This article takes an in-depth look at flow meters
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You will learn:
What is a Flow Meter
Types of Flow Meters
Selecting a Flow Meter
The Benefits of Flow Meters
A flow meter is a flow rate measuring device used to determine the linear or nonlinear mass and volumetric flow of a liquid or a gas. The many names of flow meters include flow meter, flow indicator, liquid meter, and flow rate sensor. How they are named depends on their industrial use. The purpose of a flow meter is to improve the precision, accuracy, and resolution of fluid measurement. They improve efficiency, have low maintenance, are easy to use, and are versatile and durable.
Flow meters can measure the volume, velocity, or mass of a liquid or gas. Using various calculations, they report mass flow, absolute pressure, differential pressure, viscosity, and temperature data that can be used to determine flow rate. The flow rate is calculated by multiplying the velocity (v) by the cross sectional area (A) (Q = v x A) with the units for Q being cubic meters per second (m3/s). Mass is calculated using the formula &#; = Q multiplied ρ (&#; = Q x ρ), where Q equals flow rate and ρ equals mass density. Mass is the main concern for gases, chemical reactions, and combustion.
The purpose of a flow meter is to measure the amount of a material that flows through it in a specified period of time. The compressibility of gases and their change in volume when placed under pressure, heated, or cooled changes the volume of a gas, which is not like the same gas under other conditions. This determines the type of flow meter used to measure gas flow rates. Gas flow rates are measured in cubic meters per hour (acm/h), cubic meters per second (sm3/sec), thousand standard cubic meters per hour (kscm/h), linear feet per minute (LFM), or million standard cubic feet per day (MMSCFD).
The measurement of liquid flow rates vary according to the application and industry with gallons per minute, liters per second, liters per m2 per hour, bushels per minute, and cubic meters per second (cumecs) being the common measurements. A special unit that is used in oceanography is volume of transport (sverdrup or Sv).
The control of flow is an essential part of many industrial applications and requires the use of a wide selection of flow meters specifically designed to meet the needs of all types of applications. The materials that are measured include water, oil, natural gas, and steam with the flow meters for each material sharing the same function but operating in a different manner.
Although the function of every flow meter is the same, each type is adjusted to meet the needs of an application. The two basic types of flow meters are volumetric flow meters and mass flow meters. The differences between the two types is in regard to what they measure with a mass flow meter measuring the amount of mass while a volumetric measures the volume. A volumetric flow rate is influenced by temperature and pressure, while a mass flow rate is influenced by the density of a liquid or gas. The different types of flow meters include differential pressure, velocity, positive displacement, mass flow, and open channel flow meters.
Volumetric flow meters operate linearly and make flow measurements by measuring the velocity of the flow. Unlike mass flow meters, volumetric flow meters have minimum sensitivity to viscosity changes and are connected directly to pipelines. The types of volumetric flow meters include positive displacement flow meters, turbine flow meters, electromagnetic flow meters, ultrasonic flow meters, and vortex flow meters.
Differential pressure flow meters use the Bernoulli Equation, which states that the speed of the flow of a fluid increases as its pressure decreases. To take a flow measurement, a differential flow meter places a constriction or obstruction in a pipe that creates a pressure drop across the flow. As more flow passes through the constriction, the pressure drop increases, which is proportional to the square of the flow rate.
The pressure sensors of a differential flow meter are placed before and after the constriction to accurately measure the flow rate where the constriction causes a change in the kinetic energy of the flow as it is directed through the flow meter to be measured by a second sensor. Differential pressure flow meters commonly make use of a Venturi tube that is designed to constrict and slow flow. The sub-types of differential pressure flow meters are orifice plate, flow nozzle, Venturi flow meter, and rotameter.
Orifice Plate Flow Meter Systems - With an orifice plate flow meter, a liquid or gas passes through the plate, which creates a pressure drop that varies according to the flow rate and differential pressure between the outlet and inlet portions of the flow meter. Orifice plate flow meters can be single chamber, dual chambered, or double block and bleed flow meters.
Venturi meter - A Venturi flow meter measures the flow rate by reducing the cross sectional flow area using a Venturi tube, which generates a pressure difference. A differential pressure sensor measures pressure drop as a measure of the flow rate. Venturi meters use two pressure and one temperature measurement to determine flow with the first pressure reading being taken up stream for density calculations. The second pressure reading is at the throat of the Venturi tube. Temperature readings are taken upstream so as to not disturb the flow profile.
Rotameter - A rotameter is a mechanical flow meter that includes a vertical tapered tube with a moving float that is installed such that the float can rise through the tube to measure the flow rate. The taper of the tube is smaller at the bottom and expands out to the top and has scale gradations marked on the tube. When there is no flow, the float sets at the bottom of the tube. As the fluid flow increases, the float rises until it reaches equilibrium to provide a flow rate reading.
Velocity flow meters are volumetric flow meters that are used to calculate the flow rate by computing the speed of the flow using sensors located along the flow. The accuracy of velocity flow meters depends on the density, cross sectional area of piping, and the velocity of a fluid remaining constant. Any type of device that can directly measure fluid velocity is able to measure the volumetric flow rate of a fluid in a pipe that has a set cross sectional area. The types of velocity flow meters include turbine and vortex flow meters.
Pitot Tube Flow Meters - A pitot tube flow meter has two pipes to measure fluid pressure with the difference between the pressure in the tubes being proportional to the velocity of the flow. One tube measures the impact pressure while the other tube measures the static pressure. The tubes are mounted separately or in a casing as a single unit and are at right angles to the flow.
The total impact pressure tube is L shaped with an opening that faces the flow. The static tube&#;s pressure is the operating pressure of the piping upstream from the total impact tube and at right angles to the flow. The dynamic pressure is the difference between the total pressure and static pressure from the tubes multiplied by the ratio of the dimensional constant and density. As the velocity rises, the profile in the pipe changes from elongated to turbulent or flat.
Calorimetric Flow Meters - Calorimetric flow meters, also known as thermal flow monitors, use the calorimetric principle, which states that a flowing medium absorbs heat energy and carries it away. One sensor for the flow meter is heated. As the flow passes the heated sensor, it cools the sensor. A second sensor measures the temperature in the medium after the absorption of heat from the heated sensor. The flow rate is determined by the difference between the temperatures of the two sensors. When the difference between the sensors is very low, the velocity of the flow is higher.
Turbine Flow Meters - Turbine flow meters use the mechanical rotation of a rotor that is placed in the flow to determine the flow rate with the rotation of the rotor being proportional to the velocity of the flow. They are used with clean and viscous liquids and have an accuracy of 0.5%.
Turbine flow meters are classified as rotating vane flow meters that include paddle wheel flow meters and Pelton wheel flow meters, each version of which has a different shaped rotor. The angled, twisted, or blade rotor is parallel to the flow and faces it straight on. As the flow moves through the pipe, the turbine spins, the motion of which is electronically detected by a magnetic pickup. The frequency output from the pickup is used directly or converted to an analog signal.
Electromagnetic Flow Meters - Electromagnetic flow meters, also known as mag meters, electromag meters, and magnetic flow meters, use electromagnetic induction to measure liquid velocity. With an electromagnetic flow meter, electrodes are placed in the flow that create a magnetic field and read the voltage of the flow as it passes by the electrodes. The principle of electromagnetic flow meters is based on Faraday&#;s law that states that a conductor moving through a magnetic field produces an electric signal that is proportional to the velocity of the flow. As a fluid flows through the magnetic field of the electrodes, conductive particles in the fluid change the voltage of the magnetic field. The variation of the voltage is used to measure and calculate the velocity of the flow.
Vortex Flow Meters - Vortex flow meters measure fluid velocity using the von Kármán effect, which states that when a flow passes a body, a pattern of swirling votives is generated. In a vortex flow meter, a shredder bar is placed in the flow that causes the fluid to separate and form alternating differential pressure or vortices on the back side of the bar. The vortices cause a sensor to oscillate at a frequency that is proportional to the velocity of the fluid. The sensing element converts the rate of oscillation into an electrical signal that is converted to a velocity reading.
Ultrasonic Flow Meters - An ultrasonic flow meter measures fluid velocity by sending ultrasonic waves across the flow in the direction of the flow and in the opposite direction of the flow. The ultrasonic waves and the velocity of the flow are combined to calculate the flow rate. The structure of an ultrasonic flow meter includes two transmitters and two receivers with one of each on opposite sides of the pipe at a measured distance from each other.
With an ultrasonic flow meter, sound waves are sent into the flow using transducers that make direct contact with the flow or uses clamp on transducers that are connected to the exterior of the pipe. Alternating bursts of ultrasounds are measured to determine the time it takes for sound to travel between the transducers. The difference in the transit times is proportional to the velocity of the flow.
