NFPA 17 – Dry Chemical Extinguishing
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1. What is the primary purpose of NFPA 17?
To establish requirements for the design, installation, maintenance,
and testing of dry chemical extinguishing systems.
This standard provides safety and operational guidelines to ensure
effective fire suppression using dry chemical systems.
2. What type of fires are dry chemical extinguishing systems primarily
designed to control?
Class B and Class C fires.
Class B involves flammable liquids, and Class C involves energized
, electrical equipment, both effectively suppressed by dry chemical
agents.
3. What is the minimum water pressure required to operate a dry
chemical system?
Dry chemical systems do not require water pressure to operate.
These systems rely on pressurized gas or stored pressure, not water,
to discharge the chemical.
4. What is the standard test interval for inspecting dry chemical system
cylinders?
Annually.
NFPA 17 requires yearly inspections to ensure cylinders are full,
pressurized, and ready for use.
5. What is the maximum allowable leakage rate for dry chemical
cylinders during inspection?
No more than 5% loss of pressure over 12 months.
A minimal loss ensures cylinders remain pressurized and functional
over time.
6. What are the typical forms of dry chemical agents used in NFPA 17
systems?
Powdered chemicals such as monoammonium phosphate and
sodium bicarbonate.
These agents interrupt the chemical reaction of fire and are effective
on multiple fire classes.
, 7. What is the purpose of a fusible link in a dry chemical system?
To act as a heat-sensitive release mechanism for system activation.
The fusible link melts at a specific temperature, initiating discharge
when heat from a fire is detected.
8. How should dry chemical agents be stored before installation?
In dry, cool conditions away from moisture and contaminants.
Moisture can cause clumping and reduce the effectiveness of the dry
chemical agent.
9. What is the required temperature range for dry chemical system
operation?
Typically -40°F to 120°F (-40°C to 49°C).
Extremes beyond this range can damage system components or
reduce agent effectiveness.
10. What is the purpose of a system actuator in a dry chemical
system?
To release the extinguishing agent into the protected area.
Actuators can be mechanical, electrical, or pneumatic, triggering the
system to discharge chemicals.
11. What type of pressure is commonly used in stored-pressure dry
chemical systems?
Nitrogen or nitrogen/CO2 mixture.
These inert gases safely pressurize the cylinder to discharge the dry
chemical.
Systems Practice Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of NFPA 17?
To establish requirements for the design, installation, maintenance,
and testing of dry chemical extinguishing systems.
This standard provides safety and operational guidelines to ensure
effective fire suppression using dry chemical systems.
2. What type of fires are dry chemical extinguishing systems primarily
designed to control?
Class B and Class C fires.
Class B involves flammable liquids, and Class C involves energized
, electrical equipment, both effectively suppressed by dry chemical
agents.
3. What is the minimum water pressure required to operate a dry
chemical system?
Dry chemical systems do not require water pressure to operate.
These systems rely on pressurized gas or stored pressure, not water,
to discharge the chemical.
4. What is the standard test interval for inspecting dry chemical system
cylinders?
Annually.
NFPA 17 requires yearly inspections to ensure cylinders are full,
pressurized, and ready for use.
5. What is the maximum allowable leakage rate for dry chemical
cylinders during inspection?
No more than 5% loss of pressure over 12 months.
A minimal loss ensures cylinders remain pressurized and functional
over time.
6. What are the typical forms of dry chemical agents used in NFPA 17
systems?
Powdered chemicals such as monoammonium phosphate and
sodium bicarbonate.
These agents interrupt the chemical reaction of fire and are effective
on multiple fire classes.
, 7. What is the purpose of a fusible link in a dry chemical system?
To act as a heat-sensitive release mechanism for system activation.
The fusible link melts at a specific temperature, initiating discharge
when heat from a fire is detected.
8. How should dry chemical agents be stored before installation?
In dry, cool conditions away from moisture and contaminants.
Moisture can cause clumping and reduce the effectiveness of the dry
chemical agent.
9. What is the required temperature range for dry chemical system
operation?
Typically -40°F to 120°F (-40°C to 49°C).
Extremes beyond this range can damage system components or
reduce agent effectiveness.
10. What is the purpose of a system actuator in a dry chemical
system?
To release the extinguishing agent into the protected area.
Actuators can be mechanical, electrical, or pneumatic, triggering the
system to discharge chemicals.
11. What type of pressure is commonly used in stored-pressure dry
chemical systems?
Nitrogen or nitrogen/CO2 mixture.
These inert gases safely pressurize the cylinder to discharge the dry
chemical.
