Impact of Fire on Sprinkler Sprays and Reduction in Strength of the Building Material

Posted: August 26th, 2021

Impact of Fire on Sprinkler Sprays and Reduction in Strength of the Building Material

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1. BACKGROUND
2. Introduction

Regularly, architects have conducted challenging research studies aimed at finding the best structures and features that could effectively impact fire protection and installation design. Fire protection engineers have increasingly utilized performance-oriented models that inherently could predict fire behavior, thus understanding varied cases of fires [3]. It has been important that research studies expound further on methods of fire protection in a bid to impact the performance of fire sprinklers in fire circumstances positively. There exists a limited number of engineering tools that would efficiently envisage the effects of sprinkler sprays on life safety as well as property protection. Such a shortage in quantity can bedirectly attributed to the complexities attachedto the whole interaction of the sprinkler spray within a fire environment and the effects of sprinkler spray against the strength of the used building material [3]. Therefore, this research paper seeks to establish the impact of fire on sprinklersand howfire impacts the involved building materials. Indeed, the ability of engineers to predict the effect of fire on sprinkler sprays as essential engineering tools.

• Literature Reviews

Several studies have been developed to investigate the impact of fire on the sprinkler in a bid to protect a building material from the damaging effects of wildfires. With studies in place, other kinds of highly challenging lights (HCFs) have influenced many buildings extensively due to the ineffectiveness of types of fire sprinkler technologies [1]. In this regard, this review section of the paper has drawn significant attention towards more than five studies on a sprinkler that reinforces on fire protection. All these literature from six journals have centrally focused on experimental testing to underpin on newer and more efficient, active fire protection system. All these literature have embarked on the application of Simultaneous Monitoring, Assessment, and Response Technology (SMART) to underpin system design and evaluation functions associated with an engineering tool of fire protection [6]. With the SMART design fire protection system, varied vital functions have been enlisted. They includemulti-sensor detection, to detect any form of smoke in a room, thus relaying information toa real-time fire calculator that locates the resulting direction of the smoke.

Moreover, these authors of these journals have indicated that the application of a dynamic fire sprinkler would receive a wireless kind of communication from the real-time smoke locator to start spraying out mass flows relative to the angle and direction of smoke [3]. However, a particular set of researchers have decided to subject these design fire protection functions to thorough investigations to establish the effectiveness of these functions on the entire building material [3]. Besides, another type of study on fire protection has shown that a combination of smoke coupled with temperature sensors can correctly identify just smoke other than fire at a very early stage, thus increasing the chance of suppressing the fires by a percentage magnitude [3]. Also, the research study concerning a thermal centroid-oriented algorithm by another set of researchers has found out the employment of a 6-unit sprinkler activation can help direct the mass flow at its highest concentration rates towards the location of either smoke or fire [3].

• Gaps in Reviewed Literatures

There is no particular study that designed a method that can be applied directly in the engineering field. Instead, all the design methods have been only practical in labs, therefore signifying a significant gap in research work.

1. OBJECTIVES OF OTHER RESEARCH STUDIES

First, the aim of this research study concerning establishing the impacts of fire on sprinklers and how fire has occasionally impacted the used building materials connects with objective of the reviewed journal in the sense that it is important to consider the development of a fire package, which entirely specifies the flammability properties of the sprinkler materials[4]. Therefore, obtaining the specified measurementssuch as critical heat flux, chemical heat of combustion, peak-heat release rates, and ignition times would facilitate the fulfilling of my study’s objective.

Moreover, establishing the impacts of fire on building materials required me to review how High Challenging Fires (HCF) have forced many engineers to develop new sprinkler system that would reduce the risk factors of fire on the building materials [6].

Also, the need to find the impact of fire on building materials compelled my logic to consider the risk analysis of fires against the strength of the building materials[2]. Indeed, studying how the building material used has reacted against the effects of fire help me to fulfill my study objective.

Further, studying the impact of fire on sprinkler sprays necessitated that I reviewed the study significance of using the metrics of performance-based fire protection design (PBFPD) that was intended to measure the extent on building materials used[1].

Next, establishing the impact of fire on sprinklers necessitated me to study the objective of reviewed journal in finding how spray patterns were useful in measuring the volume flux distribution as a way of zeroing fire protection [5].

