What Is It? How Does It Work? Types Of, Uses (2024)

Introduction

This article takes an in depth look at leak detectors.

You will learn more about topics such as:

• What is a leak detector?
• Types of leak detectors
• Uses for leak detectors
• Material types that require leak detectors
• And much more…

Chapter One – What is a Leak Detector?

A leak detector is a sensor used for monitoring a system that contains liquids, gasses, or other substances to ensure that the contained materials do not escape, leak, or otherwise leave the system. The leak detection process involves the use of various types of sensors, detection devices, and equipment specifically designed for sensing and detecting errors in a self-contained system.

The choice of a leak detector is dependent on the type of leaks, which are characterized by the speed gas or fluids move through a leak. The leak rate is determined by the pressure difference between the inside and outside of the pile, hole area, and the gravity of the media. A leak rate calculator computes the rate of a media out of a circular or non circular hole and is built in specific gravity values for water, seawater, diesel fuel, SAE 30 oil, and gasoline. Having the leak rate, the calculator can compute the diameter of the leak hole. Engineers use a set of complex equations to calculate the leak rate.

Leak detection can be completed manually using a hand held inspection device that provides a direct reading. Automated technical leak detection systems provide 24 hour around the clock monitoring of a system for releases and leaks and communicates its findings immediately through a signaling mechanism. The purpose of leak detection is to reduce, eliminate, and control unintended emissions of gasses or liquids.

Chapter Two – Types of Leak Detectors

In every fluid transportation system, there is a potential for leaks, which can occur at pumps, valves, connectors, compressors, open ended lines, and pressure relief systems. Whether it is pipes in a home or the movement of crude oil, leak detection is a serious and necessary part of proper maintenance and safety.

The challenge for leak detection is determining the leak's size, speed, and location. It is important to know the size of a leak a product can accommodate and the size that will cause failure. Using these factors it is possible to determine the type and kind of leak detector you will require.

In industrial settings, leak detection is a routine procedure that is necessary for monitoring product movement. In HVAC systems and commercial refrigeration, leak detection is part of loss prevention and quality control. The three common types of leak detection systems (LDS) are chemical, pressure, and acoustic.

One form of leak detection involves monitoring the molecules of a substance, such as helium, hydrogen, Freon, radioisotopes, and dyes. The characteristics and properties of the molecules are programmed into the leak detection system that responds when the molecule is identified.

Leak Detection Devices

Acoustic Leak Detector

Acoustic leak detectors work on the principle that leaks produce sound and use acoustic detection. When an acoustic leak detector is attached to a building, it records the sound waves produced by leaks and sends the leak’s location to the safety control center.

Leaks produce high frequency sounds from pipes under pressure, such as whoosh, hiss, splash, or thumping. The type of sound waves depends on their size, type of material, and type of leak since each type of leak makes a different sound. A highly sensitive transducer located in an acoustic leak detector picks up the sound waves. The loudness of the sound is directly related to the pressure in the pipe, are passed to a technician.

Flame Ionization (FID) Detection Device

An FID is an extremely sensitive detecting device that measures real time concentrations of vapors. To take its readings, it burns a sample using a hydrogen fueled flame, ionizing any material with ionization potential. Then, the current of the ions is amplified and converted into a meter readout.

Fluorescent Leak Detection

Fluorescent leak detection provides a quick, easy, and noninvasive solution for finding leaks in closed-loop circulating fluid-based systems. The dye is created to be compatible with the existing hydraulic fluid and machine surfaces and enhances the search for leaks and assists in determining if the fluid being viewed is an active leak in the system.

The fluorescent dye is added to the equipment’s reservoir and mixes with the host fluid and circulates throughout the system. Once fully circulated, violet or ultraviolet flashlight is used to activate the fluorescent response. As a technician scans equipment, if there is a leak, it will glow to show the technician where the leak is.

Fluorescent leak detection is used for fuel, heat transfer fluid, hydraulic, lubricant, and refrigeration leaks. The penetrating substance is a mixture of water, alcohol, or oil with a dye to enhance visibility.

