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UGLD as extra layer of protection

ULTRASONIC GASLEAK DETECTIONHendrik Heeze

March 2019

Honeywell Confidential - © 2018 by Honeywell International Inc. All rights reserved.

Overview

1.Fundamentals of Ultrasonic Gas Leak Detection

2.Enhancing your Safety with Diversity of Technology

3.Common Causes of Nuisance Alarms and Common Misconceptions

4.Application guidelines


Module IFundamentals of Ultrasonic Gas Leak Detection


Why Ultrasonic Gas Leak Detection (UGLD)?

• To assess and optimize a gas detection system it is important to consider both the functioning of the individual detectors and the effectiveness of the network of detectors within the system.

• Approximately 36% of major gas releases and 69% of significant gas releases are undetected by gas detectors1

• A good mix of technology is needed by assessing the effectiveness of a detector technology in a particular circumstance

• Assess the technology, number of detectors and voting according to the application.

1Health and Safety Executive (HSE) Offshore Hydrocarbons Release database (2001-2008) - (McGillivray and Hare, 2008)


How does a UGLD detect a gas leak? 4

The Principle

• High pressure gas leaks generate broadband audible & ultrasonic sound.

• Ultrasonic detectors listen for this signal in the 20kHz to 70kHz region.

• The sound travels from the source to the detector in milliseconds.

The Detection Method

• Honeywell robust patented solid state sensor produces electrical signal in response to sound pressure waves.

• Signal is analysed in frequency & time domains to determine whether it is a leak event.

• Outputs are generated (LED, Relays, 4 to 20mA, Digital Comms.) and events are logged.


Physical Principles of UGLD• Gas molecules that escape a pressurized system produces a mixture of audible and

ultrasonic noise, known as broadband noise

• Ultrasonic Gas Leak Detectors filter out the audible range – responding to sound infrequencies between 20 kHz and 70 kHz - far higher than frequencies human ear can detect

• The ultrasonic sound amplitude is proportional to the leak rate – the bigger the leak rate thehigher the sound volume

Noise spectrum of nitrogen gas leak in the 20 kHz to 60 kHz frequency band

Fundamentals of Ultrasonic Gas Leak Detection


What is a leak?

• While definitions may vary within industry segments, a useful classification of combustible gas leaks stems from a UK study of Methane releases in the North Sea1, 2:

Category

Either… …Or AndGas Cloud Volume

(m3)Quantity Released (kg)

Mass Flow Rate (kg/s) Duration (min)

Minor < 1 kg < 0.1 kg/s < 2 min < 10

Significant 1 – 300 kg 0.1 – 1.0 kg/s 2 – 5 min 10 – 3,000

Major > 300 kg > 1.0 kg/s > 5 min > 3,000

1 Health and Safety Executive (HSE) Report, OSD Hydrocarbon Release Reduction Campaign, Report on the Hydrocarbon Release Investigation Project ~ 1/4/2000 to 31/3/2001, 2001. 2 Health and Safety Executive (HSE) Report, Offshore Hydrocarbon Releases Statistics and Analysis, 2002, HID Statistics Report HSR 2002 002, February 2003.

• The standards adopted by the early pioneers for UGLD for the detection of Methane leaks was 0.1kg/s

• UGLD should be able to detect a 0.1kg/s Methane leak at a distance of 20 m or greater


Fundamentals of Ultrasonic Gas Leak Detection LEL / ppm vs. Leak Rate

• Point Detectors detect concentrations of gas in LEL or ppm

• UGLD detects leaks of defined Leak Rate

• It is not an either/or scenario – a combination is recommended

• For Point Detectors to detect, gas needs to accumulate and get to the sensor – LEL at that point

• For UGLD to detect, gas needs to move from high pressure to atmosphere at high enough leak rate

• The leak rate defines the coverage of the UGLD

• UGLD do not measure the leak rate, but will alarm to a set Sound Pressure Level produced by a leak

• UGLD should be installed at an optimal distance to detect potential hazardous leaks


Why use the Searchzone Sonik

• It reduce the risk of not detecting a leak

• Not dependent on wind direction or accumulation of gas

• Combustible and toxic gas releases are very difficult to detect in outdoor or well ventilated areas using traditional detectors that are designed to detect hazardous concentrations of gas

• Instant and reliable detection

• Low maintenance

• Cost effective – reduce total cost of ownership



Physical Principles of UGLD• If leaking at the same flow rate, the gas with lower molecular weight willproduce higher levels of ultrasound.

Methane (16), Ethylene (28) and CO2 (44) @ 0,1 kg/s Hydrogen (2) and Helium (4) @ 0.01 kg/s


SPL might vary between different devices

• Ultrasonic Gas Leak Detection is an excellent detection method for detecting Hydrogen leaks


Methane, Ethylene and CO2 @ 0,1 kg/s


• As the detector moves further from the leak, the SPL decreases

• The SPL from different gasses decrease at the same ratio over distance

• When we set a sensitivity level, the detector will only detect leaks with a SPL higher than that setting

Sound Pressure Level decreases over distance


How is the UGLD enhancing your safety

Module II

11


Fixed Gas Segmentation Or The Story Of Point – Line – Zone.

Gas Detection: Point + Line + Zone = Optimal Safety

12

• Gas Detection- Point Gas Detectors detect a gas at a specific point.

- Open Path increases the chance of “seeing” the gas by means of a Transmitter Receiver pair.

- Ultrasonic or Acoustic Gas Detectors “hear” a gas release.

• A technology Mix Approach- Mixing the above technologies enables the optimum coverage and detection.

• Robust detection, each Detector delivering its strengths.- increasing coverage and the chance of detecting gas.- reducing nuisance alarms and systematic faults.- Improving event confirmation and analysis.

Open Path IRBoundary protection, Process

areas

Point IRAt risk points, e.g., valves, pumps

flanges.

UltrasonicAt risk points when high air flows can reduce chances of point gas detection

Primary Secondary Tertiary


Diversity Of Technology

• Many factors, such as type of gas/liquid, pressures, layout, equipment, type of risk, etc. can influence the choice of detection technology

• In order to mitigate the potential spread of hazardous events, the use of technology diversification is recommended

• Ultrasonic Gas Leak Detection is one of the “newcomer” to this mix

• All technologies have their Advantages and Disadvantages

Create layers of protection by diversifying the use of gas detection Technologies

Detection Technologies• Catalytic Gas Detection

• Electrochemical Cell Sensors

• Infrared Gas Detection

• Ultrasonic Gas Leak Detection


Diversity Of TechnologyDetection Technologies Advantages and Disadvantages

Catalytic and Electrocatalytic Electrochemical Cell Infrared Gas Detection Ultrasonic Gas Leak Detection

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- Robust - Easy to install, cal., operate- Long live, low life-cycle costs- Can detect variety of gasses- Wide operation temp.- Can detect Hydrogen

- Fast response time- High accuracy- Versatile – wide range of toxic gasses

- Immune to contamination and poisoning- Fail to safe- No routine calibration- Operates in absence of / enriched oxygen

- Robust- Fail safe- Instant detection of pressurised gas leaks - Detects pressurised gas leaks from all gas types- Minimal maintenance and no consumable parts - Not influenced by changing weather conditions- Covers a large area - Area monitoring

Dis

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- Positive detection – not fail safe- Gas must defuse into sensor - Can become poisoned or inactive- Sensitivity loss, only check with cal. gas- Requires oxygen for detection- Prolong exposure to combustible gas, degrade

- Not fail safe- Gas must defuse into sensor - Limited at low temperatures (≤ -40ºC)- Unsuitable for dry environments - Narrow range of pressures

- Gas must cross IR path- Gas must be IR active- High humidity and dust increase maintenance - Large volume gas required for testing- Not for multiple gas applications- Can not replace IR source in the field

- Not suitable for low pressures - Not suited for liquids- Not for detecting concentration of the gas

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Wellheads

H2S separation

Compressor

CoolersLiquid Storage

Separator

Gas Metering

Main Limitations

• Why traditional technologies can be problematic

o Changing wind directions

o Gas dilution

o Direction of the leak

• UGLD technology limitations

o Low pressure

o Not suited for liquids

o Not for detecting the concentration of the gas


Using different detection technologies in combination with each other can bridge these limitations


Try and mimic some of the Human Sensory System for a safer work environment

• Smell

Point gas detectors


• Hearing

Ultrasonic Gas Leak Detection

• Sight

Open path

Flame

Voting - 2ooN is recommended, where N is any technology.E.g. 1 point and 1 UGLD in alarm = Shutdown



• Natural gas production facility with wellheads, manifolds, separators, compressor engines, and the pipes and storage vessels for hydrocarbon condensate

• In this instance, ultrasonic gas leak detectors are placed close to areas with high pressure gas, in conjunction with Point Detectors

• An open path detector provides perimeter monitoring of the facility

• The fuel gas skid and the storage tanks are at low pressure and for these areas point IR or catalytic detectors are selected

Create layers of protection by diversifying the use of gas detection Technologies1

Point Detector

Open Path Detector

UGLD

1 Safety in Diversity: The Advantages of Technology Diversification in Gas Monitoring Safety - May 2008 , Hydrocarbon EngineeringBy: Edward Naranjo and Gregory A. Neethling


Module IIICommon Causes of Nuisance Alarms

and Common Misconceptions


Common Causes of Nuisance Alarms

Incorrect location of the detector• When installing at a gas compressor, avoid installing straight over the compressor or next to

the noisiest part of the compressor, the gearbox and turbine engine• Install a few metres away from the compressor or source of high ultrasonic background

noise• Do not install next to potentially leaking instrumentation air lines

Incorrect sensitivity setting• Make sure that the sensitivity of the detector is set according to the ambient background

noise.• Background noise can be mapped before installation or estimates and detector sensitivity

should be set before commissioning

Incorrect delay time setting• The Searchzone Sonik detects leaks instantly, therefore a short delay time is needed to

mask out controlled leaks, like those from pressure relief valves • All plants have short derations of high levels of ultrasonic sound, which may trigger the

Searchzone Sonik, but with the correct delay time setting, this will be masked out.


Common Causes of Nuisance Alarms (cont.)

Changes in the possess or equipment• It has happened before that changes have been made to a plant, an new

compressor was put in, or there was a need for a pressure relive valve, etc. • Make sure that the Searchzone Sonik setting are check after any alterations

to the coverage area was made.

Human error• Most of the time false alarms are due to human error.• Releasing high pressure gas in the coverage area of the detector• Maintenance work close to the detector using tools, emitting high levels of

ultrasonic noise for long durations. • Disconnecting detectors, without reporting – resulting in a detector failure


Common misconceptions about UGLD

The background noise is too high• People think audible noise, ultrasonic background noise is much lower • No area is too loud!• E.g. turbine gas compressor – 110dBa, but max. 70 dBu (1m from compressor)

Too high winds• Wind does not effect ultrasonic detectors at all• Test was done in a wind tunnel • Winds need to reach sonic speeds – false alarms will be the least of your worries!

Too congested with piping• Only solid walls, deck or big structures block the ultrasound

Too close to the helicopter landing pad• It is tested that helicopters do no produce loud enough ultrasound to trigger a detector

Gas moving inside the pipes and choke valves too loud• The sound we here coming from pipes and valves are low frequencies, the high frequencies

are attenuated by the pipe wall.


Sound Level Mapping• Is a good to have but not a necessity• Many of studies on ultrasonic vs. audible background noise are available

• Examples of average Sound Pressure Levels (SPL) mapping results:

AREA AUDIBLE SPL [dBa] ULTRASONIC SPL

Compressors 100 70Helicopter deck NA 67Choke valves 94 60Generators 94 60Well bays 84 59Manifolds NA 59Metering skids NA 58Separators NA 58Coolers (fin-fans) 95 64Onshore wellheads NA <44

22


Common misconceptions about UGLD (cont.)

Installing close to the flare stack will cause false alarms• Flaring does not emit ultrasonic sound (only low frequencies) • Pressure is release before reaching the flare• If still under pressure, molecules are burned before reaching sonic flow

Steam will be detected by the detector• Only “Super Heated Steam”, the steam you can not see, will be detected• Normal low pressure steam does not produce high levels of ultrasonic sound


Application Guidelines

Module IV

24


Application guidelines

• Where and how to install?

• How many to install?

• What is the ultrasonic background noise

• What is the coverage?

• What else to take into consideration?


Where and how to install?• UGLD are installed in an elevated position looking

down over potential leak spots• 1 to 2 metres above potential leak spots• In areas with pressurised gas • Onshore and offshore, outdoors or in ventilated areas

How many to install?• This depends on the area, gas pressure and background noise• Area survey can be done, ether physical or plant drawings • Know the gas type and gas pressures• Congestion caused by piping does not block ultrasound, but

big vessels or solid structures do.

What is the coverage?• Coverage of a detector depends on the sensitively of the unit• The type of gas• What leak rates were agreed with the customer – 0.1kg/s,

0.01kg/s, etc.?• Is there “line-of-sight” to the potential leak spots?

Application guidelines


• Detectors are installed at an elevated position (Appx. 2m) over potential leak spots

• Detector sensor facing towards the leak spots

• Avoid solid decks or big vessels blocking the sound. Ultrasonic sound is easier attenuated than audible

• If blockage occurs, more detectors are needed

• Grid flooring/decks and congested piping does not block the sound to the detector.

Application guidelines 27


Where to use the Searchzone Sonik• Fixed installation

• Hazardous areas

• Outdoor and ventilated areas

• Onshore and offshore

• Any application or process with pressurised gas:- Offshore Oil & Gas Platforms

- Onshore Oil & Gas Terminals

- Refineries

- Floating Production Storage and Offloading Vessels (FPSOs)

- Gas Compressor and Metering Stations

- LNG/GTL Trains

- Well-heads

- Gas storage and transportation

- Hydrogen (oil refineries)

- Compressor stations

- Chemical plans

- CNG stations

- etc. …


Hydrogen Sulfide (H2S) Detection with the Searchzone Sonik• H2S is one of the most common byproducts of natural gas production• Some natural gas formations may contain as much as 90% of the chemical compound • H2S is a highly toxic and flammable gas • H2S is easily detected by the human nose, but it quickly impairs the olfactory sense • Concentrations between 0.5 ppm - 700 ppm, exposure can lead to eye irritation, headaches,

dizziness, vomiting, and rapid breathing • Above 700 ppm, the gas can cause shock, convulsions, inability to breathe, coma, and death

• Conventional detectors such as Solid State Sensors and Electrochemical Cells can be slow to react or trigger falls alarms, due to cross-contamination

• Use the Searchzone Sonik in combination with conventional detectors for the first line of detection – will never replace conventional detectors

• H2S is a heavier gas, but leaks together with the lighter Hydrocarbon gas, which is instantly detected by the Searchzone Sonik

• H2S detection at the speed of sound without being affected by prevailing wind conditions, gas dilution or direction of the gas cloud

• Widely used in the Middle East / Asia as early warning for H2S detection• Can muster people within seconds of loss of containment

Introducing the advanced ultrasonic gas leak detectorUGLD: SEARCHZONE SONIK™ - UNIQUE FEATURES


Introducing SearchzoneSonik™Safe and ultrasound

Is a robust and reliable gas leak detector.

Will efficiently “hear” the loss of containment of any high-pressure gas.

Is an advanced, connected, SIL 2-certified*, hazardous area ultrasonic gas leak detector.

Responds to the high-frequency sound of the gas escaping under pressure and is unaffected by environmental conditions.

Focuses on the risks, ignoring noise sources to the sides and behind it.


Robust Patented Piezo-BasedSensor• No field calibration required• No moving parts - immune to particle and liquid ingress• Withstands the harshest of environments• Fast response – Detection at the speed of sound <1sec


• Advanced diagnostic capabilities• Connect to the detector from ground level• Intuitive user interface• Chart presentation of historic background noise• Generate and export reports

Searchzone Sonik: Bluetooth ConnectionOne person Wireless Commissioning with Comprehensive Event Logging


• Complete view on background levels as recorded by SearchzoneTM

Sonik• Instantaneous reading logged every 5 minutes• Sample points displayed on a scatter plot• Display of currently set alarm level

• Choose viewing period of historic information• 1 month, 3 months, 6 months

• Use to make decisions on optimal alarm set point.

• Reduce nuisance alarms.

• Export data to .CSV file.


Focus on What is Important

• Ultrasonic noise can be generated by sources other than gas leaks.

• Introducing Focus Mode (patent pending). Effectively attenuate spurious noise from sources above, below, behind and to the sides the detector.

• ‘Hear’ only noises being generated by the immediate hazard.

• Dramatically increases confidence against nuisance alarms.


The Searchzone Sonik• Light weight

• Easy to install

• Flexible orientation setup – can point to potential leak spots

• Frequency/time domain analyses – not prone to false alams

• Superior coverage

• Bluetooth with App

• Self Test

• Al and SS

• Two detection modes – Standard and Focus modes

• Focus on potential leak and tune out peripheral high noise

Our strengths


Thank you!

For more info and live demo do visit our Honeywell stand @ 1-B219 in the M+R hall

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