QHYX-GDL Fire Sprinkler Water Supply Equipment

General Description

I. The booster and pressure-stabilizing unit is a new type of fire booster and pressure-stabilizing equipment developed and designed in accordance with Document [1996] No.108 issued by the Ministry of Construction of the People’s Republic of China in August 1996, and also complies with the provisions of 98S205 (formerly 98S176).

II. This booster and pressure-stabilizing unit is designed to solve the case where the high-level fire-fighting water tank provided for the temporary high-pressure fire water supply system cannot meet the required static pressure at the most unfavorable point in the system, and therefore a booster facility must be installed. A dedicated booster and pressure-stabilizing unit for fire service (hereinafter referred to as the “unit”) has been designed.

III. This unit is suitable for fire hydrant water supply systems and wet automatic sprinkler systems that require booster facilities in multi-storey and high-rise buildings, as well as various fire water supply and domestic water supply systems.

IV. The “unit” consists of an SQL diaphragm pressure tank, XBD-GDL multistage fire hydrant pump, electrical control cabinet, instruments, pipework and accessories.

V. The design of this unit follows the relevant technical parameters specified in the national standard “Code for Fire Protection Design of High-Rise Civil Buildings” (hereinafter referred to as “High-Rise Code”) GB50045-95 and the “Code for Design of Air-Pressure Water Supply” CECS76:95.

VI. Design technical conditions of this “unit”:

1. Working pressure of SQL pressure tank: 0.6 MPa, 1.0 MPa, 1.6 MPa.

2. Fire water storage volume of SQL pressure tank: greater than 150 L, 300 L, 450 L.

3. Pressure-stabilizing water volume of SQL pressure tank: greater than 50 L.

4. Pressure difference of buffer water volume in SQL pressure tank: 0.02–0.03 MPa; pressure difference of pressure-stabilizing water volume: 0.05–0.06 MPa.

5. Working pressure ratio: a/b value is 0.6–4.0.

VII. Operating Principle of the “Unit”

This “unit” must satisfy the following two functions:

1. Ensure that the most unfavorable point in the fire water supply pipe network always maintains the required fire-fighting pressure.

2. Ensure that the pressure tank always stores 30 seconds of fire water volume. By using the operating pressures P1, P2, Ps1 and Ps2 set for the pressure tank, the operating conditions of the pump are controlled to achieve the functions of boosting and pressure stabilization. P1 is the required fire pressure (MPa) at the most unfavorable point; P2 is the start pressure (MPa) of the fire pump; Ps1 is the start pressure (MPa) of the jockey pump; Ps2 is the stop pressure (MPa) of the jockey pump.

VIII. Full Operating Control Process

According to calculations, the required fire pressure P1 at the most unfavorable point of the fire hydrant system or automatic sprinkler system is obtained and used as the filling pressure of the pressure tank. Based on this and the selected specifications and a/b value of the pressurized water tank, P2 is determined, and then the following are set:

Ps1 = P2 + (0.02–0.03)
Ps2 = Ps1 + (0.05–0.06)

Under normal conditions, when there is pipeline leakage or pressure drop in the system, the jockey pump continuously replenishes water to maintain pressure, and operates repeatedly between Ps1 (start) and Ps2 (stop). Once a fire occurs and the system loses a large amount of water, causing the pressure to fall from Ps1 (Ps1 → Ps2) down to P2, an alarm signal is issued and the fire pump is started immediately (manual or automatic start is determined by the designer). After the fire pump starts, the jockey pump stops automatically and remains off until the fire pump stops. Then the control function of the “unit” is restored manually.

IX. Classification of the “Unit”

According to installation position:

– Top-mounted type (denoted by I)

– Bottom-mounted type (denoted by II)

According to tank arrangement:

– Vertical type (denoted by L)

– Horizontal type (denoted by W)

According to the fire water supply system served by the unit:

– Fire hydrant water supply system (denoted by X)

– Automatic sprinkler system (denoted by Z)

– Combined fire hydrant and automatic sprinkler water supply system (denoted by XZ)

X. Model Designation of the “Unit”

Example: ① ZW(L)—I—X—10—0.16
② ZW(W)—II—X—C

XI. Calculation of P1

P1 refers to the required fire pressure at the most unfavorable fire hydrant or sprinkler head in the fire water supply system. It is the minimum operating pressure of this “unit” and is the fundamental parameter that must be mastered when selecting this equipment.

