dewey Jr. [mailto:jdjr@jdjr.com] Sent: Wednesday, August 05, 2009 2:44 PM To: Clay Barnett Cc: Richard French; Jenkinson, Joel; joe.mcanally@addisonairport.net; Ritchie Dean Dailey; Ron Dailey Subject: Grate at Hangar Project for Richard French Clay: Richard French called and said that you still have concerns about the grate inlet installed at the airport. When we did the design for the hangar project, we pulled copies of the existing storm drain systems that we were connecting to and/or modifying. The existing drainage system and junction box that was removed and replaced had a “TYPE H” grate as we specified for the new junction box. I have attached a copy of the plans for the existing system prepared by Greiner. The plans for the existing system call for “TYPE H” grates on the junction box we replaced as well as the other grate inlets on the same system. The reason we specified a “TYPE H” grate was that grate had already been approved and utilized at Addison Airport. As a result of your objection to the grate, the developer has had another grate manufactured and installed in lieu of the TYPE H grate. This grate was constructed using a TYPE H design with additional members running perpendicular to the bars forming the grate. I have attached a detail and engineer’s letter from the grate manufacturer. In addition, the FAA Advisory Circular 150/5300-13 Airport Design does not have any specs or standards regarding grate inlets or castings. You indicated in a previous email that Chapter 4 Section 3 was the section that the grate inlet was not in compliance with. There is nothing in 150/5300-13 that addresses the minimum opening size, etc. for grates. Furthermore, there is no clear specification in FAA Advisory Circular 150/5320-5c Surface Drainage regarding the grate inlet openings. We simply need to get this issue resolved. We specified that particular grate because it had already been approved and used at Addison Airport. I believe as did Greiner Inc. that the grates comply with all FAA Advisory circulars. The revised (stiffened) grate obviously complies, if the TYPE H complies. Should you still have concerns with the grate as installed, I respectfully request a meeting with you, Ms. Cline, and the Airport administration to rectify this situation. I am confident that I exercised all reasonable research and engineering practices in developing the specification of the TYPE H inlet grate. I regret that you have indicted to the developer that you may file a complaint on me with the Texas State Board of Professional Engineers. I hope you will reconsider after reviewing the attached plans. Jim Dewey, Jr. JDJR Engineers & Consultants, Inc. 2500 Texas Drive Suite 100 Irving, Texas 75062 Tel: 972-252-5357 Fax: 972-252-8958