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Heptafluoropropane with water spray cooling system as a total flooding Halon 1301 replacement: System implementation parameters

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... After fire extinguishment, the C E value was measured as 76 ppm. Considering that the allowable level of HF concentration in the occupied room for re-entry by equipped response personnel is assumed as 90 ppm [21], the HF concentration in test C and D were both acceptable.Fig. 5 compared the mass of HF produced per unit mass of suppressant of BTP during the discharging process (R S ) and 5 min after stopping discharging (R E ). ...
Conference Paper
Application of 2-bromo-3,3,3-trifluoropropene (BTP) with water mist in suppressing deep seated wood crib fires was reported in this paper. Performance of the combination of the two clean fire suppressants was examined by laboratory scale experiments and compared with water mist and BTP used alone. Results showed that coupling of water mist with BTP could extinguish the wood crib fires with high efficiency, in which BTP discharged first could fast extinguish the flame, and the following water mist could cool the wood surface and stop glowing combustion. As a result, a complete fire extinguishment without re-strike was achieved in short time. Furthermore, hydrogen fluoride (HF) acid gas produced in the suppression process was acceptable for the use of water mist in conjunction with BTP.
... While a fire main may be at a nominal pressure of 0.88 MPa (125 psi), it may be operating at some pressure reduction, especially during a casualty situation. We evaluated WSCS effectiveness at reduced pressures and found that operation was effective down to a tested pressure of 0.32 MPa (45 psi), if nozzle spacing were reduced [17]. For ships machinery spaces (engine rooms) with propulsion fuel (and hydraulic and lubricating fluids), an HFC-227ea design concentration of 10.2 per cent should suffice. ...
Article
The Naval Research Laboratory (NRL, Code 6180) has successfully conducted extensive investigations for replacing shipboard Halon 1301 total flooding systems under the sponsorship of, and via interactions with, the Naval Sea System Command (NAVSEA, Code 05P9). The program has resulted in identifying agents of choice, with system design guidance. Several system types (HFC-227ea, HFC-227ea with Water Spray Cooling System, and fine water mist) are currently being implemented aboard the CVN 76 Class Aircraft Carrier and the LPD 17 Class Landing ship. Initial acceptance testing has also been conducted. This paper includes a summary of the path and reasoning used to achieve halon replacement, and a discussion on ship systems/doctrinal implementation issues, including the desire to further implement water mist as a fire suppressant modality.
Article
As the complexity and the cost of infrastructures have risen, the need for a fast, reliable, cost-effective and clean fire extinguishing system has become important. Water mist is a clean and effective technology to deal with most types of fires. Over the years, chemicals have been added to the water to improve the performance of the mist and deal with new types of fires. This review presents an exhaustive state of the art on additives for water mist technology over the last fifty years. Eleven publishers were reviewed to form the corpus of almost one hundred articles. A systematic review of the articles highlighted that alkali metal compounds have been the main focus of research. Metal-based compounds have also proved to be effective. Surfactants remain an additive of choice in the formulation of fire-fighting foams and as additives for water mist but hydrocarbon surfactants should be preferred to fluor-based ones for environmental reasons. Solvents have proved to be a new, clean and potent class of water mist additives worthy of further investigation. Overall, the toxicology and environmental impacts of most additives have not been addressed or are often overlooked as an important criterion for a water mist additive.
Article
Clean fire suppressing agents are characterized with unique chemical and physical properties. Strictly speaking, clean fire suppressants are the agents which extinguish fires without follow-up cleaning up exercise leading to business interruption. This is very different from traditional fire suppressing agents such as water, foam, and dry powder, which often result in more secondary damage. Chemical effects play a key role in the fire suppression of clean fire suppressants. In this article, a literature review of the fundamental suppression chemistry of common clean suppressing agents is performed. There are different categories of typical clean suppressing agents with associated research activities reported in the literature. Experimental methods, involving the flame configurations and the diagnostic techniques, are discussed in detail.
Article
Both clean fire suppressing agents, water mist and degradable bromofluoropropene have their limitation in application. Water mist is environment-friendly, but has difficulties in extinguishing small liquid fuel fires in compartments with good ventilation. Clean agent 2-bromo-3,3,3-trifluoropropene (BTP) is efficient in extinguishing liquid fuel fires, but generates toxic hydrogen fluoride. Combining water mist with BTP would overcome their respective drawbacks in fire suppression. Performance of a portable BTP-water mixture in suppressing gasoline pool fires evaluated by laboratory-scale experiments will be reported in this presentation. Results demonstrated that combining water mist with BTP would extinguish fires through physical and chemical mechanisms, taking the advantage of high efficiency and low concentration of acid gas. Furthermore, residue clean problems accompanying the conventional additives of metallic salts or surfactants to water mist would not be found.
