By Richard Mueller
None of us arrive at fire incidents and announce (or acknowledge) a marginal strategy even though all firefighters undertake them. Our too-often-used words of an “进攻性进攻”(offensive strategy) simply do not match our actions when we slowly and blindly search for the seat of the fire and/or occupants in low/no visibility. Just because we way say that we are acting offensively does not mean that we are acting offensively. So if we are not offensive, what are we? The marginal strategy acknowledges that it is difficult to be aggressive in low/no visibility, and that a more cautious and calculated approach is appropriate and necessary in such environments that are immediately dangerous to life and health (IDLH). The marginal strategy provides an honest and legitimate way to define thinking and corresponding actions in an environment where we might not win.
Tragedies of Strategies
On August 3, 2007,1a captain and a firefighter died after an extended offensive attack in low/no visibility. On July 22, 2008,2一名消防员死亡,三人几乎made it out after the first floor collapsed in low/no visibility, 30 minutes into the fire attack. On July 3, 2010,3当船长进入一个低/无可见性环境时，在试图定位和扑灭深夜大火时，船长在进入低/无可见性环境后死亡时，发生了另一场策略的悲剧。在这三个悲剧中，没有平民在建筑物中。消防服务risk managementplan clearly states that we will only “risk a lot (our lives) to save a lot (others lives).” Yet even as you read this there are firefighters right now crawling inside of a burning building with no one else inside.
Low/no visibility environments contain the deadliest components of our profession. We all call and know this obscurity as smoke, but in reality it is fuel. This combination of unburned gases and high temperatures in a work environment that we have never seen or worked in before creates orientation and situational awareness challenges that not all of us are able to deal with. The National Fire Protection Association (NFPA) has reported4that the three leading causes of fatal firefighter injuries (non-heart related) while operating inside of structures has nearly doubled since 1978. These three causes–getting lost, being caught in structural collapse, or being overcome by fire progress–are all the result of working too long in an environment without being able to see and by not respecting this error-producing condition.5Crawling around in low/no visibility for anextended period of timeshould not be considered or tolerated as a “normal” firefighting condition.
Some will disagree and say that they can see because they have athermal imaging camera (TIC)。Although TICs are helpful, their effectiveness is limited. Obstructions, insulation, and improper use all reduce our situational awareness as we forge forward while one of us tries to look into and interpret the 3 x 5 screen through a face piece. Some serious limitations of the TIC were highlighted by Underwriters Laboratory in their “Structural Stability of Engineered Lumber in Fire Conditions” research6。During the tests, temperatures of well over 1,200º F below a floor assembly were not detectable from above it using a TIC. Temperature readings taken with the TIC only registered 85º F above the floor. The TIC could not detect the well-involved fire burning below the floor because of hardwood flooring, carpet, and its insulated pad until the floor system was near or at its failure point! The room temperature was ambient while an inferno burned beneath. TICs only measure surface temperature, not what is happening below the surface.
The marginal strategy (1) is defined as an “interior attack with爬行能见度。它是在您的手和膝盖上进行的，因为您看不到脚。由于可能会迷失，戴上危险和/或结构，因此这个边际区域的风险很高。由于您看不到它们而没有定向周围环境，因此失去了丢失。“戴危险”意味着对您造成危害。这包括火焰，热量和有毒气体，看起来像烟雾，翻转，flashover, and背景。佩戴结构意味着失去结构完整性，从而导致结构分开。这看起来像是被抓，被困或压碎的消防公司成员。由于这些改变生命的危害的理化，只应在短时间内容忍边际思维和行动。
(1)
The term “marginal” is not new to the fire service, but looking at it as a strategy is. The word marginal implies an unsureness, a situation that could go either way. Crawling around searching for the fire, especially for extended periods of time, tilt the odds against us by the minute as we get deeper into the unknown. Firefighters can get into trouble when they choose an aggressive-offensive mindset followed by an aggressive interior attack when they cannot see how big and bad or even where the enemy is. Too often, this occurs when we are the only life safety concern inside. The reality of strategy is that we do not always get to choose. Although you may want to be offensive, the incident conditions should have more to say about how we should fight (and how long) rather than our own infallible, ego-driven decision making. We are simply kidding ourselves when we say that we are offensive in marginal/defensive conditions as we crawl slowly in fast-moving fire conditions. The “margin of error” is simply to small to operate in poor visibility for extended periods of time.
