LEVEL 2

TANK INSPECTION REPORT

CVG AIRPORT/PRIME ENGINEERING

CINCINNATI/NORTHERN KENTUCKY AIRPORT

3,000,000-GALLON SPENT DEICING FLUID STORAGE TANK No. 2

ERLANGER, KENTUCKY

CCR Job No. 2024R032 CROM Job No. 2002M048

Inspection Performed on June 27, 2024

1. Level 2 Inspection Report Sheets 1 - 15

This item has been electronically signed and sealed by Mike Miller, PE on September 30, 2024 using a

Digital Signature. Printed copies of this document are not considered signed and sealed and the signature must be verified on any electronic copies.

Michael L. Miller, P.E.

Senior Engineer IV

Kentucky License Number: 29604

CROM, LLC

250 SW 36th Terrace Gainesville, Florida 32607

2024R032, 3.0MG Spent Deicing fluid Storage Tank 2, CVG Airport, June 27, 2024 Level 2 Inspection Report 2 Erlanger, Kentucky

TANK NO. 2 INSPECTION REPORT

1.0 Introduction

CROM, LLC (“CROM”), conducted an inspection of the 3.0 MG Spent Deicing Fluid Storage Tank No. 2 in Erlanger, Kentucky on June 27, 2024. The purpose of the inspection was to evaluate the condition of the tank and its structural integrity. The goal was to determine what measures, if any, would be necessary to extend the useful life of the tank and modernize the safety appurtenances. This report fulfills the inspection requirement in accordance with AWWA D110 and ACI 350.

Chris Barton, Project Manager, performed the inspection and prepared this report under the review of Michael L. Miller, PE.

The Level Two inspection performed by CROM consisted of a comprehensive visual inspection of the tank interior and exterior, including accessories, to evaluate their structural integrity in accordance with all applicable codes and standards and to meet the requirements of AWWA D110 and ACI 350.

2.0 Scope of Work

The investigation included the interior walls of the tank, the dome, floor, and tank accessories. The inspection was a visual survey of the structure with two selective demolition coupons on the interior core wall and 4 dome cores taken for further engineering analysis.

The tank was inspected in accordance with AWWA D110 and ACI 350 to evaluate the present condition of the tank structure.

The inspection was performed on the following tank:

3.0 MG Glycol Collection Tank No. 2

140’-0” ID x 26’-1” SWD (CROM Job. No. 2002-M-048 Completed December 2022) Odor Control System – Completed 2011 (By Others)

The tank was drained and cleaned by a CVG subcontractor prior to the interior inspection or CROM personnel entering the tank. CROM used an ambient air monitor to test the quality of air within the tank prior to entry.

The inspector was provided access to the dome roof. The concrete dome was inspected for any deterioration, cracking, efflorescence, spalled concrete, signs of corrosion, or other indicators of existing problems. Tank accessories were examined to determine the extent of the weathering of the material and the condition of the bolts, fasteners, and the screens. All penetrations were checked for signs of leakage into the tank.

The interior wall was observed, where possible due to an existing CIM coating system installed by others, for any deterioration, cracking, efflorescence, spalled concrete, signs of corrosion or other indicators of existing problems. Piping and internal accessories were checked for corrosion along with the condition of their supports, bolts, and anchors.

The entire tank structure was visually evaluated, in areas that are accessible and not coated with CIM, and a record was made of all observations. Photographs were taken as an additional record of the inspection.

Level 2 Inspection Report 3

3.0 Conclusions and Recommendations

The inspection of the prestressed composite tank did not reveal any apparent problems that would cause concern for the structural integrity of the tank itself. However, there are items that should be addressed in order to minimize the potential of future problems. Please refer to those items categorized as “Fair” or “Poor” below.

The report utilizes subjective terminology to rate the condition of various elements of the structure:

• Excellent - indicates like new condition, no remedial action required.

• Good - indicates minor defects, still operable.

• Fair - indicates an element or accessory requiring remedial action before the next scheduled 5-year inspection.

• Poor - indicates immediate action required.

Tank ID Plate

Photo

Foundation

Condition Rating Unknown

Assessment Unable to visually inspect the foundation due to existing backfill.

Recommendation No apparent remedial action required at this time. Crom has voiced concerns regarding potential uplift on the structure resulting from any failure of the underdrain system.

