Vibration Hazards and Noise Hazards in Construction Industry - Example

A report on vibration hazards and noise hazards in construction industry Introduction A hazard is a scenario that poses a level of threat to health, life, environment or property. A hazard exists when it is happening (Edwards and Holt, 2008). Hazards which have already occurred are referred to as incident. This report aims at identifying, assessing and controlling a physical and a health hazard construction industry (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). Workers in construction industry are at risk exposure to various hazards that can result in injury, disability, illness or even death (Paschold and Sergeev, 2009). In this report vibration and noise hazards related to construction are identified, assessed and control measures proposed. Identification of vibration hazard Operators of large mobile equipment such as air hammers, drillers, tractors, earth moving equipment, pile drivers, graders, excavators and other large machinery may suffer from whole body vibration (Edwards and Holt, 2007). The diagram below is an example of machinery that can expose the operator to whole body vibration. Other tools that may expose the operator to vibration hazard are hand held power tools such as pneumatic hammers and drills and disc grinders. These hand held tools expose operators to hand arm vibration. The diagram below illustrates and handheld tool being operated. Health conditions induced by vibrations are slow in progression. Initially, such conditions start as pain and as exposure progresses pain develops into injury or disease. Carpal tunnel syndrome may result from hand arm vibration (Edwards and Holt, 2008). Carpal tunnel syndrome is a disease that affects hands and fingers. In the long run this disease results in permanent damages to the nerves and as a consequence one loses the sense of touch and dexterity. Harmful effects of hand arm vibration may be aggravated by working in a cold and damp environment. Vibration induced white finger is another health condition that may result from exposure to vibrations especially in the hand held vibrating tools. This is a vascular disorder which is caused by inadequate circulation (Edwards and Holt, 2007). It is more common in colder seasons (Hughes and Ferrett, 2008). Based on the intensity and duration of the exposure, this disorder may affect only the fingers or the finger tips. Whole body vibration is also associated with health conditions such as insomnia, fatigue, headache, stomach problems and shakiness during and shortly after exposure. Prolonged exposure to whole body vibration could contribute to circulatory, bowel, muscular, respiratory and back disorders (Edwards and Holt, 2008). Studies have also indicated that whole body vibration may result in increased heart rate, respiratory rate and oxygen uptake and can also result in changes in urine and blood. Furthermore, workers exposed to whole body vibration have been found to have reduced performance (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). Sensitivity to vibration varies from individual to individual. The health effects that can result from vibration are affected by three factors. First is the threshold value that can result in no adverse health effects. This is the level below which there is no risk of vibration syndrome. Exposure to sufficiently low level of vibration may not result in vibration related injuries or disease for the workers’ entire full time employment (Edwards and Holt, 2007). The second factor is the dose response relationship (Paschold and Sergeev, 2009). Studies have indicated that the number of affected people increases as the intensity and duration of vibration exposure increases. This implies that health effects of vibration may be related to the total amount of vibration energy entering the body or the hands. Thus the appearance of symptoms is dependent on the intensity of exposure (Hughes and Ferrett, 2008). The final factor is the latent period which is the time from first exposure to vibration to the appearance of symptoms. This period is dependent on the intensity of exposure. Thus, the higher the intensity, the shorter the latent period. The table below illustrates the latent period vibration induced diseases in various occupations. Occupation Stage of vibration white finger Latency (years) Foundry worker Tingling Numbness Blanching 1.8 2.2 2.0 Shipyard worker Tingling Numbness Blanching 9.1 12.0 16.8 Chain saw operator Numbness 4.0 Grinder Blanching 13.7 Based on the energy damage model, hazards are damaging energies. Thus in the case of construction equipment and tools which vibrate during operation have vibration energy which the operator comes in contact with it during the operation of the machine. Damage or injury from vibration equipments arises when the vibrating machinery which is a source of energy comes into contact with a recipient and at the point of contact the vibration energy exceeds the damage threshold of the recipient (Edwards and Holt, 2007). Thus vibrating machinery are potential damaging energy in form of mechanical vibration energy (Edwards and Holt, 2008). When this energy exceeds 85 decibels and the ear of the recipient is exposed to it for prolonged period of time, the energy cause vibrations in the ear causing hearing loss (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). In addition, the high acoustic energy triggers the formation of molecules inside the ear which damage hair cells and result in noise induced hearing loss (Paschold and Sergeev, 2009). Thus, people working in construction sites are exposed to acoustic energy produced by equipments and tools. When this energy exceeds threshold value and the recipient is exposed for prolonged period to such vibrations then vibration induced syndrome results. Identification of exposure to noise hazard Noise hazard exists in various equipments and tools used in construction industry. Some of the tools and equipment which presents noise hazard include back hoe, bulldozer, chop saw, grader/scraper, front end loader, jackhammer, nail gun, router and wielding equipment. Several factors influence the level of noise to which construction worker may be exposed to. One of the factors is the type of equipment being operated (Edwards and Holt, 2008). Another factor is the condition/maintenance of the equipment. Furthermore, when various equipment is running at the same time the worker is exposed to high levels of noise. Working in enclosed or partially enclosed spaces also increases the exposure of a worker to high levels of noise (Hughes and Ferrett, 2008). Prolonged exposure to high levels of noise can result in noise induced hearing loss. Hearing loss may result from exposure to noise levels above 85 decibels (Paschold and Sergeev, 2009). Exposure to excessive noise levels first result in the first stage of temporary hearing loss. Prolonged exposure to the excessive noise often results in permanent hearing (Edwards and Holt, 2008). Construction work can result in sporadic high noise levels. Hearing is usually damaged cumulatively and exposure limits of noise are based on 8 hour averages. Noise produced during construction exposes both workers using the machine and those not using or operating the equipment to excessive noise (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). According to energy damage model, hazards are damaging energies. Damage or injury is thought to arise when a source of energy comes into contact with a recipient and at the point of contact the energy exceeds the damage threshold of the recipient (Edwards and Holt, 2007). This model classifies hazards as potential damaging energies such as kinetic, electrical, gravitational, chemical, acoustical and mechanical vibrations among others. In the case of noise hazard, equipments and tools used in construction have acoustic energy that produces excessive noise and vibration thus resulting in noise hazard. When the equipments are being operated, they produce excessive acoustic energy which comes into contact with human ear. When this energy exceeds 85 decibels and the ear of the recipient is exposed to it for prolonged period of time, the energy cause vibrations in the ear causing hearing loss (Edwards and Holt, 2008). In addition, the high acoustic energy triggers the formation of molecules inside the ear which damage hair cells and result in noise induced hearing loss (Paschold and Sergeev, 2009). Thus, people working in construction sites are exposed to acoustic energy produced by equipments and tools (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). When this energy exceeds threshold, 85 decibels, and the recipient is exposed for prolonged period of time hearing loss results. Risk assessment of vibration hazard Risk assessment is a practical, systematic approach that is used to identify hazards and evaluate the extent of the risk taking into consideration of existing precautions. Risk is the likelihood that harm will arise accompanied with consequences (Edwards and Holt, 2007). Risk assessment for vibration should entail identification of where there may be a risk from hand arm or whole body vibration; estimation of the workers’ exposures and comparing them with the exposure action value and exposure limit value; identification of risk controls available; identification of the steps to be used to control and monitor hand arm and whole body vibration risks and recording the assessment, the steps that have been taken and their effectiveness (Paschold and Sergeev, 2009). Vibration risks assessment need to be taken into consideration by the project supervisor from the onset of the project preparation stage when planning for various stages of work (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). Coordinators involved with safety and health need to draw up a safety and health plan relation to activities on the site including specific measures aimed at preventing the risks associated with vibration (Hughes and Ferrett, 2008). The coordinators also need to ensure that during working procedures are implemented in the right way and ensure that prevention and safety principles are followed (Edwards and Holt, 2008). By taking