Question about venting fixtures on the ground floor in a multi-storey building

[EnOm]

Hi,
I have a building of 4 stories that has a DWV drainage system.
Every waste and soil stack is accompanied by a vent stack.
Waste and waste and soil stacks are connected to inspection chambers on the ground floor level. The inspection chambers are position away from the building by a reasonable distance.
All fixtures on the ground floor are connected directly to the inspection chambers.

My question is regarding venting the fixtures on the ground floor. Do I have to bring the vent pipes down to the ground level to provide a means to vent the fixtures there?
I've seen before cases where no venting was connected to fixtures on the ground level when they were directly connected to the inspection chambers.

If the answer is that it is NOT a must to connect these ground floor fixtures to the vent stacks, can someone please provide an explanation as to why not?

Regards.

 

[PEDARRIN2]

At a minimum, you would likely have to have a vent from at least one of the fixtures on the ground floor.

You have to provide some means of venting for all fixtures, but not all venting is by a vent pipe provided up from the fixture.

Some fixtures can be vented by oversizing the drain pipe, but the pipe has to connect somewhere to a branch with a fixture which is vented from a vent pipe or a vent rising off the drain pipe. This is known as combination waste and vent, which is a version of wet venting, where the drain pipe also serves as the vent pipe.

There is also a limit to connecting drainage stacks to these pipes. Check your code.

I had to look up "inspection chamber", but it appears to be a small "manhole" which serves as an inspection point outside the building. I have used similar method and not vented the inside fixtures. But this only happened where the drains were subject to freezing (in a parking garage) and inspection chamber acted as a "master trap" and I vented that. But this required approval from the local authority.