Photos

Level 2 Inspection Report 4

Wall Manhole

Condition Rating Good

Assessment Exterior unavailable for inspection. Interior coated with CIM coating installed by others. No defects noted on wall manhole.

Recommendation No remedial action required at this time.

Exterior Wall

Assessment Unable to visually inspect the exterior wall due to backfill.

Recommendation No apparent remedial action required at this time.

Dome Access Hatch

Condition Rating Fair

Assessment The hatch cover anchor bolts were not able to be unthreaded due to being coated over with epoxy by others. Four missing anchor bolts noted.

Recommendation Repair or replace defective hardware with 316 stainless steel hardware.

Level 2 Inspection Report 5

Dome Probe

Assessment One small crack noted on dome probe curb. No other defects noted on dome probe.

Exterior Tank Dome Coating System

Assessment Faded and weathered coating system and shrinkage cracks noted on exterior tank dome with no sign of corrosion, thru-cracks only due to shrinkage/curing. Exterior tank dome found to be in good condition. Minor shrinkage cracks, approximately 200 linear feet and mostly around 7 mils wide, noted on exterior tank dome with no sign of corrosion.

Recommendation Clean and seal cracks to prevent further water infiltration.

Level 2 Inspection Report 6

Tank Dome

Condition Rating Poor

Assessment CROM performed a destructive investigation of the exterior dome while onsite where cracks were noted. The destructive investigation was performed to determine the integrity of the exterior tank dome. The destructive investigation was performed in accordance with standards specified in AWWA D110-13, Section 6.4.7. Due to known deterioration on the interior of the dome, four dome cores were taken about 10 feet above each emergency overflow for further engineering analysis. The core holes were cleaned, formed, and patched back with an appropriate coating system according to manufacturer's recommendation. Dome core results show pH average 6 and the average compressive strength result was 7,563 psi.

Interior Surface Deterioration (see attached comprehensive report):

The cement paste in the near-surface concrete is very absorptive and weak, with little inherent strength. The poor-quality cement paste contains gypsum deposits at depths ranging from 0.5 to 1.5 mm. The surface deterioration is related to acid attack, although exposure to glycol solutions is not directly deleterious. However, propylene glycol can degrade in the presence of oxygen, forming acids like glycolic, formic, acetic, and oxalic acid.

The petrographic examination displayed symptoms of possible sulfuric acid attack and Microbiologically Influenced Corrosion (MIC). However, the chemical analysis of the cores did not confirm sulfuric acid as the cause of the deterioration. It did confirm that an acid attack is occurring, but the exact type of acid remains unknown.

In Core #2 and the tank's near-surface concrete, gypsum deposits suggest a connection to sulfuric acid, potentially due to MIC. The leaching of calcium and sulfate during the acid attack formed gypsum, which can further lead to sulfate attack. While bacterial growth likely contributed to sulfuric acid formation, the exact type of acid causing the distress remains undetermined.

Recommendation Crom recommends removing the low pH surface of concrete and installation of an appropriate interior coating system on the interior of the dome, according to the manufacturer’s recommendation.

Level 2 Inspection Report 7

Emergency Overflow Openings

Assessment Hard covers with minimal openings were installed over the emergency overflow openings by the airport for the odor control system operation. Cracks noted on emergency overflow openings.

Recommendation • Clean and seal cracks to prevent further water infiltration.

• Spot repair spalls and interior exposed rebar by squaring off and chipping back the concrete to provide a minimum depth of ¼" and patching back with a cementitious repair mortar.

Level 2 Inspection Report 8

Dome Ventilator

Assessment Dome ventilator screens replaced with hard covers when odor control system was installed by the airport. One of the hard covers must have blown off at some point leaving only one small opening for airflow. Missing hardware noted on dome ventilator.

Recommendation • Remove all hardcovers so that the tank will not be subjected to a vacuum load during a rapid draw-down event. If odorous air is a concern, then an air scrubbing system should be installed. Replace hard covers with screens made of 24/24 polyester mesh on dome ventilator base.

• Replace missing hardware with 316 stainless steel hardware on dome ventilator.

Odor Control System Effluent Pipe

8” Odor Control System Effluent 8”x 8” Square Flanged Vacuum Relief Damper

Level 2 Inspection Report 9

Lightning Protection/Cathode Protection Equipment

Condition Rating Good

Assessment No defects noted on lightning protection system.

