Sprinkler Head Research Articles

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.

Numerical simulations of concealed residential sprinkler head activation time in a standard thermal response room test

It is common for sprinkler heads in residential buildings to be of the concealed type. Key parameters for the thermal sensitivity of sprinkler heads are the response time index (m½s½) and conductivity factor (C factor, m½s−½). BS 9252:2011 and BS EN 12259-14:2020 outline test methods to determine whether sprinkler heads achieve adequate thermal sensitivity, stipulating that a room test be undertaken for concealed heads. In carrying out this test, neither the response time index nor C factor is defined. This paper uses computational modelling tools Fire Dynamics Simulator and B-RISK to simulate the room test. In running these simulations, maximum values for the ‘effective’ response time index and C factor needed to pass the room test can be estimated, assuming concealed heads can be represented as equivalent pendent heads. Initial deterministic simulations are used to calibrate results between Fire Dynamics Simulator and B-RISK. Monte Carlo modelling is then utilised within B-RISK, with variable parameters for the response time index and C factor (C), to estimate the relationship between the two parameters necessary to pass the room test. As a result, it is proposed that this relationship can be represented using a simple, empirical power law equation of response time index = 100 (5.4–C)2/3, where C < 5.4. Practical application: The results indicate that the minimum RTI and C factor values needed to pass the room test are greater than those needed to pass wind tunnel testing methods. In observing that equivalency is not demonstrated by the room test, and by defining the RTI/C factor relationship needed to pass the test, this paper provides fire safety engineers with amended values for concealed heads to be adopted in future assessments. In the absence of any detailed specification for sprinkler heads, it is recommended that an RTI of 290 m½s½ and a C factor of 0.5 m½s−½ may be applied.

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<sup>1/2</sup>s<sup>1/2</sup> 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.

Estimating water density for tunnel fixed firefighting system and ventilation requirements to control fires in road tunnels

A potentially dangerous fire event that can occur in road tunnels is a gasoline tanker fire, where flammable liquid fuel spills on the tunnel roadbed and catches fire. In the USA typically, the water density required for fixed firefighting systems is based on NFPA 13 and the minimum ventilation is based on smoke back layering. This work calculates the required water density based on the tunnel geometry and compares the back layering ventilation to the ventilation needed to remove saturated air. The presented methodology presents an analytical approach to calculate the water density and ventilation required to control a gasoline pool fire, which is a function of the size of the gasoline pool, without considering the growth restriction due to fuel depth and limited oxygen.The tunnel geometry parameters presented in the examples are limited to specific cross slopes and road slopes, as well as resultant fire sizes of 50 MW, 100 MW, and 150 MW. This work considers standard sprinkler heads to calculate the required density in conjunction with the ventilation required to maintain evaporative cooling. The calculations are performed with a water only system and with modifications that could be expected from the use of foam additive.

Isoniazid thermal runaway simulation based on ARC data

The law of fire occurring in the reaction of self-reactive substances is unique, when heated, comparing with common solid combustibles. In this paper, the possible thermal runaway reaction of Isoniazid storage was studied. Combined with the analysis of Isoniazid thermal stability characteristics, Fire Dynamics Simulator (FDS) was used to simulate the Isoniazid storage fire. The temperature distribution of Isoniazid storage was obtained. According to the simulation results, the temperature field of Isoniazid storage was analyzed by regression. The law of temperature distribution with height, time and distance from the center of ceiling was obtained. It was found that the ceiling temperature was highest at different heights. On the ceiling, the temperature was highest in the center. From the center to the sides, the temperature tended to drop. Therefore, when setting up the self-spraying fire extinguishing system, the sprinkler head protection roof needs to be set up, and for the stack center position, the sprinkler head should be protected.

