Personal Protective Equipment and Self-Contained Breathing Apparatus No. 2 Questions taken from Jones & Bartlett Fundamentals of Fire Fighter Skills (3rd Edition) Progress Indicator: Question 5 of 22 5.  What is used to determine the required capacity of the retention area when performing dilution? p. 503 Choices: Type of materials involved Level of terrain’s slope Rate of flow of the material Material to be used to dilute