This part of ISO 8130 specifies a method for the determination of the density of coating powders usinga gas comparison pyknometer. It can be used for all types of coating, is simple to carry out, but requires more expensive instrumentation than is often used for density determinations.The density of coating powders can also be determined using the liquid displacement pyknometer method described in ISO 8130-3. The apparatus is relatively inexpensive, but the liquid displacement pyknometer method is liable to give erroneous results, particularly if the powder swells in contact with the displacement liquid used or the displacement does not totally displace the air between the powder particles. The liquid displacement method is much slower in execution, less accurate and is only to be used if it can be shown that the same results will be obtained as for the gas comparison pyknometer method.