College】 【weak Direct Fired Chiller Discussion Fire.

<br> <BR> recent years, increasing high-rise buildings, extensive use of city gas, natural gas direct-fired chiller (the natural gas unit) is widely used. .Many tall buildings in the design of natural gas units will be set in the ground floor, the ease of urban land use stress, can also do basement car park. .But the state, "Fire Protection Design of Tall Buildings" (hereinafter referred to as "high regulation") which has no specific requirements, in order to better adapt to and serve the economic construction and social development, to propose some views, for study. .<BR> 1, the working principle of gas units and fire risk <BR> units from high and low voltage generator, condenser, evaporator, absorber and other major equipment components. .Using lithium bromide solution as absorbent, the use of such solutions within the high voltage generator in a closed, heated to boiling, the resulting water vapor into the water heater, so that the hot water heating. .Concentrated solution and refrigerant mixture of dilute solution of water and sent to high-voltage generator and heating cycles to complete the heating process. .<BR> Cooling cycle from the dilute lithium bromide solution is thickened, and then thinning the thick, water from the liquid refrigerant into vapor and then vapor into liquid by the circulation process, the heat absorbed during the cycle, .to achieve the purpose of cooling. .<BR> Natural gas unit is the use of the properties of lithium bromide solution, burning natural gas, the absorption and release heat, air conditioning required for preparation of cold and hot water. .Unit is in operation of vacuum equipment, non-explosive, but as the source of the fuel gas is a certain fire risk. .Northern natural gas composed mainly of methane, the relative density of 0  6 (air is 1) lighter than air, the explosion limits of 5 to 15%, and an A hazardous materials fire, there is a risk of explosion. .<BR> 2, natural gas units set within a two-story high-rise building underground feasibility <BR> (1), natural gas unit has been available for over 30 years of lithium bromide, is also used in China for over ten years. .With the use of high technology, the units are equipped with automatic control system can monitor the unit at any time the operational status of various parts, on-site, remote and automatic gas resources can be shut down, stop machine operation. .The unit itself is working less fire hazard. .<BR> (2), working status for the vacuum unit itself <BR> components of natural gas unit in working condition, no high-pressure conditions, are vacuum equipment, in the negative pressure operation, the unit itself can not explode .. .<BR> (3), unit set the place on fire safety is to prevent gas leakage. .Modern fire safety technology <BR> A and B gas fire fighting, the main gas source is cut off to prevent gas leakage aggregation. .Gas in the lower explosion limit is not reached, remove explosive gas mixture. .Place to install natural gas units set the concentration of combustible gas alarm systems, early detection can automatically shut off the gas gas source, open delivery, exhaust system, automatic fire extinguishing system, turn off the unit. .<BR> (4), natural gas units set the place (the room) the fire safety problems are mainly <BR> room explosion proof problem is a problem, especially for high-rise buildings set within a basement room is more prominent. .Engine room fire safety depends on its premises is set reliable fire alarm, automatic fire extinguishing system and the quality of their units, including the installation of gas piping, valves and so on. .<BR> (5), lifting the engine room can be used as a pressure relief area of the wellhead, to solve the problem of the engine room explosion <BR> of "high regulation" Article 4.1.2 states: "The oil, gas boilers should be set at the top ... ... .Construction outside the rooms, the ... ... When the above conditions must be arranged to set the device in high-rise building or podium should be arranged in the first floor or basement area by the wall ... .... "Accordingly gas boiler can be set at the top .building, then the unit compared with the gas boiler, the unit's fire risk is lower than gas-fired boiler. .Units installed in high-rise buildings and special rooms in the basement, in a reliable security measures, should be feasible. .<BR> From several domestic projects, such as Beijing Tao Ran Building, Shaanxi Trust Building, ground floor and other projects look set to the engine room, the use of the lifting unit as a pressure relief surface wellhead, the calculation of the pressure relief ratio, are in line with standard requirements .. .Wellhead pressure relief by lifting their hoisting shaft space is not listed in the explosion area, and hoisting shaft in the engine room wall or door between the set of light, as the relief area. .<BR> Sum up, room set in the ground floor, in a reliable fire safety measures, should be safe and reliable. .<BR> 3, set the ground floor in the high-rise building fire safety measures within the room <BR> (1), units should be deployed in crowded places or affixed adjacent to the next level, holes in the engine room fire protection materials with tight sealing ., and using no windows and doors, fire resistance of the hole in the wall of not less than 2.00h and 1.50h the floor and other parts of the separated, as little as possible open the door. .When to open the door, should be set outside the open self-closing fire doors grade. .<BR> (2), room and pillar sides and top of the welcome blast explosive decompression board surface should be installed to reduce explosion peak pressure generated by the explosion, protecting the main structure. .<BR> (3), units should be arranged in the ground floor or external wall by wall parts of the safety of evacuation export not less than two. .<BR> (4), loading port should be used as a pressure relief area of lightweight materials, but not the ordinary glass as a pressure relief area, the accumulation of snow and ice should be maximum security measures, its weight should not exceed 60kg /. .Relief ratio should be 0.05-0.22 (/). .<BR> (5), lifting should be set well away from main traffic officers to concentrate on places and roads, and should be near the site of explosion-prone. .<BR> (6), into the underground room of the gas pipeline should strictly implement relevant standards, should be added through the floor and wall casing protection, basement natural gas pipeline to be welded (except with the device connectors.) .Pipe should be dedicated pipe, valves should be of high quality valves. .Surge tank outlet valve should be set, such as a leak, should be able to automatically cut off the gas source. .<BR> (7), the engine room should be set to automatic fire alarm, fire extinguishing system and gas leak alarm device density, and linkage with the fire control system. .Gas leak alarm device detecting the concentration of not less than two points, and should be arranged in the equipment or parts easily spill over. .24h of the main room to watch. .When the gas concentration reaches 20% of lower explosive limit, the concentration and alarm monitoring system to timely and accurate, and cut off the gas valve and non-fire mains power supply, automatic startup accidents delivery, exhaust system. .According to the standard set fire hydrant system and fire fighting equipment. .<BR> (8), independent of the delivery room should be set, exhaust system, and with automatic fire alarm, fire extinguishing systems, gas leak detection monitoring devices linked. .Air vents should be located no fire in the Security Department, the exhaust air change rate of not less than 15 times / hour, and the air supply should not be less than the amount of air needed for combustion (18 / kcal) and the new person in the room needed .and air in order to ensure the engine room below the explosive limit of gas concentrations. .<BR> (9), the engine room fire load electricity requirements should be a power supply, and should be located at the distribution box at the end of the automatic switching device. .<BR> (10), the electrical equipment room should be "explosion and fire hazard for design of electrical installations" GB50058-92 selection. .<BR> (11), selection of safe and reliable performance of the unit, in engineering design, construction, installation, acceptance and use of national standards must be strictly enforced. .<BR> (12), unit is in use, the operator should be documented on the hills, to enhance training and education, strengthen the duty and inspection, establish and improve the maintenance and the safety management system. .<BR> <BR> <BR> <BR>.