5.1 On-line, at-line, in-line, CFMS, and other near-real time monitoring systems that measure fuel gas characteristics, such as the sulfur content, are prevalent in the natural gas and fuel gas industries. The installation and operation of particular systems vary on the specific objectives, contractual obligations, process type, regulatory requirements, and internal performance requirements needed by the user. This standard is intended to provide guidelines for standardized start-up procedures, operating procedures, and quality assurance practices for on-line, at-line, in-line, CFMS, and other near-real time gas chromatographic based sulfur monitoring systems used to determine fuel gas sulfur content. For measurement of gaseous fuel properties using laboratory based methods the user is referred to Test Methods D1072, D1945, D4084, D4468, D4810 and Practices D4626, E594.

1.1  This practice is for the determination of volatile sulfur-containing compounds in high methane content gaseous fuels such as natural gas using on-line/at-line instrumentation, and continuous fuel monitors (CFMS). It has been successfully applied to other types of gaseous samples including air, digester, landfill, and refinery fuel gas. The detection range for sulfur compounds, reported as picograms sulfur, based upon the analysis of a 1 cc sample, is one hundred (100) to one million (1,000,000). This is equivalent to 0.1 to 1,000 mg/m3.

1.2 This practice does not purport to measure all sulfur species in a sample. Only volatile compounds that are transported to an instrument under the measurement conditions selected are measured.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This practice does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this practice to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.