The two types of ultrasonic flow meters are in-line and clamp-on flow meters. In-line ultrasonic meters are the insertion type with two sets of ultrasonic transducers aligned opposite each other. Clamp-on ultrasonic flow meters are connected to the exterior of the pipe.
Hydraulic Flow Meters - The term hydraulic flow meter is a generic term that refers to flow meters that measure and monitor the flow of hydraulic fluid. Several different types of flow meters are used to monitor hydraulic fluid due to the different viscosities and flow rates of each type of hydraulic fluid. They are made of resilient material that is capable of withstanding the stress and pressure associated with hydraulic fluids.
The main parts of a hydraulic flow meter are a transducer and transmitter, which are positioned in various locations along the hydraulic line. The transducer measures the velocity of the liquid and calculates the flow level. It senses the movement of flow through the line and sends a signal to the transmitter. The three types of hydraulic flow meters are orifice, gear, and turbine. Hydraulic flow meters help to determine how efficiently and effectively the hydraulic system is running and warn of any problems.
Air Flow Meters - Air flow meters measure air velocity and pressure. The forms of air flow meters are hot wire, cold wire, vortex, membrane, laminar, vane, cup anemometer, and Pitot. They are mass flow meters that measure the mass flow of air and are used to measure ventilation installations, processes, and various industrial applications. A common use for air flow meters is in automobile engines to determine the proper air to fuel ratio.
Positive displacement flow meters pass fluids through a series of gears or gears in a chamber. They are a type of mechanical flow meter where fluids displace components in the meter, which is used for flow measurement. They consist of a chamber that is placed in the flow that blocks the movement of a fluid. In the chamber are rotating mechanisms that permit passage of a fixed amount of a fluid. The number of fixed amounts that pass through the chamber helps determine the volume of the fluid with the rate at which the mechanism turns being the flow rate. Positive displacement flow meters are used for measurements when straight pipe is not available or as a replacement for turbine flow meters and paddle wheel sensors when there is too much turbulence in the flow.
Unlike gear type positive displacement flow meters, screw flow meters have a set of screws called spindles that rotate from one end of the chamber to the other end of the chamber as a fluid passes through. The rotation of the screws by the fluid causes a pressure drop. The rotation of the screw is recorded by a sensor to deliver a measurement that is determined by the flow rate, viscosity of the fluid, and the size of the chamber.
Other types of positive displacement flow meters include oval gear, helical gear, nutating disk, rotary vane, and diaphragm. The popular use of positive displacement flow meters is due to their accuracy and ability to measure viscous, dirty, and corrosive media. The one issue with the measurements of positive displacement flow meters is the pressure drop.
While volumetric flow meters measure the velocity of the flow of gases and liquids, mass flow meters determine the flow rate by measuring the convective transfer of heat on the surface of the flow using temperature sensors in the flow or attached to the piping. They are direct measurement devices capable of measuring a wide range of temperatures with precision and accuracy. Mass flow meters are suitable for use with a variety of fluids including slurries and other viscous materials, non-conductive fluids, and other mass fluids by their density. Two common types of mass flow meters are coriolis and thermal mass.
A mass flow meter measures the mass of a fluid by its inertia as it passes through a vibrating tube equipped with sensors at the inlet and outlet. The vibration of the tube causes oscillation that is proportional to the mass of the fluid. The principle of mass flow meters is based on the Coriolis effect that states that any body moving on the earth&#;s surface tends to drift sideways from its course due to the earth&#;s rotation. The movement of the tubes twist when fluids flow through, which represents the sideways drift caused by the rotation of the earth.
Thermal Mass Flow Meter - Thermal mass flow meters use the principle of thermal dispersion, which is the rate of heat absorbed by a fluid, to measure mass flow. They have two temperature sensors with one sensor being the heating element and the other the sensing element. As the flow moves through, the heating element is cooled by the flow, which is detected by the sensing element. The removal of heat from the heating element is proportional to the mass flow rate.
Coriolis flow meters - Coriolis flow meters work on the principle of the Coriolis principle, which states that a moving mass in a rotating system experiences a force that acts perpendicular to the motion and axis of the rotation. When a fluid is flowing in a pipe, it experiences Coriolis acceleration from the introduction of rotation in the pipe. The force generated by the Coriolis inertial effect is the flow rate of a fluid. The generated inertial force is at right angles to the direction of the flow, which is used by a Coriolis flow meter to measure mass and determine the flow rate.
As a liquid or gas flows through a tube or tubes of a Coriolis flow meter, an actuator vibrates the tube, which artificially causes a Coriolis acceleration in the flow that produces a twisting force that causes a phase shift. The amount of twisting force is proportional to the mass that a meter uses to measure mass flow by detecting the angular momentum. A Coriolis flow meter can measure the flow rate in a forward or reversed direction and is used for leak testing and low flow measurements.
Open Channel Flow Meters - Open channel flow meters are non-contact flow meters that use level sensors that detect the level of a liquid, usually water, in a channel, flume, weir, or partially filled pipe. The flow rate is determined using the level of the liquid and its volume and the Manning equation, which requires uniform flow with the bottom slope and surface slope being the same to calculate the flow rate. A key factor in the use of Manning&#;s equation is the roughness or friction that is being applied to the flow by the channel, which is calculated or taken from a table. The flow rate (Q) is equal to the velocity (v) of the flow multiplied by the flow area (A), all of which are equal to the calculated roughness coefficient multiplied by the hydraulic radius (R), the area (A), and the square root of the slope (&#; &#;S).
Spring and piston flow meters are an easy view flow meter that uses a piston and spring to calculate the flow rate. As the flow enters the flow meter, it creates a pressure differential that moves the piston against the spring, which moves in direct proportion to the rate of the flow. The flow rate is viewed in the same manner as a rotameter and has a red indicator line on the piston that moves along a pre-calibrated numerical scale that is mounted on a transparent section of the body of the flow meter.
Spring and piston flow meters measure the annular flow, which is a type of fluid flow that is lighter in the center of a pipe and heavier along the pipe walls. The scales for a spring and piston flow meter are based on the gravities of fluids with oil being 0.84, and water being 1.0. Spring and piston flow meters, like rotameters, have a simple design and are an alternative to rotameters since they can be configured to transmit electrical signals.
Digital flow meters are high tech flow meters that have four components that act like sensors. Included are anemometers, thermistors, and pressure gauge transducers, all of which have direct contact with the flow and measure mass flow, gas temperature, and gas/back pressure. The one external sensor of a digital flow meter is the absolute pressure transducer that produces pressure readings without the influence of atmospheric pressure.
Anemometers measure the speed and velocity of wind and the movement of gas currents with hotwire anemometers being the most common. The wires for an anemometer are heated to a steady temperature and are exposed to the current of the flow. They measure the amount of current that is necessary for the wires to maintain their constant temperature, and the amount of heat loss caused by the current.
The thermistor monitors and controls temperature fluctuations using electrical resistors that have a resistance that is dependent on temperature. They are used as inrush current limiters, overcurrent protectors, or temperature sensors.
Gauge pressure transducers provide a comparison between the pressure in the system and the ambient pressure. Detecting the difference between the pressures helps prevent harm to the system that could be caused by excessive amounts of gas and back pressure.
Absolute pressure transducers produce readings that are unaffected by ambient pressure. They are sealed and removed from the flow of the material, which allows them to use a vacuum as their reference and zero point.
The readings that are accumulated by the four sensors of a digital flow meter measure mass flow, which is converted to volumetric flow according to flow density and the system&#;s backpressure.
There are several forms of water flow meters, each of which is designed to meet the needs of an application, maintenance requirements, and cost. They measure the volume of slurries, water, and closed pipe fluids. The types of water flow meters include mechanical flow meters, vortex flow meters, ultrasonic flow meters, and magnetic flow meters with mechanical flow meters being the most used and most economical. Each type of water flow meter is designed to measure, monitor, and control the flow of water in a pipe, hose, and other conveyance.
Water flow meters operate under the same principles of other flow meters but are designed to measure the flow of water. They are a subset and special form of flow meter that works only with water although some flow meters are water flow meters but are capable of measuring other liquids and gases.
Fuel Flow Meters measure the amount of fluid being transferred using a digital or mechanical visual display to show how much fuel has been transferred during a transaction. There are several types of flow meters that are used to monitor fuel transfer. How they complete the measurement varies between the different types.
A nutating disk fuel flow meter has a disk that the fuel makes contact with as it enters the flow meter. The disk nutates, moves back and forth, along its vertical axis as the fuel passes through. The back and forth movement of the disk provides an indication of the amount of fluid being transferred through the meter.
Oval gear fuel flow meters have gears that rotate at right angles to each other creating a T shape. The gears mesh in the center of the flow to prevent the passage of fuel. When flow enters the flow meter, it pushes against the gears and makes them rotate and moves out of the flow meter. Magnets in the gears send signals to an electronic reed switch that provides a fuel transport reading.