such risk assessment prior to onset of the project, potential risks are identified in advance and measures are put in place to reduce the likelihood of vibration hazard taking place. As opposed to risk control, risk assessment, is advantageous because workers are unlikely to be exposed to vibration hazard exceeding the recommended amount once the project is commissioned. Risk control may take place once some workers are already experiencing the effects of the hazard and may be costly to the construction firm (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). Risk assessment allows firms to identify the potential risk of various machineries to be used in the work and ensure that tools and equipments which are within standard values are acquired. In addition, for machines which have higher whole body vibration values the project managers can design the work in such away that workers exposure to vibration does not exceed the daily recommended values. Risk assessment allows the project manager to consider the chance of vibration hazard befalling anyone and the possibility of the affected workers suffering from vibration syndrome (Paschold and Sergeev, 2009). It also enables the construction project manager to plan, introduce and monitor preventive measure to ensure that vibration risk is adequately controlled at all time (Edwards and Holt, 2007). It should be noted that without effective risk assessment, there can seldom be effective control. It also enables the construction project manager to meet responsibilities for the identification and controlling significant hazards as defined in the Health and Safety in Employment Act (Hughes and Ferrett, 2008). Both quantitative and qualitative representation of likelihood will be used to asses the risk of vibration occurring. Risk is defined as: Risk=likelihood X consequence Quantitative analysis will allow the construction manger to use statistical data to derive numerical description of vibration risk. It is chosen because it is more precise (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). However, it is difficult to perform (Paschold and Sergeev, 2009). Quantitative analysis will enable the construction manager to express likelihood in either frequency or probability. Qualitative analysis on the other hand will enable the project manager to use defined terms to describe and categorize risk (Edwards and Holt, 2008). Terms that may be used in this case include certain, likely, possible, unlikely, rare or extremely rare (Hughes and Ferrett, 2008). It is chosen because it is easier to perform even though it is less precise. The consequences will be evaluated in terms of direct losses, indirect loses, tangible losses and intangible loses. Risk assessment of noise hazard Assessing the risk of noise hazard is essential in construction industry to enable the project manager to consider the chance of noise hazard befalling anyone and the possibility of the affected workers suffering from noise induced hearing loss (Edwards and Holt, 2008). It also enables the construction project manager to plan, introduce and monitor preventive measure to ensure that noise risk is adequately controlled at all time (Edwards and Holt, 2007). Without proper assessment of noise hazard in construction it is not possible to effectively control it. It also enables the construction project manager to meet responsibilities for the identification and controlling significant hazards as defined in the Health and Safety in Employment Act (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). The assessment of noise hazard will also use quantitative and qualitative analysis in order to precisely and easily capture the likelihood of the hazard. Consequences will also be evaluated in terms of direct losses, indirect loses, tangible losses and intangible loses. Control of vibration The designers have the responsibility of ensuring that the machines are well equipped with suspension seats to reduce vibration to minimum. They ought to ensure that the seats are easily accessible and adjustable. The designer also can help in reducing hand arm vibrations by decoupling handles as far as possible from the source of vibration (Edwards and Holt, 2007). The designer can also reduce vibration hazards by equipping machines such as angle grinders with auto-balancer which can help in compensating for unbalanced masses (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). Designers can also help in reduction of vibration effects by reducing grip and feed forces and selection of suitable tool attachments. The construction managers have the responsibility of replacing current work procedure with alternative that results in a lowered generation of vibration (Edwards and Holt, 2008). They also have the responsibility of acquiring models of machinery with appropriate performance when new machines are bought with preference for machines which emit lower vibrations (Paschold and Sergeev, 2009). The managers and coordinators also have the responsibility of checking that the working procedures are being implemented in the right way. The managers can