Key Points for Fire Pump Selection and Configuration
Fire pumps are the core power equipment of the fire water supply system, and the rationality of their selection and the completeness of their configuration are key inspection items in fire acceptance. Fire pump selection should follow the following principles: Flow determination — the flow of fire hydrant pumps should be determined according to the design flow of the indoor fire hydrant system (the design flow of the indoor fire hydrant system in a Class I high-rise hotel is usually 30-40L/s), and the flow of sprinkler pumps should be determined according to the design flow of the automatic sprinkler system (for Medium Hazard Class I, the operating area is 160m2 and the spray intensity is 6L/min·m2, with a design flow of approximately 20-30L/s); when the fire hydrant system and the sprinkler system share one set of fire pumps, the flow should be determined as the sum of the two. Head calculation — the head of fire pumps should be calculated according to the pressure required at the most unfavorable point (H=H1+H2+H3, where H1 is the geometric height difference, H2 is the friction and local head loss of the piping, and H3 is the working pressure required at the most unfavorable point), and a safety factor of 1.1-1.2 should be considered. Material requirements — the casing of fire pumps should be ductile iron or cast steel, the impeller should be stainless steel or bronze (corrosion-resistant), the pump shaft should be stainless steel (2Cr13 or 304), and the mechanical seal should be silicon carbide/graphite material. Control requirements — the fire pump control cabinet should have three starting modes: automatic pump start (through the fire linkage controller), manual pump start (control cabinet panel button), and mechanical emergency pump start (mechanical emergency starting device, pull rod or button); the protection rating of the control cabinet should not be lower than IP55 (inside the pump room); an automatic/manual selector switch should be provided in the control cabinet (the selector switch should be set in the manual position and remotely controlled from the fire control room). Configuration requirements — fire pumps should be configured as one duty one standby or two duty one standby (the capacity of the standby pump should not be less than that of the main pump); the main and standby pumps should be capable of automatic switching (switching time not exceeding 2min); the dual power supply switching time should not exceed 2s; the pump suction method should adopt self-priming suction (the lowest water level of the fire water tank should be higher than the centerline of the pump impeller); a filter should be provided on the suction pipe (filter mesh diameter 3-5mm); and a check valve, gate valve and pressure gauge should be provided on the discharge pipe.
Key Points for Fire Fan Selection and Configuration
Fire fans include pressurization supply fans and smoke exhaust fans, and are key equipment of the smoke control and exhaust system. The rationality of their selection and the completeness of their configuration directly affect the reliability of smoke control during a fire. Fire fan selection should follow the following principles: Air volume determination — the air volume of pressurization supply fans should be calculated according to the supply air volume required for stairwells and vestibules (the supply air volume for stairwells is calculated according to the air volume required to maintain a residual pressure of 25-30Pa when evacuation doors are open, usually 25000-35000m3/h), and the air volume of smoke exhaust fans should be calculated according to the smoke exhaust volume of the largest smoke control zone within the fire compartment (for atriums, calculated at a smoke exhaust volume per unit area of 60m3/h*m2; for general locations, the smoke exhaust fan air volume should not be less than 7200m3/h). Pressure determination — the fan pressure should be able to overcome the resistance loss of the most unfavorable loop of the duct system; the total pressure of pressurization supply fans is usually 500-800Pa, and the total pressure of smoke exhaust fans is usually 600-1000Pa. High-temperature resistance — smoke exhaust fans should be able to operate continuously for no less than 30min at 280 degrees (the type test report of the fire testing institution should include this test), and pressurization supply fans should be able to operate continuously at 70 degrees. Noise control — the noise of fire fans should meet environmental protection requirements (noise in the fan room not greater than 85dB(A), and at the inlet not greater than 90dB(A)); silencers should be provided at the fan inlet, and vibration isolators should be provided at the fan foundation. Configuration requirements — a 280-degree smoke exhaust fire damper should be provided at the inlet of the smoke exhaust fan (normally open type, fusible and closing at 280 degrees and interlocked to stop the fan), a check valve should be provided at the outlet of the pressurization supply fan (to prevent smoke backflow), and the fan control box should have three control modes: automatic (fire linkage), manual (control box panel) and remote (direct control from the fire control room). Fan installation should ensure the concentricity of the fan shaft and motor shaft (coupling connection mode) or pulley alignment (belt drive mode), and the length of the reducer at the fan inlet and outlet should not be less than 1.5 times the pipe diameter.
