Firefighter BA Air Consumption – Predicting air consumption times to improve BA Performance.
- Sep 11, 2024
- 8 min read
Updated: Sep 15
Introduction
Firefighting is a profession that demands extraordinary resilience and adaptability, especially when faced with the unforgiving environments that accompany emergencies involving fire. One commonality among these dynamic incidents is the critical use of breathing apparatus (BA) when the atmosphere becomes unbreathable. In the UK Fire and Rescue Service, firefighters typically rely on Standard Duration Breathing Apparatus (SDBA), which provides approximately 31 minutes of breathable air (London-fire.gov.uk, 2023). However, this duration can vary slightly across different fire services throughout the country. For those situations requiring extended air supply, Extended Duration Breathing Apparatus (EDBA) offers about 47 minutes on average.
Despite these time frames, it’s important to note that the full 31 minutes of air is never utilised. This is largely due to two key factors: the various physical elements that affect air consumption rates, and the stringent BA procedures that require firefighters to exit hazardous areas before their Time of Whistle (TOW) activates. This TOW, which signals roughly 25% of air remaining in a 300-bar pressure cylinder, is a crucial safety measure (Operational guidance Breathing apparatus, n.d.).
Given that firefighters must vacate hazardous environments with a quarter of their air supply still intact, efficient air consumption becomes paramount. Understanding and predicting air consumption times not only aids firefighters in gauging their operational limits but also highlights areas for improvement in their fitness. This knowledge allows firefighters to train specifically in the areas needed, ultimately enhancing their reliability and effectiveness during critical incidents.
In this article, we will delve into the latest research and insights regarding:
Factors Impacting Air Consumption
What influences how quickly firefighters use their air supply?
Predicting Air Consumption Times
How can firefighters or fire services estimate air usage based off aerobic fitness testing?
Using this Information
What does this mean for firefighters moving forward?
What We Don’t Want: The Consequences of Inefficient Air Consumption
One of the most frustrating scenarios in firefighting occurs when a firefighter enters a hazardous environment wearing breathing apparatus (BA) but has to retreat just 10 minutes later due to an impending Time of Whistle (TOW) activation. It happens. This situation not only hampers the firefighter’s ability to contribute meaningfully to the incident, but it can also create significant logistical challenges for the Incident Commander. When a firefighter is forced to leave prematurely, it can lead to resource shortages, requiring additional support that may stretch the capabilities of neighbouring stations and the wider organisation.
Moreover, returning to entry control without having made a positive impact can be disheartening for the firefighter, who may find themselves fatigued and frustrated. This is not the outcome we want. Our goal is to maximise air consumption efficiency, allowing firefighters to operate effectively for longer periods. By doing so, we can enhance their ability to save lives and minimise the number of personnel exposed to hazardous conditions.
Every second counts. Therefore, it’s crucial that we focus on optimising air usage, ensuring that we can perform our roles without unnecessary interruptions. By understanding the dynamics of air consumption and implementing strategies to improve it, we can empower firefighters to make a real difference when it matters most. To do this, we first need to understand what impacts air consumption.
So, what impacts Air Consumption Times (ACT)?
