Water Supply No. 3 Questions taken from Jones & Bartlett Fundamentals of Fire Fighter Skills (3rd Edition) Progress Indicator: Question 3 of 20 3.  The BG-4 constant dosage must be __________. Choices: 1.4 to 1.8 L/min 1.5 to 1.9 L/min 1.4 to 1.7 L/min 1.5 to 1.8 L/min