The tunnel Hirschhagen is a tunnel on the German autobahn A44 in Northern Hesse. The tunnel’s name origins from the nearby village Hirschhagen. After its completion, the tunnel Hirschhagen will be the second largest tunnel on a German autobahn.

The complete tunnel has been equipped with a sealing system according to the German ZTV-ING, using an unplasticised VLDPE geomembrane, in 3mm thickness with long-term durability. Due to the extremely high hydrostatic stress (high water pressure), an additional inspection and injection system has been installed. This system allows for retroactive leak testing as well as easy repair and maintenance. Further components of the sealing system are the protection geotextile with a Minimum mass per unit area of 900g/m², the fixing rondelles with approved pre-determined breaking point and six bar waterstops.

All sealing works have been carried out by Naue Sealing GmbH & Co. KG. A quality controlled, certified specialist for tunnelling sealing systems according to the German requirements of DVS 2225-5.