Bioenvironmental Engineering Apprentice Block IV: Chemical Controls PDF

Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 10: Ventilation Follow-Up BLOCK IV – UNIT 10: VENTILATION FOLLOW-UP Objective 10a: Identify basic follow-up actions for deficient ventilation systems. When surveying a ventilation system to verify adequate opera...

Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 10: Ventilation Follow-Up BLOCK IV – UNIT 10: VENTILATION FOLLOW-UP Objective 10a: Identify basic follow-up actions for deficient ventilation systems. When surveying a ventilation system to verify adequate operation, there may be instances when the system does not meet the criteria to control the hazard. When this happens, there are things we can do to help return the system to adequate operation. We may need to perform some troubleshooting to determine what is wrong with the system. Once corrective action has been taken, we can then determine if the system is operating normally. DEFICIENCY IDENTIFICATION Recall that we perform various surveys for ventilation systems that control a hazard. These surveys include baseline surveys and routine surveys. Ventilation system deficiencies are most commonly identified during routine surveys. Workers familiar with a system may also be able to identify changes to how the system operates. BASELINE SURVEY During a baseline survey, we conduct air sampling at the same time that we take measurements of the ventilation system. Air sampling allows us to confirm the system was adequately controlling hazards below the OEL at the time of the survey. Based on the measurements taken during the baseline survey, an acceptable range is established to compare future measurements against. This acceptable range is how we determine if a ventilation system is deficient. ROUTINE SURVEY Once the baseline survey is complete, the ventilation system is placed on a routine survey schedule. These routine surveys may occur once a year, every 6 months, or every 3 months. During the routine survey, we measure the same parameters and locations that were measured during the baseline survey and compare the readings to the established acceptable range. If measuring airflow, such as volumetric flow rate (Q) or face velocity (v), then the acceptable range is +/- 10% of the baseline measurement. If measuring static pressure (SP), the acceptable range is +/- 20% of the baseline measurement. The ventilation system is considered deficient if it is outside one of these ranges. TROUBLESHOOTING AND REPAIR If the ventilation system is found to be operating outside of the acceptable range, then it is considered deficient, and the system must be fixed. To properly address a deficient system, it is first necessary to identify what is causing the change in the system. TROUBLESHOOTING Troubleshooting is the process we follow to determine the cause of a problem. We must take care that we are not “fixing” the problem without addressing what caused the issue in the first 61 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 10: Ventilation Follow-Up place. Proper troubleshooting ensures the system is returned to baseline operating condition, prevents further damage to the system, and prevents wasted effort on repairs. For example, consider a ventilation system with a hood for capturing welding fumes, as shown in Figure 38. If our baseline face velocity was 1000 fpm, then our acceptable range is +/-10% of 1000 fpm, or 900 fpm to 1100 fpm. During a routine ventilation survey, we measure the face velocity to be 500 fpm. This system is deficient, since 500 fpm is not within the acceptable range. The following list presents some of the potential causes of a reduced airflow through the hood. Figure 38: Welding Fume Capture Hood Fan rotation direction. An incorrectly wired fan may run backwards. A backwardrunning centrifugal fan will deliver 30-50% of its rated airflow. Fan rotations per minute (RPM). A fan may slow it’s rate of rotation for various reasons. The fan could have failing bearings, causing friction when turning, or there could be an electrical issue, reducing the voltage the fan is receiving. Slipping fan belt. Fan belts tend to stretch over time. If the belt becomes loose, it will decrease the rate of rotation of the fan. Clogged or corroded fan wheel and casing. If the fan wheel is clogged or has holes, it will lose it is efficiency and will not move as much air through the duct. Clogged ductwork. If one branch of duct has a clog, airflow in that branch will decrease while increasing somewhere else in the system. Leaking ductwork. If a duct is leaking or has a hole, this creates another path for air to flow through. This will decrease the airflow through other entry points of the system, such as the fume hood. Closed or open dampers in ductwork. Some ventilation systems have dampers designed to balance airflow in the system or to close off unused parts of the system. Ensure workers understand how to set the dampers so the system operates properly. Clogged collector or air cleaning device. When an air cleaning device becomes saturated or clogged, it puts strain on the fan and decreases airflow throughout the system. With only the information that the face velocity has decreased, we cannot determine the cause of the declining airflow. Further investigation would be necessary to find the root cause of the low flow rate. It is important that we properly troubleshoot the problem; we do not want the fan speed increased to bring the face velocity back into range if