Enter the Mellon Institute from the Bellefield Ave side. 

Walk past the security desk (showing CMU or Pitt ID and signing in if necessary) and continue straight across the building. 

When you reach the T in the hallway, turn right. 

Go to the corner of the building and enter the stairwell. 

Go down two flights. 

Exit the stairwell and turn right. 

Go through the double doors. 

My office is on the left.