Interior Ladder

Assessment Ladder safety system noted to be non compliant with OSHA standard. Note: The ladder safety system is not OSHA compliant as the connection between the carrier or lifeline and the point of attachment to the body belt or harness exceeds 9 inches.

OSHA Standard requires ladders with structural or other defects be tagged “Dangerous: Do Not Use” or with similar language and removed from service until repaired or replaced. Broken cross braces noted on interior ladder.

Recommendation • The interior ladder should be immediately taken out of service and properly tagged to comply with OSHA requirements until the deficiencies are corrected.

• Install new stainless steel ladder system equipped with an OSHA compliant ladder safety system.

Level 2 Inspection Report 10

Tank Floor

Assessment Floor coated by others with CIM. Blistered and delaminated areas to CIM noted on tank floor. CROM performed a destructive investigation of the interior floor at the location of a large blister while on site. The destructive investigation was performed to determine the integrity of the floor. The destructive investigation of the interior floor showed it to be dry and the concrete in good condition with no visible cracks in the destructive opening (coupon 2.3). Areas were cleaned, prepared, and patched back according to manufacturer’s recommendation. The destructive investigation was performed in accordance with standards specified in AWWA D110-13, Section 6.4.7.

Recommendation There were multiple signs of where the CIM coating was blistered. Crom investigated a few areas as noted above in the assessment. Crom did not notice any signs of water intrusion into the tank during our inspection nor did we see any indication that it happened previously. In order to have a 100% certainty that there are no floor cracks and water infiltration the coating needs to be removed, floor inspected, and the coating reinstalled following the installation of the tanks new underdrain system.

Level 2 Inspection Report 11

Floor Wall Connection

Assessment Floor wall connection coated with CIM. Blisters filled with fluid noted in CIM at floor wall connection.

Recommendation Remove the coating system, inspect, and reinstall following the installation of the tank’s new underdrain system.

Level 2 Inspection Report 12

Interior Tank Walls

Assessment Horizontal cracks, hollows, and a delaminated CIM coating system were noted on interior tank wall. CROM performed a destructive investigation of the interior wall while onsite where cracks were noted. The destructive investigation was performed to determine the integrity of the diaphragm. The destructive investigation of the interior corewall showed the diaphragm in good condition with only surface rust and one small crack in the inside corewall surface. Areas were cleaned, prepared, and patched back according to manufacturer’s recommendation. The destructive investigation was performed in accordance with standards specified in AWWA D110- 13, Section 6.4.7.

Recommendation Following the installation of the tank’s new underdrain system, remove failed interior coating system. Reinspect walls and floor/wall joint. Repair cracks. Prepare surface and install an appropriate interior coating system.

Level 2 Inspection Report 13

Interior Piping

Assessment Pipe penetrations coated by other with CIM coating system. Corrosion noted coming from inside interior piping.

Recommendation Prepare the surface of the interior pipes and apply an appropriate coating system according to the manufacturer's recommendation.

Level 2 Inspection Report 14

Interior Tank Dome

Assessment Noted loss of concrete, spalls, and corrosion with exposed reinforcement and bolster feet noted on interior tank dome.

Recommendation • Prepare the surface of interior dome removing coating system and cleaning any corroded exposed reinforcement.

• Repair interior tank dome by squaring off and chipping back the concrete to provide a minimum depth of ¼”.

• Apply a rust-inhibiting coating system to structural steel according to the manufacturer’s recommendation.

• Patch back with an appropriate cementitious surface repair system according to the manufacturer’s recommendation.

• Apply an appropriate coating system according to the manufacturer’s recommendation.

Level 2 Inspection Report 15

Next Inspection: CROM recommends a Level 2 Inspection by June 27, 2029, in accordance with AWWA and ACI 350.

The inspection performed by CROM was a visual survey of the structure interior and exterior with minor selective destructive tests. Therefore, CROM cannot offer an opinion on the condition or performance of the covered or hidden elements of the structure not visible from the surface.

The preceding report is submitted for your review and discussion. We would be pleased to discuss the results with you. If you have any questions or concerns, please do not hesitate to contact us.

Chris Barton

Senior Project Manager III