For over twelve years, H&H has been providing engineering services to support the MDTA to maintain the reliability of the tunnel functional systems. Engineering support has included inspections, maintenance, rehabilitation, troubleshooting and emergency response at the Fort McHenry Tunnel. Work has included performing the annual inspections of the tunnel in accordance with NBIS and the new NTIS inspection requirements.  H&H has evaluated and developed a mechanical component maintenance program in accordance with the Tunnel Operations, Maintenance, Inspection, and Evaluation (TOMIE) Manual for the tunnel fire suppression, tunnel drainage, and tunnel ventilation systems. The fire suppression system was also completed in accordance with the NFPA. We have also performed the rehabilitation design and construction inspection of the tunnel ventilation, drainage system, switchgear, and electrical system repairs. H&H has coordinated the repair work with engineering, construction, and operations personnel within the tunnel.

The Fort McHenry Tunnel is located along I-95 in Baltimore, Maryland and was opened to traffic in November 1985. The tunnel is nearly 1.7-miles long crossing under the Patapsco River and has an annual traffic volume of 41.9 million vehicles. The tunnel contains eight-lanes within the four bores along I-95. The tunnel has a full-transverse ventilation system that contains 48 centrifugal fans. The Fort McHenry Tunnel is owned and operated by the Maryland Transportation Authority (MDTA).