One final note, while everyone is familiar with gravity loading, very few are probably familiar with shear loading.

Heating systems  (FHW and gravity systems) need to be gone over carefully. 

I work at an oilfield company now known as Gravity Oilfield Services (formerly Globe Energy Services).

That forces water at a high rate through your drain rather than gravity fed.

If it has a pump it is more trouble but gravity systems can last a long time.

Hi All,I have an unfinished basement that's Kng great condition I would like to finish off.I would like to remove a gravity furnace and install a new furnace and ac, a bedroom with an egress window and split the basement into a bedroom and family room.

Where possible, when I buy,  I update electrical boards if they have fuses, new wiring for extra outlets when they need more power, plumbing to insure there is good water flow,  heating if the systems need replacing or are gravity based, and roofs when needed. 

-Lift Station-  pumps sewage from lower elevation to higher so gravity can then take over.

Mine do not have a railing on the floor, so in essence gravity will pull on the end of those two sections, making the top roller eventually pop out and the door wobbling around.What a stupid concept!!

When AI can see an apple fall from a tree and discover gravity, or find some green stuff growing in a lab and discover penicillin, then I will be worried.