Lastly, meeting the objective of my study on learning how sprinklers behave during fire encouraged me to read a reviewed journal that seek to establishhow mass flow reduction impacts the effectiveness of sprinkler in influencingreinforcing fire protection [3].

1. METHODOLOGY

The research methodology involved a closed experimental testing vis-à-vis the application of a buoyancy mass flow equation in studying the impact of sprinkler spray in the fire scenario [3]. The buoyancy mass flow equation was as follows.

From the equation, Z_N = neutral pane height; C_D = discharge coefficient; W = vent width (m); T_G = upper gas layer temperature (K); p∞ = ambient density in kg/m³; T∞ = ambient temperature (K); g = acceleration due to gravity given in m/s²; H= vent height [3].

Besides, the design involved 24 tests conducted at the test compartment with a side length of 9.75 m, a width of 4.88 m, and a height of 2.44 m. The dimensions of the compartment were equally uniform to those of a regular UL1626 fire test room. The room consistingof a single doorway with a width of 1.04 m and a height of 2.24 m was adequately sealed to prevent unwanted mass losses through the cracks [3]. The construction of the room entailed materials such as gypsum board ceilings and plywood walls coupled with a black fire-resistant coating as well as a concrete floor. Further, the study applied the use of an air-propane burner to simulate a steady-state fire at the opposite corner of the room from the doorway [3]. The use of a mixture of air and propane burner was meant to decrease the effect of the sprinkler spray against a negligibleheat production rate of the fire. The levels of fuel and air were determined by the use of volumetric flow meters, whereasretaining a stoichiometric mixture. The collection of data was done after 30 minutes of igniting the fire, thus allowing for three measurements of fire sizes at 42±5, 75±5, and 96±5 kW [3]. The design obtained the heat release ratesvia the conversion of the required rate of the volumetric fuel flow.

1. RESULTS AND TESTS ANALYSIS

In table 1, the research provided a summary of collected data from 24 tests, which were classified either as un-sprinkler test runs, denoted by “D” and the sprinkler spraying test runs, denoted by “W.” These two tests were run simultaneously without turning off the fire air-mixed propane burner as a measure of suppressing the involved sources of human error that aregenerally attached to airflow rates and sprays mass flows.

Tab. 1 The collected data from both the sprinkler and un-sprinklered spray test runs [3].

In table 2, the study of theconservation of mass directs that inflow mass need always to be equated to the outflow mass. Such an analysis needs to critical in a doorway in a bid to facilitate the rapid outflow of water as the compartment testing room is regularly sealed to prevent uncontrolled mass flows. In the study scenario, the maximum mass that was brought about the fire was 1.7% of the outflow mass, thus signifying its negligibility in influencing the sprinkler sprays [3]. Therefore, this small value of fire mass was not inclusive in table 2 [3].

Tab. 2 A comparison of the out and inflow mass of sprinklers type D and W [3].

The analysis of figure 1illustrates the temperature that acted as a function of two height measurements: one for tests 10D and the other for 10W. From the graph – marked by figure 1 – it is evident that there exists an upper gas layer of the thermocouple tree, between the two stratified layers for the sprinklered as well as the unsprinklered test scenarios. Likewise, it implies that the study can approximate two different zone systems away from the sprinkler spray ifthe present experimental design would be configured, as illustrated by the graph below [3].

Fig.1 A graph of the height of both tests D and W sprays against the temperature function [3].

            To find out the required discharge coefficient as in figure 2, the experimental data needed tobe compared with anideal mass flow rate. Therefore, the calculation supposed that C_Dbe equal to one, thus removing the errors that have previously been featured in past research studies of discharge co-efficient error of about 10%. With the removal of the error, the discharge coefficient of both the W and D test runs was obtained at 0.77 in comparison with 0.76 value for the unsprinklered tests in other research studies [5].

Fig. 2 A graph illustrating the discharge co-efficient of sprays [3].

            Furthermore, the analysis of the association of M_outagainst the production rate of heat from fire indicated that the activation of the sprinkler occasioned a decrease in the determined values of the mass outflows from the room compartment. The reason is that the attached errors in each test group did not overlap, thereby implying that a considerate reduction of the mass outflow regularly happens due to the operation of sprinkler, as illustrated in the graph of figure 3. From the graph, therefore, the approximate reduction rate associated with the sprays mass flows for the final experimental tests was at 21% [3].

