Applications of Laser Methane Detector











Figure1: An Emergency Vehicle on duty. The endless works protect sleepless activities in urban cities

Back Ground

City gas is playing a very important role for sleepless activities in urban people es life, and therefore, it is needless to say that a very high safety standard and stability are required. Maintenance of gas pipelines in city gas companies includes daily maintenance and emergency tasks. In those tasks, swift and appropriate actions for gas leaks to prevent disasters are one of the most important duties for the city gas companies. In the course of fulfilling the demand for customerfs safety and satisfaction, cutting edge technologies in various fields especially in the information and sensing technologies are introduced. The laser methane detector, which can find existence of methane gas remotely, has been realized after more than two decades of rigorous research activities in Tokyo Gas and its business partners, and is now changing revolutionary the emergency jobs for the better maintenance standard in city gas companies.

Emergency Dispatch with Advanced IT technologies

Sharing true information among service people is the critical issue in the emergency tasks in order to prevent disasters. A control center communicates with branch offices and field engineers using the sophisticated IT networks. A computerized mapping system and locations of emergency vehicles using GPS (Global Positioning System) are organized for speeding up the dispatch process.

Figure 2: Huge information of buried piping is now organized with IT technologies.





Fig 3FInside of an emergency vehicle
Figure 4: Customerfs safety is protected with the cutting edge technologies.

Strategy of Gas Companies in Emergency Tasks

Prevention of secondary accidents is more important than finding locations of gas leaks and is considered as the most important goal in order to minimize human loss in emergency situations. The preventive measures include:

(1) shut off gas supply
(2) prevent ignition of gas
(3) safe evacuation

Emergency personnel are trained such that the procedures are executed promptly and adequately in the situations, and locations of floating gas are crucial information in making decisions. Because natural gas is lighter than air, they are prone to concentrate in high places such as ceiling and pipe shafts where conventional sampling gas sensors cannot be used. In such cases, Laser Methane detector can easily locate floating gas without using e.g. ladders, saving precious time in the tough situations. If quantitative information of gas is not needed, SA3C05A with no LCD display but beeping alarm may be satisfactory for the purpose. However, when more detailed information regarding concentration of gas is needed, SA3C06A is preferred. SA3C06A is also equipped with a card memory to record data so that evidence of gas detection during a mission can be recorded. Because every second in the emergency situations is precious, it is highly recommended that all the emergency vehicles should be e quipped with a Laser Methane detector so that emergency personnel can make use of the detector when needed. It is also important that the emergency staff should understand usage of the equipment very well in order to utilize full potentials of the device performance.





Figure 5: Working distances between the Laser Methane detector and targets.
Figure 6: The Laser Methane detector is becoming an indispensable tool in combination with conventional sampling detectors.

Useful Tips


Detection of methane gas beyond reach

Detecting existence of methane gas without going to the leak location is the most prominent feature of the Laser Methane detector. As a matter of fact, the detector is mainly used to find gas near ceilings, walls, under floors, and around narrow gaps between buildings. The figure shows a statistics regarding distances between the detector and the targets when the device was actually used. The distribution peaking around 3 to 5 meters supports the usage of the detectors.


A back up for conventional gas detectors

The emergency staff dispatched to a leak site has to locate leaks for repairs after the primary procedures are performed. The leak prone parts such as pipes near connections are examined extensively using conventional detectors based on stafffs experiences. But if leaks are not found with the search or the leak does not stop after the repair, a large area has to be searched without clues. In such cases, the Laser Methane detector can be a great help.

Search for floating gas

As discussed previously, it is most important to prevent secondary disasters in gas leak accidents. Methane based city gas is prone to accumulate in high places such as ceilings, locating such floating gas contributes significantly in reducing possibility of the secondary disasters using the Laser Methane detectors.


Know How



Useful Tips

Figure 7: The shoulder strap is a mandatory item to prevent the operator from accidentally dropping the LaserMethane especially during high place operation.







The LaserMethane is a detector that requires no complicated skills to operate but to simply aim a target and pull the trigger. However, there are still some useful tips that are not described in the manual. Some of the common tips are shown here for the userfs convenience.

Figure 8: Tuck the strap around the elbow, and hold it tight as shown in above photo when you aim a long distant target. It will dramatically increase the stability.



