Safety Procedures Part 1

Transcription

1 Safety Procedures Part 1 CTEC1465/2018S Computer System Support CTEC1465 Safety Part 1 1

2 Health and Safety As of July 1, 2014, new regulation requires health and safety awareness training for every worker and supervisor under Ontario s Occupational Health and Safety Act (OHSA). n/worker/index.php CTEC1465 Safety 2

3 Electrostatic Discharge Electrostatic discharge (ESD) is a phenomenon that occurs when the charges on separated objects are unequal. One object has an excess positive or negative charge, compared to the other. Typically, the objects are made of an insulating material (one that doesn't transmit electricity easily) or a conductive material that's insulated from ground. CTEC1465 Safety 3

4 Electrostatic Discharge The charge imbalance creates an electric field that can cause objects to attract or repel each other-such as when a static field makes your hair stand on end. From the perspective of a PC technician, the most interesting (and dangerous) aspect of ESD happens when statically charged objects are brought near each other. When that happens, a current can flow between them to balance their charges. This current flow is characterized by a high voltage, but low amperage. CTEC1465 Safety 4

5 Static Dangers Electrostatic discharges (the current flow) aren't dangerous to humans, even though the voltage in the system can measure in the range of thousands of volts. However, such discharges are potentially harmful to electronics. The microscopic wires and components that make up chips and other devices are very sensitive to even small amounts of current. CTEC1465 Safety 5

6 Static Dangers A static spark can melt such components, rendering them useless. Smaller discharges can alter the data stored in chips or otherwise upset their operation, without causing physical damage. This photomicrograph shows gross ESD damage to an unprotected RS-232 receiver. CTEC1465 Safety 6

7 Discharge Voltages To feel a static shock, you must experience a discharge of approximately 3,000 volts or more. Discharges of more than roughly 8,000 volts might generate a visible spark. Walking across a carpet on a dry day can generate a charge of up to 35,000 volts. Yet electronics can be damaged by a 30-volt discharge or less-much less than the minimum discharge you can feel. CTEC1465 Safety 7

8 Preventing problems with static electricity There are two ways to prevent problems from static electricity: Prevent the buildup of static charges. Prevent discharges, or discharge the charge safely. CTEC1465 Safety 8

9 Preventing static buildup To reduce the buildup of static charges, follow these tips: Don't shuffle your feet as you walk. Increase the humidity in the room or building to 50 to 60% - static charges can dissipate before growing large if the humidity level is sufficiently high. Keep yourself grounded as you work and move around. Use the tools found in a typical ESD kit, such as wrist straps and mats. You and the components you're servicing can remain connected to ground so that charges can't build up. CTEC1465 Safety 9

10 Preventing static buildup To reduce the buildup of static charges, follow these tips: Wear cotton clothing, which Is less likely to generate static charges than is clothing of many synthetic materials. Remove carpeting from rooms where you service computers and from computer rooms. Use an air ionization system to build up an opposite, and thus neutralizing, charge in the air. CTEC1465 Safety 10

11 Preventing static discharge If a charge differential does build up, you can follow these tips to prevent or reduce the likelihood of damage from static discharges: Equalize the charge safely. Unplug the equipment, and then touch a metal portion of its chassis. If you must move around as you work, keep yourself grounded with an antistatic wrist strap, so that charges can't build up. CTEC1465 Safety 11

12 Preventing static discharge To prevent damaging discharge from occurring, you need to be at equal charge potential with the device you're servicing, not at equal charge with ground. Do not leave the computer plugged in while servicing it. Always service computers on a properly grounded bench. If there's a fault in the building's wiring system, full wall current could be flowing through the ground wire. You could be injured or killed if you came into contact with the ground. CTEC1465 Safety 12

13 ESD toolkits An ESD toolkit includes tools that you can use to prevent the buildup of charge differentials and to equalize them safely. You should purchase and use a good ESD toolkit. An antistatic wrist strap is a common component of such a kit. CTEC1465 Safety 13

14 Inside the case Electrostatic discharge isn't typically a problem when the computer case is closed. The static current is dissipated through the computer's metal case to ground or is otherwise dampened before reaching sensitive components. (Of course, you should still avoid discharging static through the case!) The biggest problems with static arise when you have the computer's case open and are working with its internal components. CTEC1465 Safety 14

15 Typical internal components The typical components that you find inside a computer case include: System board (the motherboard) Hard drive Removable drives, such as floppy, CD/DVD/BD, and card reader Power supply Cooling fan Adapter cards Wires, cables, and connectors CTEC1465 Safety 15

16 Power supply Optical drive CPU with fan AGP Slot Floppy drive Hard drive CMOS Battery PCI modem (in PCI slot) PCI slot Motherboard CTEC1465 Safety 16

17 Opening the case Computer cases come in a variety of styles, all of which provide some means to access the internal components. For a typical tower (upright) case, the sides slide backward after you remove some sort of restraining mechanism. Older cases are held closed with screws, typically three per side. Newer cases use slide latches or push-button clips that require no tools and make opening the case much easier. CTEC1465 Safety 17

18 Which side to open? When removed, one side exposes the internal components, while the other side reveals the underside of the main circuit board. Although you occasionally need to open both sides of the case, most often you open the side that gives you access to the components. You can usually tell which side to open by looking at the connectors extending through the back of the computer. Ports are on this side Open this side Slide latch Those connectors are attached directly to the main circuit board. Thus, their location tells you to which side of the case the board is nearest. CTEC1465 Safety 18