10 Minutes
边际策略应仅持续10分钟或更短的时间。鉴于当今消防的这些因素，边际应成为您词汇，理解和决策的一部分：188金博网网址多少
- Lightweight building construction(buildings come apart quickly when exposed to heat and fire)
- 乘员生存剖面（不支持生命的高热量和高毒的火灾环境）
- 由于可见性和迷失方向不佳而导致的误差幅度较小
- Current firefighting technologies that can create visibility quickly (positive pressure blowers), and
- Fire companies that will not stop going inside to put out fire even though no one is inside.
Including marginal into our strategic definitions legitimizes what firefighters do “a lot” every single day (interior attacks in poor visibility) and gives practicality, honesty, and credibility to our risk-management plan (within the parameters of time and visibility). What we do finally matches the risks involved, but just like professional sports teams we will only play for a predefined period of time. At the 10-minute mark, the question that needs to be asked is: “What are we going to save?” Unfortunately, the answer to that question is less than many will admit.
CaptainStephen Marsarof the Fire Department of New York provided some answers in an article entitled “Survivability Profiling, How Long Can Victims Survive In a Fire7。” Some in the fire service did not agree or even like his article (some of his research is cited below), but that does not mean that it is not true.
NFPA指出人类温度态度的上限为212ºF。这远低于大多数结构火灾中发现的温度。当今的火灾环境可以在三到四分钟内轻松达到500ºF，并且flashover(with temperatures above 1,000º F) can develop in under five minutes8。
Scientific research on human respiratory burns9and inhalation of hot gases in the early stages of fire10reveals that occupants trapped in structural fires have limited survival times. In one experiment (which lasted 11 years), fire victims were tracked if they met three diagnostic criteria of: (1) flame burns involving the face, particularly the mouth and nose; (2) singed nasal mucus membranes; and (3) burns sustained in closed-space interior fires. Twenty-seven patients were treated; 11 additional patients didn’t meet all three of the test criteria or were dead on arrival. Of the 27 patients whose body surface burns ranged from 15 to 98 percent, 24 died (three in the first 24 hours, five within 36 hours). Respiratory burns directly accounted for 18 of those deaths (the others died of other burn injury complications). Sixty percent of the victims were found to have been exposed to heat (most at temperatures above 200º F, however some were below) and humidity for six to seven minutes (remote from the fire area). The fatality rate increased to 90 percent for those exposed to toxic smoke as well, even for only several minutes. The experiment concluded that human fire victims were most susceptible to respiratory burns from heat first, toxic smoke second, and humidly a distant third. The time of exposure for all 24 fatalities was less than 10 minutes. In the second experiment10(使用实验室小鼠和人类火灾受害者),勒thal first-degree respiratory burns were found to occur in just 230 seconds (under 4 minutes).
Additionally, carbon monoxide and cyanide found in smoke are an ever-present deadly duo. These two killer gases are referred to as the“toxic twins11“由于它们对未受保护的乘员的协同杀戮作用。2006年NFPA的一项研究表明，80％的火灾受害者死于吸入烟雾，其中87％在火中死亡的人死于有毒的血液浓度的氰化物和一氧化碳。当今塑料环境中一磅的热释放速率释放了多达19,000 btus，而1磅的木材释放了8,000 btus。在很短的时间内达到的合成材料和极端温度的增殖产生的有毒烟雾含有高水平的氰化氢，这比单氧碳二氧化碳的致命含量高30倍。在3,400 ppm的氰化氢（在大多数封闭的结构火灾中发现）的生存时间少于一分钟！
A look at the annual fire death rates in this country and a personal account of your own fire-victim survival rates show few survive when they are unable to self-escape. The 10-minute marginal window may at first seem short, but it is longer than the ability of unprotected occupants to survive in low/no visibility environments.