Key Points for Selection and Configuration of Fire Alarm Control Units
The fire alarm control unit is the core control equipment of the automatic fire alarm system, and the rationality of its selection and completeness of configuration directly affect system reliability. The selection of fire alarm control units should follow these principles: Capacity configuration — the control unit capacity should meet the total point requirements of the system and reserve no less than 20% margin (each loop can carry 200-250 addressable units). For large hotel projects (total points exceeding 3,000), multi-loop control units or an architecture of multiple cascaded control units should be adopted. Communication protocol — the control unit should support mainstream communication protocols (such as CAN bus, RS485 bus), and should provide open communication interfaces for integration with third-party systems (such as BAS building automation systems, fire remote monitoring systems). Linkage function — the control unit should have linkage control functions (able to directly output control signals to start/stop fire protection equipment), with linkage logic flexibly programmable (supporting AND, OR, delay and other logic operations). The control unit should be able to record and print fire alarm, linkage action and fault information (storage capacity no less than 100,000 records). Display function — the control unit should be equipped with an LCD graphic display panel (displaying floor plans of alarm points), with display resolution no lower than 1024*768 pixels. The graphic display device should be able to display the status of each fire protection device in the building floor plan. Regarding brand selection, mainstream domestic brands include GST (GST5000/GST2000 series, highest market share), Taihean (TX3000 series), Lida (LD128E series), etc. Mainstream international brands include Honeywell Notifier (NFS2-3030/640 series), Siemens (Cerberus FS20 series), etc. Configuration requirements: The main fire control room should be equipped with no fewer than 2 fire alarm control units (mutually backup or zone-controlled). The control unit cabinet should have adequate ventilation and heat dissipation measures. The main power supply of the control unit should use fire protection power (AC220V/50Hz), and the backup power supply should use maintenance-free lead-acid batteries (capacity should ensure the control unit operates for no less than 8h). The maximum wiring distance from the control unit to each loop should not exceed 1,200m (if exceeded, zone control units should be provided or repeaters added).
Selection and Configuration of Emergency Lighting and Evacuation Indication Systems
The fire emergency lighting and evacuation indication system is a key facility for ensuring safe evacuation of personnel during a fire, and its selection and configuration directly relate to personnel life safety. GB 51309-2018 Technical Standard for Fire Emergency Lighting and Evacuation Indication Systems sets comprehensive requirements for system design, construction and acceptance. Selection key points: System type selection — centrally controlled systems are applicable to Class I high-rise public buildings (such as hotels), consisting of an emergency lighting controller, central power supply or self-contained power supply emergency luminaires; the emergency lighting controller should be installed in the fire control room. Luminaire selection — fire emergency lighting luminaires (illumination lamps) should adopt Type A fire emergency luminaires (operating voltage no greater than DC36V). Minimum horizontal illuminance at floor level: evacuation corridors no less than 3.0lx (the code requires 1.0lx; hotels should preferably increase to 3.0lx), densely occupied areas no less than 5.0lx, stairwells no less than 10.0lx. Evacuation indication sign luminaires should adopt maintained-type luminaires (remain lit under normal operating conditions), with surface luminance no less than 50cd/m² and no greater than 300cd/m²; the arrow direction of sign luminaires should be consistent with the evacuation direction. Power supply requirements — the continuous power supply duration of the system battery: hotels with building height greater than 100m should be no less than 1.5h; hotels with building height of 100m or less should be no less than 1.0h. Luminaire installation — illumination lamps should be installed at a height no less than 2.0m above the floor (ceiling-mounted or wall-mounted); sign luminaires should be installed at a height below 0.5m above the floor (low-level installation) or above 2.2m (high-level installation); spacing between sign luminaires should be no greater than 20m (corridors) or 10m (corners). Protection rating — luminaires in outdoor or damp locations should have a protection rating no lower than IP65, and those in general indoor locations no lower than IP30. Inspection requirements: During acceptance, each luminaire should be checked individually for installation position, installation height, lighting direction and power supply; simulate main power failure to test the automatic switchover function of the backup power supply and the continuous power supply duration; check the control function of the emergency lighting controller over the luminaires (centrally controlled systems should be able to control the emergency activation time of luminaires to no greater than 5s).