Positive pressure ventilation (PPV) has been a common and growing practice throughout the fire industry worldwide. Over the past few years PPV fans powered by batteries have grown substantially in popularity, and with it a host of claimed benefits from those pushing the products. However, in the firefighting industry, selecting the most effective tool for the job has an added degree of importance. In this article we highlight some things that may be of interest if you’re considering jumping on this bandwagon.
Anything ‘battery-powered’ is dealing with a limited power source and in the race to effectiveness to stretch every watt of the limited power available. A common pulse of effectiveness is volumetric airflow (VAF), so claims of CFM (cubic feet per minute) or m3/h (meters cubed per hour) are eagerly thrown around in hopes of catching an interested ear. But higher VAF figures consume that precious fuel, as do the characteristics of the fan. Most battery-powered PPV fan manufactures have focused production efforts on fans wielding 410mm (16in) and 460mm (18in) propellers. The smaller the propeller, the less interaction with air per rotation, so to achieve a similar VAF as a fan with a longer propeller, the small blade must consume more watts for the same outcome. For instance, if a fan with a 460mm (18in) propeller required 1,000W to create 10,000 CFM, it would require 1,600W to create the same VAF if that same were designed to use a 410mm (16in) propeller, a significant increase in power consumption.
If a fan manufacturer does design a fan with a smaller propeller and does provide the additional power it will need to produce a similar VAF, it does not negate the fact that a larger jetstream of air will create higher airflow. A larger fan blade will inherently produce a larger jetstream, resulting in higher entrainment, and ultimately higher pressure in the structure. Increased pressure in the structure means increased air flow through the structure. That means ventilation jobs are more effective and completed in less time.
The unpredictable demands and challenges a firefighter may face require many specialized tools. These tools occupy compartment space on the apparatus, and the firefighter must transport the tools needed from the apparatus for deployment. Thus, storage and portability are important considerations. The paragraphs above point out why a larger propeller would be better; however, fans with larger propellers tend to be significantly bigger overall and heavier, increasing storage costs and portability effort, not including any external chargers that may be needed. For example, the space the fan takes up (WxHxD) in inches really shows the space you lose as you increase in propeller size. One manufacturer has a fan with a 16in propeller and the space that fan takes up is 6,416 cubic inches. They also make fans with 18in and 20in propellers. The space these fans take up is 8,200 cubic inches and 10,150 cubic inches, respectively. Increased size and weight can negatively impact tool availability options and can create portability and deployment challenges. Firefighters can encounter some of the harshest environments in exceptionally stressful situations with seemingly insurmountable challenges. The last thing they need is to have limited access to tools they need and additional challenges with using the ones they were able to bring.
BlowHard starts with pushing performance to very high levels. Then we look at what we call ‘relative storage’ and ‘relative portability’ to try to maximize our service to the firefighter without impacting the total service the firefighter ultimately needs. Relative Storage looks at performance relative to the space the tool will take up. High relative storage values suggest the tool performs well for the physical space it occupies. Low relative storage values may suggest the tool may perform OK but takes up a lot of space. Relative portability looks at performance relative to weight of the tool. High relative portability values suggest the tool performs well for its weight, while low values suggest it is quite heavy for the job it gets done.
The BlowHard Quickee has a 508mm (20in) propeller with every bit of the performance one would expect from a fan with this size propeller. Yet the Quickee takes up less space than any other battery-powered PPV fan that we’re aware of on the market, holding its place as #1 in the ‘Relative Storage’ category. The Quickee is one of the lightest battery-powered PPV fans as well.
The BlowHard Commando has a 610mm (24in) propeller. Its unmatched performance is in a league of its own, outperforming some gas-powered fans. Yet this ultra-powerful fan takes up less space than the smaller fans referenced above, occupying only 6,761 cubic inches of space. The Commando is also lighter than many of the smaller fans, placing it in the #1 spot for the ‘Relative Portability’ category.
In the firefighting world, things happen quickly and seconds matter. Underperforming tools can allow things to get out of control quickly. Demanding high performance should not come at the cost of additional challenges to overcome. BlowHard offers high performance with a small footprint that is easy to deploy.
For more information, go to www.blowhardfans.com
About the Author
Benjamin Hadlock is Vice President of BlowHard.
For nearly 10 years Benjamin has been a driving force in BlowHard’s strategic journey in the research and quantification of fan performance as part of product development. These efforts by BlowHard have redefined the capabilities of PPV fans, specifically with regard to overall fan effectiveness while leveraging the convenience and power of the latest battery technology. Helping to lead the quest to be a true service to the fire industry, he has been instrumental in the release of the new fan series using High Flow Jet Technology from BlowHard.
