DIN SPEC 91343:2017-04

This DIN SPEC has been prepared by a workshop (temporary committee) in the course of the PAS procedure. This DIN SPEC has been prepared and adopted by the authors named in the foreword. This DIN SPEC describes a process for the characterization of atomized coating materials, like paint sprays or, more specifically, drops or wetted particles forming a paint spray. For this purpose, guidelines for the size measurement of spherical drops or nearly spherical drops have been defined. The DIN SPEC defines guidelines for measuring the size of near-spherical droplets within the atomizing process and specifies requirements for the environmental parameters within the coating application with regard to the potential influences of a measuring system on an atomizing coating system and the spatial resolution of the method. Furthermore, guidelines for the acquisition of drop velocities and the related mass flux densities are provided. Beyond that, recommendations for the acceptable uncertainty of the measurement results are given. This DIN SPEC is valid for applications, where the drop diameters are in the range of approximately 5 μm to 500 μm. In order to cover the most common paint spray applications, spray processes in explosive atmospheres, with high voltage applications and PWIS-free (free of paint-wetting impairment substances) are included. Guidelines have been defined for the detection of outliers; that is, drops whose diameters or velocities strongly deviate from mean or characteristic values of the overall spray.