Hose Line Research Articles

On the Fire Hose Kickback Force in Solid Water Streams

This study investigates the kickback force (FK) experienced by firefighters during fire suppression using hoses of varying diameters and different nozzle sizes. Rigorous ground tests were conducted, where a fire engine was employed to propel water through a 200 ft hose line, simulating real-life firefighting scenarios while using the hip grip and clamp techniques for hose advancement. Two distinct hose sizes, 13/4 and 21/2 in., were employed with solid stream nozzles of varying diameters, facilitating the examination of kickback forces at different attacking angles. The findings substantiate that the FK exhibits variability in response to changes in the attacking angle when utilizing the clamp technique, which encompasses angles of 45°, 30°, and 15°. The 45° angle exhibits the lowest force, while the 30° angle manifests the highest force, demonstrating a notable discrepancy of up to 25% compared to the 45° scenario. The FK observed at the 15° angle for the clamp technique closely approximates the corresponding values derived from the hip grip hose advancement method. The results also underscore the necessity of regarding the NFPA nozzle reaction force as an integral component of the all-encompassing FK experienced by firefighters during hose line operations. The NFPA nozzle reaction force resulted significantly below the actual FK observed in all tested experiments, displaying the most substantial difference of 50% in the case of the 30° angle utilizing the clamp technique.

Проблема изложения требований норм в области пожарной безопасности в России

Purpose. The success of fire extinguishment directly depends on discharging the necessary and sufficient amount of extinguishing agents onto the fire. Analysis of the characteristics of modern extinguishing agents and the research works in this area has shown that when extinguishing fires at power facilities the application of water is not always appropriate, and the specifics of using other means, such as, for example, compressed air foam, have not been fully studied. The article presents the findings of the research and mathematical modeling of fluid and gas dynamics of compressed air foam through delivery hoses when extinguishing fires at power facilities. Methods. The developed measuring system, programmes and experimental techniques have been applied in the research. Existing accurate models of mathematical evaluation of fluid and gas dynamics parameters of two-phase medium have been applied for numerical modelling. Findings. As a result of experimental study and mathematical modeling pressure loss indicators have been obtained along the hose line length when compressed air foam is supplied in a wide range of expansion from 2 to 20. The relative deviation of results has been no more than 7 %. Research application field. The obtained results and further research have practical significance in improving the efficiency of fire service units in performing firefighting tasks. Conclusions. The conducted research allowed obtaining data and their application in practical activity of firefighting units will make it possible to evaluate the capacity of firefighting units in preparing preliminary planning documents for critical facilities, including power facilities, and increase the efficiency of fire extinguishment.

ОБОСНОВАНИЕ ТЕХНИЧЕСКИХ ТРЕБОВАНИЙ К РОБОТОТЕХНИЧЕСКОМУ КОМПЛЕКСУ МНОГОРЕЖИМНОГО ПОЖАРОТУШЕНИЯ

The purpose of the study is to substantiate the technical requirements for a robotic complexdesigned to eliminate man-made emergencies associated with the need to eliminate fires. Theseemergencies can occur, first of all, in radiation and chemical accidents, as well as in accidents atfire and explosion hazardous facilities. The elimination of such emergencies, as a rule, is associatedwith an increased risk for firefighters and rescuers and requires the use of heavy equipment.The article proposes a campaign that involves considering two possible options for using the complex:when extinguishing a fire over an area in the modes of a single cycle with a transportablesupply of water and when extinguishing fires in a long-term fire extinguishing mode. At the sametime, it is proposed to consider the areal fire extinguishing rate and water consumption as the main indicators for assessing the effectiveness of the complex. Under the areal rate of fire extinguishing,it is proposed to understand as the ratio of the fire extinguishing area to the time. Waterconsumption during fire extinguishing is a single value for all links in a serial chain, in the form ofwhich a scheme for supplying water to a fire source can be represented. For the first option, theamount of water flow is sequentially calculated, which depends on the pressure that is created infront of the water shaft. This indicator primarily depends on such factors as the water pressuregenerated by the pump, the pressure loss in the hose line, the excess or decrease of the water barrelin relation to the pump. According to the results of calculations for each link, the obtainedindicators are summarized. For the second option, the capabilities of the robotic complex for longtermfire extinguishing involve the use of an existing reservoir of natural or artificial origin as asource of fire extinguishing agent. At the same time, the number of factors affecting the areal rateof fire extinguishing and water consumption increases significantly. To simplify the calculations, anomogram has been developed that allows you to calculate not only the above indicators, but alsodetermine the predicted values of the time required to extinguish the fire. The data obtained as aresult of the above calculations make it possible to finally realize the main task of the studies underconsideration, that is assessment of the capabilities of a promising complex of a robotic complexfor extinguishing fires at radiation-, chemical- and explosive objects. This problem is proposedto be solved by forming the technical forms of the RTK, which can be created to solve firesat the above objects, and then by a comparative assessment of their qualities.

