Active Standard ASTM D5540 | Developed by Subcommittee: D19.03
Book of Standards Volume: 11.01
Historical (view previous versions of standard)
Significance and Use
5.1 Sample conditioning systems must be designed to accommodate a wide range of sample source temperatures and pressures. Additionally, efforts must be made to ensure that the resultant sample has not been altered during transport and conditioning and has not suffered excessive transport delay. Studies have shown that sample streams will exhibit minimal deposition of ionic and particulate matter on wetted surfaces at specific flow rates (1-5). 3
5.2 The need to use analyzer temperature compensation methods is dependent on the required accuracy of the measurement. Facilities dealing with ultra-pure water will require both closely controlled sample temperature and temperature compensation to ensure accurate measurements. The temperature can be controlled by adding a second or trim cooling stage. The temperature compensation must be based on the specific contaminants in the sample being analyzed. In other facilities in which some variation in water chemistry can be tolerated, the use of either trim cooling or accurate temperature compensation may provide sufficient accuracy of process measurements. This does not negate the highly recommended practice of constant temperature sampling, especially at 25°C, as the most proven method of ensuring repeatable and comparable analytical results.
5.3 A separate class of analysis exists that does not require or, in fact, cannot use the fully conditioned sample for accurate results. For example, the collection of corrosion product samples requires that the sample remain at near full system pressure, but cooled below the flash temperature, in order to ensure a representative collection of particulates. Only some of the primary conditioning criteria apply in this case, as in others. Temperature compensation is not applicable since the material being analyzed is not in a liquid state.
1.1 This practice covers the conditioning of a flowing water sample for the precise measurement of various chemical and physical parameters of the water, whether continuous or grab. This practice addresses the conditioning of both high- and low-temperature and pressure sample streams, whether from steam or water.
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D1066 Practice for Sampling Steam
D1129 Terminology Relating to Water
D3370 Practices for Sampling Water from Closed Conduits
D3864 Guide for Continual On-Line Monitoring Systems for Water Analysis
ICS Number Code 13.060.10 (Water of natural resources); 17.120.10 (Flow in closed conduits)