4AE3 U4 C1 Obj 2.pdf

Introduction to Plant Safety • Chapter 1 OBJECTIVE ( 2 Describe the basic hazards that may be in an energy plant, and the basic Personal Protective Equipment that may be required. In a plant, there are numerous hazards that may be present. Employees must be protected. The following are commonly...

Introduction to Plant Safety • Chapter 1 OBJECTIVE ( 2 Describe the basic hazards that may be in an energy plant, and the basic Personal Protective Equipment that may be required. In a plant, there are numerous hazards that may be present. Employees must be protected. The following are commonly encountered in the Power Engineer's workplace. • Hot surfaces and substances • Chemicals • Mists • Fumes • Explosive fuels Safety training must be provided, and exposure to these hazards must be reduced as much as possible. To reduce exposure to hazards, the employer must provide the employee with protective equipment. Personal protective equipment ( PPE) is designed to give the worker maximum protection for the specific part of the body for which it was designed. The Canadian Standards Association (CSA) publishes standards for a variety of personal protective equipment, including: ( • Protective headwear Z94.1 • Protective eyewear Z94.3 • Hearing protection Z94.2 • Respiratory protection Z94.4 • Protective footwear Zl95 The various CSA standards are referred to in this chapter. If PPE meets the CSA standard, it will be clearly marked. Make sure all PPE used meets these minimum safety standards. This way workers can be assured a reasonable level of protection. When dealing with personal protective equipment, both employer and employee have certain responsibilities. The employer must provide workers with the appropriate personal protective equipment specified for each particular job and work location. The employer shall ensure that the workers use the PPE. On the other hand, it is the workers' responsibility to wear and maintain the equipment. 4th Class Edition 3 • Part A 1-7 Unit A-4 • Introduction to Plant and Fire Safety ================== ================== PERSONAL PROTECTIVE EQUIPMENT Industrial Protective Headwear (CSA Z94.1) ( Where there is a danger of head injury, a hard hat must be worn. In most industries, this means that hard hats must be worn at all times while the worker is within plant boundaries. Protective headwear must be assembled and fitted in accordance with manufacturer's instructions. Workers wearing hard hats should check the fit of the hardhat from time to time to ensure proper fit is maintained. Part of a fit check includes ensuring the manufacturer's recommended clearance between the head/webbing and the shell of the hat. Workers should never paint their hard hats, because paint weakens plastic hats. For the same reason, only approved stickers or labels should be placed on hard hats. If a hard hat cracks, or has been involved in an accident, it must be replaced. In order to protect the wearer, the hard hat absorbs energy and becomes damaged. Damaged hard hats cannot absorb much energy, so they cannot protect the wearer. The hardhat should be appropriate for the hazards encountered. In a power plant, there are electrical hazards, high temperatures, and impact hazards. The hat must provide electrical resistance and must not soften or melt in high temperature locations. The suspension is just as critical as the shell of the hard hat itself. The manufacturer of the helmet may recommend replacing the suspension more often than replacing the shell. I Figure 1 - Hard Hat ( Bandanas, handkerchiefs, welders' caps, and hairnets may be worn under a hard hat, as long as they contain no metal parts, are worn smoothly on the top of the head, and do not compromise the fit of the hardhat. Baseball-style caps cannot be worn under protective headwear. ( 1-87----------------------- s:: 4th Class Edition 3 • Part A ) Introduction to Plant Safety • Chapter 1 Eye and Face Protection (CSA Z94.3) ( Where there is danger of injury to, or irritation of, an employee's eyes, the employer shall ensure that appropriate and properly fitting eye protection is worn. There are three different types of eye protection used. The choice depends on the type of job hazards. Safety Glasses - Spectacles Safety glasses protect against flying objects and particles. Some may have tints for UV protection. The lenses are made of shatter resistant glass or plastic. Some are designed to be worn over prescription eyeglasses. Most safety glasses are fitted with side shields for additional protection. To prevent scratching the lenses, safety glass lenses should be cleaned only with approved cleaners and wipes. Figure 2- Safety Glasses and Side Shields Safety Goggles ( Goggles are contoured to provide full facial contact around the eyes. This provides much better protection from: • • • • Flying objects Dust Mists Liquid splashes There are many different types of goggles available. They should be selected