The invention relates to a method for preparing 1,2-propanediol by reacting glycerol, which has a purity of at least 95 wt %, with hydrogen at a hydrogen pressure from 20 to 100 bar and a temperature from 180 to 240\xb0 C. The toilet bowl washer fluid reservoir drain valve spacer body includes a main body section which has a cone shape and is capable of being seated on a upper edge section of a drain valve seat in a fluid-tight manner. For each typed prefix, the network device adds an endpoint type identifier for the assigned endpoint type to route advertisements that traverse or originate with the network device and specify the prefix. Thus, high speed detection of the combustion gas temperature more suitable for a gas turbine system can be performed. Thereby, the present invention can protect electronic devices against LEMP or EMP released by an electronic weapon. LED light source substrates and are each configured to emit light having a first luminance gradient on an edge of a range, to be irradiated with light, which first luminance gradient is smaller than a second luminance gradient of light having a substantially uniform luminance on an entire range to be irradiated with light.