What is Static Water Pressure?

What Is Static Water Pressure?

Definition of Static Water Pressure: Static Water Pressure refers to the pressure on water when it is stationary or moving in a straight line at a constant speed. Static Water Pressure is also called hydrostatic pressure. In fluid dynamics, many authors use the term static pressure, not just pressure, to avoid ambiguity. In general, however, the word “static” can be discarded, and the pressure in use is the same as the static pressure at a given point in the fluid.

Static Water Pressure

How to Calculate static water pressure?

Static Water Pressure Formula

Static Water Pressure or Hydrostatic pressure in a liquid can be calculated as:

p = ρ*g*h


p = pressure in liquid (N/m2, Pa, lbf/ft2, psf)

ρ = density of liquid (kg/m3, slugs/ft3)

g = acceleration of gravity (9.81 m/s2, 32.17405 ft/s2)

h = height of fluid column – or depth in the fluid where pressure is measured (m, ft)

Extended reading: Static pressure vs dynamic pressure vs total pressure

Height of Water Column to Pressure

Height of Water Column Pressure
(m) (ft) (kPa) (bar) (atm) (psi)
1 3.28 9.81 0.098 0.097 1.42
2 6.56 19.6 0.196 0.194 2.85
3 9.84 29.4 0.294 0.290 4.27
4 13.1 39.2 0.392 0.387 5.69
5 16.4 49.1 0.491 0.484 7.11
6 19.7 58.9 0.589 0.581 8.54
7 23.0 68.7 0.687 0.678 10.0
8 26.2 78.5 0.785 0.775 11.4
9 29.5 88.3 0.883 0.871 12.8
10 32.8 98.1 0.981 0.968 14.2
12 39.4 118 1.18 1.16 17.1
14 45.9 137 1.37 1.36 19.9
16 52.5 157 1.57 1.55 22.8
18 59.0 177 1.77 1.74 25.6
20 65.6 196 1.96 1.94 28.5
25 82.0 245 2.45 2.42 35.6
30 98.4 294 2.94 2.90 42.7
35 115 343 3.43 3.39 49.8
40 131 392 3.92 3.87 56.9
50 164 491 4.91 4.84 71.1
60 197 589 5.89 5.81 85.4
70 230 687 6.87 6.78 100
80 262 785 7.85 7.75 114
90 295 883 8.83 8.71 128
100 328 981 9.81 9.68 142

Extended reading: extrusion melt pressure transducer

Extended reading: Pressure Sensor Applications-Featured Industry Applications

Static Water Pressure Calculator

The Static Water Pressure Calculator can easily and quickly calculate the pressure value. Here is a nice online tool:

Open: Hydrostatic Pressure Calculator

Static Water Pressure Gauge

In the process of industrial process control and technical measurement, because the elastic sensitive element of the mechanical water pressure gauge (Static Water Pressure Gauge) has the characteristics of high mechanical strength and convenient production, the mechanical water pressure gauge is widely used.

The elastic sensing element in the Static Water Pressure Gauge elastically deforms as the pressure changes. Static Water Pressure Gauge adopts spring tube (Bourdon tube), diaphragm, diaphragm, bellows and other sensitive components and is classified according to this. The measured pressure is generally regarded as relative pressure. Generally, the relative point is selected as atmospheric pressure.

The elastic deformation of the elastic element under the action of medium pressure is amplified by the gear transmission mechanism of the water pressure gauge. The water pressure gauge will display the relative value (high or low) relative to the atmospheric pressure.

The pressure value within the measurement range is displayed by the pointer. The indication range of the dial is generally 270 degrees.

It can be divided into precision water pressure gauge and general water pressure gauge. The measurement accuracy levels of precision water pressure gauges are 0.1, 0.16, 0.25, 0.4 and 0.05 respectively. The measurement accuracy levels of general water pressure gauges are 1.0, 1.6, 2.5 and 4.0 respectively.

Extended Reading: Up to 800°C High Temperature Pressure Sensor

Static Pressure vs Dynamic Pressure

The pressure generated by the irregular movement of air molecules on the pipe wall is called static pressure.

When calculating, the static pressure with absolute vacuum as the calculation zero is called absolute static pressure. The static pressure at which the atmospheric pressure is zero is called relative static pressure.

The air static pressure in the air conditioner refers to the relative static pressure. The static pressure is positive when it is above atmospheric pressure and negative when it is below atmospheric pressure.

Extended reading: What Is Flush Diaphragm Pressure Sensor?