Physiological Demands of a Self-Paced Firefighter Air-Management Course and Determination of Work Efficiency

To assess the physiological demands of an AMC and examine differences across BMI categories. A secondary aim was to develop an equation to assess work efficiency in firefighters. Fifty-seven firefighters (Women, n = 4; age: 37.2 ± 8.4 yr.; height: 182.0 ± 6.9 cm; body mass: 90.8 ± 13.1 kg; BMI: 27.8 ± 3.6 kg·m-2) completed an AMC per routine evaluation while wearing a department issued self-contained breathing apparatus and full protective gear. Course completion time, starting pounds per square inch (PSI) on the air cylinder, changes in PSI, and distance traveled were recorded. All firefighters were equipped with a wearable sensor integrated with a triaxial accelerometer and telemetry to assess movement kinematics, heart rate, energy expenditure, and training impulse. The AMC consisted of an initial section involving a hose line advance, rescue (body drag), stair climb, ladder raise, and forcible entry. This section was followed by a repeating loop, which consisted of a stair climb, search, hoist, and recovery walk. Firefighters repeated the course loop until the self-contained breathing apparatus air supply pressure reached 200 PSI, at which time they were instructed to lay down until the PSI reached zero. Average completion time was 22.8 ± 1.4 min, with a mean distance of 1.4 ± 0.3 km and an average velocity of 2.4 ± 1.2 m·s-1. Throughout the AMC, the mean heart rate was 158.7 ± 11.5 bpm equating to 86.8 ± 6.3% of the age-predicted max heart rate and a training impulse of 55 ± 3 AU. Mean energy expenditure was 464 ± 86 kcals and work efficiency was 49.8 ± 14.9 km·PSI-1·s. Regression analysis determined that fat-free mass index (R2 = 0.315; β = -5.069), body fat percentage (R2 = 0.139; β = -0.853), fat-free mass (R2 = 0.176; β = -0.744), weight (R2 = 0.329; β = -0.681), and age (R2 = 0.096; β = -0.571) were significant predictors of work efficiency. The AMC is a highly aerobic task with near-maximal heart rates reached throughout the course. Smaller and leaner individuals achieved a higher degree of work efficiency during the AMC.

Investigation of the technical condition of mechanical engineering objects based on computer modeling on the example of the development of clamps for troubleshooting fi re hoses

The technical state of mechanical engineering objects was investigated on the basis of computer modeling using the Autodesk Inventor computer-aided design system with the "Form Generator" calculation module. The developed designs of devices for troubleshooting fi re hoses were used as objects. Several new device designs are considered, which allow eliminating such malfunctions of pressure fi re hoses as cuts, punctures, burnouts, etc., as well as restore the operability of the hose line in the event of disconnection of the fi re hose from the connecting head.

Снижение рисков при тушении пожаров в суровых климатических условиях

The sustainability of the development of the northern territories of Russia from the Urals to the Pacific Ocean, where the bulk of the country natural resources is concentrated in the twenty-first century, is determined by the integrated approach to planning and managing the risks of using machines, structures and equipment, critical and hazardous industrial facilities and technological support and support at the stages of their operation. Climatic factors have a noticeable effect on increasing the risks of abnormal situations occurrence in emergency situations, for example, on the efficiency of fire departments activity in the winter period of the year and at extinguishing fires in harsh climatic conditions, when water may freeze inside the hoses and in the working chamber of the feed pump. Due to a malfunction in the fire equipment, the scale of the territory covered by the flames can significantly increase, and the extinguishing process will become more complicated. Operability of the hose lines in low temperature conditions is calculated using Methodological Recommendations for ensuring the operability of pump and hose systems of fire trucks when extinguishing fires in the conditions of extremely low temperatures, determining the maximum length of the hose line before icing begins. It is shown in the paper that the maximum length of the hose line, that is, the distance from the pump to the beginning of icing, should be calculated using the heat balance equation, which is based on two equations of the first law of thermodynamics — for flow and heat transfer. At the same time, it is required to combine thermal and hydraulic calculations. The methods are presented in the article for predicting the operability of pumps and hose lines in the conditions of extremely low ambient temperatures, used in fire truck systems for extinguishing fires, including at the energy facilities. It is shown that there are errors and shortcomings in the Methodological Recommendations for ensuring the operability of pump and hose systems of the fire trucks when extinguishing fires in the conditions of extremely low ambient temperatures, including at the energy facilities. It is also shown that the maximum length of the hole line, that is, the distance from the pump to the beginning of icing, should be calculated using the heat balance equation, which is based on two equations of the first law of thermodynamics — for flow and heat transfer.

