MEC232_Topic 4.pdf

MEC232 Human & Equipment Safety Ehab Abousaif, PhD Assistant Professor of Electrical Engineering – Faculty of Engineering Topic 4  Personal protective equipment (PPE) The need for personal protection implies that hazards have not been eliminated or controlled....

MEC232 Human & Equipment Safety Ehab Abousaif, PhD Assistant Professor of Electrical Engineering – Faculty of Engineering Topic 4  Personal protective equipment (PPE) The need for personal protection implies that hazards have not been eliminated or controlled. The need for first aid implies something even worse! When feasible, engineering control of the hazard is preferred over the use of personal protective equipment (PPE). We realize that some risks will always remain; our goal is to eliminate unreasonable risks, not all risks. The job of improving safety and health in the workplace will never be completely finished; so we must concern ourselves with the need to provide personal protection against hazards that have not been completely eliminated and to provide first aid when an accident does occur. Hierarchy of controls Personal protective equipment (PPE) - The basic premise of enforcement authorities is that if personal protective equipment (PPE) is needed, then the employees must be trained to use it properly. - Employees need to know when PPE is necessary, what kinds of PPE are required, and how to wear it effectively, to avoid developing a false sense of security. - If either the workplace changes or the PPE changes, the employer must take a responsible position and retrain the employee if necessary. - Both the initial training and the retraining must be documented with a certificate that identifies the names of employees trained, the dates, and the subject for which the employee is certified.  Protecting employees from workplace hazards Employers must protect employees from workplace hazards and dangerous work procedures that can cause injury, illness, and fatalities. Employers must: - Use all feasible engineering and work practice controls to eliminate and reduce hazards. - Then use appropriate PPE if these controls do not eliminate hazards. - Remember: PPE is the last control.  Hearing Protection The most important factor in selecting a type of noise protection is probably effectiveness in reducing the decibel level of noise exposure. However, this is by no means the only important factor, and selection can be somewhat complicated. Economics is always a factor, and if limited effectiveness is all that is necessary in a given situation, cheaper devices can be selected. Employee comfort is probably at least as important a factor as economics. The worker comfort factor goes beyond the simple goal of promoting worker satisfaction; it affects the amount of protection the worker will receive. If workers find a type of ear protection uncomfortable or awkward to wear, they will use every excuse not to wear it, which results in loss of protection. Sound levels and their relevance Cotton Balls: Ordinary cotton balls, without the addition of a sealing material, are virtually worthless as a means of personal protection from noise. Swedish Wool: Similar in feel to cotton, Swedish wool is a mineral fiber that has much better attenuation values than cotton. Swedish wool is somewhat effective, but is much more effective when impregnated with wax to make a better seal. One problem with Swedish wool is that it can tear when it is pulled out. To alleviate this problem, Swedish wool sometimes comes in a small plastic wrapper that is inserted with the wool. Swedish wool can be considered only fairly reusable; reuse will depend on personal hygiene, quantity of earwax, and worker preference. Earplugs The most popular type of personal protection for hearing is the inexpensive rubber, plastic, or foam earplug. Earplugs are practical from the standpoint of being easily cleaned and reusable. Workers often prefer earplugs because they are not as visible as muffs or other devices worn external to the ear. However, within this advantage lies a pitfall: Workers may be more complacent about using the earplugs when it is not immediately obvious to the supervisor whether the earplugs are being worn. The noise attenuation for properly fitted earplugs is fairly good, falling somewhere between that of Swedish wool and the more effective earmuffs. Molded Ear Caps Some ear protectors form the seal on the external portion of the ear by means of a mold to conform to the external ear and a small plug. Since human ear shapes vary so widely, fit is a problem. Molded ear caps are more visible than earplugs, which has both advantages and disadvantages, as discussed earlier. Molded ear caps may be more comfortable to the wearer, but are more expensive than earplugs. Earmuffs Earmuffs are larger, generally more expensive, and more conspicuous than Swedish wool, plugs, or caps, but they can have considerably better attenuation properties. The attenuation capability depends on design, and more variety in design is possible with earmuffs. Although some workers object to wearing conspicuous earmuffs, some workers prefer them, stating that they are more comfortable than earplugs. Helmets The most severe noise-exposure problems may force the safety and health manager to consider helmets for personal protection against noise. Helmets are capable not only of sealing the ear from noise, but also of shielding the skull bone structure from sound vibrations that can be transmitted to the ear