Effect of riser height on rotation uniformity and application rate of the dynamic fluidic sprinkler

AbstractThe objective of this paper was to investigate the effect of riser heights on rotation uniformity and application rate of the newly designed dynamic fluidic sprinkler. The dynamic fluidic sprinkler was tested using different nozzle sizes of 5 and 6 mm. The sprinkler head was mounted on 1.3, 1.5, 1.7 and 1.9 m risers at 90° in the horizontal direction and was placed about 0.9 m above the top of the cans. The following operating pressures were tested: 150 and 200 kPa. A program was written to simulate the non‐uniform of rotation of the nozzle during the full circle‐spraying process. It was found that the riser height had a significant effect on application rate and uniformity. The comparison of standard deviation with different risers showed that differences in standard deviation were much lower for the 1.9 m riser height. The deviation was in the range of 0.14 ~ 0.26, 0.14 ~ 0.42, 0.18 ~ 0.50 and 0.13 ~ 0.69 mm h−1 considering the riser heights of 1.9, 1.7, 1.5 and 1.3 m. For all the nozzle sizes, a smaller standard deviation was recorded under 150 kPa. The deviation range was 0.15 ~ 0.24, 0.17 ~ 0.45, 0.18 ~ 0.45 and 0.2 ~ 0.66 mm h−1 for 1.9, 1.7, 1.5 and 1.3 m, respectively. With respect to nozzle sizes, 5 mm gave better standard deviations and the deviation range was from 0.14 ~ 0.26, 0.15 ~ 0.45, 0.2 ~ 0.7 and 0.23 ~ 0.74 mm h−1 with radial heights of 1.9, 1.7, 1.5 and 1.3 m, respectively. The range of the coefficient of uniformity values for overlapped quadrants for the 5 mm nozzle was as follows: 78% at a spacing of 10 to 72% at 80% overlapped spacing. The highest occurred at 50% spacing and increased with an overlapped spacing of 10 to 50%, ranging from 78 to 87% with an average of 82.5%. © 2020 John Wiley & Sons, Ltd.

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

Case PresentationA 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.DiscussionThis 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.

Probabilistic assessment of off-the-shelf fire sprinkler Head activation time through laboratory experiments

The activation time of a sprinkler has a great impact on the fire growth inside a compartment. The longer time it takes for a sprinkler to activate, the higher the risk of fire to start to spread inside the compartment. In this study, the activation times of off-the-shelf half inch 68°C fire rated pendant sprinklers were assessed through experiments in laboratory settings and eventually best-fit probabilistic curve for the Response Time Index (RTI) were generated from the experimental results. The experiments were conducted in two sets; one set without smoke effect and the other set with smoke effect to determine the activation time and temperature of the sprinkler heads. The data recorded were then used to calculate the RTI and Palisade @ RISK statistical analysis software was used to analyze the best-fit probabilistic curve for the RTIs. It was observed that, average time required for sprinkler to activate was 60 seconds. It was also found that the calculated RTI were within the range of the international sprinkler design guideline. However, the calculated RTI were found to be inconsistent with specified RTI from manufacturer. Based on @ RISK software, the two best-fit RTI probabilistic curve for the two experiments were Gamma and BetaGeneral distribution curve. The probabilistic curves obtained from this work can be used as input for fire in enclosure simulations.

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.

A Study on the Establishment of Sprinkler System in Duct Passing through Fire Compartment Walls

The need for a standard review of fire prevention and related statutes and human safety protection against fire spread has emerged owing to the recent diversification of fire types and the increase in the scale of damage in the K-industrial complex's electronic parts manufacturing plant. The building law mitigates the installation of fire dampers (FDs) by fixing sprinkler heads to the inside of the exhaust duct that penetrates the fire compartment wall in the electronic components manufacturing plant. However, the clause presents only alternative applicability and does not present any installation criteria. This results in conflicting interpretations between the Fire Protection Act and the Building Act, causing major confusion in the work. Therefore, in this study, three problems of building legal fire-fighting facilities in electronic parts manufacturing plants with special process characteristics were reviewed and analyzed. In addition, performance standards and standards for inspection and maintenance of building-legal firefighting facilities suitable for preventing the spread of flames were presented.

