Hydrogen Fluoride) Production from Halon 1301 and Alternative Gaseous Fire Suppressants a Review

Acid gas (hydrogen fluoride) production from Halon 1301 and alternative gaseous fire suppressants A Review

John A. Hiltz DRDC – Atlantic Research Centre

Defence Research and Development Canada Scientific Report DRDC-RDDC-2015-R036 March 2015

IMPORTANT INFORMATIVE STATEMENTS

This work was carried out as part of the Naval Platforms Project – 01 ea.

© Her Majesty the Queen in Right of Canada, as represented by the Minister of National Defence, 2015 © Sa Majesté la Reine (en droit du Canada), telle que représentée par le ministre de la Défense nationale, 2015

Abstract ……..

Halon 1301 (CF3Br) is used as a total flooding fire suppression gas on Royal Canadian Navy ships and submarines. Because it is an ozone depleting substance it will not be used on new build naval vessels. There are a number of non-ozone depleting gaseous agents that have been evaluated as alternatives for Halon 1301 for use in normally occupied spaces. These include FE-13 (HFC-23 or CHF3), NAF-S111 (HCFC Blend), FM-200 (HFC-227ea or CF3CHFCF3, PFC-410 or CEA 410 (C4F10), and Novec 1230 (1,1,1,2,2,4,5,5,5-nonafluoro-4-trifluoromethylpentan-3-one). A concern associated with all these gaseous agents is the release of acid gases such as hydrogen fluoride (HF) when they are exposed to high temperatures and hot surfaces. The concentrations of an acid gas such as HF will have a direct impact on the risks to firefighters during re-entry procedures.

In this report the results of research on the factors affecting the concentration of HF in a space after discharge of Halon 1301 or alternative gaseous agents are reviewed. The results indicate that Halon 1301 produces significantly less HF than the alternative agents. HF production from any of the agents is very dependent on the rate at which it is introduced into the space and its design concentration. The use of ventilation and water spray or water mist to reduce the airborne concentration of HF in a space after a fire have also been studied and the results of evaluations are also included.

Significance to defence and security

Fire suppressant gases used on both current and future Royal Canadian Navy (RCN) vessels have or may have the potential to produce hazardous thermal degradation products such as HF. An understanding of severity of the risks associated with gaseous agent and how these can be reduced can be used to reduce hazards associated with their use on RCN vessels. In particular this information can be used to modify standards procedures for, for instance, the re-entry into a space where a gaseous agent has been discharged. The research reviewed in this report indicates that both ventilation of a space and the use of water spray or water mist before, during or after discharge of the gaseous agent will reduce airborne concentrations of acid gases substantially.

DRDC-RDDC-2015-R036 i

Résumé ……..

L’halon 1301 (CF3Br) est utilisé comme gaz d’extinction d’incendie par noyage total sur les navires et les sous-marins de la Marine royale canadienne (MRC). Ce produit ne sera toutefois pas employé à ces fins sur les nouveaux navires militaires, car il constitue une substance appauvrissant la couche d’ozone. Il existe un certain nombre d’agents chimiques gazeux n’appauvrissant pas la couche d’ozone qui ont été évalués comme produits de remplacement de l’halon 1301 dans les endroits normalement occupés. Ces produits comprennent le FE-13 (HFC-23 ou CHF3), le NAF-S111 (un mélange de HCFC), le FM-200 (HFC-227ea ou CF3CHFCF3), le PFC-410 ou CEA 410 (C4F10), et le Novec 1230 (1,1,1,2,2,4,5,5,5-nonafluoro-4-trifluorométhylpentan-3-one). L’utilisation de tous ces agents chimiques gazeux suscite toutefois quelques inquiétudes, particulièrement l’émission de gaz acides comme le fluorure d’hydrogène (HF), lorsque les agents chimiques en question sont exposés à des températures élevées et des surfaces chaudes. La concentration d’un gaz acide comme le HF a une incidence directe sur les risques que courent les pompiers lorsqu’ils doivent retourner dans le foyer d’incendie.

Le présent rapport comporte un examen des résultats de travaux de recherche portant sur les facteurs qui influent sur la concentration de HF là où s’est produite une émission d’halon 1301 ou d’agents chimiques gazeux de remplacement. Les résultats indiquent que l’halon 1301 produit beaucoup moins de HF que les agents chimiques de remplacement. La production de HF par ces derniers dépend grandement de la vitesse à laquelle il pénètre dans l’endroit étudié et de sa concentration nominale. L’étude porte aussi sur l’utilisation d’appareils de ventilation et d’extincteurs à eau pulvérisée ou à brouillard d’eau pour réduire la concentration de HF en suspension dans l’air ambiant en un endroit donné, à la suite d’un incendie. Le présent rapport comporte aussi les résultats des évaluations.

