5.1 The purpose of this test method is to provide data on liquid drop-size characteristics for sprays, as indicated by optical nonimaging light-scattering instruments. The results obtained generally will be statistical in nature. The number of variables concerned in the production of liquid spray, together with the variety of optical, electronic, and sampling systems used in different instruments, may contribute to variations in the test results. Care must be exercised, therefore, when attempting to compare data from samples obtained by different means.

1.1 The purpose of this test method is to obtain data which characterize the sizes of liquid particles or drops such as are produced by a spray nozzle or similar device under specified conditions using a specified liquid. The drops will generally be in the size range from 5-μm to the order of 1 000-μm diameter; they will occur in sprays which may be as small as a few cubic centimetres or as large as several cubic metres. Typically the number density of the particles can vary significantly from one point to another.

1.2 This test method is intended primarily for use in standardizing measurements of the performance of sprayproducing devices. It is limited to those techniques and instruments that operate by passing a beam of light through the spray and analyzing the light scattered by the droplets to derive size information. Such techniques do not produce images of individual drops, and therefore, are known as “optical (nonimaging) instruments.”

1.3 The measurements made, when referred to the entire spray being sampled, may be flux sensitive or spatial, as defined in Practice E799, depending on the techniques used with a particular instrument.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.