This from Bill Post: The Chicago Fire Department’s union chief on Wednesday brandished a new federal report on fighting high-rise fires to push back against potential job cuts as part of protracted labor negotiations with Mayor Rahm Emanuel’s administration. The study by the U.S. Commerce Department, the national firefighters union and other organizations focused on response times to blazes in 13-story buildings and found that crews of five or six firefighters put out fires and conducted search-and-rescue operations “significantly faster†than three-person or four-person teams. The Fire Department contract that lapsed in June requires five firefighters per truck, but Emanuel has left open the possibility of reducing staffing levels. There has been little progress in negotiations since then, but firefighters must work under the old rules for now. While most of Chicago’s high-rises are concentrated downtown and along the lakefront, Firefighters Union Local 2 President Thomas Ryan argued that other large buildings like schools and factories are found throughout the city and present many of the same challenges. He argued that the report “scientifically proves what we’ve been saying for years†and said cutting the number of firefighters at any firehouse in the city would put the public at risk. Administration spokesman Bill McCaffrey said high-rise fires are relatively infrequent, so the report represents “a very small portion of properties and fires in the city.†“And Chicago has highly skilled and well-equipped high-rise response teams, a recently rewritten high-rise response protocol and strict requirements for fire safety in high-rises — these are the most critical factors in maintaining safety in high-rises in Chicago,†McCaffrey said in an email. Information about the study can be found HERE. Excerpts from the press release: Landmark High-Rise Fire Study Evaluates Effectiveness of Crew Sizes, Elevator Use PHOENIX – When responding to fires in high-rise buildings, firefighting crews of five or six members—instead of three or four—are significantly faster in putting out fires and completing search-and-rescue operations, concludes a major new study* carried out by the National Institute of Standards and Technology (NIST), in cooperation with five other organizations. Results of the study, carried out with 13 Washington, D.C.-area fire departments, were presented today at the 2013 Metropolitan Fire Chiefs Conference in Phoenix. “Unlike most house fires, high-rise fires are high-hazard situations that pose unique operational challenges to fire service response. How big a fire gets and how much danger it poses to occupants and firefighters are largely determined by crew size and how personnel are deployed at the scene,†says lead researcher Jason Averill, a NIST fire protection engineer. “It’s not simply that larger crews have more people. Larger crews are deployed differently and, as a result, are able to perform required tasks more quickly.†An analysis of 14 “critical tasksâ€â€”those undertaken when potential risks to building occupants and firefighters are greatest—found that three-member crews took almost 12 minutes longer than crews of four, 21 minutes longer than crews of five, and 23 minutes longer than crews of six to complete all tasks. Four-person crews took nine minutes and 11 minutes longer than five- and six-member crews, respectively. The study also looked at the effect of using fire service access elevators to move firefighters and equipment up to the staging floor and concluded that most tasks were started two to four minutes faster when using the elevators compared with using the stairs. On the basis of the results of computer modeling, which incorporate data from live experimental burns, the study team concluded that smaller crews end up facing larger fires because of the additional time required to complete tasks. A three-person crew, for example, would battle a medium-growing blaze that is almost 60 percent larger than the fire faced by a six-member crew, which would start extinguishing a fire roughly three-and-one-half minutes earlier. In an office building, this difference is equivalent to four employee cubicles on fire for a three-person crew versus two cubicles for a six-person crew. Comparing the performances of different-sized crews, the researchers found that adding two members to three- and four-person teams would result in the largest improvements in starting and completing critical tasks, such as advancing the water hose to the fire location and beginning search and rescue. Improvements ranged from one minute to 25 minutes, depending on the task. The research team also evaluated whether dispatching more three or four-member crews to a high rise fire—accomplished by sounding a higher initial alarm—would be as effective as sending a low first alarm contingent of engines and trucks staffed by more firefighters. They found that a “low-alarm response with crews of size four or five outperforms a high-alarm response with crew sizes smaller by one firefighter.†“Prior to this experiment, some fire departments attempted to deploy with smaller crews on each piece of apparatus,†explains Lori Moore-Merrell of the International Association of Fire Fighters, a co-principal investigator for the study. “The logic suggested that, if the fire is big enough, just send more units, but it ignores the fact that larger crews have tactical advantages that reduce risk exposure to people and firefighters. Crews of six and even five can carry out crucial tasks in parallel rather than in series. Saving time can save occupant lives and prevent firefighter injuries and property damage.†The National Fire Protection Association (NFPA) defines high-rises as buildings that are seven stories or taller, the height that exceeds most types of fire service ladders. In most U.S. communities, new high- rises are required to have automated sprinkler systems, which are designed to control the spread of fires, not to extinguish them. But according to the NFPA, 41 percent of U.S. high-rise office buildings, 45 percent of high-rise hotels, and 54 percent of high-rise apartment buildings are not equipped with sprinklers, as compared with 25 percent of hospitals and related facilities. Moreover, sprinkler systems fail in about one in 14 fires. While much less frequent than house fires, about 43 high-rise fires occur in the United States every day. Between 2005 and 2009, according to the NFPA, high-rise structure fires averaged 15,700 annually. Average annual losses totaled 53 civilian deaths, 546 civilian injuries and $235 million in property damage. Shot Blasting And Cleaning Machine
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The shot blasting machine uses the steel shot to be sent to the high-speed rotating disc, and uses the centrifugal force to make the high-speed thrown steel shot hit the surface of the part to achieve the purpose of polishing. The shot blasting machine can generate compressive stress on the surface of the part, Moreover, there is no silicon-containing powder, and the pollution to the environment is small.