Importance pour la défense et la sécurité

Les gaz d’extinction d’incendie utilisés sur les navires actuels de la Marine royale canadienne (MRC), ou qui le seront sur de futurs navires militaires, peuvent ou pourraient dégager des produits de dégradation thermique dangereux comme le HF. La compréhension de la gravité des risques associés aux agents chimiques gazeux et des mesures permettant de réduire ces risques sera d’une grande utilité, car les résultats serviront à réduire les risques relatifs à l’emploi de ces substances sur les navires militaires de la MRC. Les renseignements colligés pourront notamment être utilisés pour modifier les procédures normalisées ayant trait, par exemple, au fait de retourner dans un endroit où un agent chimique gazeux a été libéré. Les résultats de recherche examinés dans le présent rapport indiquent que la ventilation d’un endroit donné et l’utilisation d’extincteurs à eau pulvérisée ou à brouillard d’eau, et ce, avant, pendant ou après la libération de l’agent chimique gazeux, permettent, dans tous les cas, de réduire grandement la concentration de gaz acides en suspension dans l’air ambiant.

ii DRDC-RDDC-2015-R036

Table of contents

Abstract ……...... i Significance to defence and security ...... i Résumé ……...... ii Importance pour la défense et la sécurité ...... ii Table of contents ...... iii List of figures ...... iv List of tables ...... v 1 Introduction ...... 1 2 Results and discussion ...... 2 2.1 Intermediate-scale (645 ft3) fire suppression evaluation of NFPA 2001 agents [1] ...... 2 2.2 Intermediate scale Halon 1301 replacement total flooding fire testing [2] ...... 5 2.3 Large scale (840 m3) Hydrofluorocarbon (HFC) total flooding fire extinguishment testing [3] ...... 8 2.4 Halon 1301 replacement testing—Post fire suppression compartment characterization [4] ...... 10 2.5 Large scale (500 m3) evaluation of gaseous agents [6] ...... 14 2.6 Generalized data correlations for extinguishment times and acid concentrations in fire tests with fluorinated suppression agents [9] ...... 17 2.7 Thermal decomposition products of 1,1,1,2,2,4,5,5,5 nonafluoro-4-trifluoromethylpentan-3-one (Novec 1230) during small scale fire extinguishment testing [10] ...... 18 2.8 Novec 1230 / water mist fire suppression for machinery spaces and electronic cabinets [11] ...... 20 3 Conclusions and comments ...... 23 References ...... 25

DRDC-RDDC-2015-R036 iii

List of figures

Figure 1 HF concentration versus time for the gaseous agent fire suppression tests (from Reference [1])...... 4 Figure 2 Summary of best case (minimum toxic gas production) results for the extinguishment of the 0.62 ft2 fires (from Reference [1])...... 4 Figure 3 Test space for the large scale (840 m3) HFC total flooding fire extinguishment testing (from Reference [3])...... 8 Figure 4 Concentration of HF is test space as a function of hold time (from Reference [4]). The agent (CF3CHFCF3) was released at 0 seconds. . . 11 Figure 5 Time versus temperature plots for the fire suppression test using CF3CHFCF3 (from Reference [5])...... 13 Figure 6 Time versus temperature plots for the fire suppression test when the CF3CHFCF3 and water spray cooling systems were activated at the same time (from Reference [5]). The water spray cooling system was turned off after one minute...... 13 Figure 7 Time versus temperature plots for the test where the CF3CHFCF3 system was activated at 0 seconds and the water spray cooling system was activated at 300 seconds for one minute and at 900 seconds for two minutes (from Reference [5])...... 14 Figure 8 Location of the fires in the 500 m3 test space (from Reference [6]). Used with the kind permission of the USCG Research & Development Center, New London, CT...... 15 Figure 9 Plot of HF concentration against the non-dimensional heat release rate for FM-200, CEA-410, FE-13 and Halon 1301 (from Reference [9]. . . 18 Figure 10 Plot of the effect of fire size on the production of HF for fires extinguished with Novec 1230 for three discharge times. The concentration of Novec 1230 was 5.9% (v/v) (from Reference [10]). Used with the kind permission of the copyright owner Benjamin D. Ditch...... 19 Figure 11 The effect of agent concentration on HF production for Novec 1230. A nine second discharge time was used (from Reference [10]). Used with the kind permission of the copyright owner Benjamin D. Ditch. . . 19 Figure 12 Plot of HF concentration against time for Test 12, Novec 1230, no water mist (from Reference [11])...... 20 Figure 13 Plot of HF concentration against time for Test 6, water mist activated 60 seconds prior to Novec1230 discharge (from reference [11]). .... 21

iv DRDC-RDDC-2015-R036

List of tables

Table 1 Gaseous fire suppression agents evaluated. NFPA 2001 refers to National Fire Protection Association standard NFPA 2001: STANDARD ON CLEAN AGENT FIRE EXTINGUISHING SYSTEMS. At the time of the research these Halon replacement agents were approved for use as fire suppressants in occupied spaces (from Reference [1])...... 3 Table 2 United States Naval Research Laboratory (NRL) cup burner values for n-heptane (from Reference [2])...... 5 Table 3 The effect of design concentration and discharge time on HF production of FE-13 (from Reference [2])...... 6 Table 4 The effect of design concentration on extinguishment time and HF production of FM-200 (from Reference [2])...... 6 Table 5 The effect of discharge time on HF production for FE-13 (from Reference [2])...... 7 Table 6 Comparison of the fire out times and HF production of CEA 410, FE-13, FM-200 and Halon 1301 (from Reference [2])...... 7 Table 7 Specifications for the fires used in the large scale HFC extinguishment testing (from Reference [3])...... 9 Table 8 Results of Halon 1301, FM-200 and FE-13 fire extinguishment testing (from Reference [3])...... 9 3 Table 9 Results of fire suppression testing of CF3CHFCF3 in 370 m test space on ex-USS Shadwell (from Reference [4])...... 11 Table 10 Results of CF3CHFCF3 test series with and without use of the water spray cooling system (Tests No. 4.2, 4.5, 5.2, 5.3, 5.4). Results of Halon 1301 fire suppression tests without and with WSCS (tests 6.1 and 6.2) (from Reference [5])...... 12 Table 11 Fires scenarios used in the 500 m3 test space (from Reference [6]). Used with the kind permission of the USCG Research & Development Center, New London, CT...... 16 Table 12 Results of the 500 m3 machinery space fire suppression testing (from Reference [6]). Used with the kind permission of the USCG Research & Development Center, New London, CT...... 16 Table 13 Results of the Novec 1230 / water mist testing (from Reference [11]). . 22

