Conforms to I S : 1199 & 5515 The compacting factor is defined as the ratio of the weight of partially compacted concrete to the weight of fully compacted. This consists of two conical hoppers, each with a hinged trap door. Trap door is operated by a quick release mechanism to allow a free fall to the released concrete sample. A cylindrical mould is fitted beneath the two hoppers and these three components are mounted on a rigid steel frame. The hoppers and the cylinder can be easily removed for weighing and cleaning.