Comparative Evaluation on Performance Characteristics of an Impact Sprinkler with Nozzle-Dispersion Devicesand Rotary Plate Sprinkler

Abstract. A set of nozzle and water dispersion devices were designed to obtain a desirable jet breakup and save water from an impact sprinkler (IS) at low pressure conditions. Comparative performance indicators were obtained for the commercial LP and IS sprinkler heads. Results show that under the same working conditions, the IS produced a large spray range and the water distribution in the middle of the spray range (R) was better than the LP. The best simulated uniformity from the IS was obtained for the combined spacing factor of 1.4*R and the combined uniformity was 4% larger than the LP. Considering the middle position of the spray range, the number and diameter of the droplets from the IS were larger than the droplets from the LP. However, in the end position of the spray range, the droplet diameters from the IS were quite smaller than the LP. Velocities from IS ranged between 0.2 and 6.4 m/s, while that from LP sprinkler were slightly higher ranging from 0.15 to 7.7 m/s at 150 kPa. Overall, introduction of the fixed dispersion device with a pointed tip profile combined with the 6 mm nozzle offered some advantages for the IS over the LP sprinkler at low-pressure conditions. Keywords: Dispersion device, Droplet distribution, Impact sprinkler, Low pressure sprinkler, Nozzle, Spray range, Uniformity.

수평차단막 설치에 따른 랙크식 창고의 화재방호성능 개선에 관한 연구

A rack-type warehouse is a structure that vertically loads a large amount of goods. When a fire occurs can cause massive damage. In Korea, rack-type warehouses are installed with sprinklers and fire detectors in accordance with national fire safety codes. In case of rack-type warehouse fires in Korea, sufficient fire protection performance could not be secured. In this study, the horizontal barrier was analyzed by fire simulation to improve the fire protection performance of rack type warehouse. As a result of the fire simulation, it was possible to prevent the vertical spread of the fire when the horizontal barrier was installed over a certain length. In addition, in the case of installing a horizontal barrier and installing fire detectors under the horizontal barrier, it was possible to detect the fire early compared to the existing way of fire detector installation. When the horizontal barrier is installed, the temperature distribution under the horizontal barrier is higher than when the horizontal barrier is not installed, and the sprinkler head can be operated early due to the heat collecting effect.

Removal of Smoke and Toxic Gases Through Sprinkler Head Spray

This study was conducted with the aim of reducing the concentration of smoke and toxic gases by quickly capturing large amounts of these substances using a venturi tube and sprinkler head in a fire. To this end, a new experimental model sprinkler head has been developed. The ability to remove carbon monoxide and smoke was tested using a standard sprinkler head with a scaled-down chamber and smoke of cigarettes. The carbon monoxide concentration and visibility were measured at 1, 2, and 3 min after filling the chamber with smoke. The proto-model confirmed a significant drop in the carbon monoxide concentration and a remarkable smoke dilution at a discharge pressure of 0.1 MPa. Therefore, the test model could extend the evacuation time and stay time by removing smoke and toxic gases. Keywords: Smoke and Toxic Gas, Venturi Effect, Sprinkler Head, Concentration Drop, Visibility

Assessing suitability of modified center pivot irrigation systems in corn production using low altitude aerial imaging techniques

This study evaluated corn (Zea mays var. indentata) canopy vigor and temperature variations using small unmanned aerial system (UAS) based spatiotemporal imagery data. The key objective was to develop understanding on site-specific suitability of the Mid Elevation Spray Application (MESA) and Low Elevation Spray Application (LESA) sprinkler systems in irrigating corn crop and potential water as well as energy savings. Aerial data was collected through small UAS flights at 100 m height above ground level and on 49, 59, 65, 77, 105, 114, 134 days after planting (DAP). Small UAS had 5-band multispectral and radiometric thermal imager on-board the platform. Custom image processing algorithms were developed to extract various vegetation indices (Normalized difference vegetation index [NDVI], Green NDVI [GNDVI] and Normalized difference red edge [NDRE]) and canopy temperature maps from the imagery data. Two sample T-test was performed on extracted data to understand significant difference, at 5% level, within the LESA and MESA treatments. For both the irrigation techniques, the crop vigor increased in the early growth stage (49, 65 DAP), peaked in the mid growth stage (77, 105, 114 DAP) and then decreased in the late growth stage (134 DAP). The MESA irrigated sections had higher vigor (NDVI, GNDVI, NDRE), but not significant, compared to LESA throughout the season. Similarly, the MESA irrigated areas had significantly (0.61–2.07 °C) cooler canopies than LESA. Such results were anticipated, in part due to the issues with the sprinkler heads used in LESA. The heads were being pulled off in the corn field, causing the weighted hose to damage the crop. A different kind of sprinkler head was used after this incident. However, some strips of corn had already been damaged. Overall, this study results confirm suitability of aerial imagery data in evaluating pertinent irrigation treatments. Additional season’s data would be needed to clearly understand which technique (LESA or MESA) is more suitable for irrigating corn crop in the central part of state of Washington.