Расчетное обоснование применения рукавов больших диаметров в насосно-рукавных комплексах при ликвидации чрезвычайных ситуаций

Pumping and hose complexes are one of the most efficient technical means used for supplying large volumes of water (up to 200 l/s or more) or drainage over significant (hundreds of meters) distances. Transportation of water and other technical fluids is carried out by hoses of large (over 150 mm) diameters. Operational experience showed that the use of hoses with a diameter of over 250 mm causes small losses of water pressure during transportation along the hoses, but negatively affects the operational and tactical capabilities of the complexes. Due to the large mass of the transported hoses and the significant load on the chassis, the off-road passability of the complexes is reduced; deploying a hose line in a complex natural and urban landscape and cleaning it after an emergency is time-consuming with the involvement of the great number of the uniformed force. The problem of creating new generation pumping and hose complexes required optimization of the diameter of the pressure hoses for ensuring transportation of the maximum possible amount of water over the required distances without critical pressure losses. The performed calculations show that the optimal pressure hose diameter is 225 mm considering technical characteristics of the applied pumping units. Using them it is possible to deploy the hose line at distances from 450 to 1000 m and more depending on the amount of the transported fluid and its pressure at the end of the hose line. Due to the lower mass of the linear meter of the hose and connecting heads, the load on the chassis and on the device for mechanical unfolding and cleaning of the hoses is reduced by more than 29 %, the reliability of chassis units and assemblies and the superstructure of the pumping and hose complexes increases. Correctness of the performed calculations is confirmed by their practical application at the development of the work execution plan on pumping a water-diesel mixture from the emergency zone in the Norilsk region.

Исследование параметров интенсивности охлаждения компрессионной пены при подаче по насосно-рукавным системам в условиях низких температур

Introduction. The article describes a methodology and a program of experimental studies to determine the parameters of the cooling strength of compression foam when feeding through pumping and hose systems at low temperatures. The numerical values of the parameters of the cooling strength of the compression foam when feeding through the fire hose 20 m long are determined. The experimental dependences of the parameters of the cooling strength of the compression foam on the multiplicity and mass flow are obtained. Goals and objectives. A program and methodology for experimental studies to determine the parameters of the intensity of cooling of compression foam when feeding through pumping and hose systems has been developed. To carry out experimental studies, the following tasks were set: - development of a measuring complex for determining the parameters of the cooling strength of compression foam when feeding through pumping and hose systems at negative temperatures; - determination of the physical model of the movement of the compression foam when feeding through the fire hoses; - development of a program and methodology for experimental research to determine the mass flow rate of compression foam. Methods. Methods of mathematical analysis of statistical data obtained during experimental data were used to determine the parameters of the cooling strength of compression foam when feeding through the pumping and hose systems. Results and its discussion. The numerical value of the cooling of the compression foam when feeding through the pumping-hose systems at low temperatures was obtained experimentally, depending on the multiplicity along the length of the hose line. Conclusions. 1. A program and methodology for conducting experimental studies to determine the parameters of the cooling strength of compression foam when feeding through pumping and hose systems at low temperatures has been developed. 2. As a result of the experimental studies, data were obtained on the rates and parameters of the cooling strength of the compression foam when feeding through fire hoses in winter at various negative temperatures. To measure the parameters of the cooling strength of compression foam when feeding through fire hoses at negative ambient temperatures, a measuring complex was developed and assembled. 3. The data obtained will make it possible to evaluate the parameters of the compression strength of foam cooling when feeding through the pumping and hose systems at low temperatures. Keywords: intensity of cooling, compression foam, foam-air mixture, pumping-hose system, foam generating unit, a unit for generating and supplying compression foam, low temperatures