Fluorescent dye is simple to use, visually intuitive, and extremely effective for finding leaks. Technicians can safely scan near moving parts and detect the source of small leaks or intermittent ones. Fluorescent leak detection comes in multiple colors and is easily incorporated into a preventive maintenance program. Due to its safe formula, dyes can remain in a system to identify future leaks.

Halogen Leak Detector

Halogen leak detectors are used to determine the location of halogen gasses. They use a pump that pulls in the surrounding air to sample it for the existence of halogen gas. The pumps for the process are calibrated to fit the specifications of halogen gasses and are customized to fit the application being tested.

A halide torch test method uses a flame that heats a small copper plate. If halogen gas is present, the color of the flame changes color to a greenish hue. It is a reliable detection method with some disadvantages.

Depending on the use of halogen gas and local regulations, constant monitoring may be required since halogen gas can damage the ozone layer.

Helium Leak Detector

A helium leak detector uses helium as a residual gas when testing in a closed system. It has a low atomic mass and chemical stability, giving it excellent sensitivity when detecting leaks. Since it is inert and non-toxic, it is a safe and dependable method for testing for leaks since it does not interact with substances in the system.

A helium leak detector, also known as a mass spectrometer leak detector (MSLD), locates and measures leaks using helium as a tracer gas. The helium gas is introduced into the system under pressure, which is measured to determine if there are leaks.

The use of helium leak detectors is related to vacuum and pressure testing. In the vacuum method, a pumping system, roughing or fore fine, evacuates the system to be tested, and helium is introduced to locate a leak. With the pressure system, the piece to be tested is pressurized using helium. The viability of helium as a leak detector is its ability to detect leaks that are not visible to the human eye.

Typical uses for helium leak detectors include pure gas line installations for automation and production equipment, hermetically sealed pass throughs, pressurized gas and vapor delivery systems, gas valves, as specified weldments, storage vessels for gas or pressurized liquids, manufacture and test of thin films and metals, and testing of products that must be hermetically sealed, or products that are required to have a low leak rate.

Helium leak detectors are not recommended for uses where water or other volatile contaminants may be drawn into the vacuum system. The benefits of using a helium leak detector include the ability to identify and quantify extremely small leaks reliably and consistently. Helium Leak Detectors are an excellent non-destructive testing method for production and QA applications

High Voltage (HVLD)

High voltage leak detection is a high speed pinhole or dielectric defect detection method for components made in high speed production. The product to be tested is placed between two electrodes. One electrode is the ground while the other electrode is elevated in voltage. If the material being tested is solid, the voltage from the raised electrode will not pass through to the grounded electrode, and the product is without defects.

The high voltage method is capable of detecting leaks as small as two to five microns in diameter. When a defect is detected, a visible arc or spark is produced. For products to be tested using this method, they must be electrical non-conductors and have sufficient strength to resist puncture by the voltage discharge. Also, products to be tested cannot have complex or complicated geometries.

The chart below is a brief summary and comparison of leak detection methods and their performance rated in millibars (mbar) where one mbar equals 100 Pascals (Pa).

Hydrogen Leak Detector

Hydrogen leak detection uses a highly sensitive microelectronic probe combined with a non-flammable test gas containing hydrogen and nitrogen, which is injected into the test object. The methods for detecting leaks can be performed in several ways. The test object can be placed in an accumulation chamber that detects the presence of hydrogen, or a hydrogen probe can scan the interior of a test object.

The properties of hydrogen provide several benefits for leak testing. It is a very light weight element with a high molecular velocity and low viscosity, making it easy to spread throughout the tested object and penetrates leaks rapidly. Since it does not stick to surfaces, it is an ideal tracer gas for testing various parts of an object. Hydrogen is a non-toxic natural gas that does not have any negative effects on the environment.

Infrared Open Path Gas Leak Detector

Gas leak detection systems are essential due to the nature of gasses and their volatile potential. The main purpose of gas leak detectors is to check for natural gas or other gaseous materials that have broken containment from a storage unit or pipeline. Gas leak detectors are an essential part of safety measures since small minute gas leaks can lead to explosive and dangerous conditions.

A gas leak detector process includes the use of sensors that produce an audible alarm when the presence of gas is detected. The types of sensors include combustible gas sensors, photoionization detectors, infrared point sensors, electrochemical sensors, and semiconductor sensors.