Accidental Discharge of the Fire Sprinkler System in a Level I Trauma Center Operating Room

BACKGROUND A fire sprinkler head activation occurred during cleaning being performed by environmental services (EVS) in an operating room (OR) suite of a 27 bed OR in a Level I Trauma Center. New fire pumps had recently been installed on the sprinkler system resulting in a reported 30,000 gallons of water discharged into the OR with multiple known areas of encapsulated mold from prior water intrusion. Remediation occurred while minimizing the impact on patient care, maintaining patient safety, isolating half of the OR's under negative airflow and performing air samples for clearance to return to full functionality, and following patients who were undergoing procedures in other ORs for any negative outcomes associated with this water intrusion. METHODS Extraction of water began immediately to areas both horizontal and vertical to the original OR. Removal of equipment and supplies had to occur for the evaluation of any potential contamination. All contaminated, disposable supplies were discarded and all exposed reusable trays were reprocessed by in-house sterile instrument processing department (SPD). The area impacted had to be isolated with poly wall barriers and placed under negative airflow. Specific attention was paid to those areas that had known encapsulated mold, requiring additional barriers and negative airflow. Remediation occurred and air samples were monitored during a six day period. Patients undergoing procedures were monitored for any fungal or bacterial infections. RESULTS Our impacted OR area was segregated off from the remaining OR's restricting the use of approximately half of our OR suites. Cases were able to be rescheduled with none of the patients undergoing procedures at the time of the event have developed any known procedure related adverse events. CONCLUSIONS With quick intervention and actions all water and mold remediation was completed in a timely fashion, with no negative outcomes for patients.

Effect of heat collector plate on thermal sensitivity of sprinkler heads in large terminal Halls

Heat collector plates (HCP) are commonly installed above sprinkler heads in large halls with perforated ceilings, such as in high-speed railway terminals. The thermal sensitivity of a pendent type 68 °C liquid-in-bulb sprinkler head operating with and without the HCP was investigated in this paper. Sprinkler heads were first tested in a fire chamber under a common scenario at an early stage of a fire. Air temperatures next to the sprinkler head were measured by thermocouples. It is observed that HCP gives a shorter activation time.Additionally, the standard plunge test in a wind tunnel for evaluating the thermal response of sprinkler heads was also carried out. The wind tunnel was adjusted to give air velocity of 1 ms−1 or 3 ms−1 and temperature at 90 °C. Sprinkler head was put in the work section either in parallel or perpendicular to the air flow direction. However, experimental data show that HCP is not able to shorten the sprinkler head activation time in the standard plunge test. Results suggest that the plunge test is not appropriate for studying the thermal sensitivity of sprinkler heads with HCP. This is because the HCP will change the physical environment assumed in the plunge test.

Modeling the Application Depth and Water Distribution Uniformity of a Linearly Moved Irrigation System

A model of a linearly moved irrigation system (LMIS) has been developed to calculate the water application depth and coefficient of uniformity (CU), and an experimental sample was used to verify the accuracy of the model. The performance testing of the LMIS equipped with 69-kPa and 138-kPa sprinkler heads was carried out in an indoor laboratory. The LMIS was towed by a winch with a 1.0 cycle/min pulsing frequency while operating at percent-timer settings of 30, 45, 60, 75, and 90%, corresponding to average moving speeds of 1.5, 2.3, 3.3, 4.0, and 4.7 m min−1, respectively. The application depth and CU obtained under various speed conditions were compared between the measured and model-simulated data. The model calculation accuracy was high for both operating pressures of 69 and 138 kPa. The measured application depths were much larger than the triangular-shaped predictions of the simulated application depth and were between the parabolic-shaped predictions and the elliptical-shaped predictions of the simulated application depth. The results also indicate that the operating pressure and moving speed were not significant factors that affected the resulting CU values. For the parabolic- and elliptical-shaped predictions, the deviations between the measured and model-simulated values were within 5%, except for several cases at moving speeds of 2.3 and 4.0 m min−1. The measured water distribution pattern of the individual sprinklers could be represented by both elliptical- and parabolic-shaped predictions, which are accurate and reliable for simulating the application performances of the LMIS. The most innovative aspect of the proposed model is that the water application depths and CU values of the irrigation system can be determined at any moving speed.