Search & rescue operations during interior firefighting: A study into crawling speeds

Firefighters perform search operations during fires in order to rescue people. Full-scale tests to evaluate the effectiveness of the techniques used to search a room have been organized in the absence of fire. 42 search crews completed 7 different set-ups. The crews consisted of Belgian and Dutch firefighters as trained to date. They searched four 12 m2 bedrooms and three 31 m2 office spaces. Searching an empty space was compared to searching a furnished space. The impact of using a hose line was evaluated. 4 min is a good order of magnitude for the search of a bedroom. The time needed increases with increasing surface, but not proportionally. Crews can search a larger area per unit of time in the 31 m2 office than in the 12 m2 bedroom. The average air consumption rate in the breathing apparatus is 68–70 lpm for both rooms. When using a hose, the search becomes longer in time and takes a higher air consumption rate (average: 84 lpm). The decision to take a hose line or not is therefore very important. Crews where the two firefighters are side by side are more effective than crews where they are behind the other.

On unmanned aircraft systems application for fire extinguishing in high-rise buildings

Introduction. The purpose of the study is to formulate and analyze problems that should be solved before implementing the ideas of fire fighting in high-rise buildings by using unmanned aircraft systems (UAS). To achieve this purpose, the following concepts were considered and assessed: the possibilities of water and water-based fireextinguishing solutions delivery to the fire source from a ground pumping station using a hose line; delivering compression foam along a vertically positioned hose line; and, the possibilities of UAS for fire extinguishing; supply of fire extinguishing powders and aerosols placed on the UAS to the center of fire. Methods. The adopted in Russia hydraulic calculation methods, the results of the experimental studies on the compression foam, the existing theoretical and practical advances in the field of fire-extinguishing by jet delivering fire-extinguishing substances. Conclusions. The results achieved show that one of the ways to increase fire extinguishing capability in high-rise buildings can be provided by applying UAS for continuous horizontal supply of water based solution or compression foam to the center of fire, as well as supply of fire extinguishing powders and aerosols using powder fire barrels and pyrotechnic cartridges. However, to implement each of these methods, certain problems need to be solved. They are: the fire extinguishing height limitations a large capacity of UAS needed; a hydraulic calculation methodology for compression foam supply systems; safe use of UAS under the conditions of compression foam separation; the possibilities for developing supply equipment, which can be utilized by the UAS.

Multi-scale analyses of a floating marine hose with hybrid polyaramid/polyamide reinforcement cords

This study reports a multi-scale structural analyses of a mainline floating double carcass marine hose (nominal diameter 508 mm, length 10.7 m, design pressure 2.1 MPa, weight 4100 kg). A material change in the reinforcement cords of the traditional hose is proposed, from polyester and polyamide to hybrid aramid/polyamide cords, allowing an improvement in design, reducing weight and increasing flexibility. Two models have been developed to obtain the hose responses. Firstly, a finite element model of the traditional system was built to perform a macro-scale analysis of global hydrodynamics loads in the hose line using Orcaflex™ software. Then, a non-linear finite element model was developed for meso-scale analysis using Abaqus™ software. Rubber and cords were modeled using hyperelastic models, and axial, bending and torsional stiffnesses were evaluated. Experimental tests were carried out to assess the mechanical response of an actual full-scale hose. The reduced number of layers of the hose using hybrid cords, compared to the traditional one, allowed a reduction in weight of 15%, and brought also a decrease in specific axial, torsional and bending stiffnesses of 43.9%, 52.2% and 21.6%, respectively. The multi-scale analysis predicted well the structural response of the hose line, and the reduced potential failure may increase life-time of the structure.

Особенности применения пеногенерирующих систем со сжатым воздухом для тушения пожаров

Проведен анализ результатов экспериментальных исследований пеногенерирующих систем со сжатым воздухом, приведен пример использования инженерной методики гидравлического расчета рукавных линий при движении компрессионной пены. По результатам теоретических и экспериментальных исследований сформулированы особенности применения пеногенерирующих систем со сжатым воздухом для тушения пожаров, которые учитывают отличие их тактико-технических характеристик от традиционных технологий пенного пожаротушения. Это позволило определить область применения пеногенерирующих систем со сжатым воздухом.

Pressure Losses in a Hose Line during Water Transfer to Fires

The article deals with an issue of length pressure losses in hose line during water transfer to fires. It compares currently used attributes of pressure losses, pressure losses by hydrodynamic laws and experimentally determined pressure losses in the hose line. It designs adjustments of the constants used for the simplified calculation parameters of water transport.