Infrared open path gas detectors measure gas concentration by absorbing infrared radiation at specific wavelengths as the radiation passes through a gas. The detector includes a light source and light detector, which measure the light intensity of wavelengths. The two light sources measure active and reference absorption wavelengths. The gas concentration is determined by the difference between the wavelengths.

Pressure Decay

Pressure decay leak detection uses dry compressed air to pressure test a part to determine how much air pressure the part loses. If the amount of pressure drop stabilizes outside the allowable leak rate, it is decided that the part has a leak. There are various types of pressure decay tests, which are:

• Differential or Vacuum Decay - The vacuum decay examines pressure change under negative pressure. The test compares the pressure change between the test results and a reference part
• Occlusion - The occlusion test looks for a block in a gas flow’s path. Air is passed through an object to see if the path is blocked or clear. The process of the test is to attach a product to a test port and fill it with air. F
• Burst - A product is filled with air until it ruptures.
• Crack Pressure - A crack pressure test checks for leaks before the device reaches its opening pressure. It is used to test check valves.
• Chamber Pressure - The chamber pressure test is for products that don’t have an opening. The product to be tested is placed in a chamber. A measurement is taken of any change in the pressure in the chamber to see if the part has leaks.

Residual Gas Analyzer

RGAs are a small mass spectrometer designed for environmental analysis, process control, and monitoring vacuums for contamination. They check vacuums for traces of impurities, low pressure, and leak detection using helium. RGAs are mounted on or in a vacuum chamber and can perform functions that would be difficult for other devices, including gas leaks.

A RGA examines the chemical components of a gas in a vacuum by ionizing the gasses that are present to create ions to determine the mass to charge ratio of the gasses.

Spot Leak Detectors

Spot leak detectors are used to monitor leaks in a small, confined space and are used to detect water and liquid leaks. They have a sensing probe capable of detecting leaks at a single point from a conductive fluid. Spot leak detectors are easily adjustable and can be manipulated and configured to fit the needs of any location.

The power for a spot leak detector is provided by a battery. When a leak is detected, they sound an alarm. Modern spot leak detectors are capable of sending a message to a computer or cell phone. They are an affordable and simple device that can protect against property damage due to leaks.

Ultrasonic Leak Detector

An ultrasonic leak detection device uses sound to check for leaks. Leaks produce a high frequency sound, which can be located using an ultrasonic leak detector. The source of the sound and leak are recorded on an electronic meter that provides data on the rate of the leak and its location.

The use of ultrasonic leak detection devices is new and widely used for the detection of gas leaks. They are ideal for detecting leaks that produce sounds that are outside the range of human hearing. The mechanism of the device lowers the sound’s range such that it can be heard.

Vacuum Leak Detector

A vacuum leak detector is used to test the integrity of hermetic seals, refrigerators, specialty instruments, and medical systems. It isn’t possible for a vacuum system to be completely leak free. The key factor is the rate of any leaks, which must be low to maintain the proper working pressure, gas balance, and overall pressure.

The vacuum test exposes the chamber to be tested to vacuum conditions and measures the amount of vacuum lost during a set time period. Another type of vacuum test is to charge a chamber with increased test pressure and observe how the test pressure changes. A steady reading on a pressure gauge indicates that the chamber does not leak. Changes in the gauge reading indicate the presence of a leak.

Vacuum test detectors are used to test boilers, condensers, autoclaves, and heat exchangers.

American Society for Nondestructive Testing (ASNT)

The ASNT is an organization that offers a place to exchange of technical information regarding non-destructive testing (NDT). It was founded in the 1940s to promote the study of radium and X-rays and has grown into the premiere organization regarding NDT testing. The ASNT provides technical data, educational materials, and standards for qualifying and certifying NDT technicians.

To receive Level II certification, applicants must pass these four exams:

• General Written Examination
• Specific Written Examination, which covers specific applications
• Practical Examination applicants or performance exam
• Instruction Preparation Examination

Each of the various certification levels has a set of challenges and exams for an applicant to pass before receiving certification.