Dynamic pressure, when an object is moving in a fluid, the surface is facing the direction of fluid motion. The fluid is completely blocked, and the fluid velocity here is 0. Its kinetic energy is converted into pressure energy, and the pressure increases. Its pressure is called the total resistance pressure (referred to as total pressure or total pressure, represented by P). The difference between it and the undisturbed pressure (i.e. static pressure, represented by P static) is called dynamic pressure (represented by P dynamic)

Extended reading: how to calibrate a pressure transmitter

The biggest difference between dynamic pressure and static pressure is the different definitions. Static pressure refers to the pressure on the surface of an object when it is at rest or in uniform linear motion. And dynamic pressure is the difference between total pressure and static pressure. They are all within the domain of fluid dynamics.

Both static pressure and dynamic pressure are knowledge in the field of physics. The biggest difference between them is the different definitions. Static pressure refers to the pressure on the surface of an object at rest or in uniform linear motion.

When an object moves in a fluid, the fluid facing the surface of the object is completely blocked. The velocity of the fluid is 0. Then the kinetic energy of the fluid is converted into pressure energy, which increases the pressure on the object. This pressure is called total pressure.

The dynamic pressure is the difference between the above-mentioned total pressure and static pressure.

Both dynamic pressure and static pressure are in the field of fluid dynamics. It is a branch of fluid mechanics. It studies the motion law of fluid under the action of force and its interaction with the boundary.

Read More: Differences! Static pressure vs dynamic pressure vs total pressure

Extended Reading: LORA water meter

Water Pressure Is Measured by Which Instrument

In industry, there are multiple instrument options for measuring the static pressure of water.

For example. If you need to measure the water pressure on the pipeline, you can choose a water pressure gauge or a pressure transmitter.

If you need to measure the water pressure in the tank, you can use a diaphragm pressure or differential pressure transmitter.

If Need to measure the pressure of downhole water, you can use a submersible level sensor. The latter two are also commonly used for water level measurement.

Read More: Hydrostatic Level Measurement

Read more about: How to Calculate Pressure Drop in a Pipe?


“Residual pressure” refers to the residual pressure in the pipeline, gas storage tank, and equipment after the system is shut down, such as boiler steam, air compressor station, etc.

Extended reading: wireless pressure transmitter working principle

Extended Reading: Liquid pressure sensor

Dynamic water pressure (dynamic water pressure) is the normal force acting on the interface between two parts of the moving liquid or on the contact surface between the liquid and the solid. Also known as the osmotic force.

Extended Reading: 3 inch (3″) Water Meter

In the process of water flowing in the soil, it will be affected by the soil resistance, causing the water head to gradually lose. At the same time, the infiltration of water will produce a drag force on the soil skeleton, resulting in changes in the stress and deformation in the soil body. The drag force generated by the soil skeleton is called the seepage force.

In many hydraulic structures, earth dams and foundation pit projects, the size of the seepage force is one of the important factors affecting the safety of the project. cause the construction of the project to be interrupted, and even endanger the safety of adjacent buildings and facilities

Extended reading: Featured Diaphragm Seal Pressure Transmitters

The static pressure box is a necessary accessory for the air supply system to reduce the dynamic pressure, increase the static pressure, stabilize the airflow and reduce the airflow vibration. Its function is to change the dynamic pressure into static pressure, evenly distribute the air volume, and mostly used in front of the slit tuyere.

The pressure generated by the irregular motion of air molecules hitting the pipe wall is called “static pressure”. Static pressure is the pressure perpendicular to the direction of fluid movement, and its function is to overcome the resistance in the process of fluid transportation. Then the purpose of establishing a static pressure box is to obtain static pressure.

Total pressure = dynamic pressure + static pressure: the total pressure of the fan is unchanged, and the wind speed decreases, which means that the dynamic pressure becomes smaller, and the static pressure increases.

Extended reading: Measuring Flow With Pressure Sensors

When supplying air with multiple air ducts, in order to make the air pressure of each air duct the same, it is necessary to establish a static pressure box, so that the dynamic pressure is all converted into static pressure, and then evenly distributed to each air duct.

In the same way, when the multi-air duct returns air, a static pressure box is also required. The air in front of the surface cooler can be fully mixed. Some single air duct air supply pipes are also equipped with static pressure boxes. The purpose is to use the static pressure box to reduce noise. The principle is that the speed of air entering the static pressure box is significantly slower, and the wind noise will be reduced.

The design principle of the static pressure box: the function of the static pressure box is to provide uniform pressure for each branch pipeline. Theoretically, the static pressure inside the static pressure box is equal everywhere. That is to say, the flow rate inside the static pressure box is zero everywhere. The condition for this is that the volume of the plenum is infinite.

