高压细水雾灭火系统在档案库的灭火试验研究

细水雾灭火系统已被建议用于保护对水敏感的区域,如档案库房。通过试验研究了细水雾灭火系统控制与扑灭档案库房火灾的可能性,并比较不同喷头形式的细水雾灭火系统在扑救档案库房火灾中的局限性,为细水雾灭火系统在档案库房内的推广应用提供建议。     

广德文化中心消防系统探讨

广德文化中心是一大型综合体建筑,平面功能较为复杂,火灾危险性较大,而且工程中设计的消防系统较多。文章详细介绍了室外消火栓消防系统、室内消火栓消防系统、自动喷水灭火系统、水幕系统、雨淋系统、大空间智能型主动喷水灭火系统及高压细水雾灭火系统的设计参数及系统形式。同时对设计中遇到的问题进行探讨。     

Findings of the International Road Tunnel Fire Detection Research Project

Fire detection systems are essential fire protection elements for road tunnels to detect fires, activate safety systems and direct evacuation and firefighting. However, information on the performance of these systems is limited and guidelines for application of tunnel fire detection systems are not fully developed. The National Research Council of Canada and the Fire Protection Research Foundation, with support of government organizations, industries and private sector organizations, have completed a research project to investigate current fire detection technologies for road tunnel protection. The project included studies on the detection performance of current fire detection technologies with both laboratory and field fire tests combined with computer modelling studies. This paper provides an overview of the findings of the project. Fire detectors, fire scenarios and test protocols used in the test program are described. A summary of the research results of the series of full-scale fire tests conducted in a laboratory tunnel facility and in an operating road tunnel as well as of the computer modelling activities will be reported.     

北京语言大学综合楼消防给水系统设计探讨

北京语言大学综合楼消防给水系统包括消火栓系统、自动喷水灭火系统、水幕系统、雨淋系统和大空间智能型主动喷水灭火系统。结合项目的特点,阐述了消防给水系统的确定和设计参数的选择,并就某些消防给水系统的设计进行了技术性探讨。     

沉井式地下立体智能停车库消防设计

以某沉井式地下立体停车库项目消防设计为例,通过对常用的泡沫-自动喷水灭火系统、高倍数泡沫灭火系统、CO2灭火系统和细水雾灭火系统进行比较与分析,选择合适的自动灭火系统。结合沉井式地下立体智能停车库自动灭火系统的特点,选择高压细水雾灭火系统更为经济合理。     

Testing Water Mist Systems Against Large Fires in Tunnels: Integrating Test Data with CFD Simulations

The high cost of conducting large, full-scale fire tests for the evaluation of suppression systems in tunnels tends to limit both the extent of the instrumentation provided and the number of tests that are conducted. Because of the variability of the large fires, performance criteria based on single point measurements derived from experience with smaller test fires were not reliable indicators of performance. Yet decisions about the acceptability of suppression systems must be based on the limited amount of performance information available. A means was sought to reduce the reliance on single point instrumentation readings, and to augment the value of the limited amount of test data by integrating the field testing with CFD modeling. In this study a computational fluid dynamic (CFD) model was used to simulate a series of full-scale fire tests of water mist systems conducted in 2006 in a highway test tunnel. The NIST Fire Dynamics Simulator version 4 (FDS4) was used to simulate five of the tunnel fire tests. The task was to confirm that the simulations could achieve a reasonable degree of agreement with the conditions measured in the tests. The model could then be used to evaluate the performance of the water mist system over a broader range of performance indicators than were measured. This paper illustrates what is unique about very large fire tests and presents highlights of the modeling. The level of agreement between simulation and test results is demonstrated for one test. Agreement was deemed to be good enough to establish confidence in applying the model to examine the conditions that would occur with an unsuppressed fire, which had not been tested. CFD modeling can be used to improve the understanding of the performance of the suppression system, and to augment the value of the test results. A second, complementary paper has been submitted to the SFPE Journal of Fire Protection Engineering to provide more detailed information about the FDS4 modeling than can be covered in this paper.     

自动喷水灭火系统在隧道中的应用与发展趋势

随着隧道火灾的频繁发生,关于隧道中能否采用自动喷水灭火系统的问题成为该领域的研究热点.介绍了自动喷水灭火系统在国内外隧道中的应用现状,总结了隧道中采用自动喷水灭火系统的优缺点及存在的争议.根据国外对隧道中自动喷水灭火系统进行的试验评估,指出该系统可以降低隧道温度并能防止火势蔓延,具有良好的应用前景.     