the issue was caused by a clogged duct. WORK ORDER 62 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 10: Ventilation Follow-Up Once troubleshooting has been accomplished, a work order needs to be submitted to facility managers or Civil Engineering to correct the problem. It is the workplace supervisor’s responsibility to ensure the system receives the maintenance or repairs it needs in order to protect their workers. ADDITIONAL SURVEYS RE-SURVEY After Civil Enigneering has performed maintenance on the system, we need to perform a ventilation survey to ensure it has returned to baseline operating conditions. If the system is within the acceptable range of the baseline, then no further action is needed until the next routine survey. However, if the system still does not operate within the acceptable range, all troubleshooting efforts have been exhausted, and Civil Engineering has performed all possible maintenance, you may need to re-baseline the system. RE-BASELINE A new baseline may be required if a system is no longer able to meet the original baseline parameters. This is most common with aging systems that have deteriorated over time. A new baseline should be considered if troubleshooting does not identify any issues that can be addressed to correct the airflow. Air sampling is done to ensure the system is still able to adequately control the hazards and a new acceptable range of measurements is established. RESPONSIBILITIES BIOENVIRONMENTAL ENGINEERING BE personnel are required to survey all ventilation systems that are controlling hazards. BE establishes a baseline, which is used to asses the ventilation system’s performance during future surveys. BE performs troubleshooting for deficient systems, communicates findings to the workplace supervisor, and re-surveys ventilation systems after maintenance has been completed. CIVIL ENGINEERING Civil Engineering personnel may perform routine maintenance and troubleshooting on ventilation systems (both industrial and non-industrial). For most bases, Civil Engineering HVAC personnel should be the primary point of contact to repair malfunctioning ventilation systems. WORKPLACE SUPERVISOR The supervisor is required to provide a safe work environment for personnel. The workplace supervisor should report deficiencies found with the ventilation system to Civil Engineering personnel to ensure deficiencies are resolved. The workplace supervisor must also contact BE after ventilation systems are repaired so additional ventilation surveys can be accomplished. WORKER 63 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 10: Ventilation Follow-Up The worker is required to use the ventilation system properly and to report any ventilation system malfunctions to the workplace supervisor immediately. 64 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 12: Respiratory Protection Program BLOCK IV – UNIT 12: RESPIRATORY PROTECTION PROGRAM Objective 12a: Identify roles and responsibilities of BE, the program administrator, workplace supervisor, and the worker in the Respiratory Protection Program (RPP). INTRODUCTION AND GUIDANCE In any workplace where engineering and administrative controls cannot effectively control inhalation hazards, we must resort to the use of PPE to control exposures. The PPE we recommend to control inhalation hazards are respirators. Whenever respiratory protection (RP) is required, a written RP Program with workplace-specific procedures must be established and implemented. The program must be updated to reflect any changes in workplace conditions that affect respirator use. Respirators may be required to control exposures to material with risk of health effects from long-term, low-level (chronic) exposures, short-term, high-level (acute) exposures, or both. Health effects from these exposures can vary from minor irritation and temporary illness to permanent organ damage, cancer, and even death. The proper use of approved respirators will protect the wearer from toxic levels of airborne chemicals and hazardous materials. Employees are less likely to experience illnesses from these hazards when they wear an approved respirator correctly, and are trained in the proper use, care, and maintenance of their assigned respirator. The following references should be used when seeking information about respirator use. OSHA GUIDANCE 29 Code of Federal Regulations (CFR) 1910.134, Respiratory Protection, lays out the requirements of a RPP. It also includes required fit test procedures that we must follow to ensure the respirator used will provide adequate protection. 29 CFR 1910 1000 series regulations include requirements for general air contaminants and some specific chemicals. Some of the substance-specific standards (such as lead) include special guidance regarding RP use. USAF GUIDANCE AFI 48-137, Respiratory Protection Program, lays out how the Air Force will execute the RP program to meet 29 CFR 1910.134 requirements. AFI 48-137 includes program responsibilities, the elements required in the shop’s written RP program, and fit testing procedures. OTHER GUIDANCE NIOSH Certified Equipment Listing – The listing provides the most current listing of approved respirators. NIOSH tests each respirator configuration and provides a certification number. The NIOSH certification process is how we know the respirator will protect the worker. If a combination is not certified, we cannot recommend it to the worker. 