Before extrusion, the HDPE can be pigmented to yield color-coded pipe. Common PEX tubing colors are natural (hazy clear, unpigmented), white, black, red and blue. The red and blue colors are used to help plumbers and homeowners distinguish between hot and cold water supply lines.
No, there has never been a US President from an independent party; however, at the time of his presidency, George Washington was not affiliated with a political party at all, as there were no parties in the brand new United States of America.
The 13 British colonies broke away from Great Britain on 4 July 1776 and became 13 free and independent states or 13 little nations. From 4 July 1776 to 3 March 1789, there was no autonomous sovereign called the United States of America. Barack Obama became president of the United States of America in  2009 and is the current president. Before he became president there  was George W. Bush and Bill Clinton.