1. When this “unit” is installed at the lowest floor and draws water from a water tank, the calculation formula for the fire hydrant system is:

P1 = H1 + H2 + H3 + H4 (mH2O);

H1 — Geometric height (mH2O) from the minimum water level in the tank to the most unfavorable fire hydrant;

H2 — Sum of frictional and local pressure losses (mH2O) in the pipeline system;

H3 — Pressure loss (mH2O) of hose and fire hydrant assembly;

H4 — Pressure (mH2O) required for the water jet to achieve the specified effective range.

2. When the “unit” is installed in a high-level water tank room and draws water by gravity from the tank, and the most unfavorable fire hydrant is located below the “unit”, the calculation formula for the fire hydrant system is:

P1 = H3 + H4 (mH2O)

3. When the “unit” is installed at the lowest floor and draws water from a water tank, the calculation formula for an automatic sprinkler system is:

P1 = ∑H + Ho + Hr + Z (mH2O)

∑H — Sum of frictional and local pressure losses (mH2O) from the water supply source to the most unfavorable sprinkler head;

Ho — Operating pressure (mH2O) at the most unfavorable sprinkler head;

Hr — Local head loss (mH2O) at the alarm valve;

Z — Geometric height (mH2O) between the most unfavorable sprinkler head and the minimum water level in the tank (or supply main).

4. When the “unit” is installed in a high-level tank room and draws water by gravity from the tank, and the most unfavorable sprinkler head is located below the unit, the calculation formula for the automatic sprinkler system is:

P1 = ∑H + Ho + Hr + Z (mH2O)

5. When the pressure tank and the pump are installed in different locations, P1 should be recalculated accordingly.

XII. Additional Notes

1. Booster standard of this “unit”: P1 is the minimum operating pressure of this “unit” and must meet the fire pressure required at the most unfavorable point of the fire water supply system. For a fire hydrant system, the effective jet range of the most unfavorable fire hydrant must be satisfied. It is not sufficient to take only 0.07 MPa or 0.15 MPa of static pressure as the booster standard.

2. When calculating P1, the flow used to calculate friction and local losses in the pipeline system shall be the fire water demand at the initial stage of fire. For fire hydrant systems, this is generally two hose streams with flow 2×5 (L/s) = 10 (L/s) or 2×2.5 (L/s) = 5 (L/s). For automatic sprinkler systems, it is generally taken as the flow of 5 sprinklers, usually 5×1 (L/s) = 5 (L/s).

3. The main components of this “unit”: the pressurized water tank shall provide the required fire water storage volume, pressure-stabilizing water volume and buffer water volume for the fire water supply system. Based on the determined a/b value, the diameter and specification are calculated. For fire hydrant water supply systems, the storage volume of the pressure tank shall not be less than 300 L; for automatic sprinkler systems, not less than 150 L; for combined fire hydrant and automatic sprinkler systems, not less than 450 L.

4. This “unit” is equipped with two jockey pumps (one duty, one standby). Within 3 minutes, the jockey pump flow should be able to replenish the actual pressure-stabilizing water volume in the pressure tank. The head of the jockey pump should be selected at the high-efficiency section of the pump curve corresponding to (Ps1 + Ps2)/2. The function of this “unit” is to ensure, at the initial stage of a fire before the main fire pump starts, that there is sufficient 30-second fire water volume at the required pressure for initial fire suppression until the main fire pump reaches full load.

5. The fire hydrant water supply system and the automatic sprinkler system can share one booster and pressure-stabilizing unit. When a fire occurs and the pressure in the pressure tank drops to P2, signals are sent to the fire control center or fire pump room from the fire hydrant system or automatic sprinkler system respectively. After confirmation, the corresponding fire hydrant pump or sprinkler pump is started.