其次，许多lightweight事实证明，结构成分要早于10分钟。之前引用的研究6从UL实验室表明，未受保护的轻型工程I梁可能会在短短六分钟内（几乎是10分钟边缘窗口的一半）故障，这甚至不会考虑您的响应和设置时间。
The marginal strategy is not a death sentence to the aggressive offensive fire attack. On the contrary, it reinforces the need to more quickly create conditions that allow for an offensive fire attack. Knowing that you will not be allowed to operate for extended periods of time in low/no visibility encourages“transitional”thinking and actions before entry: a 360 to better evaluate where the fire is, opportunities for an aggressive exterior attack, and creating entrance and exit openings to create an air flow path to the fire. This one/two punch of quick water on the fire (transitional attack) and faster smoke and heat removal (positive-pressure ventilation) provide early fire knockout and increased interior visibility more quickly. An 18,000 cfm positive-pressure blower will create almost 10 air exchanges in a 2,000-sq. ft. residence in 10 minutes. If visibility cannot be gained after 10 air exchanges, the fire is simply bigger and badder than we are; there’s a high probability of us losing. It’s time to think and act differently (do something different). Quickly reducing and removing heat and smoke from the structure creates legitimate offensive firefighting.
*
The addition of a marginal (and transitional) strategy to our thinking provides some middle ground and a greater margin of error to our traditional “all or nothing” (offensive/defensive) approach to strategy, where thinking and actions taken between defensive and offensive better ensure victim and firefighter survivability. Looking at fire conditions for what they are rather than as what we want them to be is an honest and intelligent definition of situational awareness. Weget to choose the future rather than the other way around. Good outcomes are the result of good thinking. If we truly value life, then we must better understand and respect the error-producing condition of smoke and low/no visibility.
END NOTES
1.“志愿者队长在空中跑得较低，在试图退出大型商业结构时死亡并死亡 - 德克萨斯州，” Niosh报告F2010-16，http://www.cdc.gov/niosh/fire/reports/face201016.html
2. “A Volunteer Mutual Aid Firefighter Dies in a Floor Collapse in a Residential Basement Fire — Illinois,” NIOSH Report F2008-26,http://www.cdc.gov/niosh/fire/pdfs/face200826.pdf
3. “A Volunteer Mutual Aid Captain and Firefighter die in a Remodeled Residential Structure Fire — Texas,”http://www.cdc.gov/niosh/fire/pdfs/face200729.pdf
4. “U.S. Fire Service Fatalities in Structure Fires, 1997-2000,” Rita F Fahy, Ph.D., NFPA July 2002.
5.错误产生条件（EPC）的概念主要来自J.T.的工作。威廉姆斯（Williams）在1980年代后期，但仍在许多领域中用于评估错误的潜在影响。该技术用于人类可靠性评估（HRA）领域，目的是评估整个特定任务过程中人为错误的可能性。
6. “Structural Stability of Engineered Lumber in Fire Conditions,” UL University fire Safety — On Line Courses, UL Laboratory,
https://www.uluniversity.us/DevelopmentPlan/Display.DevelopmentPlan.aspx?RFC=187716
7. Stephen Marsar, “Survivability Profiling, How long can victims survive in a fire?”188金宝搏是正规吗, July 2010.//www.sacthai.com/articles/2010/07/survivability-profiling-how-long-can-victims-survive-in-a-fire.html
8.“火力（视频）和讲师指南”，国家消防协会，1986年
9. Corbitt，给予Martin，Rhame和Stone。“呼吸道灼伤：临床和实验室结果的相关性”，”Annals of Surgery, Emory University, Atlanta, Ga., 1967.
10.刘，杨和张。“由于火灾早期吸入热气体，对人类呼吸道的烧伤进行了理论评估。”Burns，第32卷，（加利福尼亚州圣地亚哥：Elsevier Ltd，2005年）32：434-446
11. “To Hell and Back IV: The Toxic Twins (DVD).” People’s Burn Foundation, Indianapolis, IN.
Richard Muelleris a battalion chief for the West Allis (WI)Fire Department。He is afire instructorfor Waukesha and GatewayTechnicalCollege and atechnical rescueinstructor对于WI反应中心。他是联邦DMORT V和WI特遣队1团队的成员，也是WI Flame Group的合作伙伴。他是188金博网网址多少textbookFire Company 4and can be reached atRick@Wiflamegroup.com