Fig. 3 A graph showing a relationship between flow rates of both tests runs D and W [3].

            Based on all the data analysis and results explained above, figure 4 provides a summary analysis of all the research studies by determining the spray mass flows of a sprinkler against the heat release rate of fire combustion. Thus, such a review was critical in establishing the impact of fire on the strength of building materials. This was implemented through the reduction in the mass of outflow inside the room.

Fig. 4A graph of the mass flow rate of a sprinkler against the heat production rate of fire

• DISCUSSION AND INTERPRETATIONS

The study demonstrates that the use of fired induced mass flow can be essential in predicting the impact of fire sprinkler sprays in a residential fire circumstance. Correctly, the utilization of the standard Tyco LFII residential pendent sprinkler (TY2234) is regarded as efficient in decreasing the mass flow, which unavoidably affects the building material use [3]. As much as other research studies have failed to demonstrated how precisely the mass flow of sprinkle spray affects the building material use, this study, however, has been more categorical in applying the buoyancy-based equation. The employment of this equation was prudent in establishing the exactness ofsprinkler sprays mass flows inside the room through an experimentally determined cooling coefficient [3]. Unlike other studies in five journal articles, this research is considered more effective in its ability to find the changes in vent mass flows, especially during activation of the sprinkler. Although this work was limited to the singularity of the used items such as the sprinkler type, water flow rate, as well assmall but stable state fires, the attained results were much more impactful on the engineering fire protection tool [3]. Apart from that, clearcomprehension of how sprinkler sprays would potentially affect the fire-induced mass flows, and building material needs to be done. Therefore, the studysuggests a shift in the number and types of items used. Besides, the study recommends a change in the employed variables such asincreased water flow and different locations of sprinklersin the case of HFCs. To improve on the performance of the fire sprinkler in HCF scenarios, the direction of the study dictates the implementation of various design key functions, especially for commercialization purposes of the whole concept. Future research studies need to address the reliability of the fire protection system in terms of developing fire detection designs that do not freeze its wireless data transmission between the sprinkler and control unit [3]. Next, there is a need to consider the variability of a temperature detector in establishing the rough ambient conditions of fire detection, thus relaying promptly information about temperatures of unevenly stratified rooms of larger sizes. More so, there is a need for future work studies to redefine the performances of a fire locator algorithm concerning unflatten ceilings that occasionally disrupt the smoke sensor locator from placing the exact location of fire or smoke [3]. Therefore, the experimental results from most of these reviewed journal literature on smoke detection, sprinkler sprays activation, and initial fire suppression tests have moderately considered that design of a future fire protection design system would successfully reduce the impact of fire on building material.

VI. REFERENCES

[1] A. Alvarez, B. J. Meacham, N. A. Dempsey, and J. R. Thomas, “A framework for risk-informed performance-based fire protection design for the built environment,”Fire Technology; Norwell, vol. 50, no. 2, pp. 161-181, Mar. 2014.

[2] A. L. Gitzo, G. B. Bill, J. C. Wieczorek, and B. Ditch, “Environmental impact of automatic fire sprinklers: Part 1. Residential sprinklers revisited in the age of sustainability,”Fire Technology; Norwell, vol. 47, no. 3, pp. 751-763, Jul. 2011.

[3] P. J. Crocker, S. A. Rangwala, A. N. Dempsey, and J. D. Leblanc, “Investigation of sprinkler sprays on fire-induced doorway flows,”Fire Technology; Norwell, vol. 46, no. 2, pp. 347-362, Apr. 2010.

[4] R. G. Bill, K. Hsiang-Cheng, S. K. Anderson, and R. Ferron, “A new test to evaluate the fire performance of residential sprinklers,”Fire Technology, vol. 38, no. 2, pp. 101, 2002.

[5] X. Zhou, P. S. D’aniello, and H. Yu, “Spray measurements of an upright fire sprinkler,”Fire Technology,  vol. 50, no. 3, pp. 457-482, 2014.

[6] Y. Xin, K. Burchesky, J. de Vries, H. Magistrale, and X. Zhou et al., “SMART sprinkler protection for highly challenging fires–part 1: System design and function evaluation,”Fire Technology; Norwell, vol. 53, no. 5, pp. 1847-1884, Sep. 2017.