65 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 12: Respiratory Protection Program Manufacturer’s Literature – New respirators come with documentation from the manufacturer. In many cases, when a worker is issued a respirator, the documentation from the manufacturer is discarded with the box. BE should maintain copies of the manufacturer’s literature for all respirators and components of RP systems for reference. These documents include information on how to properly use and maintain the respirator. RESPONSIBILITIES BIOENVIRONMENTAL ENGINEERING BE is the installation subject matter expert on the RP program. BE will do the following in support of the RP Program: Provide a member to serve as the Installation RP Program administrator Determine when RP is required based on workplace hazards Work with RP purchasers to ensure procedures are in place to control the order and issuing of respirators Assist worksite supervisors, as necessary, in the preparation of the written worksitespecific procedures and annual training requirements Develop training for worksite supervisors and certify completion of training by the supervisor Review, recommend, and approve respirators for use in a shop Conduct industrial respirator and CBRN mask fit testing Authorize and evaluation units annually, other than BE, to conduct fit testing Manage respirator selection, rosters, and fit testing in DOEHRS INSTALLATION RESPIRATORY PROTECTION PROGRAM ADMINISTRATOR The Installation RP Program administrator has overall oversight of the Installation RP Program. The installation commander appoints the Installation RP Program administrator in writing. The administrator must be qualified by training or experience to oversee the RP program and conduct evaluations of program effectiveness. The administrator must be a qualified Bioenvironmental Engineer, fully qualified BE Technician, or civilian Industrial Hygienist. 66 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 12: Respiratory Protection Program WORKPLACE SUPERVISOR (UNIT RP PROGRAM ADMINISTRATOR) The commander of units using respiratory protection must appoint a unit RP Program administrator. The unit administrator is typically the workplace supervisor. The unit administrator must have attended a respiratory protection training course or been certified by BE as technically proficient to administer the program. The supervisor, or unit administrator, will do the following: Develop a written RP Program with worksite-specific procedures with the assistance of BE Review the written worksite-specific procedure and provide a copy to BE for approval annually Ensure workers adhere to the worksite-specific procedures Designate individuals responsible for use, maintenance, inspection, and care of respirators Notify BE with changes to the roster of RP users or if current workers have a change in medical status that may affect the safe wear of a respirator Maintain copies of fit test results for all personnel Develop training material and ensure workers are trained on the use of respirators in their workplace Regularly consult respirator users to assess program effectiveness RESPIRATOR USER Workers also carry responsibility within the Respiratory Protection Program. Workers must: Adhere to the conditions of the written worksite-specific procedures Maintain filter use records to ensure compliance with the change-out schedule included in the written worksite-specific procedures Report any change in medical status, which may impact their ability to safely wear a respirator, to their supervisor 67 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 13: Respirators BLOCK IV – UNIT 13: RESPIRATORS Objective 13a: Recall the operating principles, types and components of respirators. Respirators are designed to cover the entrances to the respiratory system—the nose and mouth. They vary widely by design and function and can be described in terms of the design of the respiratory inlet covering and by the mechanism used to provide protection. When effective controls are not feasible, or while they are being instituted, appropriate respirators must be used to protect workers from exposure to airborne contaminants or oxygen-deficient environments. DEFINITIONS IMMEDIATELY DANGEROUS TO LIFE AND HEALTH (IDLH) IDLH is any condition that poses an immediate threat to life, would cause irreversible adverse health effects, or would interfere with an individual's ability to escape unaided from a contaminated area. OXYGEN DEFICIENT ATMOSPHERE An oxygen-deficient atmosphere is any atmosphere that contains less than 19.5% oxygen. SKIN ABSORPTION Skin absorption is the transport of a chemical from the outer surface of the skin both into the skin and into the body. Studies show that absorption of chemicals through the skin can occur without being noticed by the worker and in some cases, may represent the most significat exposure pathway. WARNING PROPERTIES Warning properties are characteristics of a chemical that allow a person to detect them with their senses. They include odor, eye irritation, and respiratory irritation. Some chemicals have poor warning properties, while some have good warning properties. LOWER EXPLOSIVE LIMIT (LEL) The LEL is the minimum concentration, as a percentage, of flammable gas or vapor mixed with air that can be ignited. CHANGE-OUT SCHEDULE A change-out schedule identifies how long a respirator cartridge can be used in the workplace before being replaced. Change-out schedules ensure the cartridge used does not become saturated and is able to remove the air contaminant. ASSIGNED PROTECTION FACTOR The assigned protection factor is the level of respiratory protection expected to be provided by a properly functioning respirator. 