Chemical dispensing systems provide a means of mixing potable water with chemicals to provide the user with a chemical solution which is ready for use. The amount of dilution shall be fixed or adjustable. This standard applies to those devices classified as chemical dispensing systems having self- contained means of backflow protection. The devices shall be classified as follows: (a) Type A: These devices have the chemical(s) pressurized above atmospheric pressure; and (b) Type B: These devices do not pressurize the chemical(s) above atmospheric pressure with the only source of back pressure coming form an elevated hose.