Chapter Three – Uses for Leak Detectors

Leak detection equipment is used in systems where materials are sealed in a container or moved through pipes. The types of leak detection methods are internal or external, depending on where the detection device is placed. Leaks are the result of a breakdown in the containment walls of a pipe, vessel, or receptacle. Detection of these malfunctions are necessary for the safety of individuals and the environment.

Every leak detection device has a specific sensitivity level, which must be considered when installing the device. For proper use of a leak detector, it is important that it conforms and complies with the storage or piping system.

Leak Detection Device Uses

Medical Leak Detector Uses

The medical profession handles a wide variety of medicinal fluids that require careful errorless handling. These life saving substances are carried in plastic bags, bottles, and other types of containers required to meet the exacting standards of the Federal Drug Administration (FDA). Instruments and containers are put through rigorous testing before they are approved for medical use.

Medical leak detection systems test catheters, dialysis equipment, check valves, syringes, laparoscopic instruments, IV bags, and oxygen regulators to ensure that they are sufficiently sealed and leak proof. The leak detection of these tools for the medical industry is essential since failure can be life threatening and dangerous.

To ensure high quality medical instruments, they are put through a variety of testing methods, including helium trace gas testing, hydrogen gas testing, and dry air testing.

Propane Leak Detector Uses

Propane piping, connections, and fittings are threaded for ease of connection and modifications during installation. The connections are lubricated to ensure a tight and secure fit between the joined connections. During usage, propane piping is under constant pressure, which is exerted on the piping and joints. When there is a loss of pressure, the system can produce leaks.

Companies that supply propane perform constant testing to ensure there aren’t any leaks in the system. This helps in the retention of customers and prevents the loss of gas.

Air Conditioning Leak Detector

The most common types of leaks are connected with air conditioning systems. Regardless how well designed an air conditioning system is, it will eventually develop leaks. The most dangerous types of leaks are very small, which can result in the loss of refrigerant and cause damage to the air conditioner’s compressor. The method used to detect leaks in an A/C system is the injection of fluorescent dye with a tracer material. A UV light highlights the location of a leak in the system, quickly and efficiently.

The use of fluorescent dyes is a quick and easy method for finding the exact location of a leak and prevents the waste of refrigerant and fluids. Whether a leak is large or small and intermittent, it can be found and repaired. Fluorescent dyes have the added benefit of being able to check the system after repairs are completed.

Leak Detection in Hydraulic Systems

It would seem that finding hydraulic leaks would not require the use of any form of specialized equipment. If a puddle of hydraulic fluid appears on the floor, it is safe to say there is a hydraulic leak nearby. Though hydraulic fluid may be exiting the system at one point, such as a hose or connection, that does not mean that that is the origin of the leak.

The two forms of hydraulic leaks are external and internal. Generally, external leaks can be easily diagnosed and repaired. Internal leaks are more challenging and require a technical examination of the device. Various methods for leak detection are used to ascertain the location of an internal hydraulic leak. Some of the methods include a leak detecting flow meter that can be connected at various locations throughout the system. Other methods include temperature measurement and ultrasonic leak detection devices.

Leak Detection for Pipeline Testing

The testing of pipelines for the petroleum industry includes the use of nitrogen. The testing process is used on pipelines, storage containers, and various conduits. Nitrogen is used because it is an inert gas and prevents corrosion reactions by eliminating water vapor and oxygen from sensitive equipment.

The method for testing using nitrogen varies depending on the type of equipment to be tested. The typical process includes a steady channeling of nitrogen gas into the pipe, vessel, conduit, or vat while steadily increasing the pressure. The nitrogen forces out air, debris, and any other materials. Mechanical or automated devices are used to identify leaks and defects in the pipeline or components.

Leak Detection in Food Packaging

An essential part of the food industry is the testing of its packaging to ensure freshness. Leaks can cause a wide variety of problems, which makes leak detection a necessity. There are several types of leak testing methods commonly used by food producers. They include rotary, linear, integrated, and packaged. Rotary, linear, and integrated test empty food containers through the use of pressure and vacuum methods.

Packaged food testing involves testing packaging that has food in it. The purpose of the testing is to determine the resilience and seal strength of the food container. Several methods are used for these types of tests and vary according to the manufacturer. The main concern with leak detecting equipment for food producers is that the testing device matches the conditions and type of product.