This is impossible in engineering projects. Generally, the wind speed in the box can be controlled below 2m/s, or it can be greatly reduced relative to the wind speed of the inlet and outlet ducts.

Extended reading: Magnetic water meter-ultrasonic water meter-mechanical water meter

Hydrostatic pressure is: the normal force acting on the interface between two parts of a stationary liquid or on the contact surface of a liquid and a solid is the pressure exerted by a homogeneous fluid on an object. This is an omnidirectional force and is applied uniformly to all parts of the surface of the object. An increase in hydrostatic pressure reduces the volume of the object under force, but does not change its shape.

Extended reading: Industrial Pressure Transmitters|Buy from the manufacturer

Related Blogs

Static Pressure/Hydrostatic Pressure Transmitter

The Hydrostatic Pressure Transmitter measures the hydrostatic pressure exerted by a hydrostatic head. Use these hydrostatic pressure transmitters to measure the liquid level in storage tanks, processing vessels,…

How to convert a 4-20mA to 0-10V /1-5V signal?

4-20mA to 0-10v voltage, this is I/V conversion. That is current-voltage conversion, usually used for long-distance signal transmission in the industry. How to convert a 4-20mA to 0-10V…

What Is an Air Pressure Transducer?

An Air pressure transducer is a sensor that converts the mechanical signal of air pressure into a current signal. Pressure has a linear relationship with voltage or current,…

High Frequency Dynamic Pressure Sensor

Dynamic pressure sensor, the transmitter is a high frequency sensor. Sino-Inst offers a variety of  Dynamic Pressure Sensors for pressure measurement. If you have any questions, please contact…

Water Pressure Transducers

Water pressure transducers also called a water pressure sensor, are pressure transmitters that can measure water pipe pressure. For the water level/water depth measurement, in the tank, or…

Sino-Inst offers over 20 Static Pressure/Hydrostatic Pressure Transmitter. A wide variety of Static Pressure/Hydrostatic Pressure Transmitter options are available to you. Such as free samples, paid samples.  Read more about: What Are 0-10V Pressure Transducers?

Sino-Inst is a globally recognized manufacturer of Static Pressure/Hydrostatic Pressure Transmitters, located in China. Sino-Inst sells through a mature distribution network that reaches all 30 countries worldwide. Static Pressure/Hydrostatic Pressure Transmitters products are most popular in Europe, Southeast Asia, and Mid East. You can ensure product safety by selecting from certified suppliers. With ISO9001, ISO14001 certification.

Request a Quote

Please enable JavaScript in your browser to submit the form

BTU Meter for Chilled Water

What is BTU Meter for Chilled Water?

The BTU Meter for Chilled Water accurately measures the thermal energy consumed by chilled water in British Thermal Units (BTU). This is a basic measure of thermal energy in commercial and residential buildings. BTU meters are used in chilled water systems in commercial, industrial and office buildings.

BTU Meter for Chilled Water is to install a pair of temperature sensors on the ascending pipe and descending pipe passing through the heat transfer fluid respectively. The flow meter is installed on the fluid inlet or return line. The integrator collects signals from flow and temperature sensors. Use the cumulative formula to calculate the amount of cold and heat obtained by the heat exchange system.

BTU Meter in Chilled Water System

BTU Meter for Chilled Water consists of a flow measurement sensor, two temperature sensors and a microprocessor based energy calculator.

The flow sensor should be installed in the chilled water return line, and the chilled water flow direction should be installed in a vertical or horizontal position.

Two temperature sensors. A sensor is installed on the return line. The second sensor is installed on the water supply line.

The thermal energy transferred from the cooling water to the consumer over a defined period of time is proportional to the temperature difference between the flow and return flow and the amount of cooling water flowing through.

Sino-Inst offers two types of BTU Meter for Chilled Water. One uses ultrasonic measurement technology (ultrasonic BTU meter). Another uses the electromagnetic principle (electromagnetic cold and heat meter).

Extended Reading: 3 inch (3″) Water Flow Meter

Ultrasonic BTU meter is an intelligent heat metering device. Realize accurate measurement of cold and heat. It is used in heating facilities with heat metering and charging such as central heating, central air conditioning and combined cooling and heating.

Working principle

The Ultrasonic BTU meter measures the liquid flow in a circular tube based on the velocity difference method.

This series of instruments adopts advanced micro-power digital design technology such as digital transmission, digital reception, digital analysis, and digital output. The meter is accurate in measurement, reliable in operation, and more suitable for the needs of industrial sites.

