This Technical Specification specifies a method for the determination of particle density of irregularly shaped pieces of compressed fuels such as pellets or briquettes. It is not applicable to soft or semi-soft pellets. NOTE 1 The term soft pellet is defined in CEN/TS 15639. NOTE 2 Particle density is subject to variation due to the susceptibility of organic material to environmental or technical impacts such as air humidity; vibration; abrasion or biodegradation. Therefore; particle density can vary during time thus the measured values should be regarded as a momentary fuel property. NOTE 3 At the time of preparingThis document; the production of briquettes of solid recovered fuels could not be identified in the European market.