[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)

[MS90]

From the article, it doesn't sound like it's coming out of the drains. It sounds like chemicals are being released when they fill pipe sections with steam which then dissipates into the surrounding air.

The fumes exposure is probably just due to the person's proximity to the job site, not from a plumbing connection.

[ryanobjc]

See my sibling comment - it’s entirely possible for fumes to enter their work via plumbing.

So I’d really downgrade that “probably” - ambient outdoor exposure maybe, but the facts as presented better fits an indoor exposure during the day.

[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

[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.

[BubRoss]

That isn't a good explanation, since venting should exit far above the building.

[arbitrage]

> I haven't read 100% of the article

The article states that airborne particles and gasses can travel quite a distance to affect people that aren't in the localized application area of the CIPP sites.

[flaviu2]

ah, I see.

> Emissions from a nearby CIPP job got indoors through cracks in the building’s foundation and irritated workers to the point that they evacuated

This is fascinating. I've always thought of dirt and concrete as being basically impenetrable to things like this, but apparently they're not!

[ryanobjc]

Concrete is porus to water. If water can seep thru, when it’s not cracked, air can as well.

[blawson]

Water molecules are smaller than air though, so a surface can be airtight and not be watertight.

[ryanobjc]

A p trap can dry out. In my case the resulting sewer gas introduced 120ppm of CO into that bathroom, which started to dissipate and set off CO alarms on the next floor up.

This is common knowledge among the fire fighters here. They knew what was up once they found it.

So, how could VOC be entering buildings where they’re doing CIPP retrofit? Now you know.

[Scoundreller]

Why was there CO in your sewer?

[serf]

carbon monoxide can be found in trace amounts within septic tank gas accumulations.

http://medcraveonline.com/JACCOA/JACCOA-06-00228.php

[ldiracdelta]

If they are using pressure in the system, the air/gas could bubble back through even a proper p-trap.

[winrid]

The water in these can evaporate.