DRDC-RDDC-2015-R036 v

This page intentionally left blank.

vi DRDC-RDDC-2015-R036

1 Introduction

This Scientific Report reviews research on the production of acid gases, primarily hydrogen fluoride (HF), from gaseous fire suppression agents. These agents, when used at effective concentrations, are capable of extinguishing fires in shipboard spaces. In addition, they are, or have been considered to be, environmentally ‘friendly’ replacements or alternatives for Halon 1301 from the perspective of ozone depleting potential (ODP). However, when exposed to heat and open flame they can produce significant concentrations of thermal degradation products including acid gases. Acid gases can pose a considerable risk to crew entering the space after a fire has been extinguished. Also, they can impact sensitive electronic gear and materials in the space if not cleaned up properly. These hazards and approaches to reducing or eliminating acid gases after a fire will have to be considered as they affect safe re-entry and subsequent clean up procedures.

DRDC-RDDC-2015-R036 1

2 Results and discussion

2.1 Intermediate-scale (645 ft3) fire suppression evaluation of NFPA 2001 agents [1]

This research was carried out at the University of New Mexico in the early 1990s. It evaluated four gaseous fire suppression agents for use in occupied spaces as Halon replacements. The agents selected, HFC-23 (CHF3), NAF-S111 (HCFC Blend), HFC-227ea (CF3CHFCF3), and FC-3-1-10 (C4F10), had cardiac sensitization thresholds above the design (effective) concentration of that agent and therefore were suitable for use in areas where persons might come in contact with them. The agents and their characteristics are shown Table 1. A number of degradation products arising from the release of the agents into a space with a fire were monitored. These included carbon monoxide (CO), carbon dioxide (CO2), carbonyl fluoride (COF2), hydrogen chloride (HCl) and hydrogen fluoride (HF).

Testing was carried out in a 18.27 m3 (645 ft3) enclosure on two diesel pool fires; one with 0.40 ft2 and the other with 1.67 ft2 of surface area. These surface areas correspond to 0.62 ft2 and 2.6 ft2 per 1000 ft3 volume. N-Heptane (0.5 inches on top of 2.0 inches of water) was used as the fuel and a one minute preburn time used prior to the closing of the vents in the space and the introduction of the fire suppressant gas.

The concentrations of HF versus time produced by HFC-23, NAF-S111, HFC-227ea, FC-3-1-10, and Halon 1301 (CF3Br) following their release into the space with the fire are plotted in Figure 1. Agent discharge times were less than seven seconds to minimize decomposition products. The amount of agent was also increased above the NFPA 2001 design requirement (cup burner plus 20%) to minimize the formation of decomposition products. The cup burner value is the percent by volume (% vol.) of the agent in air that will extinguish a flame in a cup burner apparatus.

Several observations can be made about the results. The first is that the four replacement agents produce approximately 10 times more HF than Halon 1301 for a given fire. Also the concentration of HF released during suppression of the larger fire is approximately 10 times more than that for the smaller fire for each of the fire suppressant agents.

A summary of the results for the suppressants is shown in Figure 2. All agents were effective in extinguishing the fires. However, the weight of the proposed Halon replacements required for extinguishment was more than twice that of Halon 1301. The concentrations of HF released by HFC-23 and HCFC Blend A were much greater than those for the other agents. In addition these agents were the only ones that released COF2.

The major finding of this study is that the production of decomposition products is related to agent discharge time and the time to extinguishment of a fire. These times should be kept as low as possible to minimize decomposition products. The concentration of HF produced was also dependent on the size of the fire in the space. This indicates that early detection and suppression of a fire will reduce HF production considerably when using agents that contain fluorine.

2 DRDC-RDDC-2015-R036

Table 1: Gaseous fire suppression agents evaluated. NFPA 2001 refers to National Fire Protection Association standard NFPA 2001: STANDARD ON CLEAN AGENT FIRE EXTIT NGUISHING SYSTEMS. At the time ooff the research these Halon replacement agents were approved for use as fire suppressants in occupied spaces (from Referrence [1]).

DRDC-RDDC-2015-R036 3

Figure 1: HF concentration versus time for the gaseous agent fire supuppression tests (from Reference [1]).

Figure 2: Summary of best case (minimum toxic gas production) results for the extinguishment of the 0.62 ft2 fires (from Reference [1]).

4 DRDC-RDDC-2015-R036

2.2 Intermediate scale Halon 1301 replacement total flooding fire testing [2]

This research was carried out by the Naval Research Laboratory, Washington, DC. The purpose of the testing was to study the effect of suppression agent design concentration and discharge time on time to extinguishment of the fire and concentration of decomposition products. Three replacement agents, FE-13 (HFC-23), FM-200 (HFC-227ea), and CEA-410 (C4F10), were studied and their results compared to those for Halon 1301.

Testing was conducted in a 56 m3 (4.0 m x 3.4 m x 4.3 m) room using n-heptane as the fuel. The heptane was contained in a pan with a surface area of 0.23 m2. It was ignited (under well ventilated conditions) and after 45 seconds the vents to the room were closed and the preburn continued for a further 15 seconds prior to discharge of the fire suppression agent.

The NRL cup burner (CB) values used to calculate the agent design concentration listed in Tables 3 through 5 are shown in Table 2.