according to the type of protection required. Vented safety goggles are less prone to fogging; however, they provide little protection from vapours, mists, and dusts. Where these hazards exit, non vented safety goggles may be used. 4th Class Edition 3 • Part A 1-9 Unit A-4 • Introduction to Plant and Fire Safety === The monogoggles shown in Figure 3 are fitted with clear acetate lenses. They are used for exposure to: ( • Dust • Fumes • Chemicals • Acid Figure 3 - Monogoggles ( Goggles for welders and foundry workers are like those shown in Figure 4. CAUTION Safety goggles do not protect facial skin except around the eyes. If full-face protection is needed, goggles can be combined with face shields. Figure 4 -Welding Goggles Flip up/down protective lens 1-10 <(---------- ------------------4 -th_ _ C s_ s _E_d_ m·-on_ _ J_ • _P_a_ rl_A _ Introduction to Plant Safety • Chapter 1 ================================ == === Face Shields ( The third type of eye protection (which may also be classified as facial protection) is a face shield. Face shields should be used when working in areas where chemical and acid splashes are more likely to occur, and when performing operations like grinding. Figure 5 shows an example of a face shield ready for use at a grinding station. Welding helmets (shown in Figure 6) have specialized face shields with impact-resistant lenses and special dark welding filters. These protect welders when chipping slag, grinding, or welding. Figure 5- Face Shields Ready at a Grinding Station ( Figure 6- Welding Helmet 4th Class Edition 3 • Part A 1-11 Unit A-4 • Introduction to Plant and Fire Safety === Hearing Protection (CSA Z94.2) Continuous exposure to industrial noise can result in serious hearing loss. Workers must wear adequate hearing protection when exposed to noise. The CCOHS states the occupational exposure limit for noise exposure. Hearing protection must be worn when sound pressure levels are 80 dB or higher. ( The two main types of ear protection devices used in the workplace are the earmuff (Figure 7) and the earplug. The earmuff is scientifically designed to reduce harmful high frequency noise. Some earmuffs are designed to attach to hard hats, so they are always accessible to the worker. Earplugs may be disposable or custom molded. Disposable earplugs come in various styles and sizes, to provide comfortable fit for a variety of ear sizes and shapes. For very loud environments, such as near coal pulverizers or compressors, it may be necessary to wear both earmuffs and earplugs. Hygiene is very important when using earplugs. Earplugs, if re-used, may cause ear infections. Figure 7- Earmuff Sound Protector ( While wearing hearing protection, the worker must be able to hear voices and plant alarms. Hearing protection must not interfere with important communication. Protective Footwear (CSA Z195) Where there are hazards which may injure a worker's foot, the employer must ensure that the worker wears appropriate safety footwear. The footwear should provide crush protection to the toes and puncture protection to the sole of the foot. There are many types of specialized footwear available. Workers should ensure that their protective footwear is in good condition and appropriate for the job. The Power Engineer is required to wear CSA approved steel toe footwear. Approved footwear comes in many styles. There are: • Low profile protective running shoes • High topped heavy duty work boots • Rubber boots • Winter boots Running shoe styles are lightweight and comfortable, but offer no protection to the side of the ankle. Steel toe high top boots offer the most protection in warm, dry environments. Rubber boots may be necessary to protect feet from moisture, caustic, or acidic materials. Some boots offer additional metatarsal protection, to protect the top of the foot from impact. The majority of protective footwear has oil and acid resistant soles. 1-12 <(-------------------------------4-t_h_C_Ias_s_E_d_ii_lo_n 3_•P__ ar_l_A ( Introduction to Plant Safety • Chapter 1 Other PPE used in Power Plants ( PPE should protect against anything from minor scrapes and burns to major exposure to hazardous conditions. Work Clothing Power Engineers must wear long sleeves and long pants or coveralls in all operating areas. The clothing should be of natural or synthetic fire-resistant fibres. In many industrial sites, the clothing must have a specific "fire resistant" rating, and be branded with the letters "FR:' This includes items like toques and balaclavas worn in cold temperatures. Chemical splash outerwear provides whole-body protection against chemical exposure. When worldng in an area with hazardous chemicals, the MSDS will direct the worker as to what outerwear must be used. Any equipment from flame retardant coveralls and reinforced wrist protectors to fire resistant body suits can be part of the PPE used on the job. A Self-Contained Breathing Apparatus (SCBA) can be