Turbine fuel flow meters use a rotating turbine that rotates in the fuel around an axis. The mechanical action of the rotating turbine is converted into a flow rate. As the fuel impacts the blades of the turbine, the blades rotate at a steady speed that is proportional to the fuel&#;s velocity.
Peak Flow Meters measure how fast a person can push air out of their lungs to determine how open the airways of the lungs are. They help determine what causes a drop in lung efficiency and help decide what medications to use or if there is a need for emergency care. Peak flow meters are a portable, inexpensive tool that measures air flow.
The two ranges of peak flow meters are low range peak flow meters for small children and standard range peak flow meters for older children and adults with the standard range peak flow meter having a larger airway. The three zones of a peak flow meter are green, yellow, and red.
Green Zone - 80% to 100% peak flow rate. Asthma is under control.
Yellow Zone - 50% to 80% peak flow rate signals caution due to airways narrowing and action is needed.
Red Zone - Less than 50% means medical alert. There is severe airway narrowing and a medical professional needs to be contacted.
One of the considerations regarding the use of a flow meter is the type of flow, which can be open channel or closed conduit. Open channel flow is open to the atmosphere and is a channel, weir, or flume while closed conduit flow is in a tube or pipe. There are various features that need to be evaluated when determining the effectiveness of a flow meter. Remote monitoring, types of data, and the frequency of collection are a few of those factors.
The technology of flow meters is constantly evolving as new and more technologically advanced flow meters are introduced to the market. The applications for each type of flow meter is unique with cost being the least important factor in the selection process.
The reason a flow meter is being selected is due to the application for which it will be used. During an evaluation of a process, it has become clear that a flow meter is needed for safety, monitoring, and control of a flow. This knowledge indicates that engineers and designers have studied every detail of a process to determine where to place a flow meter. What may be overlooked in their assessment is an understanding of the issues of maintenance, calibration, and access to the flow meter, which are necessary considerations as part of the selection process.
It is important to understand the pressure, temperature, allowable pressure drop, density or specific gravity, conductivity, viscosity, and vapor pressure of the flow, which are displayed as a single reading. Flow meters monitor the toxicity, bubbles, presence of abrasives, and transmission qualities of a material to ensure the safety of workers and equipment. With gas flow, gas density changes as pressure and temperature change, common factors of a gas flow meter that have to be closely monitored to ensure accuracy.
The most important consideration when choosing a flow meter is the media to be measured, which can vary in conductivity, temperature, pressure, and viscosity. Additional factors are how clean or dirty the media is since certain flow meters are incapable of withstanding the impact of such media. Engineers and designers normally have a clear understanding of the media that will be transferred from the data collected on their matrix.
As an example, a propeller flow meter is normally used for measuring the flow of drinking water but is not capable of measuring the flow of water that has sand, dirt, iron or contains contaminants. Magnetic meters are ideal for measuring conductive materials and have no moving parts to corrode or break.
The process of flow measurement is a method of quantifying the flow rate of a medium and is based on fluid dynamics or fluid characteristics, such as thermal, acoustic, and electromagnetic properties. Flow rates are taken directly using a mechanical flow meter or indirectly calculated. The different physical properties of gases and fluids requires that they be measured separately using different flow measurement methods with a distinction made between volume flow measurement and mass flow measurement.
Gases have weak intermolecular bonds that cause their density to be influenced by temperature and pressure variations, which influences their volumetric measurement and requires adjustments and compensation in a gas flow meter to ensure accurate readings. With mass gas flow meters, compensation is not required.
The types of measurements for liquids vary according to the application and industry with gallons per minute, liters per second, bushels per minute, and cubic meters per second being the most common units of measure used. In some conditions, the flow rate of liquids can be measured in terms of energy flow in gigajoules per hour or BTUs per day.
Any mass needs force to move, which is part of Newton&#;s Second Law of Motion. In the case of fluids, in a confined pipe, the force that is applied to move the liquid is pressure. The density of the liquid determines the amount of necessary pressure, which indicates the flow rate. When a flow meter is measuring density and pressure, it uses that data to calculate flow rate.
Flow pressure is force that is measured in pounds per square inch (PSI) or kilopascals (KPa). Pressure varies depending on the type of system, the size of the pipes, and the kind of gas or liquid and can increase or decrease with the change of pipes, the addition of fittings, and the pumping mechanism.
Thermal flow meters use heat sensing elements that are isolated from the path of the flow. As liquids or gases pass through a pipe, they generate heat that is proportional to the mass flow rate. These types of flow meters have sensors that measure the flow rate of liquids or gases by recording the temperature from the heat transfer that is produced by the flow. The typical temperature ranges are -40°F to 400°F (-40°C to 204°C). Thermal flow measurement is a reading of the amount of heat that is transferred as a gas or liquid passes over the surface of a pipe.
Heat transfer is a common aspect of piping systems and is a necessary part of fluid flow analysis and the determination of the density, viscosity, and surface tension of a fluid. The three ways that heat transfer happens is convection, conduction, and radiation. Convection refers to the heat energy produced by the movement of a liquid or gas. Conduction is the exchange of heat between the material and the pipe. Radiation is the least common method of heat transfer and mainly happens in gas and oil lines. It refers to the transfer of heat between a hot surface and a cold surface.
The two basic configurations of thermal flow sensors rely on a fluid&#;s predisposition to absorb thermal energy, which can be measured by a thermal flow meter. With the heating element method, fluid flow passes across the heating element that is connected to a thermal sensor where the fluid absorbs heat from the heating element. The sensor measures how much heat was absorbed. The velocity of the fluid is directly related to the amount of energy it absorbs.
With the single heating element process, the heating element works to maintain a fixed temperature. The fluid absorbs heat from the heating element, which requires more energy to keep its fixed temperature. The mass flow is determined by the amount of energy needed.
The location of a flow meter is a major factor in providing accurate and reliable data. The best flow meter will be inaccurate if installed incorrectly. Errors in installation occur when the wrong flow meter is forced into a location, position, or flow. This determination can be damaging to the flow meter, produce incorrect data, be unsafe, and cause damage to equipment or processes.
Flow meters are normally installed on a straight pipe to avoid flow disturbances since bends, valves, tees, and reducers produce flow measurement errors. When straight pipes are not accessible, flow conditioners are used to reduce inaccuracies with a select few flow meters being able to perform under those conditions.
The size of the pipe, its material, and the direction of the flow are essential parts of the selection process. In most cases, downward flow should be avoided, and the piping should be full for accurate measurement.
The need for reporting varies between applications with some applications requiring constant and continual flow reporting and flow readouts. Data from flow meters is sent to a Supervisory Control and Data Acquisition (SCADA) system that is used for controlling, monitoring, and analyzing flow meter data and devices and can be accessed on site or remotely using specially designed software and hardware. The type of output is decided during the selection process and is normally 4 to 20 milliamp (mA).
The design of a flow meter begins with the collection of data, which is used to determine the dimensions, thickness, requirements, and bore of the meter. Flow calculations are based on flow conditions, physical properties of the meter, and the results that include discharge coefficient, beta ratio, flow velocity, pressure differential, and total pressure loss. All of the various calculations are processed and included in an engineering design drawing that is used to manufacture a flow meter.
The design of digital flow meters includes the flow meter body, transducers, and transmitters that are combined into a single instrument. Positive flow meters give precise real-time output and accurate measurements with a signal directly connected to the force of the gas or fluid. The output signal is connected to the flow meter system of a turbine or rotator wheel, plate, channel, nozzle, laminar, and pilot table system.
Basic flow meters or mechanical flow meters are designed to provide readings by the movement of a piston or turbine that moves up or down in a clear plastic tube where it registers a reading on a scale placed on the walls of the tube. They are the least sophisticated of the flow meters and have been used for many years to record flow rates.
Flow meters are made from stainless steel plates, brass, aluminum, PVC, PVDF, and nylon. Their design depends on the viscosity of the measured substance, cleanliness of the flow, pressure, temperature, and pipe size. Most recently, flow meters are being custom manufactured to meet the needs of unique and unusual media.
Flow switches and flow meters differ in how they function and monitor media flow. The main purpose of flow meters is to record and report data that is used to determine the flow rate, mass, and velocity of the flow. Users regularly check the readings and monitor the flow stream using a flow meter.
Flow Switches are mechanical devices used to control the flow of air, steam, gases, and liquids. They send messages or signals to another device, such as a pump, to tell it to shut off or turn on to protect a system from damage and warn of the need for cooling protection. Flow switches are set to be able to determine if the flow is above or below a preset rate or set point, which can be adjustable or fixed. When the set point is reached, an electrical circuit is activated and remains activated until the flow falls below the set point.
Flow switches are constructed to make or break an electrical circuit and are configured to be normally open (NO) or normally closed (NC), which are the default states of the switch. With a NO switch, the circuit is open until triggered while a NC switch is closed until triggered.
