Negarra has designed and developed the project of the smoke and gas exhaust of the boilers room and NEGARRA has also executed the job following the existing rules in accordance to the collocation of the isolated chimney systems which outer side passes by a vertical section inside the Granitic Towers of Hejduk,tribute to the recently deceased architect John Hejduk and they will also allow the constant air renewal in the subterranean service gallery and the exhaust of combustion gases of the central of boilers of the complex,very close located.