Converter forms are: wall-mounted, panel-mounted, integrated;

The sensor forms are: plug-in type, pipe segment type, and outer clamp type.

Extended Reading: Wireless Water Meter

Ultrasonic heat and cold meter product features:

  1. Transducer: As the main signal generating component in the ultrasonic heat meter. Imported piezoelectric ceramic sheets are used. Stable performance and good consistency. Ensure that the ultrasonic heat meter achieves high-precision measurement.
  2. Temperature sensor: PT1000 high-precision platinum resistance is used. And configure the precision measurement circuit. Guaranteed high-precision temperature measurement.
  3. Self-diagnosis function: the ultrasonic heat meter is in stable operation. In case of abnormal communication, insufficient power or human sabotage. The system will display the corresponding code. The system automatically saves the data. Wait for the troubleshooting to recover.
  4. Remote transmission and centralized control function: with M-BUS, 485 interface. It can realize remote data transmission and centralized control.
  5. Beautiful appearance, can be hung in any direction in four directions. Easy to read and easy to operate.
  6. Easy to install. It has the functions of dust-proof, moisture-proof, waterproof, anti-disassembly and vandalism.

To choose the right ultrasonic flowmeter.

Compared with other types of heat meters, the electromagnetic heat meter is more stable and reliable in measurement. The LCD screen simultaneously displays parameters such as cumulative heat, cumulative flow, instantaneous heat, instantaneous flow, inlet water temperature, outlet water temperature, and temperature difference.

The measurement flow range is wide, and the flow velocity can be arbitrarily set within the range of 0.3m/s ~ 10m/s. With pluggable EPROM, it can store flowmeter configuration parameters and flow and heat detection data. Data is not lost when power is lost.

Electromagnetic sensor polytetrafluoroethylene PTFE (130℃), polyperfluoroethylene propylene F46 (180℃), high temperature resistant silicone fluorine rubber (250℃) for users to choose.

The parameter units displayed on the LCD screen are:
The optional display units of instantaneous flow are: m3/h, m3/m, m3/s, L/h, L/m, L/s, G/h, G/m, G/s.
The optional display unit of cumulative flow is m3, L, G, etc.
Note: G is imperial unit: gallon.
The unit of temperature is °C, and the unit of heat is KJ;
The electromagnetic heat meter is equipped with RS485 (MODBUSE protocol) as standard, and HART protocol can also be selected.

Measurement principle:

The split type electromagnetic heat meter is based on the flow signal of the flow sensor in the system and the temperature signal of the supply and return water detected by the paired temperature sensor. And the time the water has flown calculates and displays the heat released or absorbed by the system. The heat is displayed in cumulative form, the unit is kWh, and the large display is 8 digits.

The calculation mathematical model is: Q=qmΔhdt

Q—heat released: kJ;
qm—the mass of the heat-carrying liquid flowing through the heat meter: kg/s;
Δh—the difference between the specific enthalpy of the heat transfer liquid corresponding to the inlet temperature and the outlet temperature in the heat exchange circuit: kJ/kg;
t—time: s.

To choose the right electromagnetic flowmeter.

BTU Meter Installation in Chilled Water System

With the increase of large buildings and modern buildings, the cooling system has developed rapidly. The demand for cooling capacity of industry and its chemical industry has also promoted the development of central cooling. Central cooling means that the power plant uses the cooling medium (usually fresh water and salt water) to supply the cooling capacity of the refrigerator to the user. In order to manage and account for the operation of refrigeration equipment. Settling the cooling energy consumed by the user. It is necessary to measure the cooling capacity of the relevant nodes.

The method of measuring the cooling capacity of chilled water is the same as that of hot water. The amount of cooling supplied can be seen as negative heat. Just due to the low temperature of the fluid. lead to some differences in specific practices.

Extended reading: Magnetic water meter-ultrasonic water meter-mechanical water meter

For chilled water used in air conditioners, the water temperature level is generally 5-6 °C. The cold medium is fresh water. For cooling below 5°C, use brine or other cooling media. The cold measurement method of fresh water chilled water mostly adopts the measurement method based on mass flow as shown in the figure below.

In the flow measurement of chilled water, the electromagnetic flowmeter has obvious advantages, and its characteristics are as follows:

  • Magnetic flowmeter measurements are not affected by changes in fluid density, viscosity, temperature, pressure and conductivity.
  • The electromagnetic flowmeter measuring tube has no obstructing flow parts, no pressure loss, and low requirements for straight pipe sections.
  • The electromagnetic flowmeter sensor can be equipped with a ground electrode to achieve good grounding of the instrument.
  • The electromagnetic flowmeter sensor adopts advanced processing technology, so that the instrument has a good ability to resist negative pressure.

