Backward Reaction Force on a Fire Hose, Myth or Reality?

Vera, Francisco; Rivera, Rodrigo; Núñez, César

doi:10.1007/s10694-014-0430-5

Cited by 7 publications

(12 citation statements)

References 2 publications

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“…(5). Hose tension is not higher for a 180° bend than for a 90° bend, as claimed by [15]. Although a bent hose tension lower than that of Eq.…”

Section: Hose Tensionmentioning

confidence: 67%

“…(5), the bent hose tension is independent of the bend angle for any non-zero bend angle. In practice the hose tension cannot be reduced by holding the end of the hose perfectly straight [14,15] because even an infinitesimal bend would yield the tension of Eq. (5).…”

Section: Hose Tensionmentioning

confidence: 99%

“…Unfortunately, no derivation or identification of the assumptions exists and recent publications have questioned these expressions [14,15]. This uncertainty may be increasing the reactions firefighters encounter and impeding the development of low-reaction nozzles [16].…”

Section: Introductionmentioning

confidence: 99%

“…Past work has noted that no general and correct solution for firefighting nozzle reaction exists [15,22]. For example, Albertson et al [23] neglected the contribution of fluid momentum to hose tension and nozzle reaction, which is not valid for typical firefighting.…”

Section: Introductionmentioning

confidence: 99%

“…Nazarenko [14] considered 3 a case where an external force is applied to the hose far from the nozzle, but this has no steady solution and is different from firefighter practice. Recent work [14,15] questioned the direction of nozzle reactions when a hose is held perfectly straight, but this is impossible in practice.…”

Section: Introductionmentioning

confidence: 99%

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Firefighter Nozzle Reaction

2017

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Nozzle reaction and hose tension are analyzed using conservation of fluid momentum and assuming steady, inviscid flow and a flexible hose in frictionless contact with the ground. An expression that is independent of the bend angle is derived for the hose tension. If this tension is exceeded owing to anchor forces, the hose becomes straight. The nozzle reaction is found to equal the jet momentum flow rate, and it does not change when an elbow connects the hose to the nozzle. A forward force must be exerted by a firefighter or another anchor that matches the forward force that the jet would exert on a perpendicular wall. Three reaction expressions are derived, allowing it to be determined in terms of hose diameter, jet diameter, flow rate, and static pressure upstream of the nozzle. The nozzle reaction predictions used by the fire service are 56 -90% of those obtained here for typical firefighting hand lines. Sharing these findings with the fire protection community can improve the safety of firefighters.

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“…(5). Hose tension is not higher for a 180° bend than for a 90° bend, as claimed by [15]. Although a bent hose tension lower than that of Eq.…”

Section: Hose Tensionmentioning

confidence: 67%

Section: Hose Tensionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Firefighter Nozzle Reaction

2017

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Quantification of radiative attenuation provided by fire hose nozzles

Suzanne

Testa

Doelsch³

et al. 2022

Fire and Materials

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The aim of this study was to investigate the radiative protection provided by various fire hose nozzles used by several Fire Rescue Services in France and to propose an experimental set-up to quantify it. This study combined the use of radiative sources (a radiant panel or a fire inside a standard shipping container) and metrological devices (radiative heat sensors, IR camera and spectrometer) to estimate the radiative attenuation of water sprays used to protect the firefighters against thermal effects which occur during a fire. For all the fire hose nozzles tested in this work, the maximal effective attenuation reaches 75%. For most of them, an increase of the flow rate improves the radiative attenuation. However, this study shows that a similar attenuation can be reached for different flow rates, suggesting that the droplet size diameter and the droplet volume fraction also play a significant role in the efficiency of the provided spray.

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