68 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 13: Respirators 69 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 13: Respirators ODOR THRESHOLD The odor threshold is the minimum concentration at which a chemical can be detected by a person’s sense of smell. TYPES OF RESPIRATORS AIR-PURIFYING RESPIRATOR (APR) An air-purifying respirator (APR) is a respirator with a filter, cartridge, or canister that removes specific air contaminants by passing ambient air through the air-purifying element. Because these respirators only remove contaminants from the air, they cannot be used in an oxygendeficient atmosphere. The filtering elements do not have an indefinite life. They lose their effectiveness over time as they are used. Due to degradation of the material, a change-out schedule shall be developed with the assistance from BE. This helps to ensure workers replace the filtering elements often enough to keep respirator effective. Air purifying respirators can be one of two types: Negative-pressure and powered air purifying respirators (PAPR). Negative-Pressure APR With negative-pressure air-purifying respirators (APR), air is drawn through the filtering element when the wearer inhales, creating a negative pressure inside the mask. When the wearer exhales, air is pushed out of the mask. A good seal on the face is required to ensure air only enters through the filtering element, not through breaks in the seal. Examples of negativepressure APRs are shown in Figure 40 and include: Filtering Facepiece Device (FFPD) – These may also be referred to as dust masks. The Air Force does not recognize FFPDs as respirators for controlling industrial hazards, and FFPDs may only be approved as voluntary (optional) use in these cases. BE only recommends the use of FFPDs to control hazards in medical care environments. These only require fit testing if they are required PPE in a medical setting. Half Mask Respirator – These respirators cover the wearer’s mouth and nose. They extend from above the nose to below the chin, creating a tight seal around the lower face. These offer the lowest level of protection for all industrial respiratory protection options. Half mask respirators may only be worn when required for a process; workers cannot opt to wear them voluntarily. Full Facepiece Respirator – These respirators cover the wearer’s eyes, nose, and mouth. They form a seal all around the user’s face, from the forehead down to below the chin. Like half mask respirators, full facepiece respirators may only be worn when required for a process, not as a voluntary control measure. 70 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 13: Respirators Figure 40: Negative-Pressure Air Purifying Respirators Powered Air-Purifying Respirator (PAPR) A powered air-purifying respirator (PAPR) does not rely on negative pressure inside the mask to draw air through a filtering element. As the name indicates, PAPRs are powered respirators; a battery is used to operate a pump and constantly draw air through the filtering element and into the worker’s breathing zone. PAPRs are most commonly used with a loose-fitting hood, as seen in Figure 39. Since a hood is not tight-fitting, this type of respirator does not require a fit test. However, the worker must still be trained on the proper use of their PAPR. The PAPR is a complete system that includes a battery and pump, which are attached to a belt worn by the worker. The PAPR system also includes filtering elements that attach to the pump, a loose-fitting hood, and a hose connecting the pump to the hood. Figure 39: Powered Air Purifying Respirator ATMOSPHERE-SUPPLYING RESPIRATORS When an air-purifying respirator will not effectively protect the worker, an atmosphere-supplying respirator should be considered. Rather than purify the air in the worker’s environment, these types of respirators provide air either from a clean area or from compressed breathing air. Since these types of respirators do not rely on the ambient air, they maybe used in an oxygendeficient environment. Atmosphere-supplying respirators can be one of two types: Airline or self-contained breathing apparatus (SCBA). 71 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 13: Respirators Airline Respirators Airline respirators, such as in Figure 41, are connected to a source of clean air by a breathing air hose. The source of breathing air may be an ambient air pump or a compressed air system. An ambient air pump moves air from a clean area, through the air hose, and into the respirator. Compressors pump ambient air into a compressed air system. The air hose connects to the compressed air through a pressure regulator, which allows the user to adjust the pressure provided to their respirator. Compressed breathing air must be tested to ensure it is safe to breathe. Figure 41: Airline Respirator Self-Contained Breathing Apparatus (SCBA) A SCBA, as shown in Figure 42, is not connected to a stationary source by an air hose. Instead the wearer carries their source of air on their back. The wearer has an air tank on his or her back to supply oxygen. The wearer is free from the ambient atmosphere, and mobility is not restricted. A limited supply of air imposes a time restriction on the number of minutes the SCBA is effective. The SCBA method is most often used in emergency situations (e.g., fire fighting operations or to exit an area that has become highly