What does "Wet Steam" mean to you?

Saturated steam (which is what heating boilers produce) is not "wet". It just means there's no superheat.

Wet means droplets. (Got this drummed into my head by a powerplant turbine guy- where you REALLY don't want droplets)

Something that has been mentioned on here a few times is that wet steam causes problems with radiator vents.

Wouldn't any steam entering a radiator automatically end up very wet by the time it gets to the vent just from the nature of a condenser?

Steam.

Dry Steam = Vapor gaseous state.

Wet Steam = Liquid water droplets mixed within the vapor gaseous state.

It applies to steam heating in both states of its existence as it is manipulated through the heating plant ie. boiler, and through the systems piping, changing state as it flows.

This is how I have explained it to customers and students in the past. And this is what it means to me.

Any steam which is not 0% water content is wet steam and all low pressure boiler steam is wet. If a typical fraction is say 5% how much that fraction can be influenced by surging/excessive turbulence at the surface (causing higher initial water content), lack of dropout from high riser and header velocity or short travel distance to the mains may be influenced by the specifics of the application. The higher the water content the lower the enthalpy of the steam per volume and thus the less heating capacity. That I know. What I don't know is regardless of how the steam started out by the time the steam reaches and starts filling a radiator will it still have proportionally more or less water?

Good conversation. I've always equated the steam with the results. Wet steam is loud, dry steam is not.

But now I'm not so sure. My system seems to be a perfect recipe for wet steam, but I don't have water hammer and spitting vents (unless the boiler's overfilled).

I was thinking in an entirely different direction Paul. Wet and Steamy sounds like what the female docs on Grey's Anatomy might call a McDoctor.

But none of those were choices to vote on.

It is very important that we use proper terminology when talking about technical issues. I have to look into my notes to verify this. When I got into steam heating 3 years ago I had a presentation that I would give to land lords and property managers. I wrote "wet steam is a condition in which 2% or more of the steam contains water droplets". Water is weighs much more than steams so I assume it is by volume. So no one gets confused, Steam is gas just like air, water droplets can float in air but will eventually come down due to gravity as with aerosol hair spray or an atomizer in an oil burner. These droplets can be small but they are not steam and do not have the same heat content as steam.

To measure create a simplified one pipe one radiator system. Put a drip right before the radiator inlet. Counterflow from boiler to radiator. Measure temperature at radiator (ideally multiple temperature sensors top, bottom, near and far). Configure boiler nbp to create driest and wettest steam. Run boiler for X amount of time. Over that time measuretotal condensate collected and measure area under each temperature sensor curve plotted as temperature vs time. Compare results for wettest steam config vs driest. Repeat 3 times each in randomized order.

Volunteers?😉

Usually by results as the system is operating. So it's a binary choice: wet steam/dry steam.

Wet steam meaning too wet to work well.

Dry steam meaning dry enough that entrained water does not affect system operation.

Mostly high water content shows as slow rad vent closure with "wetness" and/or heavy condensate in supplies when hot. As mentioned above, since you're trying to evaporate that additional water, fuel bills will be higher but that would require some longer term data collection.

If this were a purely scientific discussion @ethicalpaul, my vote would be different. I would vote #4: All residential steam is WET steam because it is at the saturation temperature of water. For steam to be really "DRY" it must be superheated at least one degree above the saturation temperature. At that point there can be not water in the steam. As long as the steam is at the saturation temperature, then it can contain some water vapor or actual liquid water condensate.

But I stand by my answer in this forum because we refer to wet steam as any steam that also entrains water as a result of the boiling process or as a result of the velocity of the steam traveling thru the piping system that reaches the main piping that is well above the water line of the boiler.

Wet steam in this context is relative the the industry. You can see wet steam in the videos you post and the video of the Weil McLain boiler with the glass piping.

When your system is in normal operation, there may be a little condensation on the glass pipe sections but you don't see that water moving up into the main piping. When you do some of those tests you do then the water surges past the glass pipe.

So WET steam in our world is actual water surging into the main. while saturated steam is considered Less that Wet Steam. (but not really Dry Steam)

That's my story and I'm sticking to it!

I wouldn't be surprised if the boiler mfgs. just winged it, trial and error and hope for the best.

If their boiler doesn't steam well with 2" pipe they up size the header until it is passable.

between the piping and skimming you get the steam down to a reasonable condition.