In addition to the electromagnetic flowmeter measurement, the ultrasonic flowmeter can also be used for measurement. Customers can choose according to on-site conditions.

Extended reading: Dam water level measurement

BTU Meter Calculation

The BTU (British Thermal Unit) is universally accepted as a unit of heat transfer measurement. The BTU is defined as the quantity of heat required to raise the temperature of one pound of water 1°F. The equation for heat transfer to a liquid is as follows:


Q=Heat transfer per unit time (BTU/hr)
W=Mass flow rate (lb/hr)
T2=Outlet temperature (°F)
T1= Inlet temperature (°F)
Cp=Specific heat capacity (1.0 BTU/lb for water)

Tools: BTU Calculator & BTU Formulas For Water Circulating Heat Transfer

BTU Meter vs Flow Meter

What is a BTU Meter?

BTU meters are flow meters with temperature sensors added to measure the energy consumption of any liquid heating or cooling system. BTU meters are also known as energy meters, heat meters. Commonly used are electromagnetic energy meters and ultrasonic energy meters. It is widely used in online metering of central air-conditioning cooling and heating energy metering and heating network. It can also be used to measure the performance of energy conservation measures or the loss of system efficiency that affects revenue. Read more about: What is BTU?

What is a Flow Meter?

A flow meter (or flow sensor) is an instrument used to measure linear, nonlinear,mass or volumetric flow rate of a liquid or a gas.When choosing flow meters,one should consider such intangible factors as familiarity of plant personnel,their experience with calibration and maintenance, spare parts availability,and mean time between failure history, etc., at the particular plant site.

Extended reading: Ultrasonic water meter working principle


Flow meters measure flow, and heat meters measure heat. The heat meter consists of an integrator (calculator), a flow meter, and a pair of temperature sensors. The first detection is the supply/return water temperature and flow rate, and then the integrator is used to calculate the heat. The basic principle is Q=Cm△t.

Extended Reading: Guide and Selection for Diesel Fuel Flow Meters

BTU Meter adds accessories such as thermometer and totalizer to the flowmeter. So the cost of BTU Meter will be higher than that of flow meter.
The price of the specific BTU Meter needs to be determined by the customer’s detailed measurement parameters.

Extended reading: Ultrasonic flow detectors types

BTU, short for British Thermal Unit, is a unit of measurement that shows how much energy your air conditioner uses to remove heat from your home in an hour. This may seem overly technical, but BTU is an important metric that can help you determine the type of air conditioner you need for a home of your size.

Extended reading:  Tri Clamp Sanitary Thermometers

Related Products

Related Blogs

What Is a BTU Meter?

What is a BTU Meter? A BTU meter is a special instrument that measures the thermal energy transferred in a heating or cooling system. BTU meters…

Guide for Digital Fuel Flow Meter

Digital Fuel Flow Meter is a flow meter dedicated to measuring fuel, diesel, gasoline, and petroleum. Digital Fuel Flow Meter generally has a digital display or…

Mechanical Water Flow Meters

Mechanical water flow meters refer to a type of flow meter suitable for clean water processes or applications. The working principle of a mechanical water flow…

Flow Totalizer Meter vs Flow Meter

A flow totalizer meter is sometimes referred to as a flow meter or flow totalizer. flow totalizer meter displays the flow rate from either an analog…

Velocity Flow Meters

Flow Meter Types There are many types of flow meters. Basically, there are the following types of flow meters Why are there so many types of…

Explore Oil and Gas Flow Meters

An oil and Gas Flow Meter is A device installed in a pump manifold or treating line to measure the fluid flow rate. Oil and Gas…

Strap on Ultrasonic Flow Meters

What is Strap on Ultrasonic Flow Meters? Strap on Ultrasonic Flow Meter is also often called Clamp On Type Flow Meter. The unique feature of Strap…

Sino-Inst offers over 10 BTU Meter for Chilled Water. About 50% of these are magnetic flow meters, 40% is the ultrasonic flow sensor, and 20% are other flow meter.

A wide variety of BTU Meter for Chilled Water options are available to you, such as free samples, paid samples.

Sino-Instrument is a globally recognized supplier and manufacturer of flow measurement instrumentation, located in China.

Request a Quote

Please enable JavaScript in your browser to submit the form