14
Notes in methane detection
1.
Upon measuring highly reflective material such as metallic material,
please be careful with situations as shown in Figure A, where two guide
lights (red) are visible caused by reflection, which may cause false
alarms by indicating high values regardless of the presence of
methane.
In such case, please point as shown in Figure B, where only a single
guide light (red) can be seen.
2.
For a PE (polyethylene) pipe with a wall thickness of less than 10mm,
please note that you may get wrong measurements if you keep pointing
the laser directly at the PE pipe, because laser light penetrates through
depending on its thickness.
【
Figure-A
：
Possibility of a false alarm with high values
】
Metallic pipes and similar material
When two guide lights (red) are visible, there is a
possibility of a false alarm with high values.
Bottom part or corner of the wall where
metallic or similar material is used.
【
Figure-B
：
To get correct value
】
Metallic pipes and similar material
When only a single guide light (red) is visible,
correct values can be obtained.
When only a single guide light (red) is
visible, correct values can be obtained.
