At least one degree above freezing?
They start freezing at about 30 f.
Because of the freezing temperature increases pressure in the pipe causing it to burst.
you have to have good insulation wherever you have the pipes in your house or apartment. This will keep your pipes from freezing and bursting. :)
The main purpose of such pipes is to maintain the temperature of the fluid in the pipes. A common application is the hot water from district heating plants. Pipes carrying cold fluid are typically insulated to prevent condensation and freezing on the pipes, which can lead to water damage and equipment damage.
No, it won't help at all. You need to keep the pipes above freezing temperature (32oF, 0oC) and if it happens often (like for more than two weeks a year) you should invest in insulation.
I guess you are asking about daily air temperature. Once the surface has melted, the only concern is the above ground pipes freezing. If you leave the pump running all the time, the chance of freezing is very low.
There is no single best way to keep pipes from freezing. Insulating (wrapping) pipes is a common method. Leaving the cold water faucet open just enough for a slow drip is another method to prevent freezing.
Assuming you don't mean water heating systems, and just mean normal fresh (drinking) water systems, then they freeze at 0 degrees Centigrade like all water. But in the case of for example a home, the plumbing protected from freezing in a few different ways. Firstly most homes that are lived in have some form of heating, so this keeps the ambient temperature of the water in the pipes above freezing. Pipes that are in places more likely to be exposed to freezing, such as lofts, and roof cavities will be insulated with pipe lagging to protect them from freezing. Plus remember those pipes in roof cavities will benefit from heat rising from the home/building, helping to keep those pipes above freezing. If the subject of your question is in relation to 'burst' pipes caused by frozen water in the pipes expanding and literally tearing the pipes apart, then this will start to happen at about 20 Degrees Fahrenheit or -6 degrees Centigrade. Remember that a little freezing is not a major problem, as plumbers sometimes use special freezing kits, that will freeze a short section of pipe to block it off temporarily, while they work on the pipes.
If it is at freezing temperature, then you have an issue with uninsulated pipes.
When the temperature is 47 degrees, NOTHING is in danger of freezing !
electric heat tape drain the lines during freezing weather