Факторы, определяющие тактический потенциал подразделений пожарно-спасательного гарнизона в условиях экстремально низких температур

Extinguishing fires in low temperature conditions presents special challenges in view of the fact that there are breakages of mobile fire extinguishing means, reduction of supply of fire extinguishing substances, owing to frosting of hose lines and fittings. Development of the fire to the large sizes in the conditions of low temperatures will depend in many respects on level of training of staff, the equipment technology, and also on extent of influence of climatic factors on mobile means of suppression of the fires. There is a situation when water supply decreases by fire extinguishing over time, and because of influence of a climatic factor it isn’t possible to use the tactical capacity of divisions of rescue and fire fighting garrison. The results of a research directed to definition of intensity of frosting of hose lines and hose fittings depending on various factors are presented in this article. Methods. Measuring complexes which allowed to take water temperature in each point of pumping and hose system of the fire truck developed by the staff of State Fire Academy of Emercom of Russia were used for conducting pilot study. Results. As a result of the conducted researches it was established that possibility of chilling of water in the hose line and fittings depends on temperature of air, speed of wind, diameter and material of a fire hose, a water consumption in the hose line. On the basis of the received results of researches the mathematical model for assessment of parameters of work of hose lines in the frosting mode is offered. Research application field. The received results allow to estimate previously possibilities of firefighters of divisions in case of suppression of the fires in the conditions of low temperatures. Conclusion. As a result of the conducted researches the technique of assessment of operability of the pressure head hose lines functioning in the conditions of low temperatures is formulated.

Simulation of an Attic Fire in a Wood Frame Residential Structure, Chicago, IL

The fire dynamics simulator (FDS) fire model, which is developed and maintained by the National Institute of Standards and Technology (NIST), was used to provide insight into the dynamics of a fire that occurred on November 2, 2012, within a 2 ½ story, single family structure in Chicago, IL, that resulted in the death of the captain of a fire department. The inputs for the FDS simulations are documented in this report and are based on the fire scenario, including the building geometry, interior furnishings, and ventilation conditions. The fire started in the attic and spread down through an opening into the enclosed porch on the rear of the structure. This resulted in ventilation limited (fuel rich) fire conditions in the attic and rear porch areas. Further spread of fire and hot gases from the attic downward into the second floor of the structure was limited by a closed steel-faced, wood-framed door. Note that there was no evidence of fire damage on the first floor of the structure. After exposure to the elevated temperatures and pressure from the fire in the porch area, the wood frame of the door decomposed, the steel faces of the door failed, and the door collapsed inward. The door failure resulted in the establishment of a flow path between the higher pressure and higher temperature conditions in the enclosed porch and the lower pressure and lower temperature conditions in the hallway and kitchen areas of the second floor. The temperature of the gases that flowed into the hallway exceeded 260°C (500°F) at a height of 1.86 m (6 ft). Unfortunately, a captain and firefighter were advancing a hose line in the hallway near the door at the time of the door failure. It appears that the captain was likely overcome by the rapid change in conditions before he could exit to the safety of the kitchen area. After a Mayday call, the captain was rescued from the structure, but later succumbed to his injuries.

Characterization of 17β-hydroxysteroid dehydrogenase type 4 in human ovarian surface epithelial cells

The human ovarian surface epithelium (hOSE) is a single layer of mesothelial-type primitive epithelial cells that are potential estrogen targets. It has been reported that hOSE cells can produce estrogen. However, the mechanisms that regulate estrogen level(s) in hOSE cells are not yet known. To elucidate the enzymes involved in these reactions, we examined gene expression of 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) in primary hOSE (POSE) and OSE2a cells using RT-PCR. We found that POSE cells and cells of the immortalized hOSE line, OSE2a, bidirectionally converted estrone (E1) and 17beta-estradiol (E2). Both cell types expressed mRNA for 17beta-HSD type 1 (17beta-HSD1), suggesting that the enzyme is involved in the E1 to E2 conversion. Interestingly, both cells expressed 17beta-HSD4 mRNA but not 17beta-HSD2 mRNA. We prepared an antibody against the carboxyl terminal of 17beta-HSD4 (anti-17beta-HSD4 antibody), which recognized the 80 and 48 kDa proteins in POSE and OSE2a cells based on immunoblot analysis. Furthermore, immunohistochemical study revealed the presence of 17beta-HSD4 in hOSE cells in the human ovary. These results suggest that 17beta-HSD4 is involved in estrogen inactivation and may protect against an excessive accumulation of E2 in hOSE cells.