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20 Safety Procedures, Part 2 CTEC1465/2018S Computer System Support

21 Office Hazards Part of keeping your computers safe is making sure that the environment in which they're used is free of potential hazards and operationally safe. Most of the time, this involves a simple physical inspection of the work area. Safety 2-2

22 Office Hazards Floor Surfaces Floors should be level and dry. Carpets should be secured to the floor. Cables and power cords should not cross walkways. Equipment should be protected from static electricity. Use antistatic floor mats, and if necessary, place antistatic mats under the user's keyboard and/or computer. Safety 2-3

23 Office Hazards Fire Safety Keep papers orderly so that, if a fire does break out, loose papers don't catch fire easily. It's best to store papers in metal file cabinets whenever possible. If coffee makers, hot plates, personal heaters, and other such small appliances are used, keep combustibles away from them and be sure they're used properly. Not only do these appliances produce heat that can ignite materials, but they can also catch fire themselves if left on for prolonged periods of time. Safety 2-4

24 Office Hazards Fire Safety Keep working smoke detectors in all areas of the building. Keep fire extinguishers readily available for each type of equipment you have. Safety 2-5

25 Office Hazards Electrical Safety Avoid overloading electrical circuits, which can lead to tripped breakers and fires. Label the breakers in the electrical box so you know which outlets are serviced by which breakers. Use surge protectors and uninterruptible power supplies (UPS) to protect computer equipment from surges and spikes. Safety 2-6

26 Office Hazards Electrical Safety Avoid stringing together or overloading power strips. Don't run electrical cords or network cables across walkways. If the wires inside the cable or cord become frayed, power cords won't work property, and network cables will fail. If there's no alternative, and power cords must be run across a walkway, they should be encased in cord protectors. These are most often made of a rubber or plastic strip through which the cords and cables can be easily inserted. The top of the strip is slightly domed so that people won't trip over it, and it contains ample room for the cords and cables to be protected. Safety 2-7

27 Office Hazards Electrical Safety Provide good ventilation for computer equipment so it doesn't overheat. Overheating can lead to melted components. Phone cords, network cables, and electrical lines should be secured out of the way. You can use cable ties, which are commonly available in nylon and Velcro. Some cable ties include a small tag that you can use to label the cables you've secured together. Safety 2-8

28 Office Hazards Air Quality Computers like clear, clean air, but they're often used in less than ideal conditions, such as on factory floors and in other locations where dust, dirt, and particulate matter abound. To maintain air quality, follow these guidelines: If necessary, use fans to keep the air as clear as possible. Avoid smoking around computers. The pollutants from cigarette smoke adhere to computer components and can cause them to fail. Periodically clean computer fans to remove dust and debris. Place working carbon monoxide detectors throughout the building. Safety 2-9

29 Computer Hazards The two major types of computer hazards are physical and electrical. In addition, toner and ozone emissions from laser printers and photocopiers can be hazardous. Safety 2-10

30 Computer Hazards - Physical Computer equipment -- especially laser printers, servers, and large CRT monitors -- can be heavy and bulky. Use care when lifting and moving equipment, not only for the sake of the equipment, but also for the sake of your back and other muscles. When lifting equipment, take a balanced stance. If the item is on the floor, squat close to it and use your leg muscles to lift it as you stand up. Keep your back straight with your chin tucked in. Safety 2-11

31 Computer Hazards - Physical /article/0,8599, ,00.html Grip the equipment, using your entire hand rather than just your fingers, and bring the equipment close to your body, keeping your elbows close to your body as well. With CRT monitors, keep the glass face towards your body. It is the heaviest part of the monitor and is easier to carry when placed closer to your center of gravity. Safety 2-12

32 Computer Hazards - Physical Also, make sure that you can see where you're going with the equipment! Crashing into another person, a wall, or other equipment can also be hazardous. And know the weight limitations of any office furniture on which you're going to place computer equipment. Safety 2-13

33 Computer Hazards - Physical It's also important to restrain or remove neckties, loose clothing, dangling jewelry, and long hair, so that such things don't become entangled with components. Safety 2-14

34 Computer Hazards - Physical The electronic components of computers generate heat. Many times, the heat generated by these components is enough to cause a serious burn, if they're touched. You should exercise caution working on the internal components of a computer, as they can retain heat. Even if you aren't working on a component that generates heat itself, you're working in close quarters and can accidently brush up against a component that is hot. Safety

35 Computer Hazards - Electrical Some components -- notably CRTs, power supplies, and laser printers -- contain high voltage components. Always use care when working with any electrical equipment. Be sure that it's turned off and unplugged before you begin to make repairs, unless you don't have an ESD strap. Safety 2-16

36 Computer Hazards - Electrical Without an ESD strap, you need to leave it plugged in for the electrical ground. Otherwise, you could fry internal components. Visually inspect the equipment's wiring for defects, such as faulty insulation or loose connections, before each use. Safety 2-17

37 Computer Hazards - Electrical Don't use damaged or frayed electrical cords. Remove metal jewelry, watches, rings, etc., before working on computer components. Don't place containers of liquid, including beverages, on or near computer equipment. Safety 2-18

38 Computer Hazards - Electrical Always know the electrical ratings of the computers and other equipment in your work area, so that you don't overload electrical circuits. Only specially trained technicians should attempt to repair a CRT or the high-voltage components in a laser printer. Safety 2-19

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