Table 2: United States Naval Research Laboratory (NRL) cup burner values for n-heptane (from Reference [2]).

The effect of varying the design concentration and agent discharge time for FE-13 on the production of HF gas is shown in Table 3. The concentration of HF produced by FE-13 decreased monotonically from 34000 ppm to 3000 ppm as the agent design concentration increased from 11.5% to 20.9% for agent discharge times between 5.0 seconds and 7.5 seconds. For a design concentration of approximately 18%, the concentration of HF produced by FE-13 increased from 3400 ppm to 9700 ppm as the discharge time was increased from 5.0 seconds to 17.3 seconds. Similarly for a FE-13 design concentration of approximately 20%, the concentration of HF increased from 3000 ppm to 7500 ppm as the discharge time was increased from 5.9 seconds to 19.1 seconds.

The effect of varying the design concentration of FM-200 on the fire out time (time to extinguishment) and concentration of HF produced is shown in Table 4. Fire out times varied between 12 seconds and seven seconds. The concentration of HF decreased monotonically from 8000 ppm to 2500 ppm as the design concentration of FM-200 was increased from

DRDC-RDDC-2015-R036 5

8.0% (CB + 21%) to 9.8% (CB + 48%). HF formation was very sensitive to small variations in the design concentration of FM-200, decreasing from 8000 ppm to 5100 ppm as the design concentration was increased from 8.0% to 8.3%.

Table 3: The effect of design concentration and discharge time on HF production of FE-13 (from Reference [2]).

Table 4: The effect of design concentration on extinguishment time and HF production of FM-200 (from Reference [2]).

The results of the effect of varying discharge times on the production of HF for a FE-13 design concentration of approximately 18% (cup burner + ~51%) are shown in Table 5. As the discharge time was increased from 5.0 seconds to 17.3 seconds the HF production increased from 3400 ppm to 9700 ppm. The time to extinguishment of the fire also increased from six seconds to 19 seconds.

6 DRDC-RDDC-2015-R036

The fire out times and HF production of CEA 410, FE-13, FM-200 and Halon 1301 are shown in Table 6. For all fire suppressant gases, the design concentration was the cup burner concentration plus ~50%. The discharge times were less than six seconds and the fire out times were less than eight seconds for all of the gases. Halon 1301 produced less HF than the other gaseous agents.

Table 5: The effect of discharge time on HF production for FE-13 (from Reference [2]).

Table 6: Comparison of the fire out times and HF production of CEA 410, FE-13, FM-200 and Halon 1301 (from Reference [2]).

The results of this testing indicated that FE-13, FM-200 and CEA 410 could all suppress the design fire at 20% above their cup burner concentrations. However, at that concentration the times to extinguishment were longer and decomposition product (HF) concentrations were higher than those for higher suppressant concentrations. Shorter suppressant discharge times were found to decrease HF production significantly.

The major findings of this study are that the agent concentration and discharge times should be selected to ensure that extinguishment times and decomposition products (HF) are minimized.

DRDC-RDDC-2015-R036 7

2.3 Large scale (840 m3) Hydrofluorocarbon (HFC) total flooding fire extinguishment testing [3]

The objective of this research was to verify that Halon 1301 replacements were effective for the extinguishment of fires in ship board machinery spaces. Two hydrofluorocarbon fire suppressants, FE-13 (CHF3) and FM-200 (HFC 227ea), were evaluated and their performance compared to Halon 1301.

The testing was carried out on the ex-USS Shadwell in a space with dimensions 18 m x 9 m x 6 m (56 ft x 28 ft x 20 ft). Mockups simulating diesel engines and reduction gears, a gas turbine engine, and ventilation ducts were installed in the space to create a more realistic obstructed environment. The test space and the position of the five fires are shown in Figure 3. The fires consisted of spray and pan fires. Their specifications are shown in Table 7.

Figure 3: Test space for the large scale (840 m3) HFC total flooding fire extinguishment testing (from Reference [3]).

8 DRDC-RDDC-2015-R036

Table 7: Specifications for the fires used in the large scale HFC extinguishment testing (from Reference [3]).

The results of the testing are shown in Table 8. Halon 1301 produced less HF than either FM-200 or FE-13. All fires were extinguished in each of the tests. The effect of agent concentration and discharge time on the production of HF observed for the smaller scale tests described in Reference [2] was also observed in these large scale tests. For instance the peak concentration of HF produced by FM-200 at a design concentration of 9.2% increased from 2400 ppm to between 3800 ppm and 5200 ppm as the agent discharge time was increased from six seconds to 11 seconds.

Table 8: Results of Halon 1301, FM-200 and FE-13 fire extinguishment testing (from Reference [3]). Test Agent Design Discharge Fire Extinguishment Time (s) Peak HF No. Conc. Time (s) 1 2 3 4 5 Conc (%) (ppm) 4.1 Halon ≤5.7 11 25 9 11 * 7 600 1301 4.2 Halon 4.6 10 20 10 8 * 11 600 1301 4.3 FM-200 10.0 11 16 10 9 - 13 3800 4.4 FM-200 9.2 6 12 7 4 5 - 2400 4.5 FM-200 8.2 10 28 13 13 * 12 4500 4.6 FM-200 9.2 11 25 12 10 * 12 3800 4.7 FM-200 9.2 11 13 8 7 5 7 5200 4.8 FM-200 9.2 10 10 7 * 9 7 2500 4.9 FM-200 9.2 10 8 4 * * 8 7300 4.10 FE-13 18.0 10 9 6 * 6 4 3900 4.11 FE-13 16.0 10 12 5 11 6 5 5800 4.12 FE-13 18.0 10 8 8 5 * 5 5300 4.14 FM-200 9.2 10 12 8 * 5 9 3300 * No fire at that position for the test.