Fuzzy Identification of Hydraulic Systems

The paper presents an identification algorithm in fuzzy modeling using only experimental input/output data of the physical system. The fuzzy identification and modeling provides a method to describe the dynamical behaviour of complex, ill-defined and/or nonlinear systems. The identification using linguistic rules provides a method for modeling, which operates without explicit knowledge of the physical components of the process. The paper evaluates the steps for deriving a fuzzy model from input/output data. The algorithm is verified via experiments for a hydraulic system, which consists of a hydraulic cylinder, a valve, a pump, an accumulator, a tube and a hose line.

Critical review of international standards for respiratory protective equipment - III. Practical performance tests.

This paper, the third in a series of papers devoted to review of international standards for Respiratory Protective Equipment (R.P.E.), summarizes in tabular form, compares, and critically reviews standards of different countries or organizations pertaining to practical performance tests (Man Tests). There are similarities, differences and omissions in the national standards that deserve attention. Of the countries or organizations that require Man Tests on particulate and/or gas and vapor respirators, none described in detail the tests to be performed. For example, CEN requires that Man Tests be conducted on gas/vapor respirators under realistic conditions to determine imperfections that cannot otherwise be determined by other performance tests, but does not stipulate the testing procedure. With respect to fresh-air hose, compressed-air line and self-contained breathing apparatus R.P.E., only Great Britain and CEN present specific Man-testing requirements in detail. Man Tests for all types of R.P.E. have a specific purpose: to determine any imperfections in, or malfunction of the apparatus under simulated work conditions. One major difference, however, is in the kind of work simulation activities required. In the testing of fresh-air hose and compressed-air line respirators, for instance, CEN describes in great detail, a variety of activities to be conducted. Great Britain merely states that the subjects shall work in practical conditions. Another important disparity relates to the conditions under which the test is to be performed. For example, CEN requires a heavy-duty test and a cooled chamber test, as well as tests under normal and low temperature conditions. Great Britain, on the other hand, requires only the latter two tests. Still other differences lie in the kinds of medical surveillance required during testing and the evaluation criteria used for assessment.

Problems Encountered in Laying Mains

The first problem I will touch upon will be temporary service. A great many private business institutions which include manufacturing plants, dairies, beauty parlors, hospitals, doctors, dentists, and schools, are so dependent upon water that they in some cases wTould have to close down entirely or it would be unhealthy to operate. There have been times when private services have broken and buildings and institutions have called upon the water department for a temporary supply. Whenever possible a hose line is run from the nearest hydrant and connected at the meter. Hose have been run from building to building. In such cases the meters were removed so one consumer would not be charged for another's consumption. On one occasion some repair work was necessary on a main abutting one of the large dairy companies of the city. This company, you can realize, could not operate without water. The consumption was so great and the hose line of such a length and size as to be inadequate. The Milwaukee Fire Department was called upon for a pumper to boost the pressure and quantity, which they furnished very willingly. The Milwaukee Fire Department has helped the Water Department on a number of occasions. In 1932, a cross-connection was made in Arnauld Ave. between the old 30-inch feeder main, which supplied the City of West Allis, Village of West Milwaukee, and the southwest section of the City of

Test of a Motor Fire Engine

Abstract The paper contains the results of a test of a Seagrave motor fire engine having a 4-cycle, water-cooled, six-cylinder motor, 5¾ in. cylinder bore by 6½ in. stroke, 79.3 hp. by A.L.A.M. rating. The motor operated a four-stage centrifugal pump with balanced end thrust. The maximum capacity was found to be 745 gal. per min. at 122 lb. pressure at discharge of pump, with 2-in. smooth nozzle and 250-ft. hose line with Siamese union. Gasoline used per hour, 0.218 gal. per hp. at rated load. With coal at $2 per ton (2000 lb.) and gasoline at 25 cents per gal., the cost of producing a fire stream with the motor fire engine is four times that with a steamer. As compared with the horse-drawn engine the motor engine can reach a fire in half the time, is readily converted from locomobile to pumping engine, is more easily and economically operated, and eliminates entirely the expense of maintaining horses for transportation. Its duty is nearly six times that of a steamer.