A flow switch is made up of a paddle system, permanent magnet, reed contact, and a second magnet. The flow pushes the paddle that is connected to a permanent magnet attached to the reed switch that is above the flow and outside the fluid. The paddle is always connected to an electronic circuit. The paddle turns as the gas or fluid passes into the switch, which sends a signal to a transducer like device that receives the signal and sends it to a transmitter that takes readings.
When the flow rate hits the set point, the circuit closes or opens and turns the pump on or off. In another scenario, when the set point is reached, an alarm can sound and send a warning to users.
Paddle Flow Switches
Paddle flow switches have a hinged or spring loaded paddle that makes contact with the media. The paddle remains in place as the media flows through. When there is a change in the flow rate, the paddle will deviate from its set point and cause a switch to be thrown.
Piston Flow Switch
Unlike a paddle flow switch, in a piston flow switch, a piston reacts to the change in the flow rate. Its movement activates a reed switch that requires action or activates a pump until the flow rate increases or decreases to reach the set point.
Variable Area Flow Switches
Variable area flow switches have a plastic, metal, or glass tube that floats inside the flow. The tube is moved as the flow increases and continues to float until the set point is reached. At that time, a switch is triggered that requires further action and intervention.
Thermal Flow Switches
With a thermal flow switch, a heated probe is inserted into the pipe that includes a housing that is located outside the piping. As the media passes the heated probe and dissipates its heat, a temperature drop occurs that is converted by electronics in the switch to create a switch point value.
The few flow switches listed above are a very small sampling of the many types of flow switches that are available and include ones for HVAC systems, fire systems, boilers, chillers, pumps, and air flow. They are an ideal safety device that can enhance the efficiency and performance of flow transport and transfer.
Flow Indicators
A flow indicator is a device that is designed to provide an indication that flow is occurring. Unlike a flow switch or flow meter, flow indicators do not provide data or monitor and control flow. They let operators know that flow is happening. As sight flow indicators, they provide an inside look at the flow inside a pipe. Flow indicators are also known as plain sight indicators and are the simplest form of flow monitoring device.
How a flow indicator works is dependent on its manner of providing an indication. In most instances, something is moved by the flow or a sight glass is provided to observe the flow. For indicators with devices in them, the flow moves a ball, spins a paddle, flaps, or chains. Flow indicators with a mechanism enclosed can be seen from a distance, which makes them more efficient and convenient.
Flow meters are selected to meet the needs of the media, the type of piping, and the requirements of an application. The over 200 types flow meters makes it possible to choose the correct flow meter to meet the need of an application as well as provide valuable data regarding the movement of gases and fluids. Flow meters have become an integral part of industrial processes as an important safety tool and monitoring device.
Flow meters provide accurate measurement of fluid flow rates, which makes it possible for businesses to monitor processes and identify issues that can damage processes, employees, or equipment. They help management develop methods to improve product quality, eliminate waste, and enhance manufacturing processes.
A major selling point for an investment in flow meters is their low cost, which makes it possible to make a small investment to gain precise measurement data to help improve efficiencies, minimize waste, and lower labor costs. Additionally, flow meters require little maintenance, are long lasting, and do not necessitate any upkeep.
It can easily be said that there is a flow meter for any type of application that has a volumetric transfer or transport of air, gas, water, or liquids. This versatility makes it possible to find a flow meter that can provide protection, monitor flow, and collect data for any application or condition. They can be mounted on pipes, placed above channels, and be placed in the flow or on the walls of pipes and not prohibit or interfere with the flow.
One of the primary reasons that flow meters are so widely used is due to how easily they can be installed and adapted to an existing system. This aspect of flow meters makes it possible for organizations to use a flow meter for collecting data, monitoring flow movement, and determining gas and liquid use. The assessment of the data assists in decisions regarding the viability of a product and the amount of an asset that is necessary to manufacture the product.
Unlike other tools in the manufacturing process, flow meters operate continuously providing a constant flow of real time data. Calculations of flow and mass are immediately available without the need for special procedures or actions. Management can minutely monitor hourly flow to determine the use of gases or liquids.
For safety reasons, there are areas of the United States that have enacted laws regarding the movement of fluids, gases, and liquids. The requirements of these laws demand that companies closely monitor the movement of media to ensure that the transport and transmission of the media is controlled, monitored, and completed safely. Flow meters help companies avoid penalties, fines, and business shutdowns for lack of compliance with local regulations.
For many years, going back to ancient times, flow meters have been used to measure the flow of liquids. They were placed in channels when water was being shared for irrigation and at the openings of pipes to measure flow. These types of flow meters were mechanical and did not depend on computers and electronics to complete their readings. Unfortunately, due to the crude design of the ancient flow meters, the collected information was approximate and an estimate.
Modern flow meters that had scales and provided numerical readings were introduced in the 16th century with the introduction of a tool designed to measure differential pressure and the Venturi tube. At the beginning of the 20th century, various experiments were conducted to improve the Venturi tube and improve its accuracy, which was followed in the s by the introduction of ultrasonic flow meters that were capable of measuring the velocity of liquid flow.
The event that changed the world of flow meters was the introduction of the computer age, which made it possible to produce miniaturized flow meters that had the precision and accuracy required by modern industry. Although technology has advanced flow meters from the estimates produced by the ancient flow meters of China and Egypt, mechanical flow meters still exist due to their low cost, ease of installation, and accuracy for certain applications.
Mechanical flow meters have gears, rotors, impellers, and turbines to measure media flow. They indicate the total flow rate and operate without the use of any source of power. The function of a mechanical flow meter is dependent on constant flow that moves an impeller, rotor, or other mechanical part. There are several types of mechanical flow meters with positive displacement flow meters, turbine flow meters, and rotameters being the most commonly used.
Positive Displacement Flow Meters using a mechanical element to divide a liquid into a single volume and discharging the volume. They are ideal for high viscosity fluids.
Turbine Flow Meters measure the flow rate by the rotation of impellers located in the housing of the flow meter. As the media enters, it rotates the blades to measure the flow rate.
Rotameters are variable area flow meters that have a float for measuring flow. Differential pressure of the upper and lower ends of the flow meter produce force that raises the float until it stabilizes at a point on a scale to provide a reading.
Digital flow meters are flow meters for the modern era. They include a digital computer display that provides data about many aspects of the flow depending on the type of software and hardware used to construct the flow meter. As sensors and transmitters collect data from components placed in the media stream or on the walls of piping, the data is calculated using computer software and projected in an easily readable display. Digital flow meters are more reliable, accurate, and robust than traditional mechanical flow meters and make it possible to send data to computer terminals and laptops.
The structure of a digital flow meter includes impellers to determine flow that are connected to electrode sensors that measure the induced voltage created by the rotation of the impeller to measure velocity and flow rate. Digital flow meters are easy to install, have a long life span, and require very minimal maintenance. They are not susceptible to jamming or breaking since they have no moving parts.
There are several factors to consider when installing a flow meter with the most essential part of the process being the location of a flow meter. In the majority of cases, and to ensure proper readings, flow meters are installed on a straight length of pipe away from elbows, tees, valves, fans, and pumps, which are common causes of turbulence in piping systems.
The fluid or gas that is to be measured must be a single phase media, meaning it is a gas or liquid. Two phase media are difficult to measure and provide inaccurate readings.
The orientation of a flow meter affects the precision of its readings, its accuracy, and overall performance. Flow meters are installed on straight pipes in any direction with 10 diameters upstream and 5 diameters downstream. For their most efficient operation, they are placed away from magnetic fields and vibrations, which can affect their readings. There are a wide variety of installation configurations with ones that are connected to piping such that the flow goes through the flow meter while other installations are merely sensors that are attached to the walls of the piping.
A flow meter, whether it is for gas or liquid, must always be placed such that it is always filled with fluid with an escape for the removal of second phase media. For gas and steam flow meters in horizontal piping, the flow meter should be placed at a high point to enable any condensation to drain out of the piping.
Proper downstream and upstream straight pipe lengths
Determine the Beta ratio which is ori&#;ce bore diameter to pipe diameter (β = d/D)
Understand the location of pulse tube taps
Examine tap finishes to ensure proper insulation
Ensure the proper locations of transmitters, sensors, and read outs in relation to the piping
A flow meter is a flow rate measuring device used to determine the linear or nonlinear mass and volumetric flow of a liquid or gas.
The control of flow is an essential part of many industrial applications and requires the use of a wide selection of flow meters specifically designed to meet the needs of all types of applications
One of the considerations regarding the use of a flow meter is the type of flow, which can be open channel or closed conduit. Open channel flow is open to the atmosphere and is a channel, weir, or flume while closed conduit flow is in a tube or pipe.
Flow meters can measure the volume, velocity, or mass of a liquid or gas. Using various calculations, they report mass flow, absolute pressure, differential pressure, viscosity, and temperature data that can be used to determine flow rate.