implemented when the atmosphere contains harmful components. Some sealed suits have built-in SCBAs. Safety Belts, Harnesses and Connecting Hardware (CSA Z259.1 and Z259.12) Fall protection is required when: a) A worker may fall 3 metres or more. b) There is unusual risk of injury if a worker falls less than 3 metres. Workers must remain 2 metres away from unguarded edges. ( Usually, guardrails, work platforms, or scaffolds are installed to protect workers when worldng at heights. Whenever these fall restraint controls are not practical, workers must wear full body harnesses and lanyards (fall restraint ropes). The lanyard must be attached to a secure anchor point. A lanyard may have a built-in shock absorber to cushion the shock should a fall occur. If the lanyard does not have a shock absorber, the fall must not exceed 1.2 metres. The shock absorber permits free falls of up to 2 metres. Workers using fall arrest equipment must be trained in the following: • • • • • • Fitting Care Use limitations Hazards Inspection Maintenance of the equipment Harnesses should be attached so that the harness and connecting hardware do not accidentally disconnect during use. They must be sturdy enough to handle the weight of the individual and the stresses that the apparatus may encounter during a fall arrest. All fall protection systems must be inspected prior to use to ensure that the system is adequate for the task being performed. Follow the manufacturer's inspection guidelines. ( 4th Class Edition 3 • Part A 1-13 Unit A-4 • Introduction to Plant and Fire Safety An example of a safety harness is shown in Figure 8. Figure 8 - Safety Harness for Working at Heights or in Confined Spaces ( Attachment Element for Fall Arrest - "D" Ring (Ba<;:k) Side "D" Life Line Attachment Leg Strap Respiratory Protection (CSA Z94.4) Respiratory protective equipment includes air purifying respirators and air-supplying equipment like SCBAs. In any workplace that may have respiratory hazards, the workers must be trained in the use and care of respiratory protective equipment. Workers must not have any facial hair that will interfere with the ability of respiratory protective devices to seal against the face. For this reason, most Power Engineers are dean-shaven. ( Reasonable steps must be taken to eliminate respiratory hazards. In cases where they are still present, respiratory protective equipment must be used. To ensure that the respiratory equipment fits properly, the user must be fit tested. Respiratory protective equipment must be worn: a) When airborne contaminants are in a concentration higher than the occupational exposure limits. b) When the atmosphere contains insufficient oxygen (less than 19.5%). ( 1-14 :s: E- -----------------------4th Class Edition 3 • Part A Introduction to Plant Safety • Chapter 1 == Considerations ( When deciding what type of respiratory protective equipment to use, the following considerations should be made. a) The nature of any contaminants, including dusts, mists and gasses, and their concentration. b) The need for mobility and emergency escape. c) The oxygen content. d) The warning properties of the contaminants (smell or colour). e) The likely duration of the workers' exposure. Respiratory equipment may be combined with other PPE. For example, an SCBA may be used with a total body containment, to protect the skin as well as to provide air to breathe. All respiratory equipment requires regular inspection, testing, and verification of proper operation by qualified technicians. This type of testing can include: a) Fit testing using capsules of scented gas to determine if the worker can smell the scent (indicating a leak). b) Verifying that the supply air for a self-contained breathing apparatus is properly pressurized and free of contaminants. Safety equipment should be kept in a clean and protected condition ready for use when required. Respirators used by Power Engineers Filter Type Respirators ( There are many possible airborne contaminants at industrial sites. For example, dust generated by handling materials such as sand or sawdust can be referred to as nuisance dusts. They are neither poisonous under normal circumstances, nor are they capable of producing fibrous tissue in the lungs. However, they are obviously nuisances that cause discomfort. Nuisance dusts are commonly removed with filters, which may be added to a respirator like the one shown in Figure 9. This Figure shows a half-mask respirator that can be used with a variety of filter cartridges designed to match the expected hazard. Figure 9 - Respirator 4th Class Edition 3 • Part A 1-15 Unit A-4 • Introduction to Plant and Fire Safety ==================== ================== Mineral dusts and mists containing silica, such as those from sandstone, flint, diatomaceous earth, and quartz, can turn healthy lung tissue into fibrous scar tissue. This causes a disease known as silicosis. A similar disease arising from asbestos dust