Noise hazards, examples

Atmospheric Hazards. Examples are Uie presence of toxic airborne chemical substances and parUculate matter, biological agents, noise, vibration, radiation, extremes of temperature and humidity, and lack of illumination. 

The power source may add to the inherent hazards of a tool or machine itself. For example, electrical power brings certain hazards (discussed in Chapter 12). Combustible fuels, explosives, hydraulics, and pneumatics each bring additional hazard to the tools and machines they power. Machines and tools may create noise hazards, produce air contaminants, get hot, or create other hazards. 

Not all existing procedures or program elements of the overall health and safety program need to be incorporated into the HASP. For example, if noise is a hazard, the plan does not have to cite the entire hearing conservation program. Procedures already established elsewhere may be referenced, as applicable. In another example, if a confined-space-entry procedure is required, the HASP could reference the particular procedure which is part of the overall program. The next step would be to identify confined spaces at the worksite where the procedure applies, and then provide appropriate implementation procedures (e.g., conditions to be monitored, evaluation of the space, issuance of an entry permit). If special operational procedures apply to the worksite, they can be attached to the HASP using an appendix. 

For mixtures with low sensitivity, detonation-propagation must be investigated. For example, we cannot say the mixture possesses hazards of explosion if it cannot sustain propagation of detonation. A large quantity of sample is necessary in tests of this kind. Because of the noise of explosion, the explosion test under sand (Sec.3.8)is recommeded. 

Vibrations, sound, and noise are other examples of common industrial hazards. The most common injury because of vibration is sound-induced hearing loss. The vibrations of machines, high-speed pumps, generators, boilers, and conveyers produce unwanted sound noise. The adverse effects produced by these sounds are as follows ... 

Human loudness perception depends in a complex manner on both frequency and the overall loudness of sound. (For example, bass is more difficult to hear in music played at low volume than in the same music played at high volume.) To capture this behavior, two weighting scales have been developed for use in sound hazard analysis. The most common of these is the A weighting scale, which is commonly used to assess occupational and environmental noise. The A scale weights sounds in the 1000-6000 Hz range much more heavily than low-frequency sounds. The A-weighted intensities (dBA) of some common sounds are listed in Table 5. By contrast, the C weighting scale is used for very loud sounds and is a much flatter function of frequency. 

Physical hazards include noise, vibration, extremes of temperature, compressed gases, combustible and flammable chemicals, pyrophorics, explosives, oxidizers, and reactive materials. Process employees are exposed to physical hazards on a daily basis because they woric outside on the unit among pipes containing compressed gases, fluids under high temperatures, and flammable and explosive chemicals. Examples of some these hazards on a process unit might include ... 

Engineers select and evaluate process equipment. The selected equipment must be technically sound, rehable, safe and easy to operate, serviceable, economically attractive and environmentally sound, e.g. minimal noise pollution and no mechanical and fire hazards. For example, all pneumatic valves, except for the modulating valves, are air-to-open/ spring-to-close valve type for safe shutdown unless the valve is a divert drain valve as... 

A loss control measure against identified risks by segregating the identified hazard to a specific (remote) location to protect the surrounding area from its effects and vice versa. Examples include placement of a chemical plant or process in a remote location and enclosure of an individual in an acoustic booth or enclosure to protect against noise exposure. 

In routine or repetitive jobs with inherent hazards, the employee is exposed repeatedly to hazards. For example, exposures to high levels of noise over a period of time will affect the hearing of a worker. 

Some details of the hazards to be faced need to be known for example, in the case of air contaminants, the type of chemical present and its concentration, or, with noise, sound level and frequency characteristics would be needed. 

Personal protective device Examples include earplugs or earmuffs worn as protection against hazardous noise. 

Redesigning, changing, or substituting equipment to remove the source of the hazard— for example, excessive temperatures, noise, or pressure... 

Equipment. The types of equipment that an injured employee was working with, its production and maintenance requirements, its layout in the work area, and its hazards and the methods of controlling them could all be clues in the investigation— for example, guarding, noise reduction, or controls of hazardous material. 

The basic work of providing a comprehensive assessment (Chapter 10) was done by a committee composed of the safety director, the nurse practitioner, the director of manufacturing, the supervisor of maintenance, and two production employees, one from the day shift and one from the evening shift. In addition, consultation was requested from the loss control department of their insurance carrier. The loss control engineer was an industrial hygienist who confirmed the need to monitor for noise in the manufacturing area. She also helped the nurse practitioner and the human resources director write job descriptions for all major employee classifications. The descriptions emphasized important safety considerations— for example, the amount of weight lifted and the hazardous substances handled. 

Where multiple, diverse hazards exist, the practical approach is to treat each hazard independently, with the intent of achieving acceptable risk levels for all. In the noise and toluene example, the hazards are indeed independent. In complex situations, or when competing solutions to complex systems must be evaluated, the assistance of specialists with knowledge of more sophisticated risk assessment methodologies such as Hazard and Operability Analysis (HAZOP) or Fault Tree Analysis (FTA) may be required. However, for most applications, this author does not recommend that diverse risks be summed through what could be a questionable methodology. 

This involves reducing the time during the working day that the employee is exposed to the hazard, either by giving the employee other work or rest periods. It is only suitable for the control of health hazards associated with, for example, noise, display screens and hazardous substances. However, it is important to note that for many hazards there are short-term exposure limits as well as normal working occupational exposure limits over an 8-hour period (see Chapter 16). Short-term limits must not be exceeded during the reduced time exposure intervals. 

For example, say the potential hazard was injury and illness caused by hot work (such as, welding fumes, UV light, sparks, noise, or skin injury). The hazard assessment on an oil and gas site may identify the following requirements ... 

The hazards need to be identified and the risks assessed for example, in fhe case of air contaminants the nature of the substance(s) present and the estimated exposure concentration, or, with noise, measurement of sound levels and frequency characteristics. 

Data about the ability of equipment to protect against a particular hazard is provided by manufacturers who carry out tests under controlled conditions which are often specified in national or international standards. Performance requirements for face masks, for example, are contained in two British Standards which specify the performance requirements of full-face and half/quarter masks for respiratory protective equipment. The method used to determine the noise attenuation of hearing protectors at different frequencies (octave bands) throughout the audiWe range is specified in a European standard . 

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