International comparison CCQM-K119 liquefied petroleum gas

Abstract

Table 2 provides is a list of the participating laboratories.

Advances in metrology for energy-containing gases and emerging demands

“…Further CCQM-GAWG key comparisons addressed mercaptans in methane (CCQM-K65 [90], see section 8.2), composition of refinery gas (CCQM-K77 [10], see section 7.1) and liquefied petroleum gas (LPG, CCQM-K119 [11]).…”

“…After applying a correction for the stability of these mixtures (caused by hydrocarbons migrating from the compartment containing the liquid mixture to that containing helium), the vast majority of the results agreed within the respective uncertainties with the KCRV. The latter was calculated using the measurement model of ISO 6142 [11].…”

“…Examples of the latter include biogas, biomethane and liquefied biogas (LBG)' [9]. In the CCQM-GAWG programme of key comparisons, this trend has been reflected by key comparisons on refinery gas composition [10], biogas composition and composition of liquefied petroleum gas (LPG) [11] , which were organised after a programme of key comparisons dedicated to natural gas composition only [1,[12][13][14][15]. Also the gravimetric gas mixture preparation using liquid injection has been subject of a key comparison [16].…”

Benchmarking the success of CCQM key comparisons for metrology institutes and their stakeholders

“…evidence to support CMCs), the logistics for circulating travelling standards, how to address stability issues and how to determine the KCRV, will all impact on the ability of a key comparison to assess the current state of the art of measurement capabilities. The wealth of information generated from 38 CCQM-GAWG key comparisons, has informed a strategy for a broader application of the results, to provide evidence for the CMC review process [6]. This involves a selected number of components, matrices and amount-of-substance fraction ranges (see table 1), for which several institutes have consistently demonstrated equivalence since the CCQM-GAWG was established.…”

“…The median has been selected to ensure outliers do not influence the average of the distribution. The uncertainty for laboratories that did not demonstrate equivalence was increased by adding the difference of their submitted value to the KCRV in quadrature with their submitted uncertainty in accordance with guidelines developed by the CCQM-GAWG [6]. These guidelines provide a harmonised method for dealing with discrepant results and ensure that all laboratories can use their participation in a key comparison to support their measurement services.…”