The location of a flow meter is a major factor in providing accurate and reliable data. The best flow meter will be inaccurate if installed incorrectly. Errors in installation occur when the wrong flow meter is forced into a location, position, or flow.
So you&#;ve identified the need for a flow meter, whether it&#;s to understand, control or monitor a process, a flow meter is required to see what your fluid is doing and translate it to information you can base decisions on.
There are a host of considerations when selecting a flowmeter such as cost, brand, technology, installation requirements, application etc.
To help narrow down the answer to these questions, we&#;ve compiled a list of the Top 7 Considerations for Choosing a Flowmeter. Once you understand these requirements, the considerations mentioned above will become clearer and the potential field of products narrowed.
In order to identify what type of flowmeter is suitable to a certain application, it is important to know what state the fluid being measured is in; fluid or gas. Gases compress and can&#;t be measured with a liquid meter. This is a vital information to know right from the start. This article focuses on selecting a meter for liquid measurement. You can find further information on gas flowmeters here.
Once fluid has been identified, it is vital to assess if it is clean. A dirty fluid contains solid particles, typically called a slurry, while a clean fluid will be particle free. For example, flowmeters that have wetted moving parts, such as the positive displacement (volumetric flowmeter) or turbine (velocity flowmeter) would not be suitable to dirty fluids, as it will be more susceptible to mechanical wear, plugging or erosion due to the presence of solid particles. Hence, the flow meters that have wetted moving parts are substantially applicable to clean fluids only. On the other hand, dirty fluids would be appropriate to run in an non-contact meters such as electromagnetic (velocity meter), ultrasonic (velocity meter) or Coriolis (mass meter). These also have limitations on them, but handle particles better.
Another factor to be considered is the fluid compatibility with the material composition of the wetted parts, such as the body, seals and gears/rotors/paddle of the flowmeter. Acids and bases are corrosive to metals and would more likely be compatible with thermoplastics, whereas some organic compounds may not be suitable to thermoplastics and would perhaps be compatible with metals instead. For more information on material compatibility, you can download our free Chemical Compatibility Chart.
One of the principal parameters to consider when selecting a meter is the fluid&#;s viscosity, or how thick the fluid is. Since the fluid to be measured has been identified, it is now possible to look at its properties related to flow such as the viscosity. This is defined as the measurement of resistance to flow or alternatively, it is the internal friction of a fluid, the amount of friction the molecules create as they flow over each other. The importance of this parameter in flow measurement is that it determines how well mixed a fluid is and thus how repeatable the reading may be.
For instance, a positive displacement meter, such as oval gear flowmeter, is preferable over a turbine meter to be used in a very viscous (high consistency) fluid. This is because, most high viscosity fluids would have a laminar flow and it is characterised as a smooth, and constant motion. As you can see on below diagram, the velocity profile of a laminar flow is parabolic. What does it tell us? It means that the velocity of the flow inside the pipe is not uniform, the fluid flowing close to the pipe wall is slower due to the friction between the fluid and the pipe wall, while the fluid flowing at the centre of the pipe is travelling at a faster rate.
In turbulent flow, which is characterised as chaotic and occurs mostly on less viscous or thin fluids. Its velocity profile is &#;fully developed&#;, in other words, the flow inside a pipeline is moving at the same speed or velocity at all points. A Turbine meter is a velocity meter, as it directly measures the speed of the fluid by measuring the angular velocity of the rotor which is directly proportional to the fluid velocity. A volumetric flow meter is more applicable for high viscosity fluids at low flow rates like honey, treacle or thick oils. A velocity flow meter will be a good option for a low viscous or thin fluid like solvent or water.
In order to determine whether a fluid will undergo a laminar or turbulent flow, it is good to know how to calculate the Reynolds Number. You can find a Reynolds Number Calculator here. It is a dimensionless number that helps in determining the flow characteristic or pattern of a fluid. It is a function of fluid&#;s density and viscosity. A laminar flow would have a Re< and turbulent flow would have Re>.
It is also worth highlighting that viscosity is a function of temperature. In liquids, viscosity is inversely proportional to temperature, i.e. as the temperature increases the viscosity decreases. Hence, it is important to consider the operating temperature of the system or application to be able to understand how the fluid flow will behave in relation to its viscosity.
This parameter is equally important as the prior parameters to determine the right size of the meter that will suit the application. Flowrate is the volume or mass of a fluid flowing/moving per unit time. You can convert from mass to volume through the density (the amount of volume a fluid takes up per unit mass) or specific gravity ( the ratio of the density of the substance to the density of water or how much a litre of the fluid would weigh divided by the weight of the same volume of water).
Knowing the flowrate range, it is now possible to evaluate if the flowmeter in the selected list has the capacity to handle the required flow rate. This stage is equally crucial with the earlier steps of meter selection, as this point determines if the meter will function as designed. For instance, selecting an undersized meter (it means the meter exceeds the flowmeter&#;s capacity or close to the maximum capacity) would result to damage or failure of internal components of the meter or worst case, would lead to failure of the entire meter. On the other hand, an oversized meter (it means the system&#;s flow is below or close to the minimum range of the meter) would lead to poor accuracy or inability to read/measure a flow.
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This document is current with effect from the date shown on the cover page. As the International Mine Action Standards (IMAS) are subject to regular review and revision, users should consult the IMAS project website in order to verify its status at ( http://www.mineactionstandards.org/ , or through the UNMAS website at http://www.mineaction.org ).
This document is not to be sold.
This UN document is an International Mine Action Standard (IMAS) and is copyright protected by the UN. Neither this document, nor any extract from it, may be reproduced, stored or transmitted in any form, or by any means, for any other purpose without prior written permission from UNMAS, acting on behalf of the UN.
Management practices and operational procedures for mine action are constantly evolving. Improvements are made, and changes are required, to enhance safety and productivity. Changes may come from the introduction of new technology, in response to a new explosive ordnance (EO) threat, and from field experience and lessons learned in other mine action projects and programmes. This experience and lessons learned should be shared in a timely manner.
Technical Notes for Mine Action (TNMAs) provide a forum to share experience and lessons learned by collecting, collating and publishing technical information on important, topical themes, particularly those relating to safety and productivity. TNMAs complement the broader issues and principles addressed in International Mine Action Standards (IMAS).
The preparation of TNMAs follows a rapid production and approval process. They draw on practical experience and publicly available information. Over time, some TNMAs may be &#;promoted&#; to become full IMAS standards, while others may be withdrawn if no longer relevant or if superseded by more up-to-date information.
TNMAs are neither legal documents nor IMAS. There is no legal requirement to accept the advice provided in a TNMA. They are purely advisory and are designed solely to supplement technical knowledge or to provide further guidance on the application of IMAS. TNMAs are published on the IMAS website at www.mineactionstandards.org.
This Technical Note for Mine Action (TNMA) provides additional guidance on the measurement and reporting of beneficiaries defined in IMAS 05.10, Annex B. It is based on the second edition of the Standardising Beneficiary Definitions in Humanitarian Mine Action report (SBD) published by DanChurchAid, Danish Demining Group, the HALO Trust, Humanity and Inclusion, Mines Advisory Group, Norwegian People&#;s Aid and the Swiss Foundation for Mine Action.
IMAS 05.10 specifies reporting information as minimum data requirements for the effective management of mine action programmes in order to ensure quality management of information in mine action programmes.
The aim of this document is to provide guidance on the application of methods for the measurement and the reporting of beneficiaries in the form of a TNMA.
This TNMA provides national mine action authorities, or any organization acting on their behalf, mine action organizations and donors with additional guidance on how to measure and report beneficiaries as defined in IMAS 05.10, Annex B, for the following activities:
A list of normative references is given in Annex A. Normative references are important documents to which reference is made in this technical note and which form part of the provisions of this technical note.
A complete glossary of all the terms, definitions and abbreviations used in the International Mine Action Standards (IMAS) series is given in IMAS 04.10.
In the IMAS series, the words &#;shall&#;, &#;should&#; and &#;may&#; are used to indicate the intended degree of compliance:
3.1
household
small group of persons who share the same living accommodation, pool some or all of their income and wealth, and consume certain types of goods and services collectively, mainly housing and food.
For the purpose of this TNMA, additional terms and definitions are specified in the relevant annexes.
The principles, requirements, recommendations and possibilities in IMAS 05.10 apply to the measurement and reporting of beneficiaries. Additional principles support the inclusiveness, data quality and consistency of the measurement and reporting of beneficiaries.
The method for measuring beneficiaries is different for each activity. Annexes B to E provide guidance on the measurement and reporting of beneficiaries for:
The methods used to measure beneficiaries may be adjusted to the context.
In each country, the methods to measure beneficiaries should be coordinated amongst stakeholders including:
The effort to measure and report beneficiaries should be commensurate in time and resources to those required to carry out the activity itself.