as noise. Helmets are the most expensive form of hearing protection but have the potential to offer protection from a combination of hazards. Properly designed, the helmet can act as a hard hat and a hearing protector at the same time. It must be remembered that fit is very important for all types of hearing protectors. As in noise enclosures or sound barriers, the material itself might have excellent sound- attenuation properties, but if there is a leak or crack, most of the effectiveness of the device is lost. Eye and face protection The use of safety glasses has become so widespread and so many different styles are now available that many safety and health managers have established a rule that the safety glasses must be worn throughout the plant. A general custom in industry is to require visitors to wear safety glasses during plant tours. There is a difference between street safety glasses and industrial safety glasses. Visitors or employees who claim that their prescription glasses are “safety glasses” probably mean that they have street safety lenses. Industrial safety lenses must pass much more severe tests to meet the American National Standards Institute (ANSI) standards.  Machining operations that produce chips or sparks are almost universally conceded to necessitate the use of eye protection. Notable among these operations are those of grinding machines, drill presses, and lathes. Both metal and wood materials can produce dangerous eye hazards when machined. Corrosive liquids or other dangerous chemicals also represent eye hazards when poured, brushed, or otherwise handled in the open. When working with such materials, face protection may be needed in addition to eye protection.  Workers must wear personal protective equipment over the eyes or face, when the job requires it, regardless of whether they are wearing contact lenses. In OSHA’s early years rules were observed that prohibited the use of contact lenses in certain jobs. Later research led OSHA to remove these prohibitions and permit contact lens users to wear them on the job, provided appropriate personal protective equipment is used as required for nonusers of contact lenses as well. Contact lenses have some advantages over conventional glasses (with frames). The frames of conventional glasses may partially restrict the field of view and may interfere with the seal required for full- face respirators.  Is it Easy or Just an Illusion ? The problem of providing personal protective equipment seems straightforward and easy enough to understand. However, the simplicity of the problem is an illusion, and many industrial safety and health managers fall into its trap. For instance, it would seem that if the noise level in the production area is too high, the solution to the problem would be to provide ear protection for the workers. However, anyone who has actually confronted this problem knows that the solution is not that simple. For a variety of reasons, many people do not want to wear ear protection. They may be shy about the appearance of ear protection equipment, they may feel discomfort or perhaps even pain, they may feel it interferes with their necessary hearing or efficiency, or they may feel that the use of personal protective equipment is their own business, not their employer’s.  The matter of personal protective equipment becomes very delicate when employees bring their own equipment to work. If the equipment is not properly maintained, who is responsible—employer or employee? - OSHA’s position is that the employer is responsible. As a safety and health manager, consider the following logic: If employees bring their own personal protective equipment to work, is it not possible that the equipment itself could represent a hazard? Personal protective equipment must be properly selected to match the hazard, and employees bringing their own equipment might falsely think they are safe when their equipment could actually be malfunctioning or inappropriate.  Respiratory protection Of even more vital importance than eye and hearing protection is the need for respiratory protection from airborne contaminants. Particularly hazardous atmospheres may be referred to as IDL, which stands for “immediately dangerous to life” or IDLH, which stands for “immediately dangerous to life or health.” Recently, the acronym IDLH has become more widely used. If a single acute exposure is expected to result in death, the atmosphere is said to be IDL. If a single acute exposure is expected to result in irreversible damage to health, the atmosphere is said to be IDLH. Some materials (e.g., hydrogen fluoride gas and cadmium vapor), for example, may produce immediate transient effects that, even if severe, may pass without medical attention but are followed by sudden, possibly fatal collapse 12 to 72 hours after exposure. The victim “feels normal” after recovery from transient effects until collapse. A classification of the various devices is in order. The two major classifications are: (1) Air-purifying devices versus (2) Atmosphere-supplying devices Atmosphere-supplying respirators provide clean breathing air from a source separate from the work area. These respirators protect wearers from many types of contaminants (particles, gases, and vapors). In some cases, they can also supply breathable air in places that do not have enough oxygen. Fit testing is required for respirators with a tight-fitting facepiece. Respirator Plan OSHA standard 1910.134(c) sets forth these necessary