Chapter Four – Types of Leak Detection Materials

There are many gasses, fluids, and materials that are part of industrial processes that require leak detection. This can also be said of the many appliances found in the average home. The necessity of leak detection is to protect the environment, safety, and the preservation of industrial operations.

The leak detection process refers to the variety of devices used to monitor water hazards and fluids transported by pipes and includes any device that provides leak protection. The substances that are monitored as well as the methods that are used to monitor them come in many sizes, shapes, and designs.

Materials That Require Leak Detectors

Water Leak Detection

Water leak detection covers the full spectrum of industrial, commercial, and residential leak detection. Plumbers have hand held leak detectors. Engineers use them to monitor water leakage in manufacturing. Water is an essential commodity that is fitted into every building, structure, and home. The pipes and fittings used to provide a water supply can crack, tear, break, and experience wear, which leads to leaks. Having the ability to track and repair the leaks is the job of water leak detectors.

A method for determining the existence of water leaks is infrared thermographic imaging, which is an inspection technology that uses an infrared camera that catches the thermal differences in a building. It is an exceptionally useful method for detecting water leaks. When there is a water leak, the leaking water is absorbed by the surface where it lands. Those surfaces heat up more than the surrounding surfaces, which makes them visible to an infrared scanner.

Water leak detection is necessary because water leaks can weaken the structural integrity of a building by causing rot.

Gas Leak Detection

A major use for leak detectors is the monitoring of various forms of gas. From propane to natural gas, leak detection devices are constantly used to protect the environment and people. Unlike leaks for residential properties, industrial leaks at refineries, steel mills, and gas processing plants are very dangerous and can have catastrophic consequences.

There are several forms of leak detection equipment that are used at industrial facilities. In the case of small leaks, handheld leak detectors are used to monitor the progress of leaks. To control larger leaks, complete leak detecting systems are used, which are rugged, long lasting, and are designed with alarm systems when a gas leak is detected.

When there is a serious gas leak, a number of methods are used to quickly determine the leak’s location, which include area monitoring systems and handheld leak detectors. Unlike water leaks around the house, industrial gas leaks can rapidly escalate into dangerous and life threatening conditions. Industries that move gas have several options regarding the protection and safety of their workers.

Fuel Leak Detection

Fuel is an essential part of all forms of transportation, from the family car to jet planes. The use and transport of fuel requires highly sophisticated leak detection mechanisms that can precisely pinpoint the location of a fuel leak before it becomes dangerous. The handling of fuel requires the implementation of safety measures that are designed to protect workers and the environment. Fuel spills can be extremely harmful and incur severe economic penalties for the perpetrators.

Government regulations are continually increasing and becoming more restrictive in fuel management, which has increased the pressure on leak detection manufacturers to provide solutions to meet the demand. In certain situations, the source of leaks can easily be predicted and prevented. Leak detection devices are normally installed in valve pits and low points in a system as preventative measures.

As with gas leaks, slow fuel leaks can rapidly become dangerous and require immediate attention. Leak detection producers and fuel suppliers take any form of leak seriously and have developed precautions to deal with such situations. The central part of the monitoring of fuel leaks are leak detection devices in the form of area systems and handheld monitors.

Wastewater Treatment and Leak Detection

Wastewater treatment plants are a highly complex system with concrete basins, piping, and electrical systems. A main function of wastewater plants is leak detection, which is a constant concern and a critical aspect of the process. Any portion of the system that springs a leak will discharge contaminated fluids that can have deathly results.

Area leak detection systems are necessary for wastewater processing plants, which require remote monitoring due to the toxins produced by wastewater. For sufficient coverage of the conditions of a wastewater plant, multiple leak detection systems are required to cover all forms of liquid and water leak detection that include multiple zone controllers and monitors as well as a wide array of water leak sensors.

Chapter Five – Leak Detector Regulations

Leak detection is a significant part of the Environmental Protection Agencies (EPA) concerns since leaks are a source of volatile organic compounds (VOCs) and volatile hazardous air pollutants (VHAPs). To assist producers and users of leak detection devices, the EPA published a guide for the repairing and replacing of leak detection equipment.

