Hemp Production

HEMP PRODUCTION. The basis for obtaining hemp products is hemp yarn, which can be divided into two groups: finer fabric yarn and coarse yarn for rope, cordage, and cables. Hemp is obtained from the stems of cannabis. Cut cannabis straw is left in the field for seed ripening and drying; seed heads are torn off on ridges or threshed. The subsequent processing of cannabis straw for fiber extraction differs little from the processing of flax straw: water retting, scutching, hackling, and after hackling - softening on stampers or runners. Spinning of hemp for fabric production in factory conditions proceeds in the same way as flax spinning; machines, due to the coarser and longer fiber of hemp, are constructed with appropriate modifications; similarly, tow is processed. However, the production of hemp fabrics is generally very limited; in incomparably larger quantities, hemp is used for the production of ropes, cables, etc. To this day, hemp production in the vast majority of cases has a handicraft or semi-handicraft character - larger enterprises number in the units, and even there the production process is little mechanized and mostly takes place in primitive insanitary conditions. Hemp arrives here in a crushed state, contains much shive; the following processes are carried out here: hackling - by hand (strikes with a flail on a bundle) in unheated buildings of the shed type; combing - also manually on metal combs ('brushes'); spinning - by hand or on semi-automatics, and even on the latter the feeding process is not mechanized. Such is, for example, the production process at a large Leningrad plant; on semi-handicraft and handicraft enterprises, it is even more primitive. The main professional hazard of this production (besides working in unheated rooms in winter) is dust, released in very large quantities in all processes. For example, during an inspection in 1923 at the State Petrovsky Rope Factory (near Kharkov), the following dust content was found in the air: in the combing department - 365 mg/m³, in the spinning department - 262 mg/m³, in the weaving department - 246 mg/m³, in the sewing department - 234 mg/m³, etc. At the Leningrad 'Rope' factory (1929), dust content was found: in the combing department - 85-107 mg/m³, in the spinning department - 10-27.5 mg/m³. Despite the relatively low specific gravity of hemp dust, these amounts must be considered very large; the size of dust particles in the main mass of hemp dust turned out to be less than 10 μm. According to Nikitin's data, siliceous compounds in this dust are present in small amounts - no more than 0.1-0.31%. - In connection with the inhalation of large amounts of dust, workers in hemp spinning production often develop respiratory diseases. Thus, according to Kozintsev, who examined more than 40 years ago handicraft workshops in the former Novozybkov district, 43% of workers suffer from respiratory diseases, 68% from conjunctivitis (he also mentions gum disease, found by him in 71% of workers); as for new data from the USSR, out of 1,192 workers at the Petrovsky factory (1923), respiratory diseases were found in 34.4%, skin diseases - 14.4%; out of 773 workers at the 'Rope' factory in Tver province (1925), respiratory diseases were found in 50%; out of 540 workers at Leningrad factories, lesions of the upper respiratory tract were detected in 70%, tuberculosis in 25%, conjunctivitis in 51%. Prevention. Main attention should be paid to the mechanization of the production process, which will make it possible to a large extent or completely eliminate the main hazards. Here (as for flax production) it is necessary to build factories for primary hemp processing (a number of factories have already been built in the USSR), equip them (as well as spinning factories) with improved equipment; machines should be equipped with local exhaust ventilation installations, etc.