Pro Plumbers

Wall thickness does not affect pipe or tubing size.[20] 1/2" L copper has the same outer diameter as 1/2" K or M copper. The same applies to pipe schedules. As a result, a slight increase in pressure losses is realized due to a decrease in flowpath as wall thickness is increased. In other words, 1 foot of 1/2" L copper has slightly less volume than 1 foot of 1/2 M copper.[citation needed]
When a person has a blockage in their sewage system they often try to fix it themselves by adding an acid or a base such as Drano in an attempt to dissolve or dislodge the problem. These chemicals can get into the plumbers eyes [14]when the sewage is splashed during the repair. The plumbers skin during the repair does come into contact with the sewage water.[15] The owner of the toilet might not report to the plumber they have already tried Drano a highly caustic base .