exposure is "asbestosis:' ( Toxic dusts are poisonous. They originate from materials such as lead, arsenic, and chromium. These dusts dissolve and enter the blood stream, and they can cause injury to body organs. Mists are wet fogs, such as air, containing oil or water droplets, which may contain toxic or lung damaging particles suspended in them. A significant mist hazard is associated with cooling tower operation. The mist from a cooling tower may contain the bacteria that causes the deadly Legionnaire's disease. Most dusts and mists can be filtered from the air stream. Workers should make sure that the correct respirator filters are being used. The filter cartridges must be changed on a regular basis to ensure that maximum protection is provided. The straps of the respirator should be checked to make sure they are operating correctly and are in good condition. The sealing surfaces need to be checked for cracks and nicks which could prevent a proper seal between the respirator and the face. Air Purifying Respirator When work is to be done in an area where gases, vapors, or chemical fumes are present, a filter type of respirator is inadequate. Cartridges or canisters containing activated chemicals must be used. These respirators are known as "air purifying respirators;' because they remove toxic gases from the breathing air. These respirators may be half-mask or full-face types. Where dusts are also a breathing hazard, air-purifying cartridges may be used in combination with filter cartridges. All air-purifying respirators and their component parts have limitations. a) They do not completely eliminate exposure to contaminants. However, they will reduce exposure to below hazardous levels. b) They do not supply oxygen and must not be used in atmospheres that contain less than 19.5% oxygen by volume. ( c) They cannot be used in atmospheres that are Im mediately Dangerous to Life or Health (IDLH). d) They cannot be used where chemicals have poor warning signs such as no taste or odor. Powered Air Purifying Respirator Powered air purifying respirators have built-in fans that filter and purify air, and deliver it to the wearer's mask. They are used in atmospheres where they may be removed without danger of inhalation injuries (due to lack of oxygen or airborne toxins). They have the same limitations as the air-purifying respirator. Their advantage is that positive pressure is maintained under the facepiece, which prevents infiltration of contaminants between the facepiece and the worker's face. Most power plants utilize a Self-Contained Breathing Apparatus (SCBA) for this and other purposes listed below. However, welders and sandblasters sometimes use the powered air purifying respirators, especially when working inside a workshop. Supplied Breathing Air Systems Supplied breathing air systems must be used if: a) Airborne contaminants cannot be filtered or handled by the air-purifying cartridges. b) The atmospheric oxygen is below 19.5%. These systems are designed to address specific workplace situations. They include the SelfContained Breathing Apparatus (SCBA), the Supplied Air Breathing Apparatus (SABA ) and the Supplied Air Respirator (SAR ). These systems supply compressed air of breathing-grade purity to the worker. 1-16 7------------------------- s 4th Class Edition 3 • Part A ( Introduction to Plant Safety • Chapter 1 ==================================== ( The SCBA and SABA both use compressed breathing air in cylinders. The process of air compression causes atmospheric water to condense. This condensed water dissolves airborne contaminants, and must be removed from the breathing air. Oil-lubricated compressors release carbon monoxide and oil mists to the compressed air. Therefore, all compressed breathing air must be dried and purified before it is bottled and delivered to the end user. All breathing air suppliers must have the correct drying, purification and testing equipment to ensure they produce breathable air. CSA Z180.1 code outlines the very high standards for compressed breathing air purity. Self-Contained Breathing Apparatus (SCBA) and Supplied Air Breathing Apparatus (SABA) An SCBA must be used where conditions at the work site are or may become immediately dangerous to life or health because of: a) Reduced oxygen content of the air, or b) Other contaminants that may cause acute toxic effects. The employer must ensure that employees wear a self-contained breathing apparatus or remote supplied air apparatus that: a) Will maintain positive pressure in the facepiece at all times. b) Has a capacity of at least 30 minutes. c) Provides full-face protection, where the contaminants are irritating to the eyes. ( d) In the case of a remote supplied air breathing apparatus, it is fitted with an auxiliary supply of breathable air. The auxiliary supply should be of sufficient quantity to enable the worker to escape from the area in an emergency. e) In the case of a self-contained