Tung oil and I go way back. I refinished an antique walnut mantel in 1981, and since I was a kid and didn't know better, I kept wondering why even after five coats of tung oil, the finish was still completely matte.
There isn't any solvent smell in tung oil, but that's not to say that there is no odor at all; tung oil has a very pungent distinctive odor, and I'd recommend a whiff before you commit to using it on floors.
It takes longer to dry the more coats you apply. For instance, I think you will find it necessary to double the drying time allowed after each coat. This is especially true on a hard wood.
Starting with the second coat, you will probably have to re-enter the room to make sure that excess oil is not bleeding out through the pores (esp oak, walnut, mahogany; cherry, maple,etc., not so much)
Plan on a minimum of four coats.
Don't be surprised after six coats that the floor still looks unfinished. It just soaks in and disappears, there is no gloss or buildup to a 100% pure tung oil. That's the desired effect in some instances, but very few people are after that particular feature.
Good luck, it is a great material and is very waterproof, if you can get past the issues with odor and drying time.
Casey

We did our wide plank pine floors in tung oil and I loved the look and feel, but given our particular circumstances, I'd have to say that overall it was a mistake.

On the plus side, the finish was gorgeous for someone like me who does not like a high-gloss look or feel. It was warm, returned light beautifully without any glare and without being able to see where the wood left off and the finish began--which my husband stil laughs at, but I reallly can tell with a lot of high gloss floors. I absolutley loved the way it felt under bare feet. There definitely WAS an odor with application, but I don't think it comapres to polyurathane.

Now for the bad news. Neither we nor our installer had any experience with softwood floors or tung oil finish. Neither did any of the other flooring companies we talked to (we lived in LA, and this more historic look just wasn't in vogue at all, although it looked great in our beach house). Add to that the facts that we had an active, 70 pound dog, we had more-than full time jobs and little time for maintenance, and we really did not know how to care for our floor or how to make interim repairs to the finish--well, we really could not have chosen a worse finish for our practical needs. It and the soft wood underneath it scratched easily and deeply, it wore away in high traffic areas very quickly, and changed color pretty dramatically between sun exposed and darker areas (honestly, the last didn't really bother me much--I WANTED it to turn redder over time, and it definitely did, and I had no need to relocate my rugs). The floors looked like they needed a complete overhaul maybe three years after we had them laid. It really was a disaster, and yet I can't feel too sorry--it still felt and looked so warm and organic in all the areas we hadn't trashed! When we sold it, the first thing the stagers did was strip it, sand it, and stain it the much more fashionable espresso color you see in so many LA homes. C'est la vie!

So, if you have the right wood, more knowledge, more time and more know-how than we did, I think you could get really beautiful floors with tung oil. If not, I'd go with a harder finish! Best of luck!

I am planning to finish heart pine floors with a polymerized tung oil. I recently finished a 250 year old piece of white oak with pure tung oil cut with citrus solvent and it came out fantastic. There was an odor from the citrus solvent, strong but I liked it ok, smelled clean. I don't recall the tung oil having an odor at all, but it could nave been overpowered by the citrus solvent.

The polymerized tung oils are said to hold up differently than pure finishes and should make the application somewhat less complex. I am going to experiment with pure and polymerized to see which I am more comfortable working with, which looks better and which i think will wear" best.

@dlosapio How did your heart pine floors turn out? Did you go with polymerized or pure?

@Lisa Franzino, our floors turned out beautifully and still holding up great to this day. There is some light wear but nothing abnormal and could easily be spot repaired since it's an oil finish. I have no regrets on the decision and would do it again in a heartbeat.

There are different options out there today, wax-based penetrating oil finishes. My brother went this route on a new build completed last year, looks fantastic. I will NOT use poly finishes on floors anymore, while tried and true, I feel the oil finishes lend a warmer look and feel, are are more easily repaired. When my current floors are due for refinishing, we'll be going with tung or another oil finish.