DRDC-RDDC-2015-R036 9

2.4 Halon 1301 replacement testing—Post fire suppression compartment characterization [4]

In Reference [4], the authors note that (at the time of the testing) “Little quantitative information currently exists regarding post-fire suppression compartment reentry (by the firefighting team), desmoking and venting for Halon 1301 systems”. In addition, technical guidance on reentry following fire suppression is limited to the use of Halon 1301 in machinery spaces and states that reentry should not be attempted for at least 15 minutes following a Halon 1301 release and that desmoking should not take place until the risk of reignition has been minimized by the reentry team.

The aim of this testing was to study how the replacement of Halon 1301 with a hydrofluorocarbon fire suppression agent (FM-200/HFC 227ea/CF3CHFCF3) would impact hazards associated with the reentry of a space where it had been used and how these hazards might be minimized. In particular, reentry times and the time between release of the agent and the activation of the ventilation system on HF concentrations were investigated.

Testing was carried out on ex-USS Shadwell. The test space had a free volume of 370 m3. This is the space between frames 22 and 29 in Figure 3. Fire 1 (spray and pan fire) and fires 2 and 4 (spray fires) (see Figure 3) were used in the testing. Naval distillate (F-76) was used as the fuel. Fire 1 was between 3.3 and 4.7 MW (megawatts) for fuel spray flow rates between 5.7 and 7.9 L/min. Fires 2 and 4 were 0.09 to 0.1 MW for a fuel flow rate of 0.7 to 0.8 L/min.

The fire suppression results are shown in Table 9. All fires were extinguished. Fire 4 could be reignited two minutes after the activation of the fire suppression system. The effect of hold time on the decrease in temperature at various levels in the space (4.9 m, 4.0 m, 3.0 m, 2.1 m, 1.2 m, and 0.3 m) were monitored. At all levels the temperature decreased as the hold time was increased. The change in temperature varied with level in the space. For instance at 4.9 m, the temperature decreased from 97˚C five minutes after the agent was released to 86˚C (15 min after) to 76˚C (30 min after) while at 0.3 m, the temperature decreased from 48˚C (5 min after) to 43˚C (15 min after) to 40˚C (30 min after).

The effect of hold time on HF concentration in the space was also monitored. Figure 4 shows a typical plot HF concentration versus time. The concentration started to decay exponentially 30 seconds after the maximum concentration was reached and fell to approximately 2900 ppm after five minutes and 1400 ppm after 15 minutes.

This indicated that a crew reentering a space 15 minutes after the release of this hydrofluorocarbon agent would be exposed to very high levels of HF unless techniques were available to reduce the HF concentration. Ventilation is one approach to reducing HF levels but this may leave flammable liquids in the space vulnerable to reignition as the concentration of the gaseous fire suppressant drops below the level where it is effective.

10 DRDC-RDDC-2015-R036

3 Table 9: Results of fire suppression testing of CF3CHFCF3 in 370 m test space on ex-USS Shadwell (from Refeference [4]).

Figure 4: Concentration of HF is test space as a function of hold time (from Reference [4]). The agent (CF3CHFCFC 3) was released at 0 seconds.

A series of tests using a water spray cooling system (WSCS) was run to determine if this system would enhance fire suppression and reignition performance, reduce compartment temperatures, reduce acid decomposition product generation, and enhaannce the acid concentration decay rate in the space following release of CF3CHFCF3 [5]. The results of the tests using the WSCS in conjunction with the CF3CHFCF3 fire suppression system are shown in Table 10. For all tests (3.6 to 6.2), the fires were extinguished.

DRDC-RDDC-2015-R036 11

The WSCS had a significant effect on the peak HF concentration in the fire test space, especially if it was activated prior to the release of the gaseous (CF3CHFCF3) fire suppression agent. For instance, the peak HF concentration for the test using the gaseous agent was 5000 ppm in Test 3.6 and 4100 ppm in Test 4.2, while activating the WSCS at the same time as the gaseous agent was released resulted in a reduction of the peak HF concentration to 1800 ppm. The effect was greater when the WSCS was activated one minute prior to the release of the gaseous agent. The peak concentration for this test scenario was 200 ppm. Similar results were observed for Halon 1301 where the peak HF concentration was reduced from 1100 ppm to 200 ppm when the WSCS was activated a minute before the Halon 1301 was released.

Table 10: Results of CF3CHFCF3 test series with and without use of the water spray cooling system (Tests No. 4.2, 4.5, 5.2, 5.3, 5.4). Results of Halon 1301 fire suppression tests without and with WSCS (tests 6.1 and 6.2) (from Reference [5]).

The WSCS was also effective in lowering the temperature in the test space when it was activated at the same time as, prior to, and after the activation of the CF3CHFCF3 system. Figures 5 through 7 show plots of temperature versus time for the use of agent (CF3CHFCF3) only, when the gaseous agent and the water spray were activated at the same time and when the WSCS was activated at 300 seconds for one minute and again at 900 seconds for two minutes after the release of the gaseous agent. The tags on the temperature versus time plots refer to the height of the thermocouples above the floor of the test space. The temperature in the test space at all thermocouples was reduced relative to the temperatures when the WSCS was not activated.

The major findings of this research were that water spray, when used in conjunction with acid gas producing agents, reduces the temperature in a space and results in lower acid gas concentrations in the space. Both of these factors reduce the risk associated with reentry of the space by a ship’s crew. The reduction in temperature in the space also reduces the risk of reignition of flammable fluids in a space.

