What are the common types of dry chemical agents used in NFPA 17 systems?

The correct choice identifies the common types of dry chemical agents used in NFPA 17 systems as monoammonium phosphate, sodium bicarbonate, and potassium bicarbonate. These agents are categorized as dry chemical extinguishing agents that are effective in suppressing fires involving flammable liquids, gases, and electrical equipment.

Monoammonium phosphate is a multipurpose agent that is especially effective against Class A, B, and C fires. Sodium bicarbonate and potassium bicarbonate are effective in extinguishing Class B and C fires, specifically those involving flammable liquids and energized electrical equipment. Their chemical properties allow them to disrupt the combustion process by creating a barrier between the fuel and the oxygen, as well as neutralizing the free radicals in the flame, which is essential in fire suppression.

The other options include agents that are either not utilized in NFPA 17 systems or do not represent dry chemical agents. Water and foam agents, for example, are not classified as dry chemicals and have different applications and effectiveness depending on the type of fire. Similarly, diatomaceous earth and fluoride compounds are not common dry chemical agents. Pirex and silicone-based agents also do not fit within the standard classifications of dry chemical extinguishing agents used as per NFPA 17