Residential Flashover Prevention with Reduced Water Flow: Phase 2

2021 ◽  
Author(s):  
Nicholas Dow ◽  
◽  
Daniel Madrzykowski
Keyword(s):  
Water Flow ◽  
Fire Suppression ◽  
Water Flux ◽  
Sprinkler System ◽  
Low Flow ◽  
Fire Growth ◽  
Solid Cone ◽  
Prevention System ◽  
Discharge Density ◽  
Reduced Water

The purpose of this study was to investigate the feasibility of a residential flashover prevention system with reduced water flow requirements relative to a residential sprinkler system designed to meet NFPA~13D requirements. The flashover prevention system would be designed for retrofit applications where water supplies are limited. In addition to examining the water spray's impact on fire growth, this study utilized thermal tenability criteria as defined in UL 199, Standard for Automatic Sprinklers for Fire-Protection Service. The strategy investigated was to use full cone spray nozzles that would discharge water low in the fire room and directly onto burning surfaces of the contents in the room. Where as current sprinkler design discharges water in a manner that cools the hot gas layer, wets the walls and wets the surface of the contents in the fire room. A series of eight full-scale, compartment fire experiments with residential furnishings were conducted with low flow nozzles. While the 23~lpm (6~gpm) of water was the same between experiments, the discharge density or water flux around the area of ignition varied between 0.3~mm/min (0.008~gpm/ft**2) and 1.8~mm/min (0.044~gpm/ft**2). Three of the experiments prevented flashover. Five of the experiments resulted in the regrowth of the fire while the water was flowing. Regrowth of the fire led to untenable conditions, per UL 199 criteria, in the fire room. At approximately the same time as the untenability criteria were reached, the second sprinkler in the hallway activated. In a completed system, the activation of the second sprinkler would reduce the water flow to the fire room, which would potentially lead to flashover. The variations in the burning behavior of the sofa resulted in shielded fires which led to the loss of effectiveness of the reduced flow solid cone water sprays. As a result of these variations, a correlation between discharge density at the area of ignition and fire suppression performance could not be determined given the limited number of experiments. An additional experiment using an NFPA~13D sprinkler system, flowing 30~lpm (8 gpm), demonstrated more effective suppression than any of the experiments with a nozzle. The success of the sprinkler compared with the unreliable suppression performance of the lower flow nozzles supports the minimum discharge density requirements of 2~mm/min (0.05~gpm/ft**2) from NFPA~13D. The low flow nozzle system tested in this study reliably delayed fire growth, but would not reliably prevent flashover.

https://fsri.org/research-update/fsri-releases-report-residential-flashover-prevention-reduced-water-flow-phase-1

2020 ◽  
Author(s):  
Daniel Madrzykowski ◽  
◽  
Nick Down
Keyword(s):  
Water Flow ◽  
Test Structure ◽  
Low Flow ◽  
Flowing Water ◽  
Water Spray ◽  
Water Supplies ◽  
Flow Rates ◽  
Prevention System ◽  
Reduced Water ◽  
Fire Experiments