steps, summarized here as follows: 1. Procedures for respirator selection 2. Medical evaluations for respirator users—Personnel Screening 3. Respirator fit testing 4. Procedures for proper use of respirators 5. Procedures for respirator maintenance 6. Provision of adequate supplied breathing air for air-supplying respirators 7. Employee training for when respirators are needed 8. Employee training for proper wearing, use, and maintenance of respirators 9. Procedures for continuing evaluation of the respirator program  Head protection Hard-hat rules should be carefully formulated with ample consideration for the consequences both ways. Once it has been decided that a hard hat rule is necessary, the safety and health manager should take steps to ensure its implementation. The evidence that was used to prove the need for the hard-hat rule should be compiled into an organized training package to convince workers. After the training and launching of the implementation phase, follow-up checks should be used to ensure that the rule is being followed. Corrective steps should be taken to overcome individual violations of the rule, including disciplinary actions if necessary. Hard hats seem to have won wider acceptance than hearing protection. Besides being a symbol for occupational safety and health, the hard hat has become a symbol for rugged, physical jobs. This image has appealed to males for centuries and is becoming an increasingly appealing image for female workers as well.  Safety shoes (steel-toe shoes) Safety shoes are a more expensive undertaking than hard hats because safety shoes get worn out faster and are more expensive per item. Employees may buy their own shoes at attractive discounts in some arrangements, and this encourages actual use. Safety shoes come in a wide variety of appealing styles, and employee resistance to wearing safety shoes is largely a thing of the past. The safety and health manager is usually saddled with the decision as to which jobs require safety shoes and which do not. Although applicable national standards are explicit about the design and construction of safety shoes, as with almost all personal protective equipment, the decision of where such shoes must be worn is left up to either the user or management. One place where safety shoes are clearly needed is on shipping and receiving docks. This should be obvious, but there has been some legal controversy over this issue.  Protective Clothing and Skin Hazards Occupational skin disease, especially contact dermatitis from irritants to the skin, represents a significant number of all occupational diseases reported. The safety and health manager should be alert to several skin hazard sources, such as welding, special chemicals, open-surface tanks, cutting oils, and solvents. Most welders know the value of heavy-duty protective aprons and flameproof gauntlet gloves. Leather or woolen clothing is more protective than cotton from a burn ability standpoint. Nomex™ is a treated flame- retardant fabric.  Another concern for protective clothing is chemical exposures from open-surface tanks. Gloves must be impervious to and unaffected by the liquid being handled and long enough to prevent the liquid from getting inside. If the gloves are not long enough, they can be more hazardous than beneficial. Many workers’ hands have become more irritated than their unprotected arms simply because the gloves they were wearing permitted liquids to get inside, turning the gloves themselves into dip tanks for the hands!  First aid The safety and health manager will frequently be responsible for the first-aid station and may supervise a plant nurse. The first-aid station may satisfy several additional functions besides providing immediate care for the injured. The first-aid station is often used for medical tests, screening examinations, and monitoring of acute and chronic effects of health hazards. Also, the plant nurse or other first-aid personnel may be responsible for performing some of the recordkeeping and reporting functions discussed in previous lectures. One adequately trained first-aid person is required in the absence of an infirmary, clinic, or hospital “in near proximity” to the workplace. The interpretation has sometimes depended on whether the route to the hospital crosses a railroad track If the workplace is not itself a hospital or clinic or is not directly adjacent to one, the safety and health manager is advised to be sure that at least one, preferably more than one, employee is adequately trained in first aid.  A first-aid kit or first-aid supplies should be on hand, and the safety and health manager should seek a physician’s advice regarding the selection of these materials. Unfortunately, medical doctors are hesitant to give such advice, probably because they fear subsequent involvement in litigation should an accident occur for which adequate materials are not available. Safety and health managers should do their best to obtain such advice and then document what was done to obtain information. Another first-aid consideration is the provision of emergency showers and emergency eyewash stations on job sites where injurious corrosive material exposure is a possibility. Almost everyone has seen the deluge-type shower, which is activated by grabbing and pulling a large ring attached to a chain that activates the valve. Eyewash facilities are similar to a drinking water fountain in which two jets are provided, one for each eye. Thank You gu.edu.eg