Article
A water spray mist is used to cool a compartment fire before discharge of a gaseous fire suppression. As a result, less water and less fire suppression agent is needed than required with conventional method of suppressing compartment fires. The water spray may be continued for a short time after initial discharge of the fire suppression agent, and may be restarted after the fire has been extinguished. Also, the present invention reduces the levels of toxic and corrosive gases in compartment created during the suppression of compartment fires by the use of a gaseous fire suppression agent.
Article
As part of Halon 1301 replacement research, the Navy Technology Center for Safety and Survivability at the Naval Research Laboratory (NRL) has been investigating the use of HFP (heptafluoropropane, HFC-227ea, C(3)F(7)H) as a substitute in US Navy ship compartments. HFP has been shown to readily extinguish fires in a small-sized flammable liquid storage room. In the presence of fire HFP degrades into the extremely hazardous acid gas hydrogen fluoride (HF) in quantities significantly greater than those generated from Halon 1301 extinguished fires. The presence of HF in the room's atmosphere greatly hinders recovery. To counter the HF threat, we evaluated fire suppression via HFP with the NRL- invented Water Spray Cooling System (WSCS) in a 28 m(3) (1,000 ft(3)) simulated shipboard flammable liquid storage room. The objective of this test series was to quantify the benefit of using WSCS in conjunction with an HFP system. The resulting combined fire suppression system readily suppressed a fire while greatly reducing HF concentrations and cooling the compartment. The quantified benefits of WSCS were reduced temperatures, improved reignition protection, and reduced HF levels (by 75%), all allowing for enhanced safe compartment re-entry and recovery.
Article
Real scale tests were conducted aboard me ex-USS SHADWELL with HFP with limited baseline comparison tests with Halon 1301. Two of the objectives of the full scale machinery space testing were to determine the optimum post fire suppression hold time (time prior to venting) and to evaluate the option of using a water spray cooling system (WSCS) to reduce compartment temperature and acid decomposition products and therefore expedite compartment reclamation. Results show that the WSCS system employed is a viable option for rapid reduction of compartment temperature. The low water pressure WSCS tested provided very rapid compartment temperature reduction in 15 seconds with less than 20 gallons of water.
Fire Suppression Using Heptafluoropropane in a 297 m3 Compartment
  • R S Sheinson
  • D Szwarc
  • D J Morse
  • S D Ayers
  • R L Anleitner
  • L Levenberry
Sheinson, R.S., Szwarc, D., Morse, D.J., Ayers, S.D., Anleitner, R.L., and Levenberry, L., “Fire Suppression Using Heptafluoropropane in a 297 m3 Compartment”, Naval Research Laboratory Memorandum Report (In Progress), 2004.
Fire Suppression Scaling Issues in Different Compartment Sizes
  • S Ayers
  • R S Sheinson
  • A Maranghides
  • D Morse
  • D Szwarc
Ayers, S., Sheinson, R.S., Maranghides, A., Morse, D., and Szwarc, D., “Fire Suppression Scaling Issues in Different Compartment Sizes”, Proceedings of the Halon Alternatives Technical Working Conference, Albuquerque, NM, April 30 – May 2, 2002.
Halon 1301 Replacement Total Flooding Fire Testing, Intermediate Scale
  • R S Sheinson
  • H G Eaton
  • B H Black
  • R Brown
  • H Burchell
  • A Maranghides
  • C Mitchell
  • G Salmon
  • W D Smith
Sheinson, R.S., Eaton, H.G. Black, B.H., Brown, R., Burchell, H., Maranghides, A., Mitchell, C., Salmon, G., and Smith, W.D., “Halon 1301 Replacement Total Flooding Fire Testing, Intermediate Scale,” Proceedings of the Halon Alternatives Technical Working Conference, Albuquerque, NM, May 9-11, 1995, pp. 43-53.
Chapter 7: Halon Replacement Clean Agent Total Flooding Systems The Society of Fire Protection Engineers Fire Protection Handbook
  • Phillip J Dinenno
DiNenno, Phillip J., " Chapter 7: Halon Replacement Clean Agent Total Flooding Systems ", The Society of Fire Protection Engineers Fire Protection Handbook, Third Edition, Quincy, MA: National Fire Protection Association, 2002.
Evaluating a Heptafluoropropane Fire Protection System with and without a Water Spray Cooling System in Compartments up
  • R S Sheinson
  • A Maranghides
  • R L Anleitner
  • J L Montgomery
  • B D Borman
Sheinson, R.S., Maranghides, A., Anleitner, R.L., Montgomery, J.L., and Borman, B.D., " Evaluating a Heptafluoropropane Fire Protection System with and without a Water Spray Cooling System in Compartments up to 126 m 3 (4,500 ft 3 ): Halon Replacement Agent Testing, " Naval Research Laboratory Memorandum Report, 2004