The EPA guide is intended for use by regulated industries, such as petroleum refineries and chemical producers. The guide’s material includes various problems identified regarding leak detection and repair (LDAR) programs. There are stipulations regarding different practices that can be used to increase the effectiveness of LDAR programs.

Research by the EPA has indicated that 70,000 tons of VOCs and 9,000 tons of HAPs have been released into the environment by equipment leaks each year. The recorded leaks include the full spectrum of materials and containers and include storage vessels, wastewater treatment facilities, gas, oil, and liquid transfer sites, and processing vents.

VOCs are part of the formation of ground level ozone, which is a major part of the creation of smog. Breathing in VOCs leads to respiratory diseases in children, asthmatic patients, and healthy adults.

In order to control the spread of harmful emissions, the EPA suggests the implementation of a leak detection and repair program and the replacement of equipment that has been detected as having leaks with leakless components. Leak regulations provide the options of controlling leaks as well as developing leak detection practices.

The common sources of leaks that require leak detection devices include:

• Pumps – leaks happen at the seal
• Valves – leaks occur in the stem or gland area
• Connectors – leaks occur due to gasket failure
• Sampling Connectors – leaks occur at the outlet of the line
• Compressors – leaks occur in the seals
• Pressure Relief Devices – leaks occur due to poorly seated valves and ruptured disks
• Open Ended Lines – leaks occur where the line opens to the atmosphere

New Source Performance Standards (NSPS)

The NSPS standard 40 CFR Part 60 is in regard to equipment leaks of VOCs.

National Emission Standard for Hazardous Air Pollutants (NESHAP)

NESHAP regulations 40 CFR parts 61, 63, and 65 are standards that have been enacted for new and existing sources of VHAPs.

Resource Conservation and Recovery Act (RCRA)

The RCRA was enacted in 1976 for the express purpose of overseeing the disposal of wastewater, solid waste, and hazardous waste. The focus of the act is oriented toward wastewater management and treatment plants.

Chapter Six – Benefits and Advantages of Leak Detectors

The obvious reason for the use of leak detection equipment is for environmental protection since many of the materials that travel through pipelines and are stored can contaminate the environment. Aside from the ecological benefits, there are the economical benefits of protecting the profits of a company by successfully controlling its assets as in the case of chemical production facilities and fuel production and storage plants.

Leak detection is another step in the improvement of an organization's operation. Proper management and control ensure that equipment performs flawlessly and assets are protected, a combination that can lead to financial success.

Leak Detector Benefits and Advantages

Loss Prevention Through Leak Detection

Though the major concern for leak detection is environmental protection, another factor is the cost associated with leaks and the loss of assets. Every leak allows profitable materials to escape and be unrecoverable. This significantly impacts a company's bottom line. By having an efficient and reliable leak detection system, any type of product loss is severely diminished or completely eliminated.

Precise Leak Locating

A leak detection system precisely pinpoints the location of a leak, which makes it possible to respond immediately to control and extinguish it.

Non-Invasive Leak Detection

Leak detection devices do not impinge on the operation of a facility. They are placed close to critical areas where they can provide the greatest amount of data. Their installation does not interfere or halt operation but serves the main function of protecting resources and personnel.

Leak Detection Benefits in Labor Saving

In the past, the only leaks that received immediate attention were ones that were visible or small leaks that created disasters. The process of finding leaks took digging and effort. Modern leak detection units identify, locate, and map the location of a leak before it becomes visible and have the extra advantage of avoiding the need for digging and searching. As a result, a leak is discovered and repaired with minimal damage.

Conclusion

• Leak detectors are sensors used for monitoring a system that contains liquids, gasses, or other substances to ensure that the contained materials do not escape, leak, or otherwise leave the system.
• Automated technical leak detectors provide 24 hour around the clock monitoring of a system for releases and leaks and communicate its findings by a signaling mechanism.
• In every fluid transportation system, there is a potential for leaks, which can occur at pumps, valves, connectors, compressors, open ended lines, and in pressure relief systems.
• Leak detectors are used in systems where a material is sealed in a container or moved through pipes.
• Every leak detection device has a specific sensitivity level, which has to be considered when installing the device.