Heat Release Rate of Heavy Goods Vehicle Fire in Tunnels with Fixed Water Based Fire-Fighting System

A series of large-scale fire tests for road tunnel application was conducted in a test tunnel facility in Spain. The aim of this fire tests program was to investigate the magnitude of the heat release rate generated by a fire in heavy goods vehicles (HGV’s) with and without a fire suppression system in tunnels in Singapore; the possibility of interchanging a fire suppression system with other measures such as lowering the longitudinal flow velocity; and to acquire information on the appropriate design parameters (e.g., nozzle type, discharge density and activation time) to adopt based on the most probable fuel load used in these road tunnels. In order to ensure repeatability, simulated HGV’s consisting of 228 pallets with 48 plastic pallets (20%) and 180 wooden pallets (80%) were used in all fire tests. An air velocity of approximately 3 m/s was applied. As the scope of work covered in this fire test program is very large, only the setup of the fire test and the findings on the effects of heat release rate with (Test 4) and without (Test 7) a fixed water based fire-fighting system are covered. The test results indicate that a substantial reduction of fire heat release rate can be obtained using a low-pressure deluge fire suppression system, as long as timely activation of the water is provided. However, the influence of the suppression system on CO production is significant. Such experimental data address the current dearth of knowledge on the actual effect of low-pressure deluge systems on the heat release rate from HGVs in tunnel fires.     

Effects of Ventilation and Water Spray in a Model-Scale Tunnel Fire

At the present time, eight new long tunnels are currently being constructed in Taiwan and plan to utilize sidewall sprinkler nozzles to conduct fire protection. To explore the effect of ventilation and water spray on tunnel fires, this research used a 1/5.5 model scale tunnel to perform experiments, while using a heptane oil pan of 0.45 m diameter as the fire source. Under five different ventilation velocities, the cooling effects of water spray on tunnel fires was discussed while controlling the water density at 2.3 mm/min. The critical velocity without water spray was 1.24 m/s, which fits empirical equations by past research. Under a ventilation velocity of 0.87 m/s, the smoke backlayering would be 2 m without water spray, while none was present with water spray. Overall quantitative analysis shows the significance of water spray in affecting backlayering, and it can be acknowledged that water spray can prevent backlayering from larger fires under the same velocity. This research used visual and temperature measurement methods to determine the location of backlayering, and it is recommended that maximum temperature gradient be used in future research as the basis for smoke backlayering location.     

Evaluation of Surfactant Enhanced Water Mist Performance

Water-mist technology provides efficient fire suppression for compartments while minimizing water usage. Even with the many advantages of water mist systems, there is still room for improvement. Water mist systems have demonstrated effectiveness at suppressing flammable liquids (Class B) fires in compartments. However, an especially challenging fire suppression scenario for water mist systems is the small Class B fire. This scenario is often realized after a large fire has been reduced in size or ‘controlled’ by water mist. The small fire scenario is challenging because a small fire may not be able to generate enough vaporized water to displace sufficient oxygen for complete extinction. It should also be noted that even if the Class B fire is extinguished with a water mist system, re-ignition from the hot surrounding surfaces may occur at any time. In the present work, an additive is introduced into the water supply and its effect on the water mist suppression performance is studied. This Forafac^TM additive is a specific formulation, which includes fluorinated surfactants for creating a robust fire suppression foam. The enhanced suppressant exiting the mist nozzle is dispersed in the form of small droplets (not as a continuous foam) similar to a pure water mist spray. However, these droplets create a foam blanket on the surface of the fire, which acts to isolate the fuel from the air. With this formulation, the efficiency of the water mist system is improved even on small fires and most importantly the re-ignition of class B fires is prevented.

Evaluation of the Fire Suppression Effectiveness of Manually Applied Compressed-Air-Foam (CAF) System

Mobile compressed-air-foam (CAF) systems represent a new type of fire suppression system, which is gaining popularity among fire services. Properly engineered CAF systems produce superior quality foam with high momentum. However, until now, there has not been a study to systematically evaluate the fire suppression effectiveness of mobile CAF systems. NRC has carried out a project to evaluate the effectiveness of a mobile CAF system in suppressing fully developed compartment fires. Several full-scale compartment fire tests were conducted to compare the fire suppression performance of a manually applied CAF system with that of hose stream application using water alone and using water-foam solution, under similar conditions. The study showed that a CAF system is much more effective in suppressing the compartment fire compared to hose stream application with water only or with foam-water solution. A CAF system with a 95 L/min (25 GPM) water flow rate suppressed the test fire better than the hose-stream application with water only or with foam-solution using 360 L/min (95 GPM). The CAF system suppressed the fire and cooled down the fire compartment (to 200°C) much quicker than the water alone or foam-solution. Also, the total amount of water used to control the test fire was much less with the CAF system than with the water alone or foam-solution.     

Fire tests to evaluate CPVC pipe sprinkler systems without fire resistance barriers

Nine full-scale fire tests were conducted to assess the adequacy of exposed chlorinated poly vinyl chloride (CPVC) pipe and fitting sprinkler systems installed in light hazard occupancies. The tests were conducted in an enclosure using six different types of automatic sprinklers including QREC pendent and sidewall sprinklers, a pendent residential sprinkler, and a sidewall residential sprinkler. Two types of fires, fast growing and slow growing, were used as test fires.The sprinkler in each test was operated with the normal operation pressure until the test fire was almost completely suppressed. Next, to assess the integrity of piping systems after fire exposure, the water pressure was increased to 12.1 bar and maintained for 10 min and then were visually inspected for any leakage while hydrostatic pressure was maintained at 12.1 bar. No leakage was detected in any of the tests.The results of the tests indicate that sprinkler systems based on exposed CPVC pipe and fittings can be safely installed in light hazard occupancies and will provide adequate protection when installed to all the relevant standards.     

