Burning Out: What Really Happens Inside a Crematorium

As a former machinist and mechanical maintenance engineer by trade, I can attest crematoriums are a strange beast to work on. Bone fragments are left over because the crucible like structures in which bodies are immolated reach a relatively low temperature. Industrial processes routinely eclipse these by orders of magnitude and in doing so effectively vaporize and destroy anything left over. Alas, customers want proof and so certain inefficiencies are tolerated in order to deliberately generate an ash byproduct.

Most crematoriums include elaborate air filtration systems. These are far and away better scrubber systems than you would find at a chemical refinery but the media lifespan is very low, and the maintenance cost of these devices is nontrivial. The cost is worth it however...the stench of burning bodies is to be avoided in any way considering most crematoriums are adjacent to fairly residential areas. Most furnaces have a 'hard stop' at a certain number of operations to prevent any possibility of overwhelming the filters. There is also a specific mass limit to each cremation chamber, not unlike a normalizing furnace or heat treatment furnace.

Crematoriums hate two things as far as i can gather: medical implants and the obese. If enough furnace matter includes exotic plastics and metals, some fairly dangerous conditions can occur. certain plastics and magnesium parts for example can trigger a fire inside the furnace that can easily damage or destroy it. Crematorium furnaces are equipped with, in my opinion, a very limited amount of thermal refractory material compared to other industrial furnaces.

Finally the sad truth about obesity is that you'll pay triple for a cremation. Obesity increases the combustion byproduct and shortens the furnace filter and burner lifespan as it increases the time required to properly cremate the remains. large enough people require multiple furnaces.

My family used to be in the funeral business, and as a kid I've gone on rides to pick up bodies in Hearses, dug and filled graves, and visited a crematorium.

My aunt was friends with the crematorium operator, and we got to visit one in operation. The operator was retelling the story about the big stain on the concrete floor near the furnace.

TLDR: There is a "formula" using body mass to determine whether they go in head- or feet-first. If you get it wrong, the fat sometimes liquefies and runs out onto the floor.

Whether this is true or whether he was just f'ing with a young kid, I don't know.

I believe we have a few crematoriums connected to the heat networks here in Sweden. Kind of creepy to think about, but creepy isn't a good argument against it so why not, I guess.

My father passed last week, maybe he heated up a small part of Stockholm already. I don't really know what happens next. Personally I don't care that much, I got my memories and that is enough for me. But based on what happened to the rest of my dead relatives he'll get a small plate with his name on at the corner of some church yard. It will be up for x years until they have to make room for the next batch. You can always pay to keep it up for maybe five or ten more years, but what is the point? Memories are free and worth way more than the tiny nameplate.

What a well written article. But from personal experience, it's missing something. My dad's funeral service was held in the crematorium. Afterwards they invited the closest family members to watch. Didn't warn us about what we were about to witness. First, instead of the "nice" coffin with flowers on top, he was put into a cheap-looking, thin plywood crate filled with thin, twisted strips of paper. It looked like the paper equivalent of styrofoam peanuts. The gurney was carelessly lying crooked against a wall as if it had just rolled over and bumped to a stop. Then they rolled it into the furnace in workmanlike manner and closed the room's blinds to block our view.

We all swore off cremation after that. Please leave after the service. Don't watch your loved one's cremation, it'll be a horrible last memory that taints everything that came before.

Second, the cremains are in a sealed plastic bag, inside a cardboard box. After you scatter the ashes, what do you do with the box, the bag, and the last ashes in the bag? Throw them in your household garbage? (Illegal, btw) It was my reminder that not everything has a "nice" interface.

Unrelated to the article, but related to crematoria, and a very fun 15-minute read: https://www.laphamsquarterly.org/roundtable/my-first-mistake

If you're in the SF Bay Area, I strongly recommend visiting The Chapel of the Chimes in Oakland.[1] It's one of the most amazing buildings I've ever visited in my life. It doesn't look like much from the outside, but inside it's like a labyrinth of urns. It's one of my favorite places to visit in the Bay Area. Very quiet and meditative place.

[1] - http://www.chapelofthechimesoakland.com/

Reminded me of a book written by a lady who worked at a crematorium - "Smoke gets in your eyes"

https://www.amazon.com/Smoke-Gets-Your-Eyes-Crematory-ebook/...

Another interesting read about green/bio cremation/water cremation/alkaline hydrolysis. [1]

https://news.ycombinator.com/item?id=15060177

> “What is that?” I ask, pointing to one of the silver trays of remains.

> “That’s a bone fragment. Probably a disc vertebrae,” Koslovski says, adding, “You can learn anatomy here.”

> “These are green,” I say.

> “I don’t know why. It could be something the person was treated with. It’s hard to say. It could have been cancer.”

> The crematorium puts the bones and ash that remain into a pulverizer, not unlike a food processor. The remains are then put through a sieve and into a container for the family—but not always.

If the average person knew this, would they still regard cryonics as creepy and gross by comparison?

I would have expected to see this in the Atlantic, surprising that it was in Popular Mechanics. Very nicely written. Having lost my father-in-law late last fall, the story was a little difficult but it made me realize how much in common we all have when facing the loss of a loved one. And yes, my family is planning on spreading at least some of his ashes at his favorite golf course.

I've long wondered what happens to the mercury in amalgam fillings. I guess I'll have to have a look at this.