Summer is the season of the year is the highest temperature, ground temperature up to 32-42 ℃. Hot weather conditions threaten the safe storage of hazardous chemicals. Dangerous chemical fires also occur in hot summer months. The reasons are as follows:

　　1. Higher temperature increases the volume of dangerous chemicals and increases pressure.

　　Thermal expansion and contraction is the general physical phenomenon of objects. Flammable liquid expansion coefficient is generally larger, store in an airtight container, easy to expand, heated volume increased vapor pressure at the same time, the increased pressure within the container, if more than the container can withstand the pressure, can cause the container breakdown, even burst. The phenomenon of "drum" and the crack of glass container are caused by thermal expansion. If the container is open, the liquid expands beyond its capacity to overflow and run, run, drop and leak. For example, the volume expansion coefficient of liquefied petroleum gas is 11 -- 17 times of water, and its volume is greatly affected by temperature, so when the family USES liquefied petroleum gas, it is forbidden to heat or bake with boiling water. In order to prevent this from happening, in addition to taking the heat and cooling measures, it is also necessary to control the filling amount, namely, filling according to the prescribed filling coefficient.

　　In terms of gas, the expansion coefficient is even greater. The gas is usually in a cylinder, and as the temperature rises, the pressure inside the cylinder increases. Such as oxygen cylinder 0 ℃, the pressure in the bottle of 150 kg/cm; When the temperature rises to 54.6 ℃, the pressure is up to 180 kg/cm2. The pressure is too high and the cylinder is in danger of exploding.

　　Second, the temperature rise causes the evaporation rate of the liquid to accelerate.

　　The evaporation capacity of flammable liquid is not only related to the nature of the liquid itself, but also affected by the surrounding environment. The influence of temperature on it is more important. The higher the temperature, the faster the flammable liquid vaporizes. The greater the vapor concentration on the liquid surface, the greater the likelihood of an explosive mixture of air with the air, the greater the risk of fire explosion. The evaporation rate of different liquids varies with temperature, boiling point, proportion and pressure. The difficulty of evaporation of flammable liquid is expressed by boiling point, and the lower boiling point indicates that the liquid is more evaporative. Some flammable liquid boiling point is very low, such as under the normal pressure, the boiling point of gasoline is 50 ℃, such as environmental temperature more than its boiling point, is easy to produce risk.

　　The temperature rise accelerates the decomposition and spontaneous combustion.

　　Due to the influence of environmental factors such as temperature and humidity, many dangerous chemicals are easily decomposed after being heated, releasing oxygen and even oxygen atoms to oxidize other substances and release a lot of heat. If poor ventilation, heat build-up and cause temperature rise, will speed up the oxidation, produce more heat, prompting temperatures continue to rise, when the temperature reach the substance of the spontaneous combustion point will be spontaneous combustion fire. Some spontaneous combustion point lower material such as yellow phosphorus (spontaneous combustion point is 30 ℃), if not properly kept, summer temperatures exceed its spontaneous combustion point, in the air can be spontaneous combustion fire.

　　The key to preventing dangerous chemical accidents in summer is to prevent heat and cooling. Specific measures are as follows:

　　1. There must be a qualified warehouse for hazardous chemicals.

　　The warehouse of hazardous chemicals shall be insulated with non-conductive refractory materials for roof and wall insulation, and the eaves should be lengthened to prevent sunlight from entering the warehouse; The wall should be properly thickened, open Windows, use indirect wind tunnel, double door, double roof; The window glass is painted blue or choose frosted glass.

　　2. Hazardous chemicals should be classified and stored.

　　Chemical dangerous goods are generally divided into explosive articles, water burning articles, self-inflammable substances, flammable solid, flammable and combustible gas, corrosive articles, oxidants, etc. These items should be classified, classified, divided and stored separately, and it is strictly prohibited to mix all kinds of properties with different properties and fire extinguishing methods. When storing goods, the stacking should not be too high, too large, too dense, and the stacking and crib. The stack shall be kept at a distance from the walls, pillars, beams and electric lamps, and the fire control passageway shall be kept, and shall not be stored in excess.

　　3. The temperature must be strictly controlled.

　　Set the water storage roof for the warehouse or set the cooling water pipe on the roof of the warehouse, and the temperature will be cooled when the temperature is above 30 degrees, keeping the temperature in the warehouse below 28. In the warehouse roof of stone sacks, can increase the heat insulation of the roof, warehouse roof, walls and Windows will also be painted white, use white on the reflection of sunshine, reduce the absorption of radiant heat, to achieve the effect of cooling. According to the nature and packing of the goods, it is also possible to put water on the ground of the warehouse and put ice on the ground. Some warehouses can open Windows in the morning and evening, put in cold air and close doors and Windows at noon to prevent hot air from entering.

　　4. Cooling measures for open storage and storage tanks.

　　Flammable liquids in barrels should be placed in the building to prevent direct sunlight. In the special case, temporary open storage should be used, and non-combustible materials should be used to build awnings. Sometimes, the pipe should be used to cool the water. The average volume in the barrel is 90% 95%, leaving 5% to 10% of space, which can prevent the thermal expansion of dangerous chemicals in the barrel and cause combustion or explosion accidents. Storage tank at the top of the cooling device should be set up, the temperature reaches above 30 ℃, open cooling water pump for spray cooling. Storage tanks can not be filled too full, leaving 5% - 10% volume space.

　　5. There should be lightning protection facilities.

　　Hazardous chemical warehouse, usually located in the unit or the edge of the city area, keep a certain distance with the other buildings around, so that the warehouse was formed around the open field, vulnerable to lightning strike. Therefore, the warehouse should install lightning protection device to prevent lightning strike and cause fire accident.

　　6. To strengthen the management of

　　The personnel who manage the warehouse of hazardous chemicals must be trained in fire control safety and pass the examination and pass the examination. The warehouse keeper should inspect the warehouse regularly, find the problem solved in time and ensure the safety.