Summarize:

There are several power tools that are great for cutting galvanized pipe that is located in tight spaces. If you are trying to remove a piece of galvanized pipe from a tight space, you can either use a reciprocating saw or angle grinder, depending on the space you are working in and the tool you have available. The choice between using an angle grinder and a reciprocating saw depends largely on what you have available. They can typically be used interchangeably. When cutting through steel pipe with a power tool it is important to protect yourself from hazards. Put on safety glasses to protect your eyes from flying pieces of steel. Wear gloves to protect your hands from the heat of the pipe (produced by the grinder) in addition to a slipping saw blade or sharp pipe edge.  An additional piece of protective equipment you may want to consider using is ear plugs. These can protect your ears from loud noises made during sawing. It is also a good idea to wear long sleeves and long pants to protect your skin from any bits of metal that might fly around while cutting. When cutting galvanized pipe it is important to use the right kind of blade of wheel. A blade for cutting a different material, such as wood, will not work well for cutting through galvanized pipe.Blades that are made to cut through metal tend to have smaller tines than blades made to cut wood. When you go in to start cutting, the blade of your power saw or grinder should not be touching the surface of the pipe. If it is, the blade or cutting disc can snag on the pipe and make controlling the tool difficult. It can also damage your cutting disc or blade. Instead, hold the blade or disc just slightly off the surface and turn on the tool. This will allow the tool to come up to speed before contacting the surface it is cutting.
Choose to use a reciprocating saw or angle grinder in tight spaces. Put on personal protective equipment. Make sure that the saw or grinder has a metal cutting blade or wheel on it. Start power saws or grinders before they are touching the pipe.