What is this capped galvanized pipe called, and can I transition to PEX from it?

[gruntle]

Hi all! New to the forum, I tried to find answers to my question in existing posts but I don't know the terms for what I'm trying to ask.

I'm preparing to do a kitchen remodel and will be abandoning the existing galvanized for PEX while I have the floor joists exposed. Once the kitchen is finished I'm going to replace all the galvanized with pex, the rest of pipes are easily accessible. I have no idea what these caped vertical pipes are but every cold and hot fixture line I can see has one. Can I transition to pex at these capped pipes? It's not going to be a long term solution, I just want to stay focused on completing the kitchen work before undertaking a full galvanized replacement.

The hope is to remove the cap (one from a cold line and one from a hot line) and transition to pex that will supply the kitchen.

 

[Twowaxhack]

You can connect to galvy pipe with FIP or MIP to pex adapters.

 

[RS]

The capped vertical pipes are water hammer arrestors, and work very well!

 

[Twowaxhack]

It’s been proven those air chambers are not good.

When you repipe, don’t build them.

 

[MrInfoPhilly]

The capped vertical pipes are water hammer arrestors, and work very well!

They work well in a very short span, eventually filling with water., and becoming completely useless
If you're tie into it., use a tee., then a M.i.ppex adapter and add a real hammer arrestor on the tee . If you need the hammer arrestor.