Hey, Morgan.

What I understand is that some gas companies "scrub" their gas to remove impurities and add different amounts of other impurities so that you can smell the gas better when it leaks. It's the type of amount of those impurities that can affect the amount of sulfuric acid that is produced.

Hey, Valerie.

Glad I could help.

Readers should know that I am available 24/7 to answer questions about any real estate topic, either by phone or email.

Hey, James.

Yes. And no. You're not the first one to ask that question.

When it comes to glass, glass is not glass is not glass.

Glass comes in many varieties, as I'm sure you know just from the fact that you're a home inspector and probably note when tempered or safety glass is not present in those floor-to-ceiling windows and sliding glass doors.

The best way to ship acid would be in a diamond container, but that, of course, is not feasible. Glass is mass produced, cheap, and relatively stable in the short term, so that is the best shipping method.

As a home inspector, ever see an old window in a building about 100 years old? If you have, you know that glass, while considered a solid, flows like a liquid, albeit very slowly. One of the reasons it does that is because glass is a product, not an element.

Depending on the type of glass and its uses, glass can include varying amounts of silica (the main ingredient), aluminum oxide, antimony oxide, barium, boron, calcium oxide, cerium oxide, iron, lanthanum oxide, lead, magnesium oxide, sodium carbonate, sodium chloride, sodium sulfate, thorium oxide, and others.

So the glass in my glasses will be different from the glass I drink out of, the glass on my sliding glass door, the glass in my car windshield, and the glass on the direct-vent fireplace.

The glass that acid is typically shipped in, and stored in laboratories, is Pyrex, a special type of glass produced by Corning Laboratories way back in the early 1900s I believe it was.

Pyrex was made from borosilicates which gave it a higher degree of shock resistance so that the bottles of acid would not break under normal shipping conditions in those horse and buggies or Model T's with no suspension systems, no independent axles, and no nicely paved highways.

Pyrex is still used in laboratories throughout the world and as with tempered glass have a tempered seal on it, Pyrex will have the Pyrex seal on it.

If you've ever seen a jar of acid that has been sitting for three or four decades in a glass container, you'll notice that the glass below the liquid line is foggy, and the glass above the liquid line is clear.

So while I hope the glass front of a direct-vent fireplace is tempered glass, I'm 99.9% sure that it won't be Pyrex.

By the way, tempered glass usually is created by a thermal process, not a chemical process. There is one chemical processm, though, that replaces the sodium ions in the glass with larger potassium ions, causing the glass to compress and become stronger.