What is the meaning of 'SPECIAL PROCESS'. Is manual welding a special process?. If so, why and what controls should be exercised on such processes?

Welding may or may not be. it depends upon the specific design and such.

There are a lot of threads here where Special Processes are discussed in more detail. You might want to try a search here in the forums. Or give us more details of the design, etc.

Andrews

Special processes is quite a simple concept.

They are basically processes where you cannot verify the output. Instead you are reliant on the process being performed under certain process parameters and controls that you have somehow verified as being suitable to give you the required output.

Welding is often considered a special process as there are very few people who can verify the mechanical properties of a weld without destroying the product. This is of particular importance in the welding of pressure vessels, however if you are welding a garden gate where the mechanical properties of the weld can be considered merely to 'stick' the gate together and look nice you might say that simple visual inspection is sufficiently verifying the weld - hence its not a special process.