
Health Concerns Mount as More Old Sewer Pipes Are Lined with Plastic - LinuxBender
https://www.scientificamerican.com/article/health-concerns-mount-as-more-old-sewer-pipes-are-lined-with-plastic/
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code4tee
Sounds like the building has other more serious plumbing issues. Gasses and
odors of any type shouldn’t be able to work their way back into a building via
the sewer pipes. The pipes in the building can’t leak and that’s one of the
reasons why properly installed drains have traps.

Code inspectors often use the “peppermint test” to test all the above. They
dump concentrated peppermint oil into the sewer then go around the building
and see if you can smell it. If you can then you have problems with the
plumbing.

Buildings having issues likely have bad plumbing and thus their occupants were
likely breathing sewer gasses for ages... the “liner fumes” just made all this
more obvious.

~~~
jeffdavis
I was wondering the same thing. But do you think it's possible that this
process causes backpressure that forces the gases through a trap?

Maybe it shouldn't cause backpressure if done properly, but maybe some
construction companies carelessly block one side of the pipe while it's
curing?

~~~
Enginerrrd
I'd suspect it's more likely the opposite: as the pipe is dewatered it creates
a negative pressure that pulls the water out of the p-traps which then
temporarily allows gaseous exchange with the building air.

EDIT: Nevermind, I originally was thinking that a sufficiently negative
pressure differential could overwhelm the capacity of the vent. But the more I
think about it, the pressure range that I'd expect even with an unusual
operation probably wouldn't be far enough outside normal range to do that.
...although there are definitely still some possibilities to do some stupid.

~~~
hinkley
It's possible.

On the top floor of a building I worked at long ago, there was a drain in the
floor of the men's bathroom. It had a p-trap but on windy days there was
enough vacuum from the vent stack to drain it out. I encountered a neighbor
pouring a cup of water into it one day and he explained the problem. I started
doing the same, and had to do it every couple weeks during windy periods.

But I think that's a problem for the upper floors, both due to fluid dynamics
and because the first trap that loses seal would mostly restore equilibrium.

~~~
perl4ever
My parents' house had a guest room addition with a bathroom which wasn't used
for long periods of time, and it became apparent that if the water wasn't run
enough it would start to let odors back through the pipes.

Anyway, everything uses PVC, right?

~~~
wahern
Not everywhere: [https://www.pmmag.com/articles/97318-plastic-pipe-still-
limi...](https://www.pmmag.com/articles/97318-plastic-pipe-still-limited-in-
plumbing-applications)

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engineer_22
I'm a professional engineer with experience on these types of projects. CIPP
has been used since the 80s, in the US as well as Europe (and I presume Asia
and Oceania). Originally it was done with hot water, though steam curing
processes have an economic advantage today. UV curing processes are now wide
spread as well.

In the steam curing process high temperature water is circulated through the
pipe to cause the resin compound to catalyze (industry term is "kick"). Steam
is not allowed to escape from the liner into any sewer laterals. In fact,
sewer laterals are plugged by the liner and have to be reinstated (cut out) by
a robot afterwards. At the end of the process the steam is released to
atmosphere, it tends to have an odor. From my understanding the odor is
styrene, a common industrial solvent.

Sometimes people with flaws in their plumbing report the odor is coming from
the drain. This indicates they could potentially have a more serious issue:
chronic exposure to sewer gases. I always recommend they have a plumber
investigate. Other times the airborne plume is enough to cause very sensitive
individuals to complain. There are many industry veterans who have been
working with these materials for decades - if you were serious about studying
the potential for harm, you would follow this group. They are the canary in
the coal mine. Folks with only transient exposures are at very low likelihood
of harm.

The American Society of Civil Engineers gave the sewer systems in this country
a grade of D+. Just above failing. In reality, and I see this every day, our
sewer systems are in need of immediate overhaul. CIPP is a keystone technology
for renewal of these assets, because excavation is too dangerous(!) and
expensive to be our primary mode of repair.

FYI - pipeline characterization and renewal is a growth industry with a lot of
opportunity for AI. In my opinion, a lot of these processes could be
automated.

Video below shows the CIPP process.
[https://www.youtube.com/watch?v=Swp81X4jSDk](https://www.youtube.com/watch?v=Swp81X4jSDk)

~~~
flashman
> Steam is not allowed to escape from the liner into any sewer laterals. In
> fact, sewer laterals are plugged by the liner and have to be reinstated (cut
> out) by a robot afterwards.