It’s essential to recognise that various factors can affect a firefighter’s air usage, and it would be unjust to label someone as unfit simply because they seem to "chug" through their air supply. While physical fitness is undoubtedly a significant contributor to improving air consumption and sustainability, it’s not the only factor at play. The table below outlines some of the key factors that impact ACT:
Work Rate | The more intense the physical activity, the faster our respiration increases as the working muscles need more oxygen. Respiration rate can go from 12-20 breaths per minute to 30-40 during intense exertion, consequently depleting air contents quicker. |
Physique | Optimal biomechanics can perform tasks with less energy expenditure. It was found in a study that females consume less air than males due to body type (Palm et al., 2022). Muscle tissue requires more oxygen during exertion, but well-conditioned muscles can utilise oxygen more efficiently. Conversely, excess body fat can lead to increased energy expenditure, resulting in quicker air consumption during physical activities. |
Environment | PPE and BA are an additional load which taxes the body. This ultimately increases your work rate alone. As you move with more weight, you need to consume more air to get oxygen to the working muscles. Poor load carriage ability equals quicker onset of fatigue, inflicting quicker air consumption. |
Load Carriage Ability | PPE and BA are an additional load which taxes the body. This ultimately increases your work rate alone. As you move with more weight, you need to consume more air to get oxygen to the working muscles. Poor load carriage ability equals quicker onset of fatigue, inflicting quicker air consumption. |
Time of Whistle | As mentioned above, we lose a quarter of our air contents due to time of whistle procedures meaning a quarter of our air economy is lost. |
Uncontrolled Breathing | It’s all too easy to lose control of your breathing. With adrenaline pumping, focused on the task at hand, and a whirlwind of emotions swirling, you might not even notice how quickly you're breathing. This rapid breathing can quickly deplete your air supply. |
It's clear that many factors influence air consumption, and it's overly simplistic to label a firefighter as "unfit" based solely on their air usage. However, it is fair to assert that fitness plays a crucial role in enhancing air consumption times. Improved strength and optimal muscular endurance can significantly enhance load carriage ability, while conditioning specific to stair climbing can mitigate the onset of fatigue. Additionally, having a strong VO2 max and aerobic capacity enables the body to utilise oxygen more efficiently, protecting the heart during high-intensity efforts and ultimately boosting endurance and performance.
These are just a few examples of how fitness impacts air consumption. But imagine the advantages if we could predict a firefighter’s air consumption time. The ability to forecast this metric based off a firefighter’s fitness level would be a game changer for firefighter performance and preparation. Well… the good news is that we now can.
How do we predict BA Air Consumption Times?
This is a complex issue influenced by numerous factors. Fortunately, a significant study published in January 2019, titled “Aerobic Fitness Predicts the Air Consumption Time in the Self-Contained Breathing Apparatus During Physical Tasks of Firefighters,” sought to address this very question. The study evaluated the effectiveness of proposed equations designed to forecast a firefighter's air consumption time while using self-contained breathing apparatus (SCBA) during physical firefighting tasks.
In this study, twenty firefighters were divided into two groups (G1 and G2) and tasked with completing two performance tests on separate days. The first test involved a maximal 1600-meter run, aimed at determining mean velocity and maximal heart rate. For clarity, mean velocity (1600mV) was translated to meters per minute (m/min) for analysis. The second test was a submaximal exercise where participants ran or walked at 88-92% of their maximum heart rate (MHR), all while wearing full firefighting personal protective equipment (PPE), including BA. This heart rate range was selected because studies have shown that firefighters can reach up to 90% of their MHR during simulated fire tasks (von Heimburg, Rasmussen, and Medbø, 2006; White and Hodous, 2018).
It's worth noting that the study utilised BA with a pressure of 150 bar, which is half the capacity of the standard 300 bar cylinders used by most UK Fire and Rescue Services (UKFRS). However, as per National Fire Chiefs Council (NFCC) guidelines, firefighters are not permitted to enter a building with less than 240 bar (Operational guidance Breathing apparatus, n.d.). With this bare minimum bar in mind, a pressure of 150 bar would leave approximately 90 bar remaining—just above the TOW threshold—indicating that firefighters would need to exit the hazardous area soon after that point. Given this context, we can consider the study a valuable resource for UK firefighters.
The main finding revealed a strong correlation between aerobic fitness, as measured by the 1600m maximal running test, and the air consumption time from SCBA (T_SCBA). This suggests that the proposed equation for predicting air consumption time is a valid tool for estimating T_SCBA during high-intensity firefighter activities at 90% MHR.
For context T_SCBA = Predicted air consumption time. To work out the T_SCBA (for 150bar) follow this equation:
[T_SCBA= 0.0442*1600mV + 4.5029]
Breaking down the equation:
Firstly, find your 1600mV
- Distance/Time = metres per minute mV (rounded up or down to nearest 10)
Secondly, add it to the equation:
- T_SCBA= 0.0442*m/min mV + 4.5029
Here is an example
Let’s say it took you 7:20 to complete 1600m max test:
Firstly, find your 1600mV
- 1600/7:20 = 222 metres per minute (rounded up or down to nearest 10)
Secondly, add it to the equation:
- T_SCBA= 0.0442*222mV + 4.5029 = 14:31
Therefore, your predicted BA Air Consumption Time at an intensity of roughly 90% MHR will be 14:31 (excluding time of whistle).