toxic). Figure 42: Self-Contained Breathing Apparatus (SCBA) MAJOR COMPONENTS OF A RESPIRATOR AND THEIR FUNCTION FACEPIECE The facepiece makes a tight seal on an individual’s face, keeping contaminants out of the mask. HEAD STRAPS OR HEAD HARNESS Head straps or a head harness are designed to keep the respirator in place on an individual’s face. 72 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 13: Respirators EXHALATION VALVES Exhalation valves are designed to allow air out of the respirator but do not allow air in. INHALATION VALVES Inhalation valves are designed to prevent exhaled air from adversely affecting filters, cartridges, and canisters, while allowing air to pass through when inhaling. AIR-PURIFYING ELEMENT The air-purifying element is designed to remove contaminants from the air. Filters remove particulates and cartridges remove compatible gasses and vapors. Combination filter/cartridges do both. CATEGORIES OF RESPIRATORY PROTECTION REQUIRED Only government-provided respirators shall be used by government employees at Air Force workplaces, except as authorized for voluntary use. Respiratory protection is required when any of the following conditions appear: Other means of controls do not reduce exposure below the OEL. Other means of controls are not feasible (this may include use during intermittent,nonroutine operations). Use is specified by an OSHA standard or Air Force Directive. While permanent controls are awaiting funding, or being designed or installed. Exposures could potentially be greater than an OEL, as determined by BE. Emergency situations require the use of respiratory protection. VOLUNTARY OSHA allows for the voluntary (optional) use of respirators as long as the employer has determined that the use of the respirator does not create a hazard for the worker. The Air Force is more stringent when it comes to this. The only devices that the Air Force allows for voluntary use are known as filtering facepiece devices (FFPDs), as seen in Figure 43. These devices are commonly referred to as dust masks. The Air Force does not consider these devices respirators, except in medical settings where they are required to control biological hazards. In all other situations, BE cannot recommend FFPDs to control a hazard. However, BE can authorize FFPDs for voluntary use after ensuring they do not create a hazard. Workers then have the option to wear the FFPD for comfort purposes. 73 Figure 43: Filtering Facepiece Device (FFPD) Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 13: Respirators TYPES OF FILTERS AND CARTRIDGES PARTICULATE FILTERS Particulate filters, such as those in Figure 44, can be made from non-woven fiber materials, compressed natural wood, or synthetic fiber. They will protect against aerosols such as dusts, mists, fumes, and other particulate matter, but do not protect against gases or vapors. They may not be used in oxygen deficient atmospheres or in an area designated as IDLH. How efficient a respirator filter is depends on conditions within the workplace. Factors such as particle size and the employee’s work rate will have an effect on efficiency. NIOSH certifies three levels of filter efficiency: 95%, 99%, and Figure 44: P100 Particulate Filter 99.97%. Filters that capture at least 95% of very small particles (0.3 micron) are given a 95 rating. Those that capture at least 99% receive a 99 rating, and those that capture at least 99.97% receive a 100 rating. Efficiency degradation is the reduced ability of the filter to remove particles based on workplace conditions. Some filters are prone to reduced filter efficiency from contact with oils. As a result, NIOSH has established categories of resistance to filter efficiency. Filters are designated by the following series: N (Not resistant to oil), R (Resistant to oil), or P (oil Proof). The resistance designation (N, R, or P) and efficiency (95, 99, or 100) are combined to describe a filter, as shown in Table 3. Table 3: NIOSH Filter Classifications 74 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 13: Respirators CHEMICAL CARTRIDGES Chemical cartridges, such as the organic vapor cartridge shown in Figure 45, protect against gases and vapors. They differ from particulate filters in that they use porous materials called sorbents (generally carbon) that interact with the gas or vapor to purify the air. Unlike particulate filters, cartridges are designed to protect against specific contaminants or classes of contaminants. They are effective only if the correct cartridge for a particular chemical substance is used. Therefore, you must know the hazards in order to be certain you are choosing the right cartridge. The contaminant removal mechanisms for chemical cartridges involves adsorption. Adsorption is the adherence of gas or vapor molecules to the surface of another substance called the adsorbent or sorbent. Figure 45: Organic Vapor Cartridge COMBINATION CARTRIDGES Often, cartridges will combine a particulate filter with a chemical cartridge. These combination cartridges allow for protection from a gas or vapor and particulate matter. Figure 46 shows an example cartridge that protects against both particulates (P100) and vapors (Organic Vapor). Figure 46: P100/Organic Vapor Cartridge ADVANTAGES AND DISADVANTAGES OF RESPIRATOR TYPES AIR PURIFYING RESPIRATORS Advantages: A lightweight respirator Can be worn in tight spaces Can be worn for long periods of time Disadvantages: Cannot be worn in an IDLH atmosphere Cannot be worn in an oxygen deficient atmosphere 75