An investigation was made at the Oxyacetylene Machinery Production Union into the influence of the impact strength of ABS-2020 plastic in the action of explosions of acetylene-oxygen mixtures. The investigations were made on samples produced by casting under pressure on a D3132-250 thermoplastic automatic molding machine at a molten plastic temperature of 210/sup 0/ C, a pressure of 120 MPa, and a mold temperature of 70/sup 0/C. The results obtained were used for establishment of the optimum service life expressed in the number of explosions for protective devices intended for operation under conditions of explosions of acetylene-oxygen mixtures. This paper reports on these aspects of the investigations.