Today at 1 pm mst I watched your show. I found it veery informative up to a point. When you mentioned that there are only 2 grades of copper pipe I was appalled at your lack of information. I work with copper pipe in residential, commercial and institutional places. I use 3 types specifically for residential and I know that in Home Depot or Lowe's or most other hardware store that you can buy all 5 grades of copper pipe. those grades are type 'K'- mainly used in higher pressure applications, type 'L'-used mainly for potable water, type 'M'- used mainly for heating piping, type 'DWV' mainly used for drain waste and vent piping, and type 'ACR' which is used in air conditioning piping and for medical grade gases. Since you stated that there is only 2 grades of copper piping I felt it nessessary to let you know that for the first time in over 5 years of watching your show that you have made an error. I will still watch your show because of the high quality and very informative information I find on it.