6. For fire hydrant water supply systems, the top-mounted type of this “unit” is preferable to the bottom-mounted type. For the top-mounted type, the required pump head is lower, since P1 mainly comprises the pressure losses of the hose and nozzle, and the pressure required to achieve the effective jet range. The charging pressure of the pressure tank is therefore lower, the tank operates at a lower pressure, and both steel consumption and operating cost are reduced.

XIII. Electrical Control Features

1. The electrical control system of this “unit” provides both automatic and manual control functions and can be networked with the fire control center or fire pump room.

2. Two jockey pumps are configured (one duty, one standby) and operate alternately with automatic switching.

3. Normally, the fire pipeline network is maintained at high pressure with a certain storage volume in the tank. When the system pressure drops to Ps1 due to leakage and other reasons, Pump No.1 starts automatically and stops when the pressure rises to Ps2. At the next pressure drop to Ps1, Pump No.2 starts automatically, and so on alternately, ensuring that the system pressure always remains between Ps1 and Ps2.

4. Once a fire occurs and system pressure falls from Ps1 to Ps2, the control system outputs a start signal for the main fire pump together with audible and visual alarms. After the main fire pump starts and returns a feedback signal, the control power of the jockey pumps is cut off. Thereafter the control function is restored manually.

5. The electrical control system provides a maintenance mode. If Pump No.1 fails during operation, the system can be easily switched to Pump No.2. If Pump No.2 fails, it can be switched back to Pump No.1, ensuring that the “unit” can continue normal operation with one pump under maintenance.

6. Specifications and dimensions of the control cabinet, the electrical control principle and the major components are detailed in the company’s dedicated electrical automatic control manual.

XIV. The diaphragm pressure tank is manufactured in accordance with the national standard drawing set 91SS852.

XV. Piping is made of seamless steel pipes, hot-dip galvanized steel pipes, or hot-dip galvanized seamless steel pipes.

XVI. The “unit” adopts an integrated modular steel base as structural support. The support form of the diaphragm pressure tank in this drawing set is designed as a skirt base, but a saddle-type support can also be used.

XVII. When this “unit” is installed in the top-mounted configuration, vibration isolation measures shall be provided. During the installation of rubber vibration isolation pads under the pump unit, measures must be taken to prevent the pump unit from tipping. After the isolation pads are installed, when installing pump suction and discharge pipework, fittings and accessories, measures must also be taken to prevent the pump unit from tilting, so as to ensure safe installation.

XVIII. The pressure tank is equipped with a drain device, and the pipeline system is equipped with a safety valve, remote pressure gauge and other accessories.

XIX. The area surrounding the “unit” shall be provided with drainage facilities to facilitate draining during maintenance or in case of accidental leakage.

XX. There shall be sufficient clearance between the “unit” and walls or other equipment, generally not less than 700 mm.

XXI. The “unit” shall undergo overall hydrostatic testing, strength testing and tightness testing in accordance with the current relevant regulations.

XXII. External surfaces of connecting piping, fittings and the pressure tank shall be coated with two layers of anti-rust paint, and the internal surface of the pressure tank shall be coated with a non-toxic corrosion-resistant coating.

XXIII. Installation of pumps, motors and pipelines shall comply with the relevant technical specifications.

XXIV. Operating Precautions

1. Before the unit is put into operation, commissioning shall be carried out first (by the manufacturer). After commissioning is completed, the charging nozzle of the pressure tank shall not be disassembled at will to prevent air leakage.

2. During operation, the unit does not require dedicated operators on duty, but regular inspections shall be carried out.

XXV. The pumps used in this unit are based on the company’s XBD_DL vertical multistage fire pump / XBD-LG vertical multistage fire pump / XBD-ISG vertical single-stage fire pump series. If other pumps are adopted, appropriate pumps can be selected according to the flow and head requirements listed in the tables.

XXVI. The electrical control part of this unit can be designed with reference to the company’s electrical automatic control manual.