GMI GDUnet, User Handbook Manual

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USER HANDBOOK
1-4
1.2.3 Limits of Preparation
The limits of preparation of the gas should be clear, e.g. ±2%.
These limits should be better than the accuracy required from
the instrument.
The accuracy of preparation of the gas mixtures together with
the analysis accuracy should be clearly marked on the cylinder.
1.2.4 Analysis
The cylinder analysis should be known and within the operating
requirements as specified by the operating organisation.
• Individual cylinders should be analysed.
• Limits on analysis should be clear.
• Method of analysis should be known.
1.2.5 Preferred Values
The typical values that would be used for instruments are given
below. The list is not exhaustive but can be used as a general
guide.
FOR ALL INSTRUMENTS ZERO RANGE - Control Air
Methane Instruments with 10% LEL Range - 0.5% CH
4
Methane Instruments with 100% LEL Range - 2.5% CH
4
Methane Instruments with %GAS Range - 100% CH
4
Methane Instruments with ppm Range - 800ppm CH
4
Methane Instruments with CO Range - 500ppm CO
Methane Instruments with H
2
S Range - 50ppm H
2
S
Note: This list is for guidance only and does not cover all the
ranges or gases that GMI instruments will cover.