Water Shutoff Valve in Barn - Freeze and Burst?

[braultj]

I recently purchased a hobby farm (I'm in MN) and have a water shutoff valve (not a hydrant) in the barn. I'm quite ignorant about plumbing stuff so here is my scenario. A 3/4" galvanized pipe rises about 12" vertically out of the cement, then makes a 90 degree turn to a 5" long horizontal run with a shutoff valve at the end. I put some pipe insulation on and also some straw around it to try to insulate it. I attempted to open the valve this morning but is stuck so I'm thinking it is already frozen shut. Is this a disaster waiting to happen? Or as long as I don't need the water source, can it just stay like this over winter?
thanks, Thaddeus

[JazzDad]

Hey, J. Welcome to CBN.

The problem comes when the water freezes, and subsequently expands. It can burst the pipe if that expansion is contained. You might benefit if you can take the pressure off that line (from the other end).

But let's see what other folks may say. After all, my water might freeze once every few years.

[speedbump]

I've been living in Florida for so long now that I almost forgot about things freezing and breaking like they did in Michigan.

Covering anything with straw, insulation or anything else without adding enough heat to keep the cold out, won't work in the tundra. Heat tapes have come a long way from what I've learned. You might want to look into them.

If the valve is frozen, it doesn't mean that the pipe or valve is broken... YET. If it freezes solid, it is broken. Then at some time in the future, the flood starts. So with that in mind, I would turn off the main water to this valve, thaw it out and then see if it will still hold water or if there is a rupture.

[jml755]

As others said, heat tape is your best bet. However, since the pipe rises out of the cement (can't get the tape below ground), there is a possibility in a really hard freeze (you are in MN, after all) that the output of the heat tape (wrapped around the pipe above the ground)won't keep up with the heat loss to the surrounding soil/air. Here in Michigan, the frost line is 42" for building codes. I suspect in your area, it's at least that. Thaw your valve (hand held hair dryer) and put the heat tape on. Get some foam insulation at the hardware store and put it over the pipe and tape. That will help keep the heat in the area you want it. What you're counting on is that the heat migrates from the water directly next to the tape DOWN the pipe below the cement. Keep in mind that Hot water RISES, so gravity is not your friend in this case.

I'd rectify this situation permanently next summer. I.e. put in a 4 or 6 ft hydrant.

[walkwavy]

You have a major problem starting. I am in Southern Minnesota and the frost line often is 5 feet or more so doing something at the surface will not work. I suggest you build an insulated box around the pipe, seal the bottom and hang a couple of heat lamps inside the enclosed box. The box needs to be totaled enclosed. I did this before we put in the hydrants. Shut the lamps off for one night and the pipe freezes. Heat tape will not do the trick. To thaw, I would use a torch near the floor.

[Pat]

Thermostatic controlled heat tape is superior in many ways to any light bulb arrangement. Wrap the heat tape around the pipe and secure the thermostat (typically a recognizable lump of plastic at the power cord end of the tape) to the pipe where the pipe goes into the cement. Insulate around the entire thing. The tape will heat the pipe which will heat the water. Don't worry about convection currents in the water not being your friend as the metal pipe will conduct heat downward below the surface for a distance until the heat is lost to the cold cement or earth. This is not a guarantee but a pretty effective method.

A more surefire heating method with metallic pipe is to pass an electric current through the pipe from one end to the other. As the resistance of the pipe is pretty low you need a darned good step down transformer to provide the current. Typically old fashioned transformer type welders are used for this turned down to a low heat for longer term use or higher amps for a quicker temporary thaw job.

Insulation alone will not prevent freezing, long term, for water in a pipe with no flow. Eventually enough heat will be lost through the insulation to let the temp of the water drop below freezing and potentially burst your pipe in a situation where the average temp stays below freezing for a protracted period.

Pat