Wherever possible, the beneficiaries should be accounted for individually.
In some cases (for example, direct beneficiaries of mass media EORE, indirect beneficiaries of EOD spot tasks in densely populated areas, or indirect beneficiaries of land release), it is not reasonable to count beneficiaries individually. In these cases, estimated numbers of beneficiaries may be used.
If you are looking for more details, kindly visit tnma.
During reporting, it should be clearly mentioned if the number of beneficiaries for a given activity has been estimated.
In some cases, accounting for members of an affected community individually requires efforts that are not reasonable. As specified in the relevant annexes, the NMAA and mine action organizations may use available population data at the level of the smallest administrative unit (SAU), sometimes referred to as the fourth-level administrative division. In urban contexts, it can be possible to work at smaller level, or fifth-level. Information management specialists should be involved in the definition of the possible levels.
The smallest administrative unit used in the country for the measurement of beneficiaries should be agreed across all stakeholders. This unit should also be used in the database.
Where accurate or reliable population data is not available, or where the smallest administrative units are not easily defined or are deemed unreasonably large for this method, the programme should work with the relevant organizational managers and seek advice from local authorities to identify more accurate methods of measuring the indirect beneficiaries in that context.
The NMAA, or the organization acting on its behalf, and mine action organizations should agree on a time to update population data. Where the regularity of census data allows, it should be once a year.
A person can benefit from more than one activity. When this is the case, this person should be counted as a beneficiary for each activity the person benefited from. For example, a person can benefit from a land release activity and from an EORE activity, and should be reported as a beneficiary for each of these two activities.
For a given type of activity, double counting of beneficiaries should be avoided where possible. However, it may be inevitable in some cases, and the effort to avoid it may not be reasonable. For each type of activity, further guidance is provided in Annexes B to E. In all the cases, any incidences of potential double counting should be made clear in reporting.
Measuring and reporting the number of beneficiaries from a given activity once the activity has been completed is a requirement of IMAS 05.10. These are the actual beneficiaries.
However, the NMAA, or the organization acting on its behalf, mine action organizations or the donor may anticipate the number of beneficiaries expected from a given activity. These are the anticipated beneficiaries. Anticipated beneficiaries should not be reported as actual beneficiaries. In the case anticipated beneficiaries are reported as beneficiaries, then they should not be aggregated with actual beneficiaries.
The point in time to measure the actual number of beneficiaries should be agreed. It should be carried out directly after the task is completed for some activities, such as interpersonal EORE or the referral of direct victims to the relevant services. However, the counting of beneficiaries should be delayed in other cases, such as the reduction or clearance of contaminated land. The moment in time to measure the beneficiaries of such activities should be agreed as indicated Annexes B to E.
As per IMAS 05.10, disaggregation of the data on beneficiaries by sex and age is required.
Whereas the collection of data disaggregated by pre-existing disability is required for direct victims, this is not the case for:
However, the NMAA, or the organization acting on its behalf, and mine action organizations should make efforts to collect data on the persons with disabilities amongst the beneficiaries of these activities. While it is not always possible to collect disability-disaggregated data in large groups, it is reasonably feasible at the individual and household level. The Washington Group Short Set (WGSS) of questions or the WGSS Module on Child Functioning may be used to identify persons with disabilities.
Further disaggregation may be added. For example, EORE beneficiaries may be disaggregated according to additional diversity factors such as displacement &#; as internally displaced persons, refugees or migrants &#; and/or by language in areas where beneficiaries speak different languages. As another example, VA beneficiaries should be disaggregated by the specific type of services they have received or been referred to.
The NMAA, or the organization acting on its behalf, and mine action organizations should agree on the time frame and frequency for the reporting and the aggregation of data.
The data on beneficiaries should be reported to the NMAA or the organization acting on its behalf as follows:
The NMAA, or the organization acting on its behalf, should aggregate the data contained in the reports per activity at least once a year as defined in Annexes B to E. For the purpose of ensuring the progressive management of the quality of data on beneficiaries and to track progress, the NMAA should also aggregate the data once a month. When aggregating the data on beneficiaries, for each type of activity, the number of beneficiaries for a given smallest administrative unit should not exceed the population of this unit (see 4.3.2).&#;.
For example, if in the smallest administrative unit the population comprises 450 persons, the total of the number of direct beneficiaries respectively for each type of EORE (see annex B), and direct or indirect beneficiaries respectively for land release, VA or EOD spot task should not exceed 450.
When opting for a yearly aggregation of beneficiaries, the total population of a given smallest administrative unit should constitute the maximum number of beneficiaries for each year regardless of the number of beneficiaries in the previous year. For example:
The NMAA, or the organization acting on its behalf, should aggregate the data on beneficiaries when the mine action programme has completed its objectives, and when the responsibility for the management of the mine action programme is transferred to another entity. In that case, the NMAA or the organization acting on its behalf should ensure that the aggregated number of beneficiaries for each type of activity and for a given administrative unit does not exceed the total population in this administrative unit.
As per the IMAS 05.10, 7.2, it is required to manage personal information so that the privacy of beneficiaries is kept, and to obtain consent to use this information.
The following documents have been referred to in the development of this TNMA, or are referred to in the text.
The latest edition of these references should be used. The GICHD holds copies of all references used in this TNMA. A register of the latest version/edition of the IMAS standards and references can be accessed via the GICHD website at www.mineactionstandards.org. National mine action authorities, employers and other interested bodies and organizations should obtain copies before commencing mine action programmes.
As per IMAS 05.10, reporting EORE direct beneficiaries is required. This annex provides specific guidance for the measurement and reporting of EORE direct beneficiaries.
explosive ordnance risk education
EORE
activities, which seek to reduce the risk of injury from explosive ordnance (EO) by raising awareness of women, girls, boys and men in accordance with their different vulnerabilities, roles and needs, and promoting behavioural change
EORE direct beneficiaries
persons receiving EORE safety messages through interpersonal EORE, mass and digital media EORE or EORE training of trainers in EORE delivery
As per IMAS 05.10, it is required to report EORE direct beneficiaries separately for each of the following types of EORE:
Table B.1 provides guidance to mine action organizations on counting EORE beneficiaries. It also allows others to see who has benefited from mine action/intervention, and how many people this represented.
When a person benefits from several types of EORE, this person should be counted as a direct beneficiary for each of the received types of EORE.
When a person benefits from several EORE activities under a given type of EORE, this person should be counted only once as a direct beneficiary under this given type of activity.
EXAMPLE 1:
Within an agreed reporting period, a person attended an interpersonal EORE session and a training of trainers course. This person should be measured and reported as a direct beneficiary under direct beneficiary of interpersonal EORE, and direct beneficiary of training of trainers.
EXAMPLE 2:
Within an agreed reporting period, a person benefitted from interpersonal EORE in the form of a group session and a door-to-door session. This person should be measured and reported as a direct beneficiary only once under interpersonal EORE.
Table B.1 &#; Guidance on counting EORE beneficiaries
Efforts to reach persons with disabilities should be reported. However, it is understood that identifying persons with disabilities, for example using the WGSS of questions (see 4.5), is not possible in all cases.
For example, it is not reasonable or possible during large group sessions of interpersonal EORE or through mass and digital media EORE. Though, it is possible and reasonable on other occasions including during small group sessions of interpersonal EORE such as door-to-door EORE, during the training of trainers or while evaluating/assessing the impact of EORE at the individual level.
Within each type of EORE, double counting should be avoided. However, and apart from the guidance provided in clauses 4.3 and 4.6, it is acknowledged that double counting may be inevitable as records of individual participants are not kept. In addition, it is necessary to deliver EORE several times to the same persons because:
For interpersonal EORE, the persons receiving it for the first time should be counted separately in order to understand the reach EORE has. This disaggregation is particularly important:
While it is useful for monitoring and evaluation purposes to record the number of interventions beneficiaries have participated in, recording the number of first-time beneficiaries is the most important and perhaps least burdensome information to collect. Recording the number of persons receiving EORE for the first time separately provides valuable insights for programme resource allocation, tailored support and policy development. It enhances the ability to track and analyse the impact of EORE activities, ensuring they remain responsive to the needs of affected communities. In addition, keeping a record of the number of persons receiving interpersonal EORE for the first time shows whether the activities reach those who never received EORE previously. Over time, as the number of primary attendants drops, the operators will need to adapt the EORE approaches accordingly.
The number of direct beneficiaries of digital media EORE should be measured using the data provided by the media provider. This data should indicate:
If this is a possibility, the data provided by the media provider should also indicate the geographic location of users.
The number of direct beneficiaries of mass media EORE may be estimated using broadcast figures for the medium day and time of the broadcast.
Where such data is not available, direct beneficiaries may be estimated according to the geographic reach of the radio or television channel and the average number of estimated listeners or viewers at the time the EORE messages are aired.
