ISO DIS 29945

Description / Abstract: This International Standard specifies a manual sampling method for refrigerated liquefied DME at terminals in both loading and unloading ports. It also specifies detailed precautions to ensure safety during sampling work. However, safety measures, proposed for equipment being used for sampling, such as sampling lines and sample cylinders, are limited to general terms because they are governed mostly by national regulatory requirements.

This International Standard does not include recommendations for the location of a sampling point in a line or vessel.

NOTE It is the responsibility of the user to ensure that the sampling point is located so as to obtain a representative sample. However, to prevent vaporization of DME in the line before sampling, it is preferable to locate the sampling point at a place where the pressure and temperature of the DME in the line are kept constant to ensure that a single-phase sample is obtained.

This International Standard is also applicable to the following cases, with necessary modifications:

— sampling of DME on board liquefied gas tankers where appropriate sampling apparatus is provided;

— sampling of other refrigerated, non-petroleum-based, liquefied gaseous fuels whose chemical and physical properties are similar to those of DME.

The detailed chemical and physical properties of DME differ from those of LPG, which suggests that DME requires precautions different from those of LPG. However, their basic properties are similar to each other and so general reference is made in this International Standard to precautions for LPG that have been applied in many countries. Reference can also be made to the appropriate individual items in this International Standard for precautions concerning the quality.