breathing apparatus, is fitted with an audible and tactile low air alarm warning. Some SCBAs offer the option of an air line connection to a fixed air supply, through a hose up to 100 m long. The user can use the fixed air supply or the SCBA cylinder. This allows workers to spend more time in the workspace, without being concerned about how much breathing air remains in the cylinder. Self-Contained Breathing Apparatus ( SCBA ) SCBAs are respiratory protective devices that require the wearer to carry a supply of compressed air in a cylinder. The air is regulated to the facepiece and fitted with an alarm to warn when the air supply is low. The supply air permits work to take place for short periods of time, in toxic or oxygen-deficient atmospheres. Figure 10 shows an SCBA designed to provide extensive mobility. It can be used with either a 30 or 60 minute air cylinder, charged to 31 MPa. An SCBA equipped with a 60 minute cylinder is about 5 kg heavier than one equipped with a 30 minute cylinder. Cylinders are aluminum pressure vessels, wrapped in fiberglass or carbon fibre for additional strength. Carbon fibre wrapped cylinders are lighter than fiberglass-wrapped cylinders, but are more costly. The cylinder is locked into the backpack and can be easily changed without tools. This type of equipment is designed for total portability for emergency use such as isolating equipment and rescue operations. It can also be used for maintenance jobs that can be accomplished in a short time. 4th Class Edition 3 • Part A 1-17 Unit A-4 • Introduction to Plant and Fire Safety == Figure 10- Self-Contained Breathing Apparatus (SCBA) ·..5..-.- · - '"""" . ( -. rl ' The compressed breathing air leaves the cylinder and passes through a high-pressure hose to a pressure regulator. The pressure regulator supplies air at reduced pressure to a facepiece mounted pressure demand regulator. The pressure demand regulator maintains a slight positive pressure under the facepiece to keep contaminated air out. The regulator senses the pressure under the facepiece, and supplies air each time the worker inhales. ( In supplying air only on demand, the regulator helps conserve the air in the cylinder. The regulator also contains a warning device to alert the user when the air supply is running low. The regulator makes a sound and vibrates, which is especially important when worldng in noisy environments. The regulator has an automatic shut-off that reduces airflow while putting on or taldng off the facepiece, or if the facepiece becomes dislodged. This prevents unnecessary loss of air. Some regulators have a "donning valve:' By pressing this valve before donning the SCBA, the worker can stop airflow to the facepiece. Once the regulator is mounted on the facepiece, the donning valve releases breathing air as soon as the worker inhales. Supplied Air Breathing Apparatus ( SABA ) An SABA has a full facepiece supplied air respirator. It is equipped with a pressure demand regulator identical to the SCBA, connected by an air-supply hose to an air source (either a compressor or bank of large air cylinders). When connected to the air source, the respirator delivers a supply of air to the worker. SABAs have both a supplied air respirator and small escape-sized breathing air cylinder (Figure 11). If the fixed air supply fails, the worker can switch to the escape cylinder air supply and leave the contaminated area. The escape cylinder has a low profile that does not interfere when entering or exiting tight places. This makes it suitable for entering and worldng in dangerous atmospheres. The airline allows for extended work activity, and can be detached quicldy. The escape cylinder provides 5 to 15 minutes of emergency escape breathing air. Like SCBAs, SABAs may be used for areas Immediately Dangerous to Life and Health (IDLH), because they have escape air cylinders. If the main supply air hose is severed or crimped, or if the ( air compressor fails, the air supply to the worker would also fail. Despite having small capacity, the escape bottle has enough air to allow the worker to escape to fresh air. 1-18 7------------------------- E- :S: 4th Class Edition 3 • Part A Introduction to Plant Safety • Chapter 1 == ( === Supply Air Respirators (SARs) are like SABAs in that air is supplied to the worker via airline. However, SARs differ from SABAs because they do not have escape air cylinders. Therefore, SARs cannot be used in IDLH environments. Figure 11 -Supplied Air Breathing Apparatus with an Escape Cylinder (SABA) Positive Pressure Facepiece-Mounted Regulator with Hose Harness Assembly ( Training IMPROPER USE OF ANY BREATHING APPARATUS IN A HAZARDOUS ATMOSPHERE MAY RESULT IN INJURY OR DEATH. PERSONNEL MUST RECEIVE ADEQUATE TRAINING PRIOR TO USE. The training of personnel who are required to use breathing apparatus cannot be overstressed. The manufacturers of the equipment provide excellent guidelines. 4th Class Edition 3 • Part A 1-19