As per IMAS 05.10, reporting land release direct and indirect beneficiaries is required. This annex provides specific guidance for the measurement and reporting of land release direct and indirect beneficiaries.
C.2 Terms and definitions
land release direct beneficiaries
persons whose lives and limbs are protected because they physically use/will use cleared and reduced land post-clearance for a productive, frequent and/or sustainable activity
Note to entry: It includes other members of the household.
land release indirect beneficiaries
persons who are not using the cleared and reduced land but are members of the same community as the direct beneficiaries
Note to entry: Their benefits may be found in an overall improved economic situation in the community, reduced risk or improved general livelihood.
community
<land release beneficiary> group of persons affected by common socio-economic, political and security issues living together in nomadic groups or in smallest administrative units such as hamlets, towns and cities, or portions thereof
land release
process of applying &#;all reasonable effort&#; to identify, define and remove all presence and suspicion of explosive ordnance through non-technical survey, technical survey and/or clearance
cleared area
cleared land
defined area, in square metres, cleared through the removal and/or destruction of all specified explosive ordnance hazards to a specified depth
reduced land
defined area, in square metres, concluded not to contain evidence of explosive ordnance contamination following the technical survey of a suspected or confirmed hazard zone (SHA/CHA)
cancelled land
defined area, in square metres, concluded not to contain evidence of explosive ordnance contamination following the non-technical survey of a suspected or confirmed hazard zone (SHA/CHA)
As per IMAS 05.10, it is required to report land release direct and indirect beneficiaries for the following land release products:
When portions of a confirmed hazardous area are reduced as part of a clearance task, the beneficiaries should be counted only once for the use of the cleared area including the reduced portions.
For cancelled land, no beneficiary should be counted. Beneficiaries of cancelled land may exceptionally be counted where the two following conditions are simultaneously met:
Table C.1 &#; Categories of land use and definitions of beneficiaries. Source:
IMAS 05.10, Annex B.
When reporting beneficiaries of land release, it should be specified whether these beneficiaries are anticipated or actual beneficiaries.
Beneficiaries may be counted as anticipated beneficiaries before the reduction or the clearance of the considered area. The counting is based on anticipated land use following the reduction or the clearance of the area. These anticipated beneficiaries are counted through normal survey processes (non-technical survey, household survey, community survey, etc.).
Beneficiary measurement pre-clearance should be used in a way to fit the context of the land where applicable and meet the needs of the program or organization that deals with this issue. Anticipated beneficiaries are not imaginary or unrealistic numbers, but based on a data collection that proves and clearly defines the number of beneficiaries who will use released land, although it is uncertain at that time to what extent they will use released land.
Beneficiaries should be counted and reported as actual beneficiaries after the reduction or clearance of the area. Generally, this measurement should be done six to twelve months after the reduction or clearance of the area. However, if there is a peak activity (for example, ploughing, harvesting, seasonal migration, start of the school year) before the six months, the beneficiaries should be counted then.
Beneficiaries should be counted once for each task they benefit from.
Some persons possibly benefit from more than one land release task. Often, it is not a proportionate effort to maintain a unique identification system that tracks all the beneficiaries to determine which tasks they benefitted from. These persons may then be reported as beneficiaries for each of these tasks.
For internal statistics purposes, reported on an annual basis, the NMAA, or the organization acting on its behalf, or mine action organizations should not report beneficiary numbers for a given smallest administrative unit that exceed the total population of this smallest administrative unit.
If beneficiary numbers in a given smallest administrative unit exceed its total population before all land release tasks in that area have been completed, the NMAA, or the organization working on its behalf, should continue to collect the numbers of beneficiaries but should not add these numbers to the overall total of land release beneficiaries for this area. The mine action organizations may continue to report land release beneficiaries to the donor.
These examples are based on fictitious scenarios. In cases 1 and 2, the data is not disaggregated by sex, age or disability.
During technical survey of SHA 1, no evidence was found. The SHA has been reduced and handed over to the community.
3 herders who will use the land for herding, and 9 other persons living in their households should be reported as 12 direct beneficiaries.
There are 63 people who live in the village. The total population of the village minus the direct beneficiaries should be reported as 51 indirect beneficiaries.
A clearance task is planned to release CHA 1. At this stage, it is possible to measure anticipated beneficiaries. But the anticipated beneficiaries should not be reported as actual beneficiaries.
Following a community survey and a subsequent household survey, the CHA is anticipated to be used as agricultural land. In total, five farmers from two households would then work on it. In addition, nine other persons live in these two households. They all live in a village with a total population of 45, including the five farmers and their household members.
The mine action organization anticipates:
The clearance task has started. At this stage, the anticipated beneficiaries should not be reported to the national authorities or organisations acting on their behalf as actual beneficiaries.
The clearance task has been achieved and the land is handed over. The actual beneficiaries should be reported to the national mine action center (NMAC).
The five farmers are actually using this land.
Due to births, the number of their household members has increased from nine to eleven.
The population of the village they live in has increased from 45 to 48 persons.
The mine action organization should report:
A mine action organization has cleared area 1. A technical survey has been conducted on the suspected hazardous area 2. The technical survey task resulted in area 2.1 being reduced and area 2.2 being classified as a confirmed hazardous area. The area 2.2 has been subsequently cleared.
Farmer A anticipates resuming the exploitation of area 1 and pasture in the area 2.1 after the handover.
This farmer should be counted as one beneficiary for each of these two released area. There are three other persons living in his household. These three persons should also be counted as direct beneficiaries. They live in a village with a total population of 45 persons including the three persons and their household members.
For each task, that is, the clearance of area 1 and the reduction of area 2.1, in total, the mine action organization should report:
Following the clearance of the area 2.2, farmer B resumes the exploitation of a field in area 2.2. This farmer is also a member of farmer A&#;s village. The farmer&#;s household
comprises five persons. For the clearance of the area 2.2, the mine action organization reports:
In these cases, farmers A and B are both indirect and direct beneficiaries. They also benefit several times from land clearance and reduction.
When aggregating the reported numbers of beneficiaries for the three tasks, the mine action organization, the national mine action centre (NMAC) should not report a total number of beneficiaries that exceeds the total population of the relevant smallest administrative unit.
When adding the number of beneficiaries for each of these tasks, the total number of beneficiaries exceeds the total population of this administrative unit.
The NMAC should not report more than a total of 45 beneficiaries.
It should report:
31 indirect beneficiaries (population of this administrative unit &#; direct beneficiaries).
Children from the smallest administrative units (SAU) A, B and C go to this school.
During non-technical survey the mine action operator collected the following data.
The lives and limbs of the children, teachers and other staff working in this school are protected following the clearance. The mine action organization collected the following information.
Internally displaced children do not access this school.
The breakdown of the children from SAU A, B and C who go to this school as follows:
Other persons that are working in that school:
As the household members of these persons are also direct beneficiaries, the mine action organization also collected the following information:
The mine action organization should report:
For the measurement of indirect beneficiaries, the mine action organization does not include Internally displaced persons since they are not using the school. The mine action organization should report:
As per IMAS 05.10, reporting victim assistance direct and indirect beneficiaries is required. This annex provides specific guidance for the measurement and reporting of victim assistance direct and indirect beneficiaries.
victim assistance
VA
<mine action> broader and specific efforts to address the needs and rights of EO victims
victim assistance direct beneficiaries
persons who are referred to, or receive, emergency and ongoing medical care; rehabilitation services, including prosthetics and orthotics; psychological and psycho-social support; and socio-economic inclusion, for example, inclusive education, self- or waged employment, as well as inclusive sports, leisure and cultural activities
victim assistance indirect beneficiaries
persons who live in the same household as a direct beneficiary of VA, and persons injured, survivors and other persons in need of services that are met during EORE and land release interventions and on whom information on their needs has been shared with organizations/authorities providing services in the sector VA is part of
referral
<mine action> delivery of information on available services to victims
VA services
<mine action> services including:
As per IMAS 05.10, it is required to report VA direct and indirect beneficiaries separately for each of the following categories of victim assistance.
When persons are referred to VA services by mine action organizations, the NMAC or the NMAA, they and their household members are measured and reported as beneficiaries as follows:
When persons receive VA services from mine action organizations, the NMAC or the NMAA, they are measured and reported as beneficiaries as follows:
In addition to the above, persons in need of services can benefit from the effort of the mine action sector to promote the multi-sector approach. As developed in IMAS 13.10, VA is part of, and dependent on, wider efforts such as national policies, plans and legal framework related to health, human rights, education, disability, labour, poverty reduction and social protection (see IMAS 13.10, Annex B).
When persons with needs are met during EORE and land release, mine actions organizations are required (see IMAS 13.10:, 5.2) to communicate these needs to the NMAA, or the organization acting on its behalf, donors and actors in the sectors of which VA is part.[1] The NMAA and NMAC should also engage in efforts to promote this broader multi-sector effort (see IMAS 13.10, 5.1).
