Did I almost cause a fire? (pizza box+oven=?)

So this evening the pizza people managed to mess-up one of the two pizzas we picked up for dinner at home. One of us was assigned to return to the store and exchange the faulty food while I was put in charge of keeping the 1 good pie warm for 10-15 minutes. My question for the board is this: was I unwise to place the the pizza in the middle rack of an oven at 350 degrees? How likely was this approach to result in a fire?

I’ve looked around on the web and while this question definitely comes up with some regularity I was unable to find any science-based answer.

Cardboard will self ignite at 427f so a fire was unlikely

Paper (corrugated boxes are made from cellulose based paper fiber) auto ignites at 450 degrees F, give or take (see Ray Bradbury movie for details. You were within the safe zone for paper alone. Grease, though, may react and burn at a lower temp if it dripped onto a burner and the flame could catch the box. Maybe.

cool, thanks!

does anyone know where i might look for a citation to this effect?

here you go:

cite

I’d also point out that you probably didn’t need to go as high as 350 to keep it warm… I would have opted for around 200, which is as low as my oven goes.

I actually did set a pizza box on fire inside my oven and at a much lower temp than 350. It was too close to the heating element and someone hadn’t closed the box tightly so it sort of sprung back up into the coil.

Luckily I had a fire extinguisher but it created a godawful mess.

QFT.

Just because the average temperature of the oven is set below the combustion temperature of cardboard doesn’t mean that parts of the oven don’t get hotter than that. Grease dripping from the box onto a heating element can ignite too.

Combustion isn’t likely, but it is possible at 350º. Some places even put warnings on their boxes with the reheating instructions saying not to heat in the box for this reason. It’s not even necessary to heat the oven to 350 to keep it warm, since the pizza warmers at pizza places don’t go above 150º

Honestly, waiting 10 - 15 minutes sitting in a closed up box you could have just wrapped it in towels and it would have stayed nice and warm.

We get pizza and salads delivered at least once a month, and we always keep the pizza warm in the oven. When we order the pizza, we turn the oven on to 200 degrees. When the pizza comes, we turn the oven off, throw the pizza in, and eat our salads.

The pizza always comes out warmer and better than when we ordered it. As long as the oven is somewhat hot, you don’t even need it on, thus minimizing any risk of grease/paper/whatever hitting the hot elements.

When a brown paper bag will dinner rolls caught fire once when I was young, I had them close the oven door and turn off the heat. The oyxgen gets consumed, and he fire goes out. Much less messy.

There are some frozen meal products like meat pies that are meant to be put in the oven with their paper pan. There are also recipes that use parchment wrapping to cook fish for example in the oven. I still don’t think ovens and paper are a good mix though.

The resultant fire from a pizza box could be significant considering all the grease, and would make a mess. Ovens, especially self cleaning varieties are by definition quite fire proof, and should be able to contain such an event.

Why not just put the pizza on a proper pan where it can breath and the risk of fire is basically eliminated?

What chain was this? I’ve worked for Domino’s and Pizza Hut (among others), and SOP is to send a driver out with a replacement, even if the order was a carryout. It’s really not fair to make you drive all the way back to the store because of our ineptitude.

That said, I’m a veritable expert at keeping pizza warm. Assuming that everything was done properly (a big assumption, granted) and the pizza was popped into a corrugated cardboard box as soon as it came out of the oven, you’ve got a long time before it goes cold. Simply wrapping it in a towel will buy you even more time. Domino’s doesn’t even employ warmers; once the food is safely ensconced in the box, it goes into another box made of thick Styrofoam. This alone will keep it warm for three or four hours. The oven route is fine too, but turn the oven to its lowest setting—150° F on most ovens. This is sufficient; anything higher will cause the pizza to dry out very quickly. Also (and this is particularly true of Domino’s boxes), at 350° F the box will start to brown in very short order. You really shouldn’t attempt this at home without professional supervision, but if you really must, take an empty Domino’s box and pop it in the oven at 350° for about five to ten minutes. The box will become almost completely discolored on the inside and outside, and the smell will permeate your kitchen. If there were food in the box, it would permeate that too. You’ll taste burnt cardboard in the crust.

And as a head’s up, next time this happens call the store and complain vociferously. Whine like a little bitch if you must—really lay it on. Both Dom’s and Pizza Ho will generally (but not always) completely refund the cost of the order, and will usually give you future credit to boot.

Washoe: It was Pizza Pizzahere in Toronto. There was no delivery service because it was Christmas night. I’m sure we could have gotten some free pizza out of the situation but that really wasn’t the object of the excerise.

Lots of interesting info in here, thanks everyone!

Circa 1978 we had pizza delivered but had to wait for my father to arrive. The pizza and box went in the oven. Being a 12 year old, I don’t what temperature my mom set the oven or just how long it was in there, but the box went up in flames and she tried to put it out with a can of baking soda set aside for fires. It didn’t work. The fire department used a fire extinguisher to put it out. The also put an exhaust fan on the door to clear the smoke. I suspect the fire was out just be keeping the oven door closed. I was outside in the back and not paying attention to what was going on in the house.

We had fire extinguishers after that…

I assumed as much, but I like to make people aware of the generous refund policies of the major chains.

Simple answer: A grease fire is class “B” hazard. Baking soda has an alkali base and will work pretty well on small grease fires. It combines with the liquid grease and turns in to a foamy, soapy sludge that smothers the fire The technical term for this action is saponification

The cardboard box, however, is a class “A” fire and requires a different chemical to extinguish. This chemical is called monammonium phosphate. It becomes kind of a sticky paste and coats the combustible material, smothering the fire

Stoves are vented. Closing the door is a good idea because it helps prevent flames from migrating from the front but it can still propagate out the vent. If you have a conventional stove with a hinged top you can see the vent located under one of the burners.

Interesting. I knew the fire extinguishers were classified on account of the class “C” at work, but I had no idea that the fires themselves were classified. Are all standard fire extinguishers class “A”? I was always under the impression that, with the exception of metal fires, any extinguisher would do.

QFT:confused: