Division 9.5.1.1 Gas specifications

The following gas specifications shall be considered:

1. (a)

   Purified gases shall be used to blend with calibration gases and to adjust measurement instruments so as to obtain a zero response to a zero calibration standard. Gases with contamination no higher than the highest of the following values in the gas cylinder or at the outlet of a zero-gas generator shall be used:

   1. (i)

      F12 % contamination, measured relative to the mean concentration expected at the emission limit value. For example, if a CO concentration of 100,0 μmol/mol is expected, then it would be allowed to use a zero gas with CO contamination less than or equal to 2 000 μmol/mol;

   2. (ii)

      Contamination as specified in Table 6.9, applicable for raw or dilute measurements;

   3. (iii)

      Contamination as specified in Table 6.10, applicable for raw measurements.

   Table 6.9
   Contamination limits, applicable for raw or dilute measurements [μmol/mol = ppm]
   It is not required that these levels of purity are internationally and/or nationally recognized standards traceable.
   Constituent	Purified Synthetic Airf1	Purified N2
   THC (C1 equivalent)	≤ 0,05 μmol/mol	≤ 0,05 μmol/mol
   CO	≤ 1 μmol/mol	≤ 1 μmol/mol
   CO 2	≤ 10 μmol/mol	≤ 10 μmol/mol
   O2	0,205 to 0,215 mol/mol	≤ 2 μmol/mol
   NOx	≤ 0,02 μmol/mol	≤ 0,02 μmol/mol

   Table 6.10
   Contamination limits applicable for raw measurements [μmol/mol = ppm]
   It is not required that these levels of purity are internationally and/or nationally recognized standards traceable.
   Constituent	Purified Synthetic Airf2	Purified N2
   THC (C1 equivalent)	≤ 1 μmol/mol	≤ 1 μmol/mol
   CO	≤ 1 μmol/mol	≤ 1 μmol/mol
   CO2	≤ 400 μmol/mol	≤ 400 μmol/mol
   O2	0,18 to 0,21 mol/mol	—
   NOx	≤ 0,1 μmol/mol	≤ 0,1 μmol/mol

2. (b)

   The following gases shall be used with a FID analyzer:

   1. (i)

      FID fuel shall be used with an H₂ concentration of (0,39 to 0,41) mol/mol, balance He or N₂. The mixture shall not contain more than 0,05 μmol/mol THC;

   2. (ii)

      FID burner air shall be used that meets the specifications of purified air in paragraph (a) of this point;

   3. (iii)

      FID zero gas. Flame-ionization detectors shall be zeroed with purified gas that meets the specifications in paragraph (a) of this point, except that the purified gas O₂ concentration may be any value;

   4. (iv)

      FID propane span gas. The THC FID shall be spanned and calibrated with span concentrations of propane, C₃H₈. It shall be calibrated on a carbon number basis of one (C₁);

   5. (v)

      Reserved;

3. (c)

   The following gas mixtures shall be used, with gases traceable within ±1,0 % of the international and/or national recognized standards true value or of other gas standards that are approved:

   1. (i)

      CH ₄ , balance purified synthetic air and/or N ₂ (as applicable);

   2. (ii)

      Reserved;

   3. (iii)

      C₃H₈, balance purified synthetic air and/or N₂ (as applicable);

   4. (iv)

      CO, balance purified N₂;

   5. (v)

      CO₂, balance purified N₂;

   6. (vi)

      NO, balance purified N₂;

   7. (vii)

      NO₂, balance purified synthetic air;

   8. (viii)

      O₂, balance purified N₂;

   9. (ix)

      C₃H₈, CO, CO₂, NO, balance purified N₂;

   10. (x)

       C₃H₈, CH₄, CO, CO₂, NO, balance purified N₂.

4. (d)

   Gases for species other than those listed in paragraph (c) of this point may be used (such as methanol in air, which may be used to determine response factors), as long as they are traceable to within ± 3,0 % of the international and/or national recognized standards true value, and meet the stability requirements of point 9.5.1.2;

5. (e)

   Own calibration gases may be generated using a precision blending device, such as a gas divider, to dilute gases with purified N2 or purified synthetic air. If the gas dividers meet the specifications in point 9.4.5.6, and the gases being blended meet the requirements of paragraphs (a) and (c) of this point, the resulting blends are considered to meet the requirements of this point 9.5.1.1.