FIXED FIRE FIGHTING AND EMERGENCY VENTILATION SYSTEMS FOR HIGHWAY TUNNELS – LITERATURE SURVEY AND SYNTHESIS FHWA-HIF-20-016 FFFS-EVS for Highway Tunnels – Literature Survey and Synthesis January 2020 Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. FHWA-HIF-20-016 TBA TBA 4. Title and Subtitle 5. Report Date Fixed Fire Fighting and Emergency Ventilation Systems January 2020 Literature Survey and Synthesis 6. Performing Organization Code TBA 7. Principal Investigator(s): 8. Performing Organization Bill Bergeson (FHWA), Matt Bilson (WSP), Bill Connell (WSP), Bobby Report Melvin (WSP), Katie McQuade-Jones (WSP) TBA 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) WSP USA, Inc. TBA One Penn Plaza th 250 West 34 Street 11. Contract or Grant No. New York, NY, 10119 DTFH6114D00048 12. Sponsoring Agency Name and Address 13. Type of Report and Period Federal Highway Administration Covered U.S. Department of Transportation TBA 1200 New Jersey Avenue, SE 14. Sponsoring Agency Code Washington, DC 20590 TBA 15. Supplementary Notes 16. Abstract There is a lot of global experience with fixed fire fighting systems in road tunnels, particularly in Australia and Japan, but also in several recently constructed tunnels in the United States and Europe. The U.S. first implemented FFFS in their tunnels in the 1950s, however, this approach did not become routine, partly due to unsuccessful tests of FFFS in the Offneg Tunnel in Europe. Because FFFS were not routinely applied in all tunnels, the present-day approach can vary between planned facilities and regions, especially in critical design areas such as operational integration with the emergency ventilation system (EVS). Recent testing, fire incidents, and modeling efforts have demonstrated that FFFS lessen the fire hazard by cooling combustion products and (in certain circumstances) suppressing the fire (reducing the fire heat release rate [FHRR]). Further research and a design-focused approach to computational modeling and testing is needed to develop a set of suggested practices on the integration of FFFS and the EVS. The end goal of the research is to facilitate design of the FFFS and EVS in an integrated manner. 17. Key Wor ds 18. Distribution Statement Fixed fire fighting system, FFFS, deluge, tunnel, tunnel ventilation No restrictions. 19. Security Classif. (of 20. Security Classif. (of 21. No. of Pages 22. Price this report) this page) TBA UNCLASSIFIED UNCLASSIFIED Form DOT F 1700.7(8-72) Reproduction of completed page authorized i FFFS-EVS for Highway Tunnels – Literature Survey and Synthesis January 2020 Notice This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document. They are included for informational purposes only and are not intended to reflect a preference, approval, or endorsement of any one product or entity. Quality Assurance Statement The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement. ii FFFS-EVS for Highway Tunnels – Literature Survey and Synthesis January 2020 ACRONYMS Abbreviation Detail AASHTO American Association of State Highway Transportation Officials AFFF Aqueous Film Forming Foam AHJ Authority Having Jurisdiction AID Automatic Incident Detection ASHRAE American Society of Heating Refrigeration and Air-conditioning Engineers CCTV Closed-Circuit Television CFD Computational Fluid Dynamics CO Carbon Monoxide EVS Emergency Ventilation System FFFS Fixed Fire Fighting Systems FHRR Fire Heat Release Rate FHWA Federal Highway Administration FLS Fire-Life Safety FPLS Fire Protection and Life-Safety LHD Linear Heat Detector MTFVTP Memorial Tunnel Fire Ventilation Test Program NBFU National Bureau of Fire Underwriters NFPA National Fire Protection Association NCHRP National Cooperative Highway Research Program PIARC World Road Association, Permanent International Association of Road Congresses SCADA Supervisory Control and Data Acquisition SFPE Society of Fire Protection Engineers TOMIE Tunnel Operation Maintenance Inspection and Evaluation U.S. United States VMS Variable Message Sign iii FFFS-EVS for Highway Tunnels – Literature Survey and Synthesis January 2020 SUMMARY The main goal of this research is to facilitate the design of the fixed fire fighting systems (FFFS) and emergency ventilation system (EVS) in an integrated manner. The introduction identified 16 questions to help focus the review and synthesis, and the responses to those questions are summarized as follows: 1. What types of tunnels are constructed and how? The four main tunnel types are circular, rectangular, horseshoe, and oval. They are constructed by boring, blasting, excavating, or by sinking a precast tube. 2. What are the principal functional systems? The principal functional systems include EVS, FFFS, closed circuit television (CCTV), public address and communications, signage, lighting, standpipe, supervisory control and data acquisition (SCADA), public address (PA), power, and drainage. 3. What are the U.S. fire-life safety (FLS) approaches for highway tunnels? The primary FLS approach for highway tunnels is compliance with National Fire Protection Association (NFPA) Standard 502 via an engineering analysis showing the FLS goals are met. For longer tunnels, this usually includes an EVS at a minimum. 4. Where do FFFS fit into the overall FLS picture for a U.S. highway tunnel? For tunnels complying with NFPA 502, FFFS should be considered as part of the overall FLS design. Historically, FFFS have had limited use in United States (U.S.) tunnels, but they are becoming more common in line with international practices. 5. How does the tunnel construction affect the fire protection life safety (FPLS) system? The tunnel construction will greatly affect the FPLS systems and their installation. For example, a transverse ventilation system cannot be used unless separate air ducts are part of the tunnel construction. FFFS and other systems are less affected by construction type. However, routing of pipework and other elements requires sufficient clearance above the roadway, space for ancillary equipment must be considered, along with supporting infrastructure to supply/remove water from the FFFS. 6. What are the design FHRRs recommended? NFPA 502 states that a representative FHRR for an HGV is 150 MW, and a flammable liquid tanker is 300 MW. These values should be used only as a starting point in determining the design FHRR for a given tunnel. The final determination of the design fire should be made after considering all relevant factors on a case-by-case basis for each tunnel (e.g. tunnel geometry, traffic makeup, facility risk, etc.). 7. What is the impact of FFFS on FHRR? The expected impact of FFFS varies with system type, application rate, droplet size, and nozzle type. However, various small and full-scale tests indicate that a reduction in peak fire heat release rate (FHRR) of 50 to 70% is likely (assuming prompt activation of the system and a water application rate of 0.15 to 0.20 gpm/ft2, or 6 to 8 mm/min) [1] [2] [3] [4]. Information on nozzle type and impacts on the FHRR could be better documented and this is an area where further research would be beneficial. Laboratory scale testing has shown that FFFS only reduces the FHRR for liquid fuel spills if an aqueous film forming foam (AFFF) is added [5]. iv FFFS-EVS for Highway Tunnels – Literature Survey and Synthesis January 2020 8. How do different types of FFFS and their activation and application rates affect the fire? Droplet diameter varies between deluge and mist systems. Mist systems tend to provide greater temperature reduction, but deluge systems have a greater ability of reaching and cooling the burning surface. Water mist droplets are unable to penetrate the fire plume and reach the seat of the fire. For shielded fires water spray cannot reach the seat of the fire and thus performance is similar between deluge and mist. Delayed activation of FFFS limits the reduction in peak FHRR achieved [6]. Typically, a higher water application rate results in a slightly lower peak FHRR [2] [3]. However, for deluge system water application rates of 0.15 gpm/ft2 (6 mm/min) and greater, the difference in peak FHRR (e.g. between 0.15 gpm/ft2 and 0.20 gpm/ft2) is small and unlikely to be of significance for integrated FFFS-EVS designs. 9. What is the role of laboratory scale testing and full-scale testing? Combustion modeling remains a heavily researched topic, and the full physics of combustion are not completely understood. Generating experimental data in full and small- scale tests allows theories to be tested, computational fluid dynamics (CFD) models to be calibrated, and other practical insights to be gained about how fires burn in tunnels. 10. What is the role of computational fluid dynamics (CFD) modeling? CFD models are a relatively quick and cost effective means of investigating a particular fire scenario in a tunnel where the FHRR is specified a priori. CFD can be reliably used to predict gas phase cooling. However, for FHRR or fire spread prediction, in order to draw any useful conclusions from a model, it must be calibrated against experimental data. CFD also has a limited ability to model certain aspects of FFFS in tunnels (e.g. FFFS interruption of the combustion/pyrolysis process). 11. How do water application rate and other design parameters link to NFPA 502 goals? As per Table 4-4, the water application rates (with deluge systems) of 0.30 gpm/ft2 to 0.15 gpm/ft2 (12 mm/min to 6 mm/min) could achieve fire control.