12 DRDC-RDDC-2015-R036

Figure 5: Time versus temperature plots for the fire suppression test using CF3CHFCF3 (from Reference [5]).

Figure 6: Time versus temperature plots for the fire suppression test when the CF3CHFCF3 and water spray cooling systems were activated at the same time (from Reference [5]). The water spray cooling system was turned off after one minute.

DRDC-RDDC-2015-R036 13

Figure 7: Time versus temperature plots for the test where the CF3CHFCF3 system was activated at 0 seconds and the water spray cooling system was activated at 300 seconds for one minute and at 900 seconds for two minutes (from Reference [5]).

2.5 Large scale (500 m3) evaluation of gaseous agents [6]

This testing was carried out on the US Coast Guard fire test vessel STATE OF MAINE. The test space had a nominal volume of 500 m3 (10 m x 10 m x 5 m) and had a mock-up of a diesel engine in the middle of the space. Four gaseous agents were tested: Halon 1301, FM-200, CEA-410 and NAF-SIII (a hydrochlorofluorocarbon blend) against the proposed (at that time) International Maritime Organization (IMO) protocol for the evaluation of gaseous agents for use in machinery spaces.

The locations of the fires in the test space are shown in Figure 8 and the fire scenarios are listed in Table 11.

14 DRDC-RDDC-2015-R036

Figure 8: Location of the fires in the 500 m3 test space (from Reference [6]). Used with the kind permission of the USCG Research & Development Center, New London, CT.

The HF concentrations were monitored during the testing. The results are shown in Table 12. The Halon 1301 alternatives produced significantly (5–10+ times) more HF than Halon 1301 for similar agent release times and fires. As had been observed in the earlier studies discussed in this report [1–4], the concentration of HF produced by the agent depends on fire size, agent concentration, agent release time, and the time to extinguishment of the fire.

The hazards associated with the release of HF by these gaseous fire suppressant agents were discussed. Short term exposure (one minute) to between 250 ppm and 1000 ppm HF can be dangerous to occupants of a space [7, 8] and irritation can occur at 100 ppm. The peak HF concentrations produced by all the agents, including Halon 1301, were above these limits.

DRDC-RDDC-2015-R036 15

Table 11: Fires scenarios used in the 500 m3 test space (from Reference [6]). Used with the kind permission of the USCG Research & Development Center, New London, CT.

Table 12: Results of the 500 m3 machinery space fire suppression testing (from Reference [6]). Used with the kind permission of the USCG Research & Development Center, New London, CT.

16 DRDC-RDDC-2015-R036

2.6 Generalized data correlations for extinguishment times and acid concentrations in fire tests with fluorinated suppression agents [9]

Equations that can be used to predict extinguishment times and concentrations of HF produced by fires suppressed with heptafluoropropane (FM-200), trifluoromethane (FE-13), and perfluorobutane (CEA-410), as well as bromotrifluoromethane (Halon 1301) have been developed. The extinguishment time correlation is of the form tex / td = fi (Q*, C / Ccb) where tex is the extinguishment time, td is the discharge time, Q* is a non-dimensional heat release rate defined in Equation 1, C is the agent concentration, Ccb is the heptane cup burner concentration, and the index i designates the particular agent. The HF concentration correlation is of the form ) [HF] = gi (Q*, C / Ccb .

The non-dimensional heat release rate is shown in equation 1,

(1) where: Q = heat release rate (kW), td = discharge time (sec), tfb = freeburn or preburn time (sec), V = enclosure volume (m3), ΔHC,O = heat of combustion per gram oxygen (heptane = 12.68 kJ/g a), n' = moles of air per unit volume, [O2] = oxygen concentration at time of discharge, and MWox = molecular weight of oxygen (32 g/mole).

The results of the analysis indicated that the optimum HF concentration curve fits incorporated the non-dimensional heat release rate (Q*). For two of the agents, FM-200 and CEA-410, HF concentrations had very good correlations with the non-dimensional heat release rate by itself, while for FE-13 and Halon 1301, the correlations improved when both Q* and non-dimensional agent concentration were considered.

A plot of HF concentration against Q* for data from FM-200, FE-13, CEA-410 and Halon 1301 testing is shown in Figure 8. These show clearly that HF concentration increases as Q* increases. From equation 1, it can be seen that an increase in extinguishment time will increase Q*, as will a decrease in the fire test compartment volume.

The results of this study could be used to estimate the time to extinguishment and HF concentrations that might be expected based on the agent concentration, release time, heat release rate and volume of a space (fire size to volume ratio).

DRDC-RDDC-2015-R036 17

Figure 9: Plot of HF concentration against the non-dimensional heat release rate for FM-200, CEA-410, FE-13 and Halon 1301 (from Reference [9].

2.7 Thermal decomposition products of 1,1,1,2,2,4,5,5,5 nonafluoro-4-trifluoromethylpentan-3-one (Novec 1230) during small scale fire extinguishment testing [10]

The testing reported in Reference [10] was carried out in a 1.28 m3 (45 ft3) enclosure and the effect of fire size, agent discharge time, and agent concentration on thermal decomposition products of Novec 1230, specifically HF and COF2, were evaluated. The HF concentration included both HF directly released from the agent and HF produced by the hydrolysis of COF2 in the test space.

