On the Experimental Rationale of Quality Indicators of Fire-Fighting Layflat Delivery Hoses for Fire-Rescue Equipme

Abstract

The urgency of the necessity of experimental substantiation of quality indicators of the fire-fighting layflat hoses for fire – rescue equipment and methods of their estimation is noted, taking into account the modern approaches set out in European standards. The results of experimental researches of fire-fighting layflat hoses for fire – rescue equipment by quality indicators are presented: resistance of the hoses to the action of working hydraulic pressure, resistance of the hoses to the action of the proof hydraulic pressure, burst pressure and abrasion resistance. Delivery fire hoses are one of the main types of fire fighting equipment. Delivery fire hoses in the course of operation undergo mechanical wear, are exposed to the sun's rays, microbiological putrefactive processes, accidental ingress of chemically active substances, the influence of low and high temperatures, irreversible processes of material aging. All this causes the appearance of defects of different nature. Analysis of the causes of failure of delivery fire hoses showed that of all failures more than 60% are fistulas, as well as breaks and disruptions of heads - 30% and 10% respectively. The analysis of the presence and nature of defects during the regular testing of workers and decommissioned fire hoses showed that the defects are divided into: explicit (gusts and fistulas) that violate the tightness of the hoses; visible cuts, abrasions, missing and chemical corrosion from contamination of fuel and lubricants that do not violate the tightness of the hoses; hidden (unnoticed cuts, breaks in the threads of the power frame, etc.) that do not violate the tightness of the hoses. Studies have shown that only 75% of defects are detected during hydraulic testing, and undetected defects result in hoses failing in a fire. To date, requirements for assessing the quality of delivery fire hoses for fire - fighting equipment in Ukraine are set out in the standard DSTU 3810-98. At the same time, these requirements are to some extent obsolete and do not meet the current regulations of the leading countries in the world on this issue. In view of the above, it is urgent to experimentally justify the quality indicators of the fire-fighting layflat hoses for fire – rescue equipment and methods of their evaluation, taking into account the modern approaches set out in European standards. The results of the pilot studies will be used to justify the provisions of the draft national standard of Ukraine that will be developed and to improve the existing test base. Keywords: abrasion, burst pressure, experimental research, fire – rescue equipment, layflat delivery fire hoses,, proof pressure, quality indicators, technical requirements, specifications, working pressure