Hi all
Iam working on a 25 floor hotel project where I have two water supply connections from the tank
at the terrace floor,one a boosted water supply using pumps for the top three floors and the other
a gravity line for the remaining lower floors.Client has asked for air release valve at the risers.
My question is that will it be enough if I provide air release valve only at the riser of boosted water supply
or is it also required for the gravity line riser also.

Regards,

you are looking at something like this.
if you have questions, call them directly.
[www.spirotherm.com]

It's a 25 floor hotel, and there's no engineered plan?

Paul48

What do you mean by that??

My description is very clear and any layman should understand this

actually your question is not that clear.. you give us nothing to go on as far as pipe size, demand, pressures (both on the street and desired increase with the pump running) and bladder tank size. do you have a sprinkler system or any other fire protection calculated into this building?
maybe where you are located the plumbers handle all the details but in the USA, a project this size requires engineered plans, blue prints and system specifications.

Wow...