By developed length and the amount of fixture units attached (1 FU =7.48 gallons) 1 cu ft
Fixture waste can accumulate in vent, eventually clogging it.
Lack of proper venting is a common problem.
Basin
BAD Venting
By developed length of piping and fittings for venting and fixture units connected to it for water supply or drainage
Poor venting, particle stoppage .. Tieger plumbing
Trap seal loss occurs when you have poor venting and as one fixture drains it creates negative pressure created and it pulls the trap seal (water) from another trap and allows sewer gases to enter the structure
When your bathtub gurgles when you flush the toilet, it is likely due to a problem with the plumbing system. This could be caused by a blockage in the drain pipes, improper venting, or a malfunctioning plumbing fixture. It is important to address this issue promptly to prevent further damage to your plumbing system.
To drain the over flow from a tank or fixture
No problem as long as the venting is above the flood level rim of each fixture
A clean out drain is actually any fixture or clean out plug /cap that will allow access to a waste or soil line and having an out door sink connected to this type of system may be forbidden by local codes as venting is a problem, trapping is another and winter freeze ups possibly Tees in general are used strictly for clean outs and not connecting any waste to it as the TEE will not drain at a right angle to the waste
It's best to have a separate waste and vent line for a shower drain. Introducing a shower drain to a tub drain without a separate line can lead to drainage issues and potentially cause backups or slow draining in the system. It's important for each fixture to have its own dedicated waste and vent line to ensure proper drainage and venting.