This study was designed to be an initial step to investigate the potential of low flow nozzles as part of a retrofit flashover prevention system in residential homes with limited water supplies. Not all homes have water supplies that can meet the needs of a residential sprinkler system. Current alter- natives, such as including a supplemental tank and pump, increase the cost of the system. These homes could benefit from an effective fire safety system with lower water supply requirements. The experiments in this study were conducted in a steel test structure which consisted of a fire room attached to a hallway in an L-shaped configuration. Three types of experiments were conducted to evaluate nozzles at different flow rates and under different fire conditions. The performance of the nozzles was compared to the performance of a commercially available residential sprinkler. The first set of experiments measured the distribution of the water spray from each of the nozzles and the sprinkler. The water spray measurements were made without the presence of a fire. The other two sets of experiments were fire experiments. The first set of fire experiments were designed to measure the ability of a water spray to cool a hot gas layer generated by a gas burner fire. The fire source was a propane burner which provided a steady and repeatable flow of heat into the test structure. Two water spray locations were examined, in the fire room and in the middle of the hallway. In each position, the burner was shielded from the water spray. The results showed that for equivalent conditions, the nozzle provided greater gas cooling than the sprinkler. The tests were conducted with a fire size of approximately 110 kW, and water flow rates in the range of 11 lpm (3 gpm) and 19 lpm (5 gpm). The second set of fire experiments used an upholstered sofa as the initial source of the fire with the water spray located in the same room. As a result of the compartment size and water spray distribution, the nozzle flowing water at 23 lpm (6 gpm) provided more effective suppression of the fire than the sprinkler flowing 34 lpm (9 gpm) did. The nozzle was similarly effective with the ignition location moved 1.0 m (3.2 ft) further away. However, the nozzle failed to suppress the fire with a reduced water flow rate of 11 lpm (3 gpm). The results of this limited study demonstrate the potential of low flow nozzles, directly flowing water on to the fuel surface, with the goal of preventing flashover. Additional research is needed to examine larger room sizes, fully furnished rooms, and shielded fires to determine the feasibility of a reduced water flow flashover prevention system.

Modeling of Reduced Water Flow through Concrete Caused by Crystallization Technology

2006 ◽  
Vol 9 (8) ◽  
pp. 723-730
Author(s):  
Abdelaziz Al-Khlaifat ◽  
Awni Al-Otoom
Keyword(s):  
Water Flow ◽  
Flow Through ◽  
Reduced Water

Impacts of reduced water flow on the riverside intakes

2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Ahmed Awaad ◽  
Fahmy Abdelhaleem ◽  
Tarek Nasralla ◽  
Basma abdelrhman
Keyword(s):  
Water Flow ◽  
Reduced Water

scholarly journals Effects of canopy-mediated abrasion and water flow on the early colonisation of turf-forming algae

2007 ◽  
Vol 58 (7) ◽  
pp. 657 ◽  
Author(s):  
Bayden D. Russell
Keyword(s):  
Water Flow ◽  
Interactive Effects ◽  
Light Penetration ◽  
Physical Processes ◽  
Percentage Cover ◽  
Negative Effect ◽  
Flow Through ◽  
Per Se ◽  
Reduced Light ◽  
Reduced Water

Algal canopies form predictable associations with the benthic understorey, and canopy-mediated processes may maintain these associations. Three canopy-mediated processes that are inherently linked are water flow through a canopy, abrasion of the substrate by the canopy, and light penetration. These processes were experimentally reduced to test the hypotheses that turf-forming algae would be: (1) positively affected by reduced abrasion by kelp canopies; (2) positively affected by reduced water flow; and (3) negatively affected by shading (reduced light). Biomass of turf-forming algae was greater when abrasion was reduced, but less when light was reduced. In contrast to predictions, reduced water flow had a negative effect on the percentage cover and biomass of turf-forming algae, rejecting the second hypothesis. It seems, however, that this negative effect was caused by an increase in shading associated with reduced canopy movement, not a reduction of water flow per se. None of the factors accounted for all of the change seen in understorey algae, indicating that it is important to study the interactive effects of physical processes.

Selective permeability barrier to urea in shark rectal gland

2005 ◽  
Vol 289 (1) ◽  
pp. F83-F89 ◽  
Author(s):  
Joshua D. Zeidel ◽  
John C. Mathai ◽  
John D. Campbell ◽  
Wily G. Ruiz ◽  
Gerard L. Apodaca ◽  
...  
Keyword(s):  
Activation Energy ◽  
Epithelial Cells ◽  
Water Flow ◽  
Water Permeability ◽  
Apical Membrane ◽  
Basolateral Membrane ◽  
Water Flux ◽  
Rectal Gland ◽  
Basolateral Membranes ◽  
Urea Permeability

Elasmobranchs such as the dogfish shark Squalus acanthius achieve osmotic homeostasis by maintaining urea concentrations in the 300- to 400-mM range, thus offsetting to some degree ambient marine osmolalities of 900–1,000 mosmol/kgH2O. These creatures also maintain salt balance without losing urea by secreting a NaCl-rich (500 mM) and urea-poor (18 mM) fluid from the rectal gland that is isotonic with the plasma. The composition of the rectal gland fluid suggests that its epithelial cells are permeable to water and not to urea. Because previous work showed that lipid bilayers that permit water flux do not block flux of urea, we reasoned that the plasma membranes of rectal gland epithelial cells must either have aquaporin water channels or must have some selective barrier to urea flux. We therefore isolated apical and basolateral membranes from shark rectal glands and determined their permeabilities to water and urea. Apical membrane fractions were markedly enriched for Na-K-2Cl cotransporter, whereas basolateral membrane fractions were enriched for Na-K-ATPase. Basolateral membrane osmotic water permeability (Pf) averaged 4.3 ± 1.3 × 10−3 cm/s, whereas urea permeability averaged 4.2 ± 0.8 × 10−7 cm/s. The activation energy for water flow averaged 16.4 kcal/mol. Apical membrane Pf averaged 7.5 ± 1.6 × 10−4 cm/s, and urea permeability averaged 2.2 ± 0.4 × 10−7 cm/s, with an average activation energy for water flow of 18.6 kcal/mol. The relatively low water permeabilities and high activation energies argue strongly against water flux via aquaporins. Comparison of membrane water and urea permeabilities with those of artificial liposomes and other isolated biological membranes indicates that the basolateral membrane urea permeability is fivefold lower than would be anticipated for its water permeability. These results indicate that the rectal gland maintains a selective barrier to urea in its basolateral membranes.

Influence of Sediment Disturbance and Water Flow on the Growth of the Soft-Shell Clam,Mya arenariaL.

1990 ◽  
Vol 47 (9) ◽  
pp. 1655-1663 ◽  
Author(s):  
Craig W. Emerson
Keyword(s):  
Water Flow ◽  
Growth Rates ◽  
Free Stream ◽  
Maximum Growth ◽  
Coastal Development ◽  
Low Flow ◽  
Stream Velocity ◽  
Soft Shell Clam ◽  
Sediment Disturbance ◽  
Soft Shell

The importance of sediment disturbance and water flow to the production of the soft-shell clam, Mya arenaria, was assessed in laboratory flumes by measuring growth rates of clams exposed to a gradation of bed shear stress, free-stream velocity, and frequency and depth of sediment disturbance over a 10-m period. In the absence of sediment disturbance, growth of soft-tissue was directly proportional to both free-stream (U) and shear (U*) velocity (r2 = 0.64 and 0.72, respectively). It was suggested that increased organic seston flux linked higher water flow to higher growth. In all treatments, maximum growth rates were observed with daily disturbance of the top centimeter of sediment. No level of disturbance resulted in growth rates lower than those of undisturbed clams in low flow (U = 0.4 cm∙s−1, U* = 0.1 cm∙s−1). The stimulation of growth under maximum sediment disturbance was removed when U exceeded ~3 cm∙s−1(U* = 0.7 cm∙s−1). An energy budget for M. arenaria indicated that the amount of organic material suspended during sediment disturbance was insufficient to account for the increased growth in clams subjected to high levels of disturbance. It was suggested that the sediment disturbance associated with intense clam harvesting, and changes in local hydrography resulting from coastal development, may be responsible for some of the unexplained growth variation in commercial clam stocks.

