Safety and labor protection
Characteristics of work place
Usability testing aims on holding some testing procedures on computer. Because of this thing, we should pay attention on people who will test created web site. It is convenient that for this testing we need only PC. Certainly, we should carefully check user’s training process, introductory briefing before starting work on computer.
In our case we take usual classroom per 20 students. We should notice that each student will work only with one computer, i.e. two persons cannot use the same device. In addition, working place should be done in way that distance from screen of two rear computers ought be not less than 2.0m and distance between side surface of monitor not less than 1,2m
In the room where personal computers are used, window openings must be equipped with devices controlled type:blinds, curtains, etc.
In computer class window openings must be equipped with devices of controlled type:blinds, curtains, etc.
Used furniture for users working with computers must meet the following requirements:
- height of the working surface of the table should be adjusted in the range 680 - 800 mm; if not possible height of the working surface of the table should be 725 mm;
- desktop should have legroom height of not less than 600 mm, depth at knee level not less than 450 mm at the level of elongated legs not less than 650 mm;
- desk chair (chair) should be lifting - swivel and adjustable height and tilt angles of the seat and back, as well - the distance back from the front edge of the seat;
- workplace should be equipped with a footrest having a width of not less than 300 mm, a depth of not less than 400 mm, height adjustment, up to 150 mm and the angle of inclination of the supporting surface of the platform to 20 degrees; Support surface should be grooved and have at the front edge of a side height of 10 mm;
- workplace with a personal computer must be equipped with easily movable lectern for documents.
For normalization factor of aeroionic premises with computers is necessary to use the automatic control mode ion air environment. Women of the establishment of pregnancy and during lactation are not permitted to perform all activities associated with using of computers.
Analysis of dangerous and harmful factors.
When operating a personal computer to the test person can have an effect, dangerous and harmful production factors:
- fever surfaces PC;
- hot or cold air in the working area;
- selection in the workplace air of a number of chemicals;
- high or low humidity;
- high or low level of positive and negative ions;
- high voltage in an electrical circuit, circuit;
- increased level of static electricity;
- elevated levels of electromagnetic radiation;
- increased electric field intensity;
- absence or lack of natural light;
- lack of artificial illumination of the working area;
- increased brightness of light;
- high contrast;
- direct and reflected glare;
- eyestrain;
- monotony of the labor process;
- emotional and nerve strain.
The main harmful factors while using the computer include: prolonged sitting position, the electromagnetic radiation, the load on the vision, the overload of the wrist joint, the possibility of respiratory diseases, allergies, pregnancy disruption, etc.
Prolonged sitting position leads to tension in your neck, head, arms and shoulders, low back pain in children - and even to scoliosis. Prolonged sitting position still leads to stagnation of blood in the pelvic organs, and as a consequence, to prostatitis and hemorrhoids. It's no secret that a sedentary lifestyle leads to obesity. Pain in shoulders occurs when the intervertebral discs, which leads to a protrusion in which either side (herniated disc). Hernia can damage the spinal cord and nerve processes. The consequences can be very diverse, from pain in the back and limbs, paralysis of limbs and death. One of the common causes of degenerative disc disease is muscular dystrophy back.
Man driving mostly sedentary lifestyle may be ill pain of shoulders. Signs of incipient disease: back discomfort and pain, headaches, disturbances of the internal organs. Risk factors for disease hemorrhoids include: sedentary lifestyle, obesity, excessive consumption of smoked, spicy, salty and spicy foods, pelvic inflammatory disease and other obesity occurs because of malnutrition, physical inactivity, including a sedentary lifestyle, inadequate response to stressful situations, overly long sleep, the use of hormonal drugs, over- the body edible oils, etc.
Obesity increases the workload on the heart, change the configuration and position of the heart in the chest cavity, increased cholesterol levels, as a result it is deposited on the walls of blood vessels (atherosclerosis). Increased fat accumulation in the chest cavity affects the respiratory system, leading to the appearance of dyspnea and hypoxia organs and tissues.
Load vision. The human eye responds to smaller vibration and text on the screen to flicker. Eye muscles that control the lens are in constant tension, which necessarily leads to a loss of visual acuity. Equally important for the prevention of visual dysfunctions have: the right or recommended the selection of colors, fonts, layout of windows in your application, the orientation of the display monitor.
Prolonged work at the computer is huge strain on the eyes as the image on a monitor is composed not of continuous lines, both on paper and of individual dots, luminous and shimmering. User inevitably deteriorating eyesight, eyes begins to tear, user has a headache, fatigue, double vision and distorted image. Overloading the joints of the hands leads mainly to the phenomenon as carpal tunnel syndrome.
Stress and its reasons.
Stress is an emotional experience, the internal stress caused by events in life. Stress arises in the first place, the loss or damage of data. Reasons: lack of backups, computer viruses, hard drive crash, operating errors. Sometimes stress is the cause of heart attacks. Stresses are emotionally positive and emotionally negative, short-term and long-term, acute and chronic, physiological and psychological (emotional and informational). Working at a computer is one of the factors causing stress (stressor). The body's reaction to stress is the start of biochemical processes that are aimed at the suppression of an emergency. Stressful situations and related experiences in the body cause many negative developments.
Influence on respiratory system.
Respiratory diseases in this context are mainly allergic in nature. This is because for a long time the computer case and the last board into the air a number of harmful substances, as well as the computer creates around itself electrostatic field, attracting dust that settles in the lungs. Thus this computer deionized environment and reduces the humidity. Allergies are increased sensitivity to various stimuli, manifested in specific reactions when in contact with them. This causes the symptoms of allergies such as rhinitis, lacrimation, skin rash, anaphylactic shock. The computer is a pretty serious source of a number of allergens.
For example, the monitor case, heating up to 50-55 ° C in the air starts to produce a pair of phosphate. In addition to the monitor becomes hot and the motherboard, power supply, processor, video card, which may also be released into the environment harmful organic and inorganic substances (fluorine -, chlorine -, phosphorus). In addition, the computer has a lot of places where dust and dirt accumulate, multiply microbes and fungi. Dust from the monitor screen gets weak static charge which is enough, what would the dust settled on the user's body and in his airway. Allergies increases fatigue, increased irritability and decreased immunity. Allergy triggers a number of diseases: eczema, hemolytic anemia, asthma, etc. The most serious manifestation of allergies is anaphylactic shock, which is accompanied by difficulty breathing, seizures, loss of consciousness, low blood pressure, and often death.