Is there resin on the side of the liner that's plugging the lateral? In other
words, you may still get odors if the thing that's doing the plugging is
releasing chemicals on its exterior.

~~~
abduhl
The whole liner is resin. It is produced in a factory per job (“wetted out”)
and then brought to a job on a refrigerated truck then pulled into place and
cured via steam/water/UV.

They’re cured from the inside out but the whole thing is “resin”.

The more important point though is that any odor that is coming in from the
line is indicative of a problem with the lateral connection - if odor is
bleeding off from the CIPP install then there is every indication that sewer
gases are also making their way in. There is no positive air pressure exerted
by the install on the lateral due to the curing process.

Edit - just to clarify, the point is that you shouldn’t be smelling ANYTHING
if the connection is in proper order - odor from the CIPP install or from
sewage. If you smell one but not the other then it most likely is NOT the
connection because there is no (substantial) difference in the driving air
pressures between normal operation and during CIPP installation (because the
CIPP seals across the lateral, preventing pressure in the lateral). If you
smell the chemicals during install then it is imperative you get your line
checked because you are most likely (~100%) also breathing in noxious fumes
from sewage and you are so accustomed to it that you no longer notice it.

~~~
jessaustin
_...you are most likely (~100%) also breathing in noxious fumes from sewage
and you are so accustomed to it that you no longer notice it._

Is this a thing that is possible for humans? I shudder to imagine this, so
much exposure to sewage that one ceases to notice its odor.

~~~
abduhl
You can get used to any smell given a long enough exposure. Ever been to
someone's house that just reeks of dog or cat?

Beyond that, it can happen in an acute sense as well. Hydrogen sulfide becomes
undetectable above a certain exposure. You will usually pass out shortly
afterwards (and then die because hydrogen sulfide is heavier than air and you
are now on the floor). The standard advice given for people who enter confined
spaces is that if you smell hydrogen sulfide (rotten eggs) you should be aware
and check your sniffer. If you are still in the confined space and you
suddenly stop smelling rotten eggs, you are literally seconds away from dying
and should retreat to fresh air immediately or deploy SCBA.

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RaceWon
> I see no mention of p-traps [1]. How exactly are these fumes getting into
> places when there's essentially an airlock in every drain connection?

Well they are doing this because the underground piping is presumbly cracked
and/or porous; this would enable fumes from the process to leech into
buildings through the pipe walls. We are only protected from sewer gases if
the entire system is air tight.

It is also possible that her building had some issues with its plumbing; for
instance I have seen fitures removed either during renovation or even on a
permanant basis that were not properly capped off--while there would be some
constant leakage of sewer gas it is really not dangerous (or even that
noxious) in low concentrations; the chemicals used in the lining process
however might be.

~~~
Spooky23
This isn't in the building, it's way that municipal utilities retrofit pipes
in the street that are leaking. If they catch the leak before it collapses,
they are able to inject this sleeve and basically put a plastic cast inside
the pipe.

They did it on my block when I was telecommuting from my front porch. The
smell comes from the excavation holes. It's loud process and they use high
pressure air to do it. It smelled like somebody stained a deck, and lasted
about a half hour. There was some residual smell that mostly went away after
they covered the hole. You wouldn't know it had happened a few hours later.

If you've ever dealt with the public with stuff, people freak out about
anything smelly or any visible involving radio.

~~~
RaceWon
> This isn't in the building, it's

The building drainage system in many areas is not "protected" by a house trap.
Many municipalities require a backwater water valve which is essentially a
check valve with a mechanical moving part. I can easily envision (and I have
held a Master Plumbers License) this failing.

Furthermore once you trench to bring sewer, and water into a building (these
services while in a manner of speaking are kept separate they often share a
common or very nearby trench) it's very easy to not backfill properly thereby
also allowing vapors to enter a structure in some instances. It depends: did
they use dynamite to blast for the foundation or to bring in these services?
There are all kinds of variables that could allow trench to building fumes.

I agree people do freak involving odors, but on the other hand different
people have different actual physical tolorances to chemicals.

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muthas
A couple items to note here:

\- while agreed that a trap should help contain gasses, in order to cure the
resin involved they have to inject high-pressure steam into the piping...
possible that it could cause bubbles to pass through functional traps

\- even if the trap system worked perfectly, the fumes from the cure process
get vented to the local atmosphere through outlets set up during the CIPP
process. This exposes workers to the largest amount of byproduct chemical
vapors, but it's entirely reasonable to think that it could get accumulated or
trapped in buildings as well.

The CDC has a good article about this very topic:
[https://blogs.cdc.gov/niosh-science-
blog/2017/09/26/cipp/](https://blogs.cdc.gov/niosh-science-
blog/2017/09/26/cipp/)

~~~
throw3737273728
I caught a whiff of this venting to the local atmosphere in downtown SF a few
years ago, and it was shocking. The smell is so strong and noxious you can’t
believe that there isn’t some serious problem happening in your midst. No
warning either. It’s about as frightened of a smell as I’ve ever been.

