The problem with frozen plumbing pipes is in the remedy. If the pipes are thawed with a blowtorch, and if the open flame or the torch is allowed to come too close to combustible material—such as insulation, wooden joists or flooring—you can start a fire. Another danger from the use of a torch arises when both ends of a pipe are clogged with ice and heat is applied in the center.
This is likely to cause the water to flash into steam—which might result in an explosion. It is far better to adopt the slower and more conservative procedure of melting ice by the use of a blow dryer or heat gun.