Measuring of Braking Distances of Firefighting Trucks

The paper addresses the driving dynamics of emergency fire trucks. It focuses on the issues of braking, measuring real braking distances and calculating adhesion coefficients. It presents the results of measuring the real braking distances for firefighting vehicles - type water tenders. Measurements were taken on dry asphalt and depending on the vehicle's speed of travel. Experiments were conducted on five types of firefighting vehicles. The results of measurements are mainly used by fire protection units to the drivers’ self-education to improve safety when driving to intervene.

Adaptation of Fire-Fighting Systems to Localization of Fires in the Premises: Review

Fire protection is a basic safety issue for all categories of buildings. The criteria for effective fire suppression and the characteristics of extinguishing systems in insulated areas depend on a combination of factors. The main influences include the type of combustible material, ambient temperature, type of spray extinguisher, air inflow and outflow conditions, and space geometry. This article analyzes the most widely used fire-extinguishing technologies in different locations. The main aspects of using the pulsed delivery technology of extinguishing liquid are considered. Based on the analysis of publications from the last decade, it is possible to develop intelligent systems for recording fires and extinguishing fires in the premises.

ПОРІВНЯННЯ ПОЛІОЛІВ ЯК КАРБОНІЗУЮЧИХ АГЕНТІВ ВОГНЕЗАХИСНИХ КОМПОЗИЦІЙ ІНТУМЕСЦЕНТНОГО ТИПУ

Purpose. To study the influence of the carbonizing agent structure on the formation of thermal insulating char layer of intumescent system acid donor/polyol and on the fire protection efficiency of the system at high temperatures. Methodology. A fire retardant mixture of an acid donor (phosphates ammonium, urea, melamine)/ polyol was chosen as a model intumescent system. Dispersion of vinyl acetate copolymer with ethylene was used as a polymeric component. The study applied the characteristics of the char layer of the intumescent composition at a certain temperature. The volumetric intumescent coefficient (K, cm3/g), mass of char residue (m, %), structure and density of the char layer are proposed as the main estimated parameters of flame retardant effect. IR spectroscopy was used to identify products of thermolysis of intumescent systems. Determination of fire protection efficiency of intumescent coatings was carried out in a mini-oven under standard fire conditions. Findings. The influence of polyol structure on the formation of thermal insulating char layer of intumescent acid donor/polyol system and the prediction of fire protection efficiency of this system under high temperature conditions has been investigated. It has been shown that under conditions of thermal shock the fire protection efficiency is more dependent on the nucleophilic reactivity of the polyol towards the unsaturated phosphorus atom of the acid donor than on its thermal stability. It has been found that pentaerythritol, dipentaerythritol, starch, dextrin, xylitol and sorbitol are the most effective carbonizing agents, regardless of the structure of the acid donor. It has been proved by infrared spectroscopy that at high temperatures as a result of the decomposition of pentaerythritol one of the reaction products is the aldehydes interacting with pentaerythritol with the formation of oligomeric compounds with a simple ether bond C-O-C. At the same time, pentaerythritol can be considered as a universal source of carbon framework for intumescent flame retardants regardless of the phosphate structure used. Originality. It has been shown that an important factor to increase the fire protection efficiency of intumescent systems is the use of polyols with an increased nucleophilicity in the esterification between polyol and phosphoric acid.Practical value. The optimal polyols as carbonizing agents for formulation of intumescent coatings with enhanced fire protection properties have been determined.

ПОРІВНЯННЯ АМІНІВ ЯК ГАЗОУТВОРЮВАЧІВ ВОГНЕЗАХИСНИХ КОМПОЗИЦІЙ ІНТУМЕСЦЕНТНОГО ТИПУ

Purpose. Study of influence of blowing agents amines structure on the construction processes of thermal insulating char layer of intumescent system ammonium polyphosphate/pentaerythritol/amine and fire protection efficiency of this system at high temperatures. Methodology. A fire retardant mixture of ammonium polyphosphate/pentaerythritol/amine was chosen as a model intumescent system. Dispersion of vinyl acetate copolymer with vinyl ether of versatic acid was used as a polymeric component. A step-by-step study of the characteristics of the char layer of the intumescent composition was applied in the study, consisting in the analysis of the characteristics of the char formed after keeping the intumescent composition samples at a certain temperature between 100 and 800 °C, char residue mass (m, %), structure and density of the formed char layer. The method of infrared spectroscopy was used for identification of products of thermolysis of intumescent systems. Determination of fire protection efficiency of intumescent coatings was carried out in a mini-oven under standard fire conditions. Findings. The influence of the structure of amines blowing agents on the formation of char layer of intumescent system ammonium polyphosphate/pentaerythritol/amine was studied. Physico-chemical parameters of char layer formed during high temperature swelling of intumescent system components with varying amine: urea, melamine, dicyandiamide, guanidine, thiocarbamide, formylthiosemicarbazide, thiosemicarbazide, phenylethylcarbamide have been determined. In the temperature range 200–400 oC for systems with linear amines (urea, thiocarbamide, thiosemicarbazide), there is a rapid formation of insulating layer with intense outgassing (high intumescent coefficients K) and the same rapid its destruction with significant losses of char residue mass (Δm). The presence of melamine, dicyandiamide and guanidine in intumescent system provides constancy of intumescent coefficient at minimal mass loss. Chemical transformations of intumescent systems were studied by the method of infrared spectroscopy when the investigated amines were varied. It was found that linear diamines do not form stable spatially branched phosphamide compounds with phosphates as the basis of a thermostable heat-insulating frame. At the same time in IR spectra of char residue systems with melamine, dicyandiamide and guanidine the absorption bands of P-N-C bonds (1070–1050 cm-1) and P-N (980–950 cm-1) up to 600–700 oC are observed. Fire tests proved that melamine, dicyandiamide and guanidine are blowing agents providing maximum protection of metal against fire and can be used for composition of fire retardants for steel constructions.Originality. It has been proved that amines in intumescent polyphosphate system perform at least two functions: blowing agents by means of thermal destruction to incombustible gases and nucleophilic compound that takes part in char layer formation by aminolysis of electrophilic substrates.Practical value. The optimum amine blowing agents for developing formulations of intumescent coatings with enhanced flame retardant properties have been established.