Note: If you have a T_SCBA of 14:81 for example – you would need to reconvert that into an actual time as minutes only go to 60, therefore 14:81 would mean an T_SCBA of 15:21.
So, What Now?
It’s evident that air consumption during the use of breathing apparatus (BA) is limited by a variety of factors, including environmental conditions, personal fitness levels, and established procedures and guidelines. However, the good news is that approximately 80% of these factors are controllable, presenting a vital opportunity to enhance firefighter performance.
Building a solid foundation of strength can lower work rate intensities, while an optimal aerobic capacity helps maintain performance over longer durations. Understanding and improving lactate threshold allows firefighters to operate at higher intensities for extended periods, promoting sustained air consumption rather than rapid depletion. Additionally, participating in air management courses has shown promise in improving these metrics (Jagim et al., 2023). I plan to delve deeper into these topics in future articles.
The key takeaway here is that predicting firefighter air consumption times can significantly benefit not only firefighters but also fire services, coaches, personal trainers, and occupational health professionals. By gaining insights into a firefighter’s fitness, tailored training programs can be developed to enhance performance, health, and air consumption efficiency. This is not just advantageous for the firefighters themselves; it ultimately benefits the communities they serve and protect.
If you're curious about your own air consumption time, I encourage you to perform the 1600m maximal test and apply the relevant equation. What do your results indicate? Are you satisfied, or is there room for improvement? If improvement is needed, consider engaging in targeted training and retest to track your progress.
You can find the study that this article has been based off by following this link: https://www.researchgate.net/publication/345494482_Aerobic_fitness_predicts_the_air_consumption_time_in_the_self-contained_breathing_apparatus_during_physical_task_of_firefighters
Be Strong. Be Reliable. Be Ready for anything.
References:
Jagim, A.R., Luedke, J.A., Dobbs, W.C., Almonroeder, T., Markert, A., Zapp, A., Askow, A.T., Kesler, R.M., Fields, J.B., Jones, M.T. and Erickson, J.L. (2023). Physiological Demands of a Self-Paced Firefighter Air-Management Course and Determination of Work Efficiency. Journal of Functional Morphology and Kinesiology, 8(1), p.21. doi:https://doi.org/10.3390/jfmk8010021.
London-fire.gov.uk. (2023). Breathing Apparatus (BA). [online] Available at: https://www.london-fire.gov.uk/about-us/services-and-facilities/vehicles-and-equipment/breathing-apparatus-ba/#:~:text=Standard%20Duration%20Breathing%20Apparatus%20(SDBA [Accessed 10 Sep. 2024].
Operational guidance Breathing apparatus. (n.d.). Available at: https://nfcc.org.uk/wp-content/uploads/2023/10/Operational-Guidance-Breathing-Apparatus.pdf [Accessed 10 Sep. 2024].
Palm, A., Kumm, M., Storm, A. and Lönnermark, A. eds., (2022). Breathing air consumption during different firefighting methods in underground mining environment. [online] ScienceDirect. Available at: https://www.sciencedirect.com/science/article/pii/S0379711222001382 [Accessed 10 Sep. 2024].
von Heimburg, E.D., Rasmussen, A.K.R. and Medbø, J.I. (2006). Physiological responses of firefighters and performance predictors during a simulated rescue of hospital patients. Ergonomics, 49(2), pp.111–126. doi:https://doi.org/10.1080/00140130500435793.
White MK;Hodous TK (2018). Reduced work tolerance associated with wearing protective clothing and respirators. American Industrial Hygiene Association journal, [online] 48(4). Available at: https://pubmed.ncbi.nlm.nih.gov/3591644/ [Accessed 11 Sep. 2024].
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