LAX/HKG : thank you for your kind words,
To answer your questions:
- The lounge is open daily from 6.30 till 22H

- I might be lucky because during my stay i only experienced a siren once or twice
(it wasn't the nonstop siren's call) it struck me as a faint background noise on level 14
you can't hear a thing from normal traffic though
the insulation is good
i bet if on higher floors you won't hear a thing

You might wish to be certain to evade all noise by requesting
- uneven numbers (faces the pool area / inner court)
- those even numbers facing the Doubletree hotel

The only reference of sirens i could find on TA is by Pepper NOV2020
(in the timeperiod we all thought the world is ending by the apocalypse by the 3rd horseman Pestilence)
https://www.tripadvisor.com/ShowUser...ton_Texas.html