Comparative Study on Pressure Reduction of Sprinkler Piping Systems with an Orifice

The recent increase in the number of high-rise buildings has led to increased pressure on sprinkler piping systems. This overpressure results in the supply of large quantities of water to a small number of open sprinkler heads due to the aging of buildings or malfunctioning of sprinkler heads. This induces significant water damage during incidents such as fires, resulting in long-term restoration needs of electrical and infrastructure facilities. Therefore, this study intends to mitigate this damage by introducing an orifice in sprinkler piping systems to reduce the water pressure at sprinkler head openings. Various types of data values were calculated by increasing the pressure and simultaneously varying the orifice specifications for each type of pipe. Currently, there are no test data of this kind, rendering the obtained data useful in the design and construction of orifices for pressure reduction in sprinkler piping systems.

MAPPING BUILDING INTERIORS WITH LIDAR: CLASSIFYING THE POINT CLOUD WITH ARCGIS

Accurate maps of building interiors are needed to support location-based services, plan for emergencies, and manage facilities. However, suitable maps to meet these needs are not available for many buildings. Handheld LiDAR scanners provide an effective tool to collect data for indoor mapping but there are no well-established methods for classifying features in indoor point clouds. The goal of this research was to develop an efficient manual procedure for classifying indoor point clouds to represent features-of-interest.We used Paracosm’s PX-80 handheld LiDAR scanner to collect point cloud and image data for 11 buildings, which encompassed a variety of architectures. ESRI’s ArcGIS Desktop was used to digitize features that were easily identified in the point cloud and Paracosm’s Retrace was used to digitize features for which imagery was needed for efficient identification. We developed several tools in Python to facilitate the process. We focused on classifying 29 features-of-interest to public safety personnel including walls, doors, windows, fire alarms, smoke detectors, and sprinklers.The method we developed was efficient, accurate, and allowed successful mapping of features as small as a sprinkler head. Point cloud classification for a 14,000 m2 building took 20–40 hours, depending on building characteristics. Although the method is based on manual digitization, it provides a practical solution for indoor mapping using LiDAR. The methods can be applied in mapping a wide variety of features in indoor or outdoor environments.

Application of Sprinkler Head Discharge Obstruction in Semiconductor Factories

Semiconductor factories are significantly affected by the spray pattern of ceiling sprinkler heads owing to the large scale and complex mix of organic/exhaust ducts and multiple pipes. Therefore, sprinkler heads are installed in the spray disorder section of the lower barrier. However, more efficient installation measures are needed to mitigate the absence of detailed installation standards and interference with human and equipment transport lines. Currently, installation causes major confusion at construction sites and increases construction costs. The purpose of this research is to overcome these challenges by evaluating the operation status of sprinkler facilities in semiconductor factories, identify problems, and suggest more efficient installation measures. An installation plan that considers maintenance and fire extinguishing performance together is reviewed, and supported systematically with a relevant checklist.

Flow-Velocity and Pressure Fitness of Sprinkler Pipes Applied with Orifice

The sprinkler design of buildings is based on the top-floor end sprinkler head, and the water flow rate and pressure are designed. When the floor is close to the bottom floor pump, unnecessary flow rate, pressure, and flow velocity become inevitable. Moreover, when the sprinkler head is opened to less than the actual fire time reference number, the excessive flow rate, flow velocity, and pressure are generated. Therefore, the damage to the water or droplet particle becomes less significant, which can be disadvantageous for efficient fire suppression. Therefore, in this study, we applied an orifice to the branch pipe of each sprinkler head to decrease the excessive flow rate, flow velocity, and pressure. It was confirmed that the design value was maintained for each floor of the high building. When the orifice was applied, the flow rate and positive well were reduced, which could prevent overpressure.

Structural Features and Smoke Resistance of Water Mist Curtain of Upper Spray Nozzle

Due to its structural limitation, the super-long tunnel faces the difficulty in smoke suppression on the ceiling. For this, the authors aim to develop a water mist curtain with an upward sprinkler head and analyze its smoke suppression performance. FDS numerical simulation was conducted to analyze the changes over time of different parameters such as temperature, smoke spread, radiative heat flux density, CO volume fraction, and the distance between the sprinkler head and the ceiling, and explore the smoke-proof and fire extinguishing effect of the improved water mist curtain together with the tunnel's smoke exhaust system. The results show that with the spray flow rate of 12L/min and droplet size of 300μm, the water mist system with upward sprinkler heads has a more efficient smoke suppression efficiency than the conventional one; the improved water mist system reduced the temperature at the tunnel ceiling by more than 40%, and the CO volume fraction by about 33%, thereby significantly decreasing the smoke density on the ceiling; it reduced the radiative heat flux density at a height of 2m by about 47%, and especially when coupled with the tunnel smoke exhaust system, the smoke suppression performance is better; the smoke volume fraction decreases with the distance between the sprinkler head and ceiling at the height of 5m from the ground. The research findings provide a reference for the smoke suppression of the water mist system and smoke exhaust system in the future.

Activation Conditions of Sprinkler Head Considering Fire Growth Scenario

The aim of this study is to investigate the gas temperature and velocity during sprinkler activation considering the fire growth scenario based on the thermal response model of the sprinkler. The fire source is assumed to have time square fire growth scenarios with a maximum heat release rate of 3 MW. Eight types of standard and fast-response sprinkler heads with an operating temperature range of 65–105 ℃ and a response time index range of 25–171 m^1/2s^1/2 were adopted. The temperature difference between the gas stream and the sensing element of the sprinkler head decreased as the fire growth slowed down, and the RTI value decreased. The overall gas temperature and velocity conditions predicted using the FDS model at sprinkler activation were in reasonable agreement with those of standard test conditions of the sprinkler head response. However, the sprinkler head could be activated at lower limits of gas temperature and velocity under the current test conditions for a slowly growing fire scenario.

The Prisoner Who Cried Wolf, and Then Swallowed a Sprinkler Head

Case Presentation: A 37-year-old man presented from jail reporting foreign body ingestion of a sprinkler head. While initial radiography did not reveal the foreign body, subsequent imaging with computed tomography demonstrated the sprinkler head. When confronted with this discrepancy the patient admitted to having the sprinkler head in his possession and choosing to swallow it after his initial radiography. Discussion: This case demonstrates the importance of maintaining a high threshold for real illness in situations where there is suspected malingering, a situation not infrequently encountered in the emergency department.

A Study on Analyzing the Operation Time of the Sprinkler Head near the Beam with Fire Simulation

In this study, the dangers surrounding vehicular fires were identified by means of statistical analysis of the national fire information system. The analysis was conducted on the operation time of the sprinkler fire extinguisher, which plays the most essential role during the initial fire extinguishing attempt, in case of a fire outbreak. A simulation was created using the application guidelines pertaining to a sprinkler head located close to a beam as provided in NFSC 103. The operation time of the sprinkler head was analyzed for the case of a parking lot fire where a fan was operated. Fire Dynamics Simulator was used as the simulation program. If the revised guidelines were applied to thesimulation, the sprinkler head located directly above the fire source was activated approximately 1 minin advance compared to the sprinkler head operating under current standards. Therefore, it was found that the revised guidelines were suitable and aided in early fire extinguishing attempts. In the case where a fan was operated along with the detector, during the outbreak of a fire, it was found that the operation of the sprinkler head located directly above the fire was delayed by two or more minutes compared to the simulated case where no fan was operated.