Know How 1: How to aim a long distant targets


Maximum detecting distance of the LaserMethane is 30 meters (in low range). However, once you try to point a target, you will soon recognize that aiming a distant target is not an easy task. Small body movement in holding the equipment results in unacceptable movement of the guidance laser beam at the target. This movement, of course, becomes more prominent in distant targets. In this situation, try the shoulder strap, which is included in the standard accessories (see figure 7). Tuck the strap around the elbow, and hold it tight as shown in figure 8. It will dramatically reduce the shake and help you point the target more accurately.

Figure 9: This handgrip is designed for both right and left-handed operators. It is very useful for long hour use.



Know How 2: Usage of the Handgrip Band


The handgrip band is very useful for long hour use. It is surprising to discover how the handgrip band can significantly change the feeling of weight of the LaserMethane. Note that this band is designed for both right and left-handed operators.

Figure 10: You may experience difficulties in seeing the red guidance laser when your target is far away. Using the gunsight in such situation may be useful.



Know How 3: The Gunsight Device


When you use the LaserMethane under the sunlight, you may experience difficulties in seeing the red guidance laser on distant targets. The gunsight on the top surface of the LaserMethane (see figure 10) is what you want. It surely is a glow tech deviceh, but it can solve your problem to a certain extent.


Figure 11: You may have difficulty to see the red guidance laser when you use it outdoor, especially on a sunny day. However, this problem can be resolved very easily by using a so called gDot Sighth scope, which is also widely used for telephotograph by digital cameras.



Know How 4: Utilization of a gDot Sighth Scope


The glaser pointerh, which is employed to provide guidance for the operator to pin point where the laser is being pointed, is really effective when using the LMD indoors, but when using it outdoors, the sunlight may cause difficulties in seeing the laser pointer on targets. Of course the standard gunsight device can help you to a certain extent, but a so called gdot sightg scope, which is usually sold for telephotograph by digital cameras is much more effective. To mount this scope on the LMD, special brackets will be necessary. For further information, please contact your local sales agent.


Figure 12: Display of gReflect Modeh



Know How 5: About the gReflect Modeh


There is a display mode called the gReflect Mode.h
This gReflect Modeh indicates how much laser beam is reflected back from the target. This mode will enable you to determine whether gas really does not exist or whether the laser just does not reflect back from the target. It is recommended to use this mode when you presume the reflection rate from the target is low.


Figure 13: Convenience to use gLock Modeh button when you wish to inspect leakage continuously.



Know How 6: About the gLock Modeh


Many users may know this glock modeh already. When you wish to detect leakages continuously, you will need to keep pulling the trigger but if you push in the button on the side, the trigger will be locked and shall enable continuous laser scanning without pulling the trigger. This is some consideration for the operators who are involved in the actual operation at the scene of detection.


Figure 14: Earphones are necessaries in a noisy environment. (standard accessory)



Know How 7: Earphones


When you have to use the LaserMethane Detector at noisy places like factories, it may be difficult to hear the beep sound telling the leakage. Assuming such use, the beep sound can be listened by using the earphone. The earphone is included in the standard accessories.


Figure 15: By capping the lid on the device and intentionally creating an error, the LMD will record an error showing that there is no data during this period.



Know How 8: Identification of measured data


When conducting methane gas leak detection at several locations, it may be difficult for you to distinguish which data is necessary. For easy identification keep the LaserMethane Detector in continuous measuring mode (refer to gLock Modeh) and close the cover/cap on the front between the each measurement like a camera when not shooting photographs. In this condition, the measurement will be recorded as an error. This enables the operator to distinguish the correctly measured data and non-measured data during situations such as moving from one location to another.


Know How 9: gSenior Modeh (Zoomed display function)


Normally, the liquid crystal display on model SA3C06A displays numerical values and a graph. Actually, the display pattern can be changed in three ways by pushing the gDISPh button on the console while pulling the trigger. One of the display modes will display magnified numerical values without the graph. This magnified display mode may benefit those who have difficulty in seeing small characters (presbyopia).

Standard Display
@ (numerical value + graph)
Reflection Status Display
@ (Reflect Mode)
Enlarged Number Display
@ (Senior Mode)

Figure 16: The display can be changed by pushing the gDISPh button on the console while pulling the trigger.

© 2005 TOKYO GAS ENGINEERING SOLUTIONS CORP. all rights reserved.