ALMA G2 Inspection Report 27th April 2010

ALMA, Airborne Laser Methane Assessment, is an instrument for remote detection of an increased methane gas concentration in ambient air (the gas cloud coming from a leak or other sources) from helicopters.

What is ALMA G2?

ALMA G2, Airborne Laser Methane Assessment Generation 2, has a 2.5 times faster scanning rate, 50% more Laser power from better optics, simplified design, and has been constructed per aviation standards compared to ALMA G1 that was used for RMOTC testing (USA Department of Transportation Rocky Mountain Oil Testing Center).

Why does ALMA exist?

To greatly increase the effectiveness of the gas leak inspection performed by gas companies resulting in safer and more environmentally friendly pipeline systems.

Details of the Inspection:

On 27th April 2010 Pergam-USA performed an airborne inspection of 200 miles of pipeline. Pergam's ALMA G2 natural gas detection system was mounted aboard Obrien Helicopters Bell 206 Jet Ranger. The inspection began at Compressor Station 420 - Palmetto and followed the pipeline to its termination point at West Palm Beach. The operational pressure of the pipeline is 1230 PSI. Diameters of pipes varied from 30 inches to 36 inches.

The results on the 27th April 2010 were 6 detections. The wind speed varied around 5-10 knots and was mostly a tailwind or headwind. This report includes a description of the ALMA G2 installed on a Bell 206, details of each detection, and a table with additional data. The ALMA G2 used had the optional left and right cameras installed for documenting the pipeline and pictures from these cameras are included in the details of each pass.

During inspection three sets of data was collected for the entire inspection path. The results are summarized below by each set. More details for each detection are given in the main body of the report.

The first set includes 3 detections (Numbers 1, 2 and3) and the flight path is shown below (Fig 1A):

The second set includes 1 detection (Number 4) and the flight path is shown below (Figure 1B):

The third set includes 2 detections (Numbers 5 & 6) and the flight path is shown below (Figure 1C):

Description of ALMA G2

ALMA G2, Airborne Laser Methane Assessment Generation 2, is an instrument for remote detection from helicopters of an increased methane gas concentration in ambient air (the gas cloud coming from a leak or other sources). The ALMA G2 is based on an infrared laser with radiation wavelength ~ 1650 nm of which Methane absorbs. A laser beam is emitted from the Optical Unit (OU) and hits a topographic object (soil, grass, trees, concrete, asphalt, etc.). The system analyzes the laser light back scatter to determine how much if any of the laser energy was absorbed by the methane in natural gas. A unique detection algorithm allows for real-time measurement of total methane content along the laser light path from the OU to the topographic object. The system compensates for atmospheric methane using a laser rangefinder. The D-Box and operator laptop with C-Box (control panel) are for system control, data and video storage, and data analysis. The system continually records the inspection data including GPS location information. The on-line software is used for system control and real-time inspection data monitoring from the laptop. The data process software is used for off-line review of inspection data and generation of a report. The system includes a Digital Video Recorder, up to four video cameras, and a monitor to assist the pilot in aiming the laser. The operator monitors the data provided by the system to confirm gas detections, helps the pilot with navigating along the pipeline, and determines if an area needs further inspection.

Pictures of ALMA G2 Installed on JetRanger Helicopter

The ALMA G2 system consists of 4 parts:
  • Optical Unit (Housing the Laser, Rangefinder, and Cameras)
  • D-Box (Housing the Digital Video Recorder and Electronics)
  • Laptop with C-Box (Control Panel) & GPS
  • Pilot Monitor

Figure 2 – ALMA G2 Optical Unit

Figure 3 - JetRanger with ALMA G2 Optical Unit (grey) Mounted to Belly

Figure 4 – ALMA G2 D-Box Secured to Backseat with Seatbelt

Figure 5 – ALMA G2 Laptop with C-Box. Held by Operator in Either Front or Back Seat.

Figure 6 – ALMA G2 GPS Mounted on Instrument Console.

Figure 7 – ALMA G2 Pilot Monitor Mounted to Side of Instrument Console.

Using ALMA’s Gas Detection Report to Find the Source of Gas

Important Information:

  • The ALMA equipment detects the gas cloud coming from the leak in the pipeline not the leak itself. See diagram below.
  • ALMA’s laser must pass downwind of the pipeline to detect the gas cloud.
  • ALMA can detect methane gas coming from other sources than the pipeline such as animals, farms, cars/trucks, etc…

Information in Report about Each Gas Detection (Potential Gas Leak)

How to Find Gas Source

Step 1: Go to gas detection location per GPS coordinates or map, and picture

Step 2: Search for the Source of the Gas.

  • The location from step 1 is where the gas was detected at that particular time. Walk to the pipeline and inspect the area around the pipeline in both directions as illustrated below by the orange oval.
  • Remember ALMA can detect methane gas coming from other sources such as animals, farms, cars/trucks, etc…

Map of detection location and picture from pilots camera at the detection location

Pictures from the left and right cameras at the detection location

Additional Information: Google Map Images For Each Location showing value, latitude and longitude given below.

Green line : Helicopter Path

Red Arrow : Location of Detection

Detection 1 and 2

Detection 3

Detection 4

Detection 5

Detection 6