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The largest crude oil storage tank in an oil reserve is a 10×104 m3 outer floating roof oil tank with a diameter of 80m and a tank height of 21.80m. The tank protection uses a fixed low-multiple foam fire-extinguishing system and a cooling water system.
The low-multiple foam fire extinguishing system uses 6% aqueous film-forming foam mixture. The top of the tank wall is sprayed. The cooling water ring pipe is arranged on the lower side of two wind resistant coils and three reinforcing rings. The total flow rate is 215 (L/s). , A total of 744 nozzles, low-multiple foam fire extinguishing system uses 12 PC8 foam generators are uniformly distributed on the top of the tank wall, foam mixing liquid supply strength: 12.50L / (min.m2), continuous supply time is 30min, the other Three PQ8 foam guns are used in the tank area to extinguish the dispersed fire. The design flow rate of the foam mixture in the tank area is 120L/S. The reserve pool is equipped with a foam fire pump station and a foam station to ensure that foam can be mixed within 5 minutes after the foam fire pump starts. The liquid is transported to the furthest protection object. There is a stainless steel tank and a foam liquid pump in the foam station. The balanced proportion mixing device stores the foam liquid in an amount of 10.40m3 for extinguishing the tank, and 2.60m3 for the foam gun. The amount of foam liquid required for the net is 3.60m3. Considering the reserve amount, the stainless steel foam tank can store 24m3 of foam liquid.
The fire protection and maintenance unit shall carry out a commissioning and maintenance of the tank foam fire extinguishing system at the request of the owner. After the commissioning staff has studied the system technical documents and operating procedures, and has used the management unit to understand the operation situation, he has prepared a check and commissioning plan that will be implemented after the management unit agrees.
(1) Check the fire-fighting water source and fire-fighting water supply equipment. The working status of the system water supply pipe network and the opening and closing status of the valve are in compliance with the test plan requirements.
(b) Check that the working conditions of the foam fluid storage and supply equipment comply with the test plan requirements.
(3) Check the working conditions of the foam mixing liquid supply equipment and the pipe network in line with the requirements of the test plan.
(4) Select the most unfavorable storage tank as a test object, and check that the opening and closing states of the valves meet the requirements of the test plan. The test protocol requires the foam gun to be used for spraying foam. Therefore, connect a fire hose and a PQ8 foam gun to the foam fire hydrant and install a spring pressure gauge on the pressure gauge port on the foam mixture manifold to check the dry tube. The control valve on the opening and closing is flexible and in working condition.
(e) Check if the control function of each remote control valve meets the requirements.
(6) Check whether the switch between the power source and standby power of all fire-fighting pumps and foam liquid pumps is accurate and reliable.
(7) Close the outlet valve of each fire pump, open the return valve, and start the test for each pump automatically and manually.
(8) Self-cutting and mutual-investment tests are conducted on the fire pump and its standby pump. After the test is completed, the pump control cabinet and valves are reset in order.
(9) Open the relevant valves to ensure that the fire-fighting water supply to the foam gun of the test object, and conduct the water-spray test by manual and automatic control. The valve in the area that is not subjected to the water-spray test shall be closed, and the foam mixture shall be injected after the water-spray test. The residual water in the pipe is drained. When the water spray test is performed, the inlet pressure and range of the foam gun shall be checked.
(10) The relevant valves used for the spray foam test shall be in a quasi-operating state. To reduce flushing troubles, the foam mixture should be reduced as far as possible into the scope of the pipe network, and spray foam tests should be conducted manually and automatically. Do not infuse piping in fire embankments and pipe networks that are not related to testing.
(11) The pipeline shall be flushed in time after the foam injection test. All the pipe sections filled with the foam mixture shall be flushed and the valves on the system shall be restored to the quasi-operating state.
Second, the case description
This case involves more fire prevention content and mainly analyzes the following:
(a) Regular examination and testing of foam fire pumps.
(ii) Periodic inspections of system components such as foam tanks, foam proportioners, foam generators, foam hydrants, pipes, valves, etc.
(c) Periodic tests of low multiple foam fire suppression systems in storage tanks.
Third, key knowledge and basis
(1) It is mainly based on the "Code for Construction and Acceptance of Foam Fire Extinguishing Systems" and "Design Specification for Foam Fire Extinguishing System".
(b) Key knowledge points:
1. Start-up tests for fire pumps and backup power: A start-up test for fire pumps and backup power is performed on a weekly basis. Fire pumps are water pumps, foam pumps, and foam mixing pumps. The foam liquid pump can only deliver foam liquid, which is currently only used when selecting a balanced proportional mixing device; the foam mixing liquid pump only delivers the foam liquid mixture when using a ring-pump proportioning mixer. Fire pumps and backup power are one of the key equipments of foam fire extinguishing systems and directly affect the operation of the system. Therefore, a weekly start-up test should be performed manually or automatically to control the fire pump and backup power to see if it is operating normally. During the test, the pump can run back or idle, but the idle time should not exceed 5 s. After the test, the pump and backup power and related equipment should be reinstated. The test shall be performed by specially qualified personnel. The test results shall be filled out with the system weekly inspection records.
2. System spray foam test: This case is a liquid spray foam fire extinguishing system for a fixed top tank. In accordance with the specifications, the system must be inspected and tested every two years. Inspection refers to the complete inspection of all components, facilities (including power distribution and water supply facilities), pipes and fittings of the system. The test refers to the spray foam test. In principle, the spray foam test is to be tested according to the functional acceptance requirements during system acceptance. However, considering the many problems involved in the low foam foam fire-fighting system spray foam test, it cannot directly go to the tank. In order to avoid disassembling the relevant pipes and foam generators, the construction unit may conduct tests in conjunction with the actual conditions of the unit. For example, using a foam fire hydrant on a foam mixture pipe, connect a hose and a foam gun for testing. In addition, the use of tank maintenance opportunities, approved by selecting a tank for testing.
IV. Matters needing attention (1) This case does not involve linkage reliability and linkage methods in inspection tests.
(II) In this case, the cross-cutting issue of oil storage and depot operations was not considered in the inspection tests.
First, scene description