SPATIAL DISTRIBUTION OF MINIMUM RIVER RUNOFF IN THE PRUT AND SIRET BASINS (WITHIN UKRAINE)

2020 ◽  
pp. 80-91
Author(s):  
K.S. Surai ◽  
O.G Obodovskyi ◽  
O.O. Pochaevets
Keyword(s):  
Water Flow ◽  
Close Correlation ◽  
River Basins ◽  
Low Flow ◽  
Winter Period ◽  
Water Runoff ◽  
Similar Distribution ◽  
Drought Assessment ◽  
Approximation Coefficients ◽  
Two Parameters

This article gives an estimation of minimum river water flow of the Prut River and the Siret River basins. There are two special periods of low flow between floods. The first one runs from August to November (summer-autumn period) and the second one runs from December to February (winter period). These periods were separated because of different genetics of runoff formation. It was found that 7 days is an optimal period with a stable minimum water flow. Physical and geographical features of the river basin, comparative flow and precipitation graph, scientific works of American scientists became the confirmation for giving preference to 7-days period. All series of observations are homogeneous according to the calculations in the program StokStat. In general, all samples are homogeneous for at least one criterion with 1% level of significance and can be used for further research. The samples of the average 7-day minimum water runoff from the beginning of observations until 2018 became the basis for the construction of maps of the distribution of the minimum water runoff across the study area. The result of this work represents two current maps of the distribution of runoff modules (l*s / km2) of the summer-autumn and winter low water periods. There was conducted the research of the connection between the actual values and the values taken from the maps. The connection between calculated and cartographed minimum modules of water flow showed a close correlation, the approximation coefficients are R2 = 0.9731 and 0.986 for two maps. In this case, the connection line is at an angle close to 45°. We can see a decrease of minimum water flow modules in the direction from west to northeast and a parallel decrease in the density of the distribution of isolines. The altitude has a similar distribution in this area, so there was evaluated a correlation between these two parameters. It is close, the approximation coefficients are R2= 0.5618 and 0.6661 for winter and summer-autumn periods. Consequently, the constructed maps are reliable and can be used in the future to determine the value of minimum flow modules from other parts of the basins for practical and scientific purposes. In particular, this concerns the estimation of the minimum runoff of the river basins, for solving various water management tasks: planning water supply and water intake works, designing and constructing hydrotechnical structures, performing reclamation works, drought assessment.

Novel water flow facility in france range extension to low flow rates (10 000 ml/h down to 1 ml/h)

MAPAN ◽  
2011 ◽  
Vol 26 (3) ◽  
pp. 203-209
Author(s):  
Christopher David ◽  
Pierre Claudel
Keyword(s):  
Water Flow ◽  
Range Extension ◽  
Low Flow ◽  
Flow Rates

scholarly journals CRACK HEALING UTILISING BACTERIAL SPORES IN CONCRETE

2017 ◽  
Vol 12 (3) ◽  
pp. 103-114
Author(s):  
Alan Richardson ◽  
Leon Amess ◽  
Simon Neville ◽  
Christopher Walton
Keyword(s):  
Water Flow ◽  
Bacterial Spores ◽  
Life Cycle Costs ◽  
Repair System ◽  
Self Healing ◽  
Flow Test ◽  
Reproduction Process ◽  
Healing Agent ◽  
Scale Test ◽  
Reduced Water

This self repair system is based upon harmless ground borne bacteria as the self-healing agent. The bacteria are activated after the concrete is cracked and the bacterial spores are exposed to moisture and air. The bacterial reproduction process creates a calcite by-product which fills the cracks in the concrete. By sealing the cracks in concrete, an effective barrier to air or liquid borne deleterious materials are formed and as a consequence of this, enhanced durability is achieved in the structure, resulting in lower life cycle costs. The concrete/mortar prisms were cracked and tested for water flow. They were then left for 56 days to heal and were subject to a test for water tightness. Healing was observed and a reduced water flow (74% and 32% healed) measured with the healed samples when compared to the specimens that were cracked and subjected to a water flow test without any healing agent. The number of samples were limited and a larger scale test is recommended for further work; however, this is a proof of concept of the process of healing and testing.

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