Question 17 - Which portable extinguisher is the least suitable for use on Class B fires?
Question 18 - Most foams (except for Class A) are usable in ____ concentrations in water.
Question 19 - If at any time a valve through which water is flowing is closed quickly, ____.
Question 20 - Aqueous film-forming foam is a ____ foam.
Question 21 - ____ extinguish a fire by smothering.
Question 22 - NFPA 72 is the National ________ Code?
Question 23 - NFPA 13 is the National ________ Code?