Experimental and numerical study of sprinkler fire protection systems: Effect of initial pressure on system performance

The present study concerns the reliability and efficient design of full-scale automatic sprinkler systems for the fire protection of industrial facilities and process plants. In particular, sprinkler systems filled with pressurized air at idle state (dry pipe) were considered. In this prospect, Computational Fluid Dynamics (CFD) simulations were carried out in the framework of the OpenFOAM package to study the flow in the piping subsequently to the activation of one sprinkler head. A VOF (Volume of Fluids) approach was used to compute the air/water interface accounting for the compressibility of air (perfect gas), while turbulence was considered using the RANS-based k-e realizable model. In addition, specific routines were developed for the pump and sprinkler modelling, taking into account the phenomenon of choked flow when sonic velocity is reached at the outlet. The numerical results were first compared to measurements on a test bench of Gridded typology (scale 1 in volume) for the purpose of validation. Then, the influence of various parameters (i.e. initial pressure in the system, dimension of the outlet orifice) on the flow dynamics were assessed for sprinkler systems of Gridded and Tree typologies. In particular, the performance was evaluated in terms of time constant of the systems, i.e. the time necessary to reach steady-state water flow at the opened sprinkler head required to control a specific fire hazard.

Reliability of sprinkler system in Australian shopping centres –A fault tree analysis

The purpose of this research is to determine the reliability of sprinkler systems in shopping centres by utilising the fault tree analysis (FTA) method and the collection of data through a physical survey. As such, a comprehensive review of sprinkler systems in the low rise shopping centre buildings with less than four levels was conducted in two Australian cities: Melbourne and Adelaide. Data from eighteen buildings were collected and are presented in this paper. This study only includes wet pipe systems, as these are the most commonly found sprinkler system installations throughout Australia and New Zealand. Although Australian Standards and building regulations are taken as references, the methodology can be used in any other jurisdictions. The data related to the failure frequency, time required for repair and sprinkler downtime due to tenancy changes were collected during site surveys. This data has been used to carry out FTA to derive the likelihood of the failure of the sprinkler system. It is observed that the failure probability of a sprinkler system in Australian shopping centre buildings lies in a range of 1.4% and 9.8% (i.e. reliability range of 90.2% and 98.6%). Compared to a previous study on high-rise office buildings (Moinuddin & Thomas, Fir Saf J. vol 63 pp 52–68, 2014), the reliability of shopping centres is found to be 3%–4% higher. Similar to high-rise office buildings, sprinkler head's failure and isolation of the main stop valve during tenancy upgrades have significant effects on the reliability of the sprinkler system. However, more regulated sprinkler isolation and better maintenance of other components in the shopping centres result in better reliability.

FIRE SAFETY IN THE BUILT-ENVIRONMENT: A CASE STUDY IN A RESIDENTIAL FACILITY

Abstract In light of the spread of residential fires worldwide, this paper aims to identify the current fire safety code requirements for providing the minimum level of safety in residential facilities, hence, mitigating the risk of fire occurrence. The paper also presents the findings of a case study to demonstrate the compliance level of a sample residential facility, with code requirements. The case study building is composed of three floors and a basement. It can accommodate 214 persons. It was built in 2013, and it is located in Khobar, Saudi Arabia. The study revealed that the assessed facility had an adequate distribution of fire detection and notification systems. Moreover, the level of the housekeeping practices and concentration of hazardous material was found to be acceptable. However, the means of egress, fire doors and fire suppression systems were not up to code requirements. The study recommended measures to improve the level of safety in the building. These include increasing the number of fire exits; installing sprinkler heads on each floor; distributing fire extinguishers sufficiently; and installing fire rated doors. This study aims at raising awareness about the incidences of fires accidents in residential facilities and their catastrophic implications. It serves to provide a standardized fire safety management checklist, for the use of design professionals and property managers, towards the effective design and maintenance of residential facilities.