The effect of agent release time and fire size on the HF concentration is shown in Figure 10. HF production increased monotonically with fire size and also with the discharge time of the agent into the test space. The effect of agent concentration on the production of HF is shown in Figure 11 for a nine second discharge time. The lower agent concentration resulted in slightly higher HF concentration for larger fires. At longer discharge times (>25 seconds), the lower agent concentration resulted in a significant increase in HF production. The trends in the effect of fire size, agent discharge time, and agent concentration for Novec 1230 on HF production were the same as those observed for Halon 1301, FE-13, FM-200 and CEA-410.

18 DRDC-RDDC-2015-R036

Figure 10: Plot of the effect of fire size on the production of HF for fires extinguished with Novec 1230 for three discharge times. The concentration of Novec 1230 was 5.9% (v/v) (from Reference [10]). Used with the kind permission of the copyright owner Benjamin D. Ditch.

Figure 11: The effect of agent concentration on HF production for Novec 1230. A nine second discharge time was used (from Reference [10]). Used with the kind permission of the copyright owner Benjamin D. Ditch.

DRDC-RDDC-2015-R036 19

2.8 Novec 1230 / water mist fire suppression for machinery spaces and electronic cabinets [11]

This study evaluated the effectiveness and hazards associated with the use of Novec 1230 for fire suppression in a submarine machinery space and how those hazards, specifically the concentration of HF in the space following agent release, could be reduced by using a water mist system in conjunction with the Novec 1230 system. Full-scale fire tests were carried out in a mock-up of a submarine machinery space (7.32 m x 4.88 m x 4.2 m high, volume 148.5 m3) on large heptane fuel fires (1.49 m2, ~3 MW).

The results of the testing are shown in Table 13. The effect of water mist on HF concentrations in the space can be seen by comparing the results of Test 12 (Novec 1230, no water mist prior to Novec 1230 discharge) with those for Test 6 (water mist activated 60 seconds prior to Novec 1230 discharge). Plots of HF concentration against time are shown in Figures 12 and 13. For Test 12, the water mist system was turned on eight minutes after Novec 1230 discharge. The HF concentration in the space dropped rapidly once the water mist system was activated. For Test 6, the water mist system was activated before the Novec 1230 discharge and the HF concentration immediately dropped after it had reached its maximum.

Figure 12: Plot of HF concentration against time for Test 12, Novec 1230, no water mist (from Reference [11]).

20 DRDC-RDDC-2015-R036

Figure 13: Plot of HF concentration against time for Test 6, water mist activated 60 seconds prior to Novec 1230 discharge (from Reference [11]).

DRDC-RDDC-2015-R036 21

Table 13: Results of the Novec 1230 / water mist testing (from Reference [11]).

22 DRDC-RDDC-2015-R036

3 Conclusions and comments

All gaseous fire suppressant agents containing halogens (F, Cl, or Br) will produce acid gases when used to extinguish fires. The concentration of acid gas or gases produced depends on the size of the fire, volume of the space, the concentration of the agent, the discharge time of the agent and the fire suppression time. It is important that the concentration and discharge time for a gaseous fire suppressant agent be optimized to minimize acid gas production.

Ventilation can be used to reduce the concentration of acid gas in a space after a fire. However, activating ventilation will also reduce the concentration of the agent below that which is necessary for fire suppression/extinguishment. This may result in reignition of a fire or fires in the space.

The use of water spray or water mist in conjunction with acid gas producing agents significantly reduces acid gas concentrations in a space. The water spray or water mist system will also cool the space and aid in the prevention of reignition of flammables.

Safe re-entry procedures for a space after a discharge of a gaseous agent containing halogens should consider how HF concentrations in the space can be minimized. For instance, the US Navy doctrine indicates that re-entry should not take place until 15 minutes after a Halon 1301 discharge. Even 15 minutes after a Halon discharge, the results summarized in this report indicate that HF levels may constitute a risk to firefighters. Water spray and water mist used in conjunction with these agents decrease the concentration of HF in the space considerably and therefore the risks associated with re-entry. An ability to monitor or test for HF levels in a space would provide the firefighters with information on the hazards arising from acid (HF) gas in the space. Tactics such as ventilation of and the use of water in the space could then be used to minimize hazards.

DRDC-RDDC-2015-R036 23

This page intentionally left blank.

24 DRDC-RDDC-2015-R036

References .....

[1] Moore, T.A., Dierdorf, D.S. and Skaggs, S.R. (1993), Intermediate-Scale (645 ft3) Fire Suppression Evaluation of NFPA 2001 Agents, In Proceedings of Halon Alternatives Technical Working Conference, 11–13.

[2] Sheinson, R.S., Eaton, H.G., Black, B.H., Brown, R., Burchell, H., Maranghides, A., Mitchell, C., Salmon, G. and Smith, W.D. (1994), Halon 1301 Replacement Total Flooding Fire Testing, Intermediate Scale, In Proceedings of Halon Options Technical Working Conference, 43–53, Albuquerque, New Mexico, U.S.A.

[3] Sheinson, R., Maranghides, A., Eaton, H., Barylski, D., Black, B., Brown, R., Burchell, H., Byme, P., Friderichs, T., Mitchell, C., Peatross, M., Salmon, G., Smith, W. and Williams, F. (1995), Large Scale (840 m3) HFC Total Flooding Fire Extinguishment Results, In Proceedings of Halon Options Technical Working Conference, 837–848, Albuquerque, New Mexico.

[4] Black, B.H., Maranghides, A., Sheinson, R.S., Peatross, M.J. and Smith, W.D. (1996), Real Scale Halon Replacement Testing Aboard ex-USS Shadwell: Post Fire Suppression Compartment Characterization, In Proceedings of Halon Options Technical Working Conference, 423–434, Albuquerque, New Mexico.

