Academic literature on the topic 'Fire sprinklers Fire sprinklers'

Sprinklers are automatically activated fixed installation suppression devices. They have found extensive applications due to minimum protection they provide for a wide range of applications including residential and warehouses. Modelling sprinkler atomization is a challenging task, due to the stochastic nature in impingement of water jets and the added complexity of sprinkler configuration. In the literature, a spray initiation framework has been developed to address the multidimensional stochastic complexity associated with fire sprinklers. The initial sprinkler spray is completely characterized in terms of the following main parameters: droplet spatial location (radius, elevation angle and azimuthal angle), droplet velocity, droplet diameter and the spatial volume flux. The present thesis aims to improve the prediction of the initial sprinkler spray characteristics through exploring different physics based modelling approaches. The sub-models for film flow and sheet trajectory adopted in the development of the fire sprinkler spray models are reviewed. Three new deterministic approaches for sprinkler atomization have been proposed by employing an existing film submodel and a detailed water sheet trajectory sub-model which has never been used for fire sprinkler applications. The developed methods simulate the orthogonal impingement of water jet to a deflecting disk, with the potential to be adapted for tilted deflectors. A comparative analysis is carried out between the three introduced methods and a reference model in terms of their predictions for droplet median diameter and initial droplet location for a range of ambient temperatures and water injection pressures. The developed methodologies have been further expanded by incorporating random behaviour to the spray formation procedure. The stochastically predicted mean velocity and volume median diameter have been compared against robust experimental data and empirical correlations. The improvements obtained by the developed methodologies are promising. In further steps, a dimensionless formulation for predicting spray characteristics, sheet breakup distance and droplet sizes, in impinging atomizers have been developed. The developed formulation is validated for impingements led the spray to occur in the rim breakup mode. Building on the proposed methodologies, a semi empirical model has been developed capable of predicting the near field spray characteristics such as spatial distribution of droplet sizes, velocities and spray volume flux from local volume fraction measurements. The research outcome would benefit the computation fluid dynamic packages to initialize the spray in a more realistic manner. The study undertaken would lead to more efficient fire suppression and/or water and fire interaction studies. In addition to this, the methodology could reduce the cost of experiments in order to quantify new sprinkler sprays.

This thesis demonstrates how the response of fire detection and automatic sprinkler systems can be designed or analyzed. The intended audience is engineers involved in the design and analysis of fire detection and suppression systems. The material presented may also be of interest to engineers and researchers involved in related fields. National Bureau of Standards furniture calorimeter test data is compared to heat release rates predicted by a power-law fire growth model. A model for calculating fire gas temperatures and velocities along a ceiling, resulting from power-law fires is reviewed. Numerical and analytical solutions to the model are outlined and discussed. Computer programs are included to design and analyze the response of detectors and sprinklers. A program is also included to generate tables which can be used for design and analysis, in lieu of a computer. Examples show how fire protection engineers can use the techniques presented. The examples show how systems can be designed to meet specific goals. They also show how to analyze a system to determine if its response meets established goals. The examples demonstrate how detector response is sensitive to the detector's environment and physical characteristics.

The purpose of this research is to identify how uncertainty in fire safety system effectiveness should be considered in a new risk-informed design fire tool, B-RISK. Specific objectives were to collect the available data on fire safety system effectiveness from the literature, investigate methods to improve fire safety system effectiveness data collection, develop the risk-informed design fire tool to propagate the uncertainties, and recommend methods to rank the sources of uncertainty for fire safety system effectiveness for appropriate model selection. The scope of the research is limited to the effects of systems on fire development and smoke spread and does not include the effects of the fire on systems (such as loss of structural integrity) or interactions with occupants. Sprinkler effectiveness data from recent New Zealand Fire Service data is included with a discussion of the uncertainty in this type of data and recommendations for improving data collection. The ability of the model to predict multiple sprinkler activations is developed in conjunction with a hydraulic submodel in B-RISK to include water supply pressure effects on sprinkler effectiveness. A new method of collecting reliability data on passive fire protection elements such as doors was developed. Data collected on the probability for doors in shared means of escape to be open and the time doors are open during occupant evacuation using this method is presented. Available data on smoke management system effectiveness is listed, along with a discussion of why there is more uncertainty associated with these systems compared with sprinkler systems. The capabilities of B-RISK for considering fire safety system effectiveness are demonstrated using Australasian case studies.

1994 ändrades den svenska lagstiftningen så att trä blev tillåtet i byggnader över tvåvåningar. Det finns vissa funktionskrav som ska uppfyllas för brandsäkerhet. Dettaarbete innehåller intervjuer med aktörer från byggbranschen som berör deras ochandra aktörers kunskapsnivå i ämnet. Möjligheter att bygga högt med träfasadpresenteras. Studien visar att flera möjligheter för att använda träfasader i höga husges i Boverkets byggregler. Olika aktörerna i byggbranschen uppfattar att de självahar goda kunskaper men att kunskapsbrister i branschen gällande brandskyddskravfinns.<br>The Swedish legislation of building code was changed in 1994, allowingconstruction of wooden buildings over two floors. To do so there are certainfunctional requirements that must be fulfilled to obtain fire safety. This studydetermines the level of knowledge of different contractors in the constructionindustry in the subject through interviews. The possibilities of using wooden facadesin high-rise building are also presented. The study shows that several possibilities touse wooden facades i high rise buildings are possible according to the legislation.Contractors in the industry consider their knowledge to be sufficient but believesthere is a general lack of knowledge in the industry regarding fire safetyrequirements.