Rather than providing information that permits the identification of persons in need of services, data is shared for the purpose of facilitating a needs-based response by those stakeholders responsible for delivering the particular service. When sharing data on the need for particular services in such a manner that the data does not allow to identify the persons in need, these persons are counted as indirect beneficiaries.
These examples are based on fictitious scenarios.
In this case, a conflict resulting in significant contamination recently ended. The NMAC centralizes operational data from mine action operators and reports to the NMAA.
The Ministry of Health is responsible for the coordination of the efforts towards persons with disabilities. It includes the establishment of a directory of existing services and for the collation of data regarding the needs of persons with disabilities. The Ministry of Health is also responsible for preparing a governmental plan of action including budgeting, programming and the delivery of services.
The Ministry of Health has established a forum regrouping several actors from the health, education, economics, development, social protection and human rights sectors. The NMAA is a member of this commission and reports data concerning beneficiaries of victim assistance every semester.
A mine action operator has referred a direct victim to the following VA services:
In addition, six other persons live in the same household.
The mine action operator reports this person to the NMAC as a direct beneficiary of referral. The six other persons living in the same household are reported as indirect beneficiaries of referral.
A mine action operator has referred a direct victim to VA services provided by a service provider outside of the mine action sector. This person has also received VA services provided by the NMAA/NMAC or mine action operator, including emergency and continuing medical care, rehabilitation, psycho-social support, or services that support access to socio-economic inclusion (inclusive education, economic inclusion and social inclusion).
The mine action operator should measure and report this direct victim to the NMAC as a direct beneficiary:
The persons who are part of this direct victim&#;s household are measured and reported as indirect beneficiaries:
Based on cases 1 and 2, it is possible to measure the number of people who were referred and/or received each type of service separately.
D.4.3. Indirect beneficiaries of the promotion of victim assistance
In the course of EORE and land release interventions, mine action operators have collected data on the needs of the local population. The aggregated data indicates that 40 persons (who may also be direct or indirect beneficiaries) from different geographical areas are in need of prosthetic and orthotic services. The collected data also indicates in which geographical areas these persons live. The mine action operator reported this information to the NMAC, which in turn shared it with the NMAA.
Since the information on the needs for services was shared with the NMAA, these 40 persons are measured and reported by the mine action operator as indirect beneficiaries.[2]
As per IMAS 05.10, reporting EOD spot task direct and indirect beneficiaries is required. This annex provides specific guidance for the measurement and reporting of EOD spot task direct and indirect beneficiaries.
EOD spot task direct beneficiaries
persons reporting the EO and the members of their household, and those whose freedom of movement or normal activities were prevented by the presence of an EO and the threat that it posed, real or perceived
EOD spot task indirect beneficiaries
household members of those spot task direct beneficiaries whose freedom of movement or normal activities were prevented by the presence of an EO, and any other persons evacuated to carry out the EOD task safely
Although EOD is part of land release operations, as per IMAS 05.10, it is required to measure and report land release beneficiaries and EOD spot task beneficiaries separately.
An EOD spot task is an EOD task conducted outside of a reported SHA or CHA. Such operations may involve a single item of EO or several items at a specified location.
As per IMAS 05.10, it is required to report EOD spot task direct and indirect beneficiaries as follows:
For a given spot task, the beneficiaries should be individually accounted for.
It happens that some persons benefit from more than one EOD spot task. Often, it is not a proportionate effort to maintain a unique identification system that tracks all the beneficiaries to determine which tasks they benefitted from. These persons may then be reported as beneficiaries for each of these tasks.
If beneficiary numbers in a given smallest administrative unit exceed its total population before all EOD tasks in that area have been completed, the NMAA, or the organization working on its behalf, should continue to collect the numbers of beneficiaries but should not add these numbers to the overall total of EOD beneficiaries for this area. The mine action organizations may continue to report EOD beneficiaries to the donor.
In urban or other densely populated areas, it is not always a proportionate effort to obtain precise numbers of persons evacuated, or household member counts for indirect beneficiaries. In those instances, estimates may be used. For example, these estimates can be determined using:
Sources of indirect beneficiary figures should be recorded and reported (that is, the actual count of evacuated persons, population density data or key informant interview).
Beneficiaries should be recorded per task, not per item of EO. Therefore, if a task includes more than one item of EO, reasonable effort should be made to ensure beneficiaries are not double counted.[4]
Although EOD tasks do not result in land release per se, operators may wish to report on the nature of the areas to which access was inhibited by the presence of EO. This should be done using the same land use categories as for reporting beneficiaries of land release outlined in Annex C.
This example is based on a fictitious scenario. Age, gender and other factors are not disaggregated.
In this smallest administrative unit composed of a village and surrounding lands, the latest census indicates a population of 2,160 inhabitants. During the conflict, this administrative unit was situated on the frontline. SHAs and CHAs have been identified and marked. Items of explosive ordnance are also reported on a regular basis. The government has put in place EOD teams to conduct EOD spot tasks across the national territory. The NMAC is responsible for the operational management, including tasking, of these EOD teams. The EOD teams report to the NMAC.
During this season, person A goes to a community kitchen garden every morning. This day, while hoeing, person A sees a possible explosive ordnance.
Person A warns the three other persons who are currently working in the garden. They all evacuate the garden. They two other persons who work in this community garden to warn them not to come.
Person A informs the police, which deploys an EOD team. The EOD team decides to evacuate persons in a 200-metre radius. According to the police, 17 persons have been evacuated.
During the task, the EOD teams dispose of three items of explosive ordnance.
Person A&#;s household is composed of A&#;s two parents and two siblings.
Direct beneficiaries
Indirect beneficiaries
As the population has returned to this administrative unit shortly after the end of the conflict, numerous EOD spot tasks have occurred. The NMAC assesses that two more years will be necessary to locate and dispose of EO.
When compiling the EOD spot tasks reports for the first 12 months, the NMAC obtains the following figures:
The total number of beneficiaries therefore exceeds the total population of this administrative unit. The NMAC should not report more than a total of 2,160 beneficiaries from this administrative unit.
In this case, the NMAC should report 340 direct beneficiaries and 1,820 indirect beneficiaries.
When reporting to the NMAA, the NMAC should stipulate that the reported number of EOD spot tasks beneficiaries exceeds the total population of this unit.
Although it is commonly used in the humanitarian sector, including the mine action sector, the term &#;beneficiary&#; can be perceived as inappropriate, especially by the concerned persons.
The term can be perceived as implying that the persons supported through humanitarian services are passive with regards to humanitarian matters, thus denying their agency. On the contrary, IMAS are encouraging the active participation of affected communities.
There is no broad agreement on alternative terms that would better reflect the agency of the affected population regarding mine action. However, mine action stakeholders should use alternative terms, at least when engaging with the affected populations.
For example, instead of direct and indirect beneficiaries, they may rather refer to persons directly or indirectly supported or aided.
Management of IMAS amendments
The IMAS series of standards are subject to formal review on a three-yearly basis. However, this does not preclude amendments being made within these three-year periods for reasons of operational safety and efficiency or for editorial purposes.
As amendments are made to this IMAS they are given a number. The date and general details of the amendment shown in the table below. The amendment is also shown on the cover page of the IMAS by the inclusion under the edition date of the phrase &#;incorporating amendment #.&#;
As the formal reviews of each IMAS are completed, new editions may be issued. In this case, amendments up to the date of the new edition are incorporated into the new edition and the amendment record table cleared. Recording of amendments then starts again until a further review is carried out.
The most recently amended IMAS are posted on the IMAS website at www.mineactionstandards.org.
[1] For example, health, rehabilitation, education, employment, social protection and inclusive development.
[2] Moreover, these persons can also be measured and reported as direct beneficiaries of victim assistance if, regardless of their needs for prosthetic and orthotic services, they have been referred to services or accessed services that address other needs.
[3] To obtain population density figures (population per square kilometre or mile), the size of the area of the entire administrative unit is needed. In cases where this data is not publicly available, GIS-trained staff can calculate the approximate area based on the boundaries of the smallest administrative unit. This figure is then applied to all EOD spot tasks within this geographical area. In areas where the population density of the smallest administrative unit is not appropriate to the nature of the contamination, operators may coordinate to agree on what administrative unit best applies and will be used.
[4] Beneficiaries for spot tasks consisting of items of small arms ammunition (<20 mm calibre) should not normally be counted.
[1] Online tools can be used as an interpersonal approach as long as they allow interaction.
[2] Beneficiaries of comprehensive sessions should be reported separately from those of ad hoc or otherwise time- or scope-limited sessions.
[3] For example, during a conflict, the use of EO can evolve as outlined in TNMA 12.10/01 on IED risk education. The transition towards the management of residual contamination (see IMAS 07.10) is another example.
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