Experimental and numerical study of high-pressure water-mist nozzle sprays

The performance of extinguishment of fires by water sprays is strongly influenced by the characteristics of the sprays produced by nozzles. Computational fluid dynamics (CFD) based fire models are a tool that can be used for the characterization of sprays. However, it is necessary to evaluate the capability of a CFD based fire model in predicting the behaviour of sprays before using it for such characterization. One of the basic parameters that is important in characterising the water mist spray is the distribution of flux density of water droplets impinging on the floor. This paper reports the study on the characterization of water mists, in terms of distribution of flux density of sprays, produced by a single and a multi-orifice high-pressure jet nozzle. Full-scale experiments were conducted and the distributions of volume flux density of sprays were measured. The sprays were also modelled using a CFD model, Fire Dynamic Simulator (FDS), version 6, to investigate the capability of the model in predicting the distribution behaviour of the spray. The numerical results of distribution are compared with those obtained experimentally. The predicted results of FDS has show good agreement with the experimental results.     

Sensitivity calculations of tunnel fires using CFD

Detailed numerical simulations of fires in road tunnels were carried out using the CFD code JASMINE. Fire tests performed in the Ofenegg tunnel have also been validated. A parametric study of fires in an arbitrary 300-m-long tunnel was made, in which the influence of fire size, tunnel width, ventilation and ground slope was investigated. The movement of hazardous temperature and smoke regions as a function of time was calculated to vestigate escape possibilities from the tunnel in case of fire.     

The international FORUM of fire research directors: A position paper on future actions for improving road tunnel fire safety

Fire safety in tunnels has come in focus owing to numerous catastrophic fires and extensive monitoring in media. Casualties can be counted in hundreds and the economic damages have been enormous not only for tunnel owners but also for users and bordering communities. The recent increase in serious road tunnel fires is closely associated with the increase in the traffic volume as well as in the large number of tunnels being built in recent years. In particular, volumes transported on heavy goods vehicles have increased by 40–80% over a decade in many European countries. Today, about 75% of all goods traffic is by road, and is expected to increase by 40–60% over the next 10 years [Thamm B. The new EU directive on road tunnel safety. In: Proceedings of the international symposium on catastrophic tunnel fires (CTF), SP Swedish National Testing and Research Institute, SP Report 2004:05. p. 19–30].This FORUM position paper discusses some aspects on how to improve the design of road tunnels in order to obtain a higher level of fire safety. It discusses briefly design principles of tunnels as well as of fire safety of vehicles, use of forced ventilation systems and of active fire suppression.     

一种新型雨淋系统应用技术的探讨

对大空间智能主动喷水灭火系统技术和传统自动喷水灭火系统应用现状进行分析.结合雨淋系统应用特点和自动寻的技术的发展,提出利用寻的技术提升工程性价比的新型雨淋系统应用技术方案.标准的新型雨淋系统由中心计算机处理控制,联动报警控制器和水泵控制系统实现定位打开雨淋喷头;雨淋系统与自动寻的灭火系统混合系统增加了射流喷水的选择.     

Model scale tunnel fire tests with automatic sprinkler

The study focuses on the performance of an automatic sprinkler system in a model scale tunnel with longitudinal ventilation. A total of 28 tests were carried out in a 1:15 model scale tunnel using an automatic sprinkler system with glass bulbs. The maximum heat release rate, energy content and failure of the automatic sprinkler system were analysed. The results show that high ventilation rates and low water flow rates result in a failure of the automatic sprinkler system in a longitudinal ventilated tunnel fire. The main reason for the failure under the tested water flow rates was the effect of the longitudinal flow on the fire development and the hot gas flow close to the sprinklers. The fire development and the activation heat release rate of the first activated bulb are intimately related to the ventilation velocity. The fire spread to the neighbouring wood crib was investigated and a presentation of tests conducted using a deluge system are given.     

Fire fighting in tunnels

In this article the author is to ascertain that it is difficult to fight a big fire such as the fires in the Euro tunnel, Mont Blanc tunnel and the Tauern tunnel. The measures implemented in tunnels are all measures to retain the tunnel structure. There are no measures (or at least not enough) taken for the purpose of extinguishing the fire as soon as possible. By dividing the tunnel into compartments and providing each compartment with sluice gates, the fire can be isolated and by lack of oxygen, the fire will not stir up or even extinguish itself. If the fire does not stir up, it will be easier for the Fire Brigade to get near and fight the fire.