Here you have the best NFPA CFPS practice exam questions
It was determined that a total-flooding carbon dioxide suppression system installed in a process room requires an overpressurization vent. The system will flow 156 pounds of carbon dioxide per minute, and the enclosure strength has been calculated to be 9 lb/ft2 (71 kg). What is the minimum vent size recommended for this application?
In a total-flooding carbon dioxide suppression system, the required vent size is calculated to account for the overpressure that could develop due to the rapid release of gas. Given the flow rate of 156 pounds of carbon dioxide per minute and the enclosure strength of 9 lb/ft², we need to ensure that the vent is large enough to handle the flow without exceeding the pressure limits of the enclosure. Based on common engineering practice, a higher vent size than calculated is generally safer to ensure adequate pressure relief. Among the provided options, 50 in² (323 cm²) is the most appropriate choice as it provides a sufficient margin of safety for the given conditions.
How much depth of particle-sized dusts of organic materials such as wood or food products can, under the right set of conditions, result in a flash fire or explosion?
A depth of less than 1/8 in. (3 mm) of particle-sized dusts of organic materials such as wood or food products can, under the right set of conditions, result in a flash fire or explosion. Even a thin layer of combustible dust, if dispersed in the air and ignited, can cause a significant hazard.
The performance of fire alarm audible notification in a wide open space can be analyzed using a condition called free-field condition, where the sound pressure level (SPL) decreases roughly by a specific decibel value every time the distance from the source is doubled. Which of the following choices is the specific decibel value attributed to the free-field condition?
The free-field condition describes how sound propagates in an open space without significant reflections or obstructions. In such conditions, the sound pressure level (SPL) decreases by 6 decibels (dB) every time the distance from the sound source is doubled. This is a well-established acoustics principle known as the inverse square law.
Electrical equipment used in Class I, Division I hazardous locations is often referred to as:
Electrical equipment used in Class I, Division I hazardous locations is often referred to as explosion proof. This type of equipment is designed to contain any explosion originating within its housing and prevent the ignition of the surrounding flammable atmosphere.
The entrainment of air from the surrounding atmosphere in a rising fire plume has the effect of:
The entrainment of air from the surrounding atmosphere into a rising fire plume will increase the total mass and volume of the plume. This is because more air is being added to the plume. This additional air cools the plume because the entrained air is relatively cooler than the fire plume. Additionally, the added air will dilute the concentration of fire products within the plume.