I got a lot of interest over the fire stopping sleeve, so, I thought I would show you all this.
These collars are used for pipe penetrations through rated floor/ceiling assemblies.
The material inside the collar is like the fire putty or caulk and will expand when heated.
These typically will be wrapped around PVC or plastic piping. However, you need to make sure that the system meets UL listed requirements for this type of system.
Basically, each type of pipe and size have different listings and uses depending on the rating required. It gets complicated, but you need to ask the contractor to provide the appropriate listing and you need to ensure that the appropriate materials are being used and the rating is met.
These penetrations have to be protected and these collars do that. It allows penetrations in rated floors and ceilings without compromising safety.
Stay safe and inspect regularly.