Toilet vent pipe..cast iron to asbestos

[dgman]

I was at my neighbors house yesterday to look at his remodel job ... he has torn all the plaster from his interior walls.  We noticed that the vent stack for his toilet started out cast iron but about half way to the ceiling it transitioned to asbestos pipe.  We thought that kind of odd.  Today I was in my attic and noticed that the vent pipe for my  toilet was also asbestos pipe ... at least the part in the attic so I assume that the vent transitioned from cast iron to asbestos somewhere in the wall, just like my neighbors.   These houses are single story, track houses built in the early 50's.  I was just curious and wondered if anyone knew a reason why the builders would make the transitions from cast iron to asbestos pipe.
Thanks.

[Robert Adams]

Odd. Have seen many houses up until the 70s have asbestos flue pipes in the attic but not vent pipes.

[JTTHECLOCKMAN]

Too many jokes about hot air. 

[KC]

I was at my neighbors house yesterday to look at his remodel job ... he has torn all the plaster from his interior walls.  We noticed that the vent stack for his toilet started out cast iron but about half way to the ceiling it transitioned to asbestos pipe.  We thought that kind of odd.  Today I was in my attic and noticed that the vent pipe for my  toilet was also asbestos pipe ... at least the part in the attic so I assume that the vent transitioned from cast iron to asbestos somewhere in the wall, just like my neighbors.   These houses are single story, track houses built in the early 50's.  I was just curious and wondered if anyone knew a reason why the builders would make the transitions from cast iron to asbestos pipe.
Thanks.

Cost?

[Admiral]

Cost?

Likely; that pipe was a lot cheaper than cast iron....

[daddo]

Probably had an abundance of asbestos and needed to get rid of it someway. Why not put it in homes piping.

Just like fluoride- why not stash it in the water supply.

[Robert Adams]

Probably had an abundance of asbestos and needed to get rid of it someway. Why not put it in homes piping.

 Just like fluoride- why not stash it in the water supply.

Sad part is asbestos is a wonderful product and an extremely useful mineral and has many handy material qualities but it has the drawback of getting stuck in your lungs and abrading them.

[dgman]

Do you think the asbestos pipe was cheaper than steel pipe.  I ask because the vent for the sink which ties into the vent for the toilet is steel.  We are talking about 8 to 10 feet of pipe.

[blackhat]

Asbestos Cement pipe is and was uncommon in sizes smaller than 4". 
It's a PITA to work with and labour intensive for joints, especially with anything besides full lengths.

[Snipe Hunter]

Asbestos Cement pipe is and was uncommon in sizes smaller than 4". 
It's a PITA to work with and labour intensive for joints, especially with anything besides full lengths.

Is it asbestos pipe or asbestos wrapped? I see iron vent stacks in attics insulated with asbestos to control sweating.