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The discharge coefficient of a solid stream nozzle for a standard orifice with sharp edges is a dimensionless number that indicates the ratio of the actual flow rate to the theoretical flow rate of the nozzle. The discharge coefficient depends on the geometry and the flow conditions of the nozzle.the typical discharge coefficient of a solid stream nozzle for a standard orifice with sharp edges is about 0.62, which means that the actual flow rate is about 62% of the theoretical flow rate.This value is based on the experiments conducted by the National Bureau of Standards (now NIST) and reported in the paper “Discharge Coefficients of Fire Nozzles”1.The paper also provides a formula to calculate the discharge coefficient for different nozzle diameters and pressures123

Probabilistic fire models are categorized into network, statistical, simulation, and behavioral models. Network models use graph theory to represent the fire spread and the fire protection system in a building. Statistical models use historical data and probability distributions to estimate the likelihood and consequences of fire scenarios. Simulation models use mathematical equations and numerical methods to describe the physical and chemical processes of fire and its effects on the environment and the occupants. Behavioral models use psychological and sociological theories to predict the human response and evacuation behavior in case of fire. Network models are not a common category of probabilistic fire models, and they are not mentioned in the sources provided by the user. Therefore, network models are the correct answer.

References:Probabilistic Fire Simulation Assessment Using Simplified Model and Zone Modelling of a Kitchen Fire Scenario;Computer Fire Models for Fire Investigation and Reconstruction;Fire Behavior

The phenomenon of convergence cluster formation in human fire behavior was identified in 1979 in a university dormitory fire. This phenomenon refers to the tendency of people to gather in groups near familiar exits or locations during a fire, rather than seeking alternative escape routes1. This can result in congestion, delay, and increased risk of injury or death2. The university dormitory fire occurred at the Providence College in Rhode Island, where 10 students died and 40 were injured. The fire started in a trash chute and spread to the upper floors. Many students tried to escape through the main stairwell, which became blocked by smoke and flames. Some students jumped from the windows, while others remained trapped in their rooms. The fire revealed the lack of fire safety education, fire drills, and fire protection systems in the dormitory3. References:

Human Behavior in Fire Emergencies

Human Behavior in Fire: Understanding Human Behavior for Better Fire Safety Design

Providence College Dormitory Fire

The answer is C. Human factor plays a significant role in most industrial fire and explosion losses.According to a study by Allianz Global Corporate & Specialty (AGCS), human error is the cause of 80% of all industrial accidents, including fires and explosions1. Human error can include mistakes, negligence, violations, or sabotage. Some examples of human errors that can lead to fires and explosions are:

Improper handling or storage of flammable or combustible materials

Failure to follow safety procedures or regulations

Lack of training or supervision

Poor maintenance or inspection of equipment or machinery

Ignoring or disabling alarms or warning systems

Smoking or using open flames near hazardous areas

Intentional or accidental ignition of explosives or incendiaries

To prevent or reduce the impact of human errors, industrial facilities should implement effective risk management strategies, such as:

Providing regular and adequate training and education for workers and managers

Establishing and enforcing clear and consistent safety policies and rules

Conducting thorough and frequent audits and inspections

Installing and maintaining reliable fire protection systems and equipment

Developing and practicing emergency response and evacuation plans

Encouraging a positive safety culture and communication among all stakeholders

The maximum allowable travel distance from any part of a smoke compartment to the door in a smoke barrier in a new health care facility is 200 ft. (60 m). This is based on NFPA 101: Life Safety Code, 2018 Edition, Chapter 18, Section 18.3.7.3, which states that “the travel distance from any point in a smoke compartment to reach a door in the required smoke barrier shall not exceed 200 ft (61 m).” A smoke compartment is a space within a building that is enclosed by smoke barriers on all sides, including the top and bottom. A smoke barrier is a continuous membrane, or a combination of materials, that is designed to restrict the movement of smoke.A smoke barrier door is a door assembly that is installed in a smoke barrier to allow access between smoke compartments123

Smoke detector

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The smoke detector type that contains a small amount of radioactive material and functions by sensing a decrease in conductance of the air when smoke particles enter the chamber is theionization smoke detector. Ionization smoke detectors use a small amount of americium-241, a radioactive element, to ionize the air molecules inside a sensing chamber. This creates a low-level electric current between two electrodes. When smoke enters the chamber, it disrupts the ionized air and reduces the current flow. This triggers the alarm to sound.Ionization smoke detectors are more sensitive to small particles of smoke, such as those produced by flaming fires1.However, they may also be more prone to false alarms from cooking or steam, and they require proper disposal of the radioactive source2.

References:

Smoke Detector Types: Which Type of Smoke Detector Is Best? - X-Sense

How Does Your Smoke Detector Work? - ThoughtCo

The duration of required fire flow in public supply systems depends on the type of occupancy, construction, and exposure of the building, as well as the availability and reliability of the water supply. According to NFPA 1, Fire Code, Table 18.4.5.1.2, the minimum duration of fire flow for most occupancies ranges from 1 to 4 hours, with some exceptions for high-rise buildings, health care facilities, and special hazards. The fire flow duration is intended to provide enough water for fire suppression and exposure protection until the fire is under control or extinguished.References: NFPA 1, Fire Code, 2023 Edition, Section 18.4.5.1.2 and Table 18.4.5.1.2; NFPA Fire Protection Handbook, 21st Edition, Chapter 9, Section 9.2.2.

The types of overspray collectors associated with spray booths can be categorized into venturi scrubbers, waterfall scrubbers, dry filter, and cartridge filter. Venturi scrubbers use a high-velocity water spray to capture the overspray particles in a turbulent zone. Waterfall scrubbers use a curtain of water flowing over a perforated plate to wash down the overspray. Dry filter collectors use a series of filters, such as paper, fiberglass, or synthetic media, to trap the overspray. Cartridge filter collectors use pleated cartridges with high surface area and efficiency to capture the overspray. These collectors also have a self-cleaning mechanism that uses compressed air to dislodge the overspray from the cartridges.

References:Spray Booth Filters: Types and Selection;Spray Booths and Paint Finishing Operations;Spray Booth Filters: Types and Selection;Spray Booth Filters: Types and Selection;Spray Booth Filters: Types and Selection

Fire tests typically relate to two types of fire properties, fire resistance and reaction to fire. Fire resistance is the ability of a building element or component to prevent the passage of heat and flames from one side to another, while reaction to fire is the response of a material or product in contributing to the development and spread of a fire. Fire resistance tests are usually performed on systems or assemblies, such as walls, floors, doors, or windows, while reaction to fire tests are usually performed on materials or products, such as sealants, insulation, cladding, or plastics.References:International Standards and Classifications for Fire Testing - Sika;Testing for Fire Resistance and Reaction to Fire – ICC NTA;‘Reaction to Fire’ Vs ‘Fire resistance’ - Ask HILTI;What is the difference between Reaction to Fire and Resistance to Fire …;Reaction to Fire vs Resistance to Fire | Nullifire UK

The correct answer is C. A thermocouple is a temperature measurement device that consists of a pair of wires of different metals or alloys welded together at a point to form a junction. The junction is exposed to the temperature to be measured, while the other end of the wires is connected to a reference junction at 0°C. The thermocouple produces a voltage difference between the two junctions that depends on the temperature difference.This voltage difference can be calibrated to give the temperature in degrees using a thermocouple table or a formula123