The main uses of the shot blasting machine are as follows:
â‘ The shot blasting machine generates compressive stress on the surface of the parts, which can improve their fatigue strength and ability to resist tensile stress corrosion;
â‘¡The shot blasting machine can correct the distorted thin-walled parts;
③The process of shot blasting cleaning machine replaces the general cold and hot forming process, and the forming of large thin-walled aluminum parts can not only avoid residual tensile stress on the surface of the parts, but also obtain favorable compressive stress for the parts. It should be noted that the use temperature of the parts processed by the shot blasting machine should not be too high, otherwise the compressive stress will automatically disappear under high temperature, thus losing the expected effect. Their operating temperature is determined by the material of the parts. For general steel parts, it is about 260-290 °C, and aluminum parts are only 170 °C.
The shot blasting cleaning machine is realized by relying on the high-speed rotating throwing head to vigorously throw the abrasive particles to the surface of the workpiece, and there are several blades inside the throwing head.
When working, the abrasive enters the center of the throwing head through the feeding port. There is a shot dividing wheel in the center of the throwing head that rotates with the throwing head. The outside of the shot dividing wheel is a directional sleeve. Send to the end of the blade near the center of the throwing head. Due to the centrifugal force, the abrasive particles are accelerated along the length of the blade until they reach the tip of the blade and hit the workpiece surface at a very high speed.
The function of the pelletizing wheel is to correctly "feed" the abrasive to the blade according to certain requirements. Once the opening of the pelletizing wheel is seriously worn, the abrasive will hit the end of the blade, causing abnormal wear of the blade, and the divergent flow of the abrasive will become without rules. Therefore, it is necessary to regularly check the wear of the pelletizing wheel according to the requirements of the instruction manual and replace the severely worn pelletizing wheel in time.
The location of the directional sleeve opening determines where the abrasive is fed to the blades by the pelletizing wheel. The shape of the opening on the directional sleeve affects the shape of the abrasive divergence and the size of the hot zone. The so-called hot zone, even an area where the abrasive is concentrated on the abrasive diverging surface, is caused by the uneven distribution of the abrasive on the blade. The positioning of the adjustable directional sleeve can be properly adjusted according to the wear of the opening to ensure that the throwing head works in a good operating state.
The blades in the throwing head are in direct contact with the abrasive, and its quality is closely related to the performance of the throwing head.
The wear resistance of the blade directly determines the life of the blade and the operating cost of the shot blasting machine. Therefore, the blades of the blasting head must be made of high wear-resistant materials. The wear resistance of the blade is not only related to the material of the blade, but also closely related to the working conditions of the shot blasting machine. For example, if there is 1% sand in the abrasive, the life of the blade will be shortened by 80%. It is not an exaggeration to say that the life of the separation device determines the life of the shot blasting machine.
Worn or cracked blades can cause vibration when the impeller rotates at high speed. Therefore, the integrity of the blades should be checked frequently, and the defective blades should be replaced in time. In order to ensure the stability of the throwing head, the blade replacement must be carried out in pairs, that is, the blade opposite to the unsatisfactory blade must be replaced at the same time to obtain a good dynamic balance. If it is suspected that a problem with the blades is causing the throwing head to not work properly, all blades need to be replaced.
The casting defect of the blade will inevitably accelerate the wear of the blade, which is even more serious when chilled cast iron shot is used as the abrasive. After analyzing the worn blades, it is believed that the blades with casting defects will cause the abrasive particles to bounce during the movement. If there is sand in the abrasive, it will increase the wear of the blade.
Yesterday the National Institute of Standards and Technology released a high rise fire fighting  study at the Metropolitan Fire Chiefs conference meeting in Phoenix Arizona. The Chicago Fire Fighters Union Local 2 has already cited it in an effort at negotiations with the city as to why the Chicago Fire Department can’t afford to cut crew size.
From the Chicago Tribune: