DOES YOUR EXISTING
GAS LEAK DETECTION SYSTEM
PICK UP LEAKS?
Gassonic – More than 2.500 ultrasonic gas leak detectors installed worldwide in the process industry
THE
ULTRASOUND ADVANTAGE Technologies that have traditionally been used in
in all Gassonic products, leaking gas itself does not
fixed installations to detect hydrocarbon gas leaks,
have to reach the sensor – just the sound of the gas
such as Catalytic/IR Point Sensors and IR Open Path
leaking.
Sensors all have one limitation: in order for a leak to be detected, the gas itself must either be in close
Unlike other technologies, the Gassonic ultrasonic
proximity to the detector or within a pre-defined area.
gas leak detectors have no delicate optical alignment
Unfortunately, outdoor environmental conditions such
which can be affected by vibration, rain and fog, or
as changing wind directions and quick dispersion of
solar radiation. Nor can they be saturated by poison-
the gas cloud from a leaking outdoor installation often
ous or highly concentrated gases. On the contrary,
cause traditional gas detection systems to fail simply
the detectors’ stainless steel microphone is mainte-
because the gas never reaches the detector.
nance-free.
The Gassonic Ultrasonic Gas Leak Detectors are
To ensure full integrity and failsafe operation of
based on robust microphone technology; they detect
our most advanced ultrasonic gas leak detectors,
outdoor leaks by sensing the distinct high frequency
Gassonic A/S has developed and patented the
ultrasound emitted by all high pressure gas leaks.
Senssonic™ self-test technology.
With the unique ultrasonic sensing technology found
Alone or in combination The Gassonic ultrasonic gas leak detectors can be used alone or in conjunction with traditional detection methods.
TRADITIONAL GAS DETECTION TECHNOLOGIES Infra-red point detection Detection technology: Infra-red light Coverage: The gas must come into physical contact with the detector
Catalytic point detection Detection technology: Pellistor sensor Coverage: The gas must come into physical contact with the detector
IR open path detection Detection technology: Infra-red light Coverage: Gas must pass through a predefined beam of infra-red light
WHAT
IS ULTRASOUND? A sound wave is simply a pressure pulse in the air,
while they exist beyond the range of normal human
which is detected by the human ear the same way
hearing, they can be detected by Gassonic’s special
that it is detected by a microphone. The human ear
microphone technology which is an integrated part of
can only perceive sound waves in the frequency range
the Gassonic gas leak detectors. When a pressurised
between 20Hz and 20kHz.
gas is released through a hole or a fissure, the leak produces “broad-band” acoustical noise, ranging
Sound waves with a frequency range higher than
from the audible frequency range up to the ultrasonic
20kHz are commonly referred to as ultrasound; and
frequency range.
THE ACOUSTICAL DETECTION RANGE OF THE GASSONIC MM0100 AND THE GASSONIC OBSERVER Very few background noises will occur in this range. However, leaking gas will produce ultrasound clearly detectable within this range. The Gassonic gas leak detector responds to sound that falls within this range.
Gas Leak Rate •
The leak rate corresponds to how much gas is released from a leak per second. The leak rate unit of measurement is kilograms/second (kg/s).
•
A gas leak that generates a high leak rate is dangerous since it can quickly accumulate into an explosive and dangerous gas cloud.
•
2 0 HZ
H UM AN H E AR I N G
2 0 K HZ
ULT R AS OUN D
From gas dispersion studies, a gas leak rate of 0.1 kg/s is considered to be a small gas leak. As an
1 0 0 K HZ
example, a 0.1 kg/s gas leak can be formed by a leak of 4 mm at a gas pressure of 40 BAR (700 psi).
ACOUSTICAL SOUND WITHIN the human hearing range. Most background noise in plants and other industrial facilities, including turbines, motors, and compressors, falls within this frequency range. The Gassonic detectors do not respond within this area.
ACOUSTICAL SOUND BEYOND the human hearing range.
Acous tical s ound within the human hearing range. Mos t background nois e in plants and other indus trial facilities , including turbines , motors , and compres s ors , falls within this frequency range. The GAS S ONIC detectors do not res pond within this area.
•
Gassonic ultrasonic detection technology can detect a leak at a leak rate of 0.1 kg/s up to 20 m. away.
THE
FIELD TESTS ON AN OFFSHORE INSTALLATION
NATURE OF LEAKING GAS The concentration of leaking gas is always highest
door installations even very large gas leaks dilute
closer to the source of the leak, gradually diluting as
quickly and are significantly affected by changing
it drifts away from the source. Traditional detection
wind directions – making them very difficult to detect.
technologies rely on a build-up of the concentration
Instead of measuring a concentration in LEL, Gas-
of the leaking gas. In closed indoor gas installations,
sonic ultrasonic detection technology detects gas
these technologies work fairly well. However, in out-
leaks instantly at a pre-defined leak rate.
have shown that a pressurised gas pipe flange with a 3 mm leak and gas pressure of 55 BAR emitted a gas cloud approximately 4 metres long and approximately 2 metres wide. Measurements made in the centre of the gas cloud revealed concentrations of 100% LEL. However, just 7 metres in front of the leak or 1 metre to either side of the gas cloud, the concentration of the gas cloud was reduced to 0% LEL. In this practical field test, none of the existing fixed detectors on the platform complex reacted to the leak. In contrast, the ultrasound emitted from the same leak was detected instantly by the Gassonic leak detection technology up to 19
2 M ET R ES
DETECTION RADIUS OF A TYPICAL GAS LEAK
0-5% LEL 4 M E T RE S
5-25% LEL 100% LEL
GAS LEAK 55 BAR
metres away.
Comparative Gas Release Event Tree Operators in the petrochemical industry are con-
ards at the earliest stage (initiation), before they
stantly looking at ways to reduce risk, prevent loss,
have time to develop or escalate has a significant
and ensure safe and reliable production. One of the
impact on major accident risk reduction. Traditional
key elements in achieving this and increasing the
gas detection systems need to wait for the gas to
overall efficiency is by speeding up the response time
form a vapour cloud, which may or may not ignite, and
of the F&G detection system.
which may or may not allow loss prevention by enabling shutting down the gas facility in time. Ultrasonic
The Gas Release Event Tree below puts the effects
Gas Leak Detectors respond at the speed of sound
of a gas leak into perspective. It is evident that the
at gas leak initiation, unaffected by changing wind
deployment of appropriate technology to detect haz-
directions and dilution of the gas.
Event tree for gas release Gas Release
Immediate Ignition
Vapor Cloud Forms and Ignites
Liquid Rainout and Ignition
Explosion Occurs
Toxic Chemical
Yes
Outcome Jet Fire
Yes
Vapor Cloud Explosion
Yes No
Flash Fire
No Yes No
Pool Fire Yes
No
Ultrasonic gas detection
Conventional gas detection
No
Toxic Exposure No Consequences But Environmental Impact
HOW TO ENSURE
FAILSAFE OPERATION 2 M ET R ES
In field instrumentation, particularly in harsh outdoor
DETECTION RADIUS OF A a high-quality sound transducer an airTYPICAL GAStransmitting LEAK
environments, faults or breakdowns can occur. What
borne ultrasonic signal to the detector’s microphone
is NOT acceptable is when such faults or breakdowns
system. This ensures that the microphone and the
are left un-revealed, especially if safety is involved.
electronics are tested continuously within well-
To meet the challenge of ensuring failsafe operation Gassonic A/S has developed SENSSONIC™ self-test
defined tolerances, and that the operator is warned if 0-5% LEL the detector should fail this regular test. 5-25% LEL
technology.
100% LEL The SENSSONIC™ technology provides reliable and
for our most advanced ultrasonic4gas M E Tleak RE S detectors,
failsafe operation for the Gassonic ultrasonic gas SENSSONIC™ self-test technology provides a full
leak detectors, protecting your assets and ensuring
acoustic integrity test of the Gassonic Observer
human safety in your industrial facility.
ultrasonic gas leak detector every 15 minutes using GAS LEAK 55 BAR
GASSONIC
SYSTEM IMPLEMENTATION acoustical ultrasonic background noise in the area to be covered should then be decided. If the plant facility is still under construction, Gassonic A/S can be consulted to estimate optimal locations.
Plant Mapping To determine the optimal trigger level for the Gassonic detectors at a given location, and thereby decide the coverage radius, an ultrasonic background noise mapping can be performed. Gassonic may assist customers doing this.
Onsite system commissioning An ultrasonic gas leak detection system can be commissioned by means of simulated nitrogen gas leaks at a leak rate of e.g. 0.1 kg/s. This will verify that the To ensure maximum performance from an ultrasonic
wellhead areas, etc., can be potential leak sources in
detection system picks up leaks according to the pre-
gas leak detection system certain factors should be
high pressure gas installations.
defined performance standards.
Determining a leak size
Regular maintenance
taken into consideration.
Initial considerations
The next decision to make is what leak size needs
Normally the Gassonic detectors do not need main-
First of all, it should be considered which facilities are
to be detected. Even leaks as small as 2 mm can
tenance or calibration. However, if plant regulations
to be monitored – is it an open or a very congested
be detected by the Gassonic gas leak detectors. For
require so, the portable test unit Gassonic 1701 can
facility? One should be aware that all joining parts,
optimal installation of the detectors, the gas pres-
be used.
including pipe flanges, valves, manifold systems,
sure of the system as well as the level of the average
THE GASSONIC
PRODUCTS AND SERVICES The Gassonic products are developed in close cooperation with the world’s leading oil and gas suppliers to ensure reliable operation in some of the harshest
· ATEX, UL/ULC, IECEx and GGTN (K) certified for installation in hazardous environments. · Patented
environments on Earth. All Gassonic products are
CONCERNS
designed to withstand tough corrosive environments
The Gassonic Surveyor
and constantly changing weather conditions. They
· Intrinsically safe, EEXi, stainless steel enclosure
are designed for permanent monitoring of manned or
· 4-20 mA analogue output
unmanned on- and offshore gas installations. Instal-
· Visual local indication (LED)
Background noise immunity
lation locations include remote arctic locations as
· ATEX and IECEx certified
Most noise sources (machines, turbines,
well as desert conditions.
generators) generate sound below the de-
The GASSONIC MM0100
tectable frequency range of the Gassonic
The Gassonic ultrasonic gas leak detectors are all
· Intrinsically safe, EEXi
detectors. However, to ensure that the ultra-
based on robust and proven microphone technology.
· Namur alarm relay output
sonic gas leak detectors are not influenced
The detectors are low-maintenance devices and easily
· Substantial track record
by other noise sources onsite, it is normally
tested and calibrated onsite with the portable unit,
· ATEX and UL/ULC certified
recommended to perform a background
the Gassonic 1701. The product range includes:
noise mapping survey prior to installation.
The Gassonic Services The GASSONIC OBSERVER
· Onsite noise mapping survey
False alarms
· Stainless steel EEXd, explosion proof enclosure
· Detector allocation
Spontaneous air releases from certain indus-
· Senssonic™ self-test technology ensuring failsafe
· Onsite commissioning
trial sources could also trigger an ultrasonic
· Personnel training
gas leak detector. Therefore, the Gassonic
operation. · 4 -20 mA analogue output and RS 485 digital communication interface.
detectors have a built-in delay function to prevent such false alarms from occurring.
ABOUT
GASSONIC Gassonic A/S has a long and distinguished history.
products and services by engaging in and maintaining
Formerly part of the Innova family it was formed after
constructive and energetic dialogue with our clients.
the break-up in the early 1990’s of the Danish instrument manufacturer Brüel & Kjær. Having acquired
It is key for us to make our experience and expertise
both its skilled workforce and its highly-qualified
available to our customers. Therefore, we strive not
development team, Gassonic is continuing the gas
only to sell our products, but also to assist our cus-
analysis and detection operations begun by Brüel
tomers by offering a variety of services to optimise
& Kjær decades ago. Today, Gassonic is part of the
their feeling of safety.
General Monitors family of companies. The ultrasonic gas leak detection technology is now
GASSONIC A/S Energivej 42 A DK-2750 Ballerup Denmark Tel +45 44 700 910 Fax +45 44 700 911 mail@gassonic.com www.gassonic.com
At Gassonic we focus on building the greatest possible
so well-established that it is being used worldwide by
level of reliability and safety for our clients. To do so,
most of the major oil and gas producers. Gassonic
one of our main objectives is to continually develop our
has local representation all over the world.
G A S S O N I C – G A S L E A K D E T E C T I O N AT T h E S p E E D O F S O u N D !