How to select the type for the liquid level display device of the fire water tank?

Selection Guide for Fire Water Tank Level Display Devices 

The core principle for selecting the liquid level display device of the fire water tank is to comply with the mandatory requirements of GB50974-2014 "Technical Code for Fire Water Supply and Fire Hydrant System", while also matching the installation conditions, environmental characteristics and functional requirements of the project site. The following are the specific selection steps, key dimensions and adaptation schemes, with particular emphasis on the selection suggestions of the WH311 series. 

I. Core Basis for Selection (Must Read) 

Before making the selection, it is essential to clearly define the strict requirements of the regulations to avoid the situation where the project fails the fire safety inspection due to non-compliance with the standards. 

Dual display function: Both on-site water level display (next to the water tank) and remote display in the fire control room must be available simultaneously. 

Alarm function: It should support both high and low water level audible and visual alarms, and the alarm signals need to be connected to the fire control host. 

Measurement accuracy: The error of water level measurement should be ≤ ±1cm, meeting the "value consistency" inspection requirements during the acceptance process. 

Stability: The equipment should be able to adapt to the humid, corrosive and electromagnetic interference conditions of the pool, without the risk of frequent malfunctions. 

II. Key Selection Dimensions and Decision Points 

Selecting based on measurement principles (core dimension) 

Devices based on different principles are suitable for different scenarios, and this is the first step in the selection process. 

Measurement principle - Representative product - Advantages - Disadvantages - Applicable scenarios 

Immersion type static pressure WH311 series, with high accuracy (±1cm), strong stability, fast response, and support for联动 control. Requires contact with water body, installation requires wiring. The preferred choice for new projects, suitable for standard fire-fighting water tanks / water storage tanks. 

Float-type ordinary connecting rod float level gauge: Low cost, simple structure, poor accuracy (error ±5cm), prone to jamming, short lifespan. Suitable for temporary projects and small-sized water tanks with low precision requirements. 

External-mounted ultrasonic/radar acoustic electronic external-mounted liquid level gauge. No need to break the tank, no contact with water, easy to install. Limited by tank material/thickness, the accuracy is medium (±2cm). Suitable for renovation of old water tanks, water tanks containing corrosive liquids, and explosion-proof areas. 

Wireless transmission type WH311-LoRa/NB-IoT version, wireless liquid level meter. No wiring required, battery-powered, remote monitoring. Batteries need to be replaced regularly (3-5 years). Signals are affected by obstructions. Suitable for difficult-to-wire locations (such as old residential areas, mountainous buildings) 

Selection suggestion: For new fire protection projects, 90% or more should opt for the submerged static pressure type (such as WH311), considering both accuracy and stability; for renovation projects, external mounting or wireless submerged types should be preferred. 

2. Select based on functional requirements 

Based on the project scale and the requirements for intelligence, select the device with the corresponding functional configuration: 

Functional requirements, selection criteria, compatible products 

Basic model (meets acceptance criteria) On-site + Remote Dual Display, High/Low Water Level Alarm WH311 Basic Version (4-20mA signal output) 

Intelligent monitoring supports联动 of fire control main unit, data recording, and remote viewing via APP for WH311 intelligent version (with RS485/4G transmission 

Centralized management of multiple water tanks, supporting multi-point access and unified monitoring platform. WH311 + multi-channel acquisition module. 

Extreme environment adaptation: Lightning protection, corrosion prevention, wide temperature operation. WH311 enhanced version (Triple lightning protection + 316 stainless steel material) 

3. Select equipment based on the on-site environment 

Environmental factors directly affect the lifespan and stability of equipment, and therefore require special attention: 

Damp / corrosive environments (such as coastal buildings, chemical industrial parks): Choose IP68 protection grade + 304/316 stainless steel material, such as WH311 fully sealed laser welding structure, resistant to salt fog and leakage prevention. 

Drought-prone areas (such as mountainous regions, high-rise buildings): Choose products with built-in lightning protection modules, such as the WH311 triple lightning protection design, to prevent damage from lightning strikes. 

Low temperature / high temperature environments (such as extremely cold areas in the north, and hot workshops in the south): Choose models suitable for wide temperature range operation. The WH311 model can adapt to -20℃ to 80℃, and in extreme environments, it can be upgraded to a custom model ranging from -40℃ to 85℃. 

Space limitations (such as a small underground water tank): Choose a compact and easy-to-install submersible probe. The WH311 probe has a diameter of only 28mm and can be installed through a narrow well opening. 

III. Precise Selection Plans for Different Scenarios 

New commercial complex / high-rise building 

Requirements: High precision, dual display, interlocking control, lightning protection and corrosion prevention 

Recommended configuration: WH311 Intelligent Edition (4-20mA + RS485) 

Configuration plan: Pool immersion probe + On-site WH6 display meter + Fire control room display meter + Fire control host linkage module 

Advantages: Complies with mandatory regulations, supports centralized monitoring of multiple water tanks, and passes the acceptance inspection in one go. 

2. Renovation of Firewater Tanks in Old Residential Areas / Schools 

Requirements: No need for water shutdown during construction, easy installation, low cost 

Recommended selection: WH311 wireless version (LoRa/NB-IoT) or external-mounted liquid level gauge 

Configuration plan: Wireless probe placed in the pool + Mobile APP / Cloud platform for monitoring 

Advantages: No wiring required, quick installation in 1 hour, does not affect normal use of the building. 

3. Chemical Industrial Park / Corrosive Liquid Storage Pool 

Requirement: Anti-corrosion property 

Recommended configuration: WH311 316 stainless steel version + external-mounted auxiliary monitoring system 

Advantages: 316 stainless steel is resistant to strong acids and strong alkalis. The external coating prevents the probe from directly contacting corrosive liquids, providing dual protection. 

4. Remote mountainous areas / Outdoor fire water tanks 

Requirement: No mains power supply, remote monitoring 

Recommended model: WH311 Solar Wireless Version 

Configuration plan: Solar power supply + NB-IoT transmission + Cloud platform data viewing 

Advantages: No wiring required, no electricity bills, suitable for outdoor scenarios without power supply. 

IV. Selection Avoidance Pitfall Guide (Common Mistakes) 

Just considering the price without considering the accuracy: The low-priced float-type liquid level meter has poor accuracy. During the acceptance process, it is prone to be returned due to "excessive display error". It is recommended to choose the submerged type first. 

Ignore the protection level: The pool environment is humid, and equipment below IP65 is prone to water ingress and damage. Therefore, an IP68 protection level must be selected. 

Over-reliance on wireless products: Wireless signals are affected by obstructions such as walls and terrain. The core fire protection project recommends a dual backup system consisting of both wired and wireless connections. 

V. Summary of Selection Process 

Specify the project type: new construction / renovation, indoor / outdoor, conventional / extreme environment. 

Compared with the specification requirements: Verify the core functions such as dual display, alarm, and linkage. 

Matching measurement principle: New type of input type (WH311) is introduced, while the existing ones are replaced with external mounting / wireless type. 

Verify the certification qualifications: Ensure that the products comply with national standards and that all necessary documents are complete.