2. Harmful and dangerous factors of active group and how to protect from them.
1. Mechanical factors are characterized by kinetic, potential energy and mechanical action on a man: elements that move and spin, noise, vibration, blast wave, acceleration, gravitational pull, static stress, smoke, fog, dust in the air, abnormal barometric pressure and others.
Occupational noise - a collection of different by the tone and strength of sounds, which arise from vibrational motions of different bodies and are transmitted in the airspace.
After long-acting noise, human acuity of hearing reduces, blood pressure changes, attention diminishes, energy consumption for the same exercise increases, increased jitters appears.
In areas of trade, noise level should not exceed 80 dB, which is the maximum permissible level of noise.
For noise control are used collective (shock-absorbing walls, screens, etc..) and individual (ear plugs, headphones) protective devices.
EXAMPLE. Since 2002, our aircraft in terms of noise pollution can not land at European airports. Therefore, our airlines fly on Boeing B-737 (747) and Airbus A-310, A-320.
Vibration - complex oscillating process that occurs at periodic shifts in body weight from equilibrium, and also from periodic change of body shape that it had in a static state.
After prolonged action of vibration, which excess of the GDR, workers may be injured by vibration disease.
The main methods of anti-vibration is the use of spring and rubber gaskets, dampers, shock absorbers, special foundations for equipment, balancing mechanisms, rotating, active methods of suppression of signal.
2. Thermal factors - have heat energy (temperatures of heated and refrigerated items and surfaces, temperatures of fires, chemical reactions, abnormal microclimate parameters).
As a result of high temperatures in human arises burns, heat stroke. As the result of reduced temperature occur body frostbite and hypothermia.
The main hazards that accompany the action of thermal factors are increased or decreased temperature, toxic products of combustion, smoke, reduced oxygen concentration and increased concentration of carbon dioxide (СО2) and carbon monoxide (CO) emissions. Inhalation of products of combustion, air with little oxygen (less than 14%), a high content of carbon dioxide and carbon monoxide the coordination is losing, poisoning is developing.
Indirect negative factor with significant forms of thermal factors, such as fire, is a psychological factor that increases the material losses and casualties.
The main methods of preventing and combating manifestations of thermal factors is usage of equipment in a fire- and explosion-proof version, automatic systems for fire prevention, fire and special extinguishing.
3. Electrical factors are electricity, static electricity, ionizing radiation, electric field.
An electric current passing through the human body, causes thermal, electrolytic, mechanical and biological negative effect.
Common electrical injuries include electric shock, at which the excitation of the muscles of the human body is, which can cause convulsions, stop breathing and heart.
Local electrical injuries include burns, skin metallization, electrical plates, mechanical damage and electrooftalmia.
Factors that affect the degree of destruction of human by electric current:
a
I, U, t, ~, -, S, f, Rл
mperagevoltage
time of passing current through the human body
kind of current (direct or alternating)
current path in the human body,
frequency of alternating current,
total electrical resistance.
Technical protective devices from the effect of electric current: isolation, grounding, vanishing, low voltage, safety signs, personal protective equipment, and others.
4. Electromagnetic factors are light, ultraviolet and infrared radiation, electromagnetic radiation, magnetic field.
Sources:
of electromagnetic fields are atmospheric electricity, solar radio emission and galaxies, electric and magnetic fields of the Earth, artificial sources of radiation;
of permanent magnetic fields are electromagnets, solenoids, pulse settings half periodic or capacitor type, molten and metal -ceramic magnets.
Action of electromagnetic fields on humans depends on tension of electric and magnetic fields, energy flow, the oscillation frequency, the size of the irradiated surface of the body and the individual characteristics of the organism.
The negative effect of permanent magnetic and electro-static fields depends on the tension and time of action. As a result of field action that have tension, exceeding the maximum permissible level, disorders of the nervous, cardiovascular system, digestive organs and some blood biochemical parameters are developing.
The most effective method of protection against electromagnetic radiation is fixing reflecting or absorbing screens.
5. Ionizing radiation- is a quantum (electromagnetic and corpuscular) radiation, under the influence of which appearance ions from neutral atoms.
Ionizing of living matter causes the disruption of molecular connections and changes in the chemical structure of different compounds. Changes in chemical composition of a great number of molecules cause cell ruin.
Diseases caused by ionization can be sharp or chronic.
Sharp destruction comes at irradiation with large doses during the short period of time. Large doses of X-ray and Gamma radiation can entail death.
Safety of persons workings with radioactive compounds is provided in such way: establishment of maximum permissible irradiation doses by the different types of ionizing radiation; application of defense with time and distance; implementing of general protective device; use of personal protection equipment.
6. Chemical factors – caustic, toxic, poison, flammable and explosive materials.
On the impact for man chemical materials are divided into:
Generally toxic,
Irrigative,
Sensitizing (after short time influence on organism it causes enhanceable sensitiveness to this material- allergic diseases)
Carcinogenic (draw development of malignant tumors)
Mutagene (draw change in the genetic cells code of organism)
Harmful materials often develop complex negative influence on the organism. For example an ammonia has a strong irritating action and simultaneously generally toxic.
On the hazard influence on organism harmful and toxic substances are divided into:
I class – extremely dangerous: most insecticides, chlorine.
II class – high dangerous: acids, predominant majority of pesticides.
III class – moderately dangerous: a vanillin, mineral oil, synthetic cleansers, tobacco, grain dust.
IV class – low hazard: ammonia, acetone, benzol, ethyl spirit, dust.
In order to eliminate poisoning possibility and appearance of professional production caused diseases there are special maximum allowable concentrations (MAC) of harmful substances in the working environment. These norms are provided by sanitary code.
Maximum allowable concentrations (MAC) of harmful substances in the air of working environment are the concentrations during the everyday work (except weekend) that is 8 hours per day or another time, but no more than 41 hours per week that cannot cause disease or deviation in the health state. Such deviations are checked with the help of modern research methods in the working process or in the remote terms of life of the present or the next generation.
At simultaneous content in the air of the working area of several harmful substances with the same directed action the sum of its actual concentration ratio (S1, S2, S3,…Sn) in midair to its MAC (MAC1, MAC2, MAC3,…MACn) must not exceed 1.
Calculation is carried out with a formula:
7. Biological factors – dangerous and harmful micro and macro organisms, products of their vital activity and vital activity of people.
Influence of separate types of living organisms on a man can in some cases make a serious danger.
Pathogenic microorganisms lead to the , in that number by infectious disease.
Complex of measures for increasing the epidemiology safety is directed on:
Removal or dismissing of action even of one of the following factors:
Infection source
Ways of transmission and distribution of infection