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teekert
They did this in my City (the Netherlands) the fumes were really bad for some
days and seemed to penetrate houses very well.

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flaviu2
I haven't read 100% of the article, but from skimming over it, I see no
mention of p-traps [1]. How exactly are these fumes getting into places when
there's essentially an airlock in every drain connection?

[1]:
[https://en.wikipedia.org/wiki/Trap_(plumbing)](https://en.wikipedia.org/wiki/Trap_\(plumbing\))

~~~
mshook
Because you need to vent the pipes. Otherwise the sewer system would just be a
giant vacuum pump.

It's even described in the article you mention.

[https://en.m.wikipedia.org/wiki/Drain-waste-
vent_system](https://en.m.wikipedia.org/wiki/Drain-waste-vent_system)

~~~
flaviu2
I'm familiar with vents, but indoor vents are basically one-way air valves. I
don't know if this is required by code, but it's definitely common practice
(you don't want poop smell coming out of your vents)

~~~
Scoundreller
Vent stacks need to be above _that_ roof’s line, but your building might be
next door and taller with open windows downwind.

Or a crack in the stack.

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supercommand
It should be noted the fumes are from the cast in place pipe liner (cipp)
which is a Fiberglas style sock that is pulled through the existing pipe and
then filled with compressed steam.

This has quite a few voc’s that really give your stomach a churn if you are in
close proximity.

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baybal2
I found irrational preference for "retrofit" and "intermediate" solutions over
proper replacement even costs are unfavourable rather puzzling.

ADSL — often required new wiring or a DSLAM on premises to deliver acceptable
signal

DOCSiS — same, you have to rewire all coax in the building to deploy it.

House heat insulation — often ends up with inefficient house designs
perpetuating because of hopes "we can always add insulation later"

Piping — used to work in a trade company in Canada for half a year as an
intern. Tried to import and popularise polypropylene piping there. Got hit by
ferocious marketing FUD counterattack by a company selling crap PVC piping in
a month after I sent booklets to prospective clients. Their main argument was
that "PVC piping is a cheaper "intermediary" solution for plastic piping as
PVC pipe can still be joined by plain mechanical means, unlike polypropylene"
even when doing so negates their entire point of using plastic piping for its
physically continuous joints.

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pkaye
For a second, I though they were referring to the trenchless piping method
used on the sewer lateral. They pull a plastic pipe with a winch through a
older pipe with a metal head that expands out the old pipe. Fortunately there
are no fumes during this process.

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3fe9a03ccd14ca5
> _The sleeve hardens to form a continuous plastic liner along the old pipe’s
> inner walls._

I didn’t finish reading the article, but this sounds amazing. Isn’t plastic
one of the least reactive materials we know about and an excellent choice for
this? It seems like maybe the issue is in the curing process.

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Havoc
This aside...hows the general plastic pipes & microplastics situation?

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aaron695
Maybe is a Russian listening device with unintended side effects like in Cuba?

That would explain why 'workers' aren't dropping dead and people far away
under the cube law are legitimately sick?

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randyrand
“ Davis has recovered from most of what she says her doctor told her were
neurological effects from a chemical exposure.”

Is this another way of saying the placebo effect?

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AlleyTrotter
No mention of the actual chemicals being used. Seems they would at least
include the MSDS sheets for the process for a well researched article.

~~~
therealcamino
The article mentions a number of chemicals and links to a paper describing the
emissions at the job sites.

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purplezooey
Seems like if we can just let people know ahead of time to not go inside for a
while you'd be good.

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source99
If anyone is interested in the subject this is my company. www.sewerai.com

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randyrand
I thought plastic was inert?

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0xADADA
any great empire expands until it can no longer afford the maintenance of its
own infrastructure, at which point it collapses under its own corpulence.

~~~
3fe9a03ccd14ca5
“Societies grow inexorably more complex until one day they become really
simple again (collapse)”

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Reason077
Why do people act surprised when “a noxious odour that smells like paint
thinner” makes them feel sick?

