al quarto piano

on the fourth floor

→ al
phrase Rare #44,209
on the fourth floor Can also mean 'to the fourth floor' depending on the sentence and direction of movement.
IT: L’ufficio è al quarto piano.
EN: The office is on the fourth floor.

Allarme di sicurezza al quarto piano!

Security alarm on the fourth floor!

— Essi vivono (1988)

Allora, che dobbiamo fare al quarto piano?

So, what should we do on the fourth floor?

— The Garden of Sinners Chapter 5: Paradox Paradigm (2008)

Però che stanno facendo al quarto piano?

But what are they doing on the fourth floor?

Stanno andando al quarto piano del parcheggio.

They're going to the fourth floor of the parking lot.

— Infernal Affairs (2002)