also reduce the risk of vibration by acquiring jigsaws which employ mass balancing as they generate low vibrations (Hughes and Ferrett, 2008). The managers can also reduce vibrations by ensuring that each employee handling such machines has anti vibration gloves. Hierarchy of controls includes prevention, engineering and policy/procedural (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). Prevention controls include elimination of substance, material, plant or equipment. It also entails replacing with less hazardous substance, material, plant or equipment and exclusion of non essential personnel. In the case of vibration hazard some equipments whose magnitude of vibration is far beyond the recommended level may be eliminate and be replaced with less hazardous equipment (Edwards and Holt, 2008). By acquiring machinery such as compressors which are remotely controlled construction managers are able to exclude non essential personnel (Hughes and Ferrett, 2008). Engineering controls can be attained through enclosing processes, automating all or part of the process, using local exhaust ventilation, fit guarding, implementing inspection and testing regime and implementation of preventative maintenance (Edwards and Holt, 2007). Some machines such as hand arm vibrators can be fit guarded with springs to reduce vibration transmission to personnel. Policy/procedural controls include reduction of exposure, writing safe system of work, regulating workplace inspections, emergency arrangements, pre-employment medicals, health surveillance programs and use of personal protective equipment (PPE) (Paschold and Sergeev, 2009). In the case of Vibration for instance, machine which have vibration levels exceeding the recommended levels may require reduction of exposure by for instance putting in place job rotation. Replacing machinery with less hazardous machinery may fail either because of lack of funds or the machine may be replaced but fails to attain the required levels. Fit guarding some machinery with springs may fail when the maintenance is not carried out on regular basis (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). Job rotation to reduce exposure levels may fail where not enough manpower is available to allow rotation to take place. Preventive controls are the most appropriate way of reducing vibration related disorders. This is because by eliminating equipment which is more hazardous and replacing them with those which are less hazardous and excluding non essential manpower, it is possible to reduce vibration related hazards. Control of noise hazard The construction managers have the responsibility of ensuring that the machines are well maintained. They also have the responsibility of ensuring those workers and any visitors to the construction site puts on hearing protection devices to reduce exposure to noise (Edwards and Holt, 2008). The managers also have the responsibility of acquiring and using the commonly accepted engineering and administrative controls. The designers on the other hand have the responsibility of designing quieter equipments (Hong-Bin, Ying-Ze and Guo-Zhen, 2008). Prevention controls for noise include substituting existing equipment with quieter equipment. Engineering controls include retro-fitting existing equipment with damping materials, mufflers, or enclosure. Policy/procedural controls include reduction of exposure through job rotation (Edwards and Holt, 2007). Replacing machinery with less hazardous machinery may fail either because of lack of funds or the machine may be replaced but are not well maintained (Hughes and Ferrett, 2008). Fit guarding some machinery may fail when the maintenance is not carried out on regular basis (Paschold and Sergeev, 2009). Job rotation to reduce exposure levels may fail where not enough manpower is available to allow rotation to take place (Ericson, 2005). Combinations of the three hierarchies of control are essential for ensuring that noise hazard is greatly reduced. References Edwards, D., and Holt, G. 2007. Perceptions of workplace vibration hazards among a small sample of UK construction professionals. Engineering, Construction and Architectural Management, vol. 14, no. 3, pp. 261 – 276 Edwards, D., and Holt, G. 2008. Construction workers' health and safety knowledge: Initial observations on some test-result data. Journal of Engineering, Design and Technology, vol. 6, no. 1, pp. 65 – 80 Hong-Bin, C., Ying-Ze, Y., and Guo-Zhen, L. 2008. Control Effect on Occupational Hazards in Construction Project of the Alumina Plant. Chinese Journal of Public Health Engineering, vol. 7, no. 3, pp. 139-142. Paschold, H., and Sergeev, A. 2009. Whole-body vibration knowledge survey of U.S. occupational safety and health professionals. Journal of Safety Research, vol. 40, no. 3, pp. 171-176 Hughes, P., and Ferrett, E. 2008. Introduction to Health and Safety in Construction: The Handbook for Construction Professionals and Students on NEBOSH and Other Construction Courses, 3rd Ed. London: Routledge Ericson, C. 2005. Hazard analysis techniques for system safety. New York: John Wiley and Sons. Read More