Trans-Koolau Tunnel

After 19 years of drawing in heavy salt air from the Pacific Ocean, the housings on the Trans-Koolau Tunnel are still reading in excess of 9 mil of zinc. When they were delivered, the readings were between 10-12 mils.

After 19 years of drawing in heavy salt air from the Pacific Ocean, the housings on the Trans-Koolau Tunnel are still reading in excess of 9 mil of zinc

The ventilation for the tunnels is accompleshed by a false, flast concrete ceiling which runs for the entire lenght of the tunnels. The area between each arch of hte tunnel and the false ceiling is separated into two sections by a concrete divider, with one compartment used for inhaling exhaust air and one compartment used for distributing fresh air. Large fans either draw or blow air into the spearated compartments.

The coating condition is in excellent condition. The Hawaii Department of Transportation is very impressed with how unbelievably sound the structure still is.

Coating Thickness

Desc	Read. 1	Read. 2	Read. 3	Read. 4	Read. 5	Avg.
Inside below lip	8.90	8.40	8.50	8.80	8.90	8.70
Outside top cover	12.30	12.10	11.50	13.20	12.10	12.24
Bottom cover just above stencil	7.40	7.60	7.90	8.20	8.30	7.88
Man hole opening	4.80	4.90	5.60	4.30	5.40	5.00
Black flange	7.80	7.80	7.90	7.70	7.40	7.72