West windows of a typical office floor need no blinds and offer broad views; ceilings are designed to recover heat from lighting strips. Dark glass around ground floor meeting rooms can be screened with drapery. The roof deck affords a good view toward City Hall. The intersection of the angular end wall with window walls repeats at small scale the relationship of Benjamin Franklin Parkway to the city's street system.
The typical floors are loft spaces with circular columns forming 15 by 40 ft. bays. The long strips of window on the west front need no blinds at all. Air is supplied through the sills and exhausted at the window head with no obstruction.
The combination of concrete sun-screen and dark gray glass gives virtually every worker a glare-free vista down the parkway to the Philadelphia Museum of Art and the vast park beyond it--at least where the space has been left unpartitioned, as the architects recommended. The angular spaces at the south end of each floor are well suited for private executive offices. Floor-to-ceiling windows in these offices (equipped with drapery) provide side-long views west along the parkway, and those at the southeast corner have windows facing east toward Philadelphia's unique City hall.
At the top of the building is a penthouse with employee's cafeteria and lounge, opening onto a roof deck. On two sides of the building, screen walls rise a fill story above the deck to match the cornice height required by the city's Art Commission. Only at the gap above the entrance and at the very deliberate "window" cut through the west screen (which is aligned, for purely symbolic reasons, with the buildings vertical core) can the fine view of the west be seen. The effect from the cafeteria is like looking through a peephole. It seems perverse to have blocked off such an exceptional view (even though most employees can look the same way from their desks on floors below).
Undoubtedly, Giurgola was determined not to let the profile of the building trail off at the top with a stack of diminishing penthouses (as most of its larger neighbors do). Then too, he must have considered the height limitation a bit arbitrary, considering the much greater heights allowed on blocks immediately to the south and east. What better way to indicate an arbitrary height restriction than with these great concrete planes, seen in sharp profile against the sky?
John Morris Dixon, "Philadelphia" in The Architectural Forum (January/February 1971), pp. 40-5.