EN 15469:2007 – Petroleum products – Test method for free water in liquefied petroleum gas by visual inspection
1 Scope
This test method covers the use of a pressure cylinder to determine the presence of free water in liquefied petroleum gas (LPG) by visual inspection below 0 °C.
2 Terms and definitions For the purposes of this European Standard, the following term and definition applies.
2.1 liquefied petroleum gases (LPG) petroleum gas, which can be stored and/or handled in the liquid phase under moderate conditions of pressure and at ambient temperature, consisting predominantly of propane, butanes, with small proportions of propene, butenes and pentanes/pentenes
3 Principle An LPG sample is transferred into a pressure transparent cylinder filled to 50 % of its capacity. The sample is left below 0 °C for not less than 1 h; then it is observed for the presence of ice lumps. The results of the test shall be shown as pass, if ice is not present, or fail, if ice is present. The LPG sample, containing dissolved water and/or free water, in condition of saturated vapour pressure and above 0 °C, is clear and does not become cloudy, which makes it difficult to distinguish the two liquid phases. Indeed, as both LPG and water are colourless, it is rather difficult to locate the separation surface between the two liquids at laboratory temperature, and it is only by using a transparent container and under optimal lighting conditions that it could be realised. Alternatively, since ice is far less transparent than water and can be better observed, the visibility of the water can be improved if it is frozen. 4 Significance and use The test is used to detect liquid water transported with LPGs. Excess water content in LPGs can cause corrosive conditions degrading equipments. It can also separate and freeze, causing blockages of valves, pumps and regulators.
5 Apparatus
5.1 The sample cylinder will be fitted, preferably with a bottom valve, the stem of which will be short enough so as not to retain possible free water during the transfer of the sample to the test cylinder (5.2).
If it is not possible to get such an equipment, use a classical sample cylinder with procedure 7.1.2.
5.2 The test cylinder will be a transparent container with a capacity of 250 ml and suitable for the pressure of the product to be tested with a suitable thermometer in contact with the liquid to be tested. It is fitted with a bottom valve and a top vent valve.
NOTE A transparent container made of plastic or glass as described in test method EN ISO 3993 [1] or any other transparent LPG container provided of a bottom and a top vent valve may be used.
EN 15469:2007 – Petroleum products – Test method for free water in liquefied petroleum gas by visual inspection