What is a purge dam typically constructed of?

A purge dam is typically constructed of water-soluble paper, also known as rice paper, due to its unique properties that facilitate effective purging during processes like pipe welding or testing. This material is designed to dissolve in water, making it ideal for applications where the dam needs to be removed without leaving any residue or requiring extensive cleanup.

The use of water-soluble paper allows for the purging of pipelines by holding back water or other liquids, thereby enabling technicians to perform work with minimal disturbance to the environment and ensuring a clean operation. Additionally, it is lightweight and easy to handle, making it a practical choice in various industrial settings.

Other materials, while they may have some uses in construction or other applications, do not possess the specific advantages that water-soluble paper offers for this particular purpose.