[5] Maranghides, A., Sheinson, R.S., Black, B., Peatross, M. and Smith, W.D. (1996), The Effects of a Water Spray Cooling System on Real Scale Halon 1301 Replacement Testing and Post Fire Suppression Compartment Reclamation, In Proceedings of Halon Options Technical Working Conference 435–446, Albuquerque, New Mexico.

[6] Back, G.G., Beyler, C.L., DiNenno, P.J., Hansen, R.L., Waller, D. and Zalosh, R. (1997), An Evaluation of the International Maritime Organization’s Gaseous Agents Test Protocol, (Report CG-D-24-97) United States Coast Guard.

[7] Sax, N.I. (1984), Dangerous Properties of Industrial Chemicals, New York, New York, USA: Van Nostrand Reinhold Company.

[8] Meldrum, M. (1993), Toxicity of Substances in Relation to Major Hazards - Hydrogen Fluoride, London, UK.

[9] Zalosh, R. and Heyworth, S. (1996), Generalized Data Correlations for Extinguishment Times and Acid Concentrations in Fire Tests with Fluorinated Suppression Agents, In Proceedings of Halons Options Technical Working Conference, 319–330, Albuquerque, New Mexico.

[10] Ditch, B.D. (2002), Thermal Decomposition Products Testing With 1, 1, 1, 2, 2, 4, 5, 5, 5 nonafluoro-4-trifluoromethyl pentan-3-one (C6 F-ketone) During Fire Extinguishing, WORCESTER POLYTECHNIC INSTITUTE, MSc Thesis.

DRDC-RDDC-2015-R036 25

[11] Kim, A. and Crampton, G. (2011), Fire Protection of Submarine’s Machinery Space and Electronic Equipment Cabinets, (Client Report B4715.1) National Research Council of Canada.

26 DRDC-RDDC-2015-R036

DOCUMENT CONTROL DATA (Security markings for the title, abstract and indexing annotation must be entered when the document is Classified or Designated) 1. ORIGINATOR (The name and address of the organization preparing the document. 2a. SECURITY MARKING Organizations for whom the document was prepared, e.g., Centre sponsoring a (Overall security marking of the document including contractor’s report, or tasking agency, are entered in Section 8.) special supplemental markings if applicable.)

DRDC – Atlantic Research Centre UNCLASSIFIED Defence Research and Development Canada 9 Grove Street P.O. Box 1012 2b. CONTROLLED GOODS Dartmouth, Nova Scotia B2Y 3Z7 (NON-CONTROLLED GOODS) Canada DMC A REVIEW: GCEC DECEMBER 2012

3. TITLE (The complete document title as indicated on the title page. Its classification should be indicated by the appropriate abbreviation (S, C or U) in parentheses after the title.)

Acid gas (hydrogen fluoride) production from Halon 1301 and alternative gaseous fire suppressants: A Review

4. AUTHORS (last name, followed by initials – ranks, titles, etc., not to be used)

Hiltz, J.

5. DATE OF PUBLICATION 6a. NO. OF PAGES 6b. NO. OF REFS (Month and year of publication of document.) (Total containing information, (Total cited in document.) including Annexes, Appendices, etc.) March 2015 36 11

7. DESCRIPTIVE NOTES (The category of the document, e.g., technical report, technical note or memorandum. If appropriate, enter the type of report, e.g., interim, progress, summary, annual or final. Give the inclusive dates when a specific reporting period is covered.)

Scientific Report

8. SPONSORING ACTIVITY (The name of the department project office or laboratory sponsoring the research and development – include address.)

DRDC – Atlantic Research Centre Defence Research and Development Canada 9 Grove Street P.O. Box 1012 Dartmouth, Nova Scotia B2Y 3Z7 Canada

9a. PROJECT OR GRANT NO. (If appropriate, the applicable research 9b. CONTRACT NO. (If appropriate, the applicable number under and development project or grant number under which the document which the document was written.) was written. Please specify whether project or grant.)

10a. ORIGINATOR’S DOCUMENT NUMBER (The official document 10b. OTHER DOCUMENT NO(s). (Any other numbers which may be number by which the document is identified by the originating assigned this document either by the originator or by the sponsor.) activity. This number must be unique to this document.)

DRDC-RDDC-2015-R036

11. DOCUMENT AVAILABILITY (Any limitations on further dissemination of the document, other than those imposed by security classification.)

Unlimited

12. DOCUMENT ANNOUNCEMENT (Any limitation to the bibliographic announcement of this document. This will normally correspond to the Document Availability (11). However, where further distribution (beyond the audience specified in (11) is possible, a wider announcement audience may be selected.))

Unlimited

13. ABSTRACT (A brief and factual summary of the document. It may also appear elsewhere in the body of the document itself. It is highly desirable that the abstract of classified documents be unclassified. Each paragraph of the abstract shall begin with an indication of the security classification of the information in the paragraph (unless the document itself is unclassified) represented as (S), (C), (R), or (U). It is not necessary to include here abstracts in both official languages unless the text is bilingual.)

14. KEYWORDS, DESCRIPTORS or IDENTIFIERS (Technically meaningful terms or short phrases that characterize a document and could be helpful in cataloguing the document. They should be selected so that no security classification is required. Identifiers, such as equipment model designation, trade name, military project code name, geographic location may also be included. If possible keywords should be selected from a published thesaurus, e.g., Thesaurus of Engineering and Scientific Terms (TEST) and that thesaurus identified. If it is not possible to select indexing terms which are Unclassified, the classification of each should be indicated as with the title.)

fire suppression, gaseous fire suppressants, Halon 1301, alternative gaseous agents, acid gas