ThisThis Heal Healthth Ha Hazzardard E Evvaluaaluationtion ( H(HHHEE) )report report and and any any r ereccoommmmendendaatitonsions m madeade herein herein are are f orfor t hethe s sppeeccifiicfic f afacciliilityty e evvaluaaluatedted and and may may not not b bee un univeriverssaalllyly appappliliccabable.le. A Anyny re reccoommmmendaendatitoionnss m madeade are are n noot tt oto be be c consonsideredidered as as f ifnalinal s statatetemmeenntsts of of N NIOIOSSHH po polilcicyy or or of of any any agen agenccyy or or i ndindivivididuualal i nvoinvolvlved.ed. 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AdditionalAdditional HHEHHE reporreporttss areare avaavaililabablele atat hhtttpp::///wwwwww..ccddcc..govgov//nnioiosshh//hhehhe//reporreporttss This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved. Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports HETA 94-0425-2513 NIOSH INVESTIGATORS: July 1995 Pete Fatone, M.S. Gulfstream Aerospace Corporation Randy L. Tubbs, Ph.D. Savannah, Georgia Leslie MacDonald, M.M.S. I. SUMMARY In February 1995, the National Institute for Occupational Safety and Health (NIOSH) conducted a health hazard evaluation at Gulfstream Aerospace Corporation at the request of management. The safety staff of this company were interested in evaluating their pneumatic hand-held power tools for hand-arm vibration (HAV). The NIOSH investigators collected vibration measurements on 30 tools that are used by workers throughout the plant. In most instances, the tools were tested when a worker was using the tools assigned to them on work pieces that were in the production phase. The vibration of 19 tools exceeded all exposure time zones recommended by the American National Standards Institute (ANSI) and the American Conference of Governmental Industrial Hygienists (ACGIH). The vibration levels of the remaining 11 tools fell into one of the suggested time zones, ranging from one-half hour to eight hours of daily exposure. A spectral analysis of the acceleration data showed that nine out of ten tools marketed as either "ergonomic" or "vibration-reduced" possessed lower vibration levels than their conventional counterparts. This was found to be the case for drills, rivet guns, routers, bucking bars, and sanders. The results of this investigation indicate that a potential health hazard exists for employees at Gulfstream Aerospace Corporation from using hand-held pneumatic power tools that produce excessive hand-arm vibration. Continued use of these tools without any intervention by management may lead to employees experiencing tingling and numbness in their fingers as a precursor to hand-arm vibration syndrome. The data show that usage should be restricted for nearly all of the tools tested, as only three tools fell into the 4-8 hour exposure time zone. Recommendations for addressing this potential hazard are provided in Section VIII of this report. KEYWORDS: SIC 3721 (Aircraft), hand-arm vibration, HAV, acceleration, hand-arm vibration syndrome, pneumatic tools, ergonomics. Page 2 - Health Hazard Evaluation Report No. 94-0425 II. INTRODUCTION On September 23, 1994, the National Institute for Occupational Safety and Health (NIOSH) received a management request for a health hazard evaluation from Gulfstream Aerospace Corporation located in Savannah, Georgia. In March 1994, Gulfstream Aerospace Corporation started an ergonomic program, incorporating a medical management program and a system to identify, evaluate, and abate workplace hazards with engineering controls. Gulfstream Aerospace Corporation's next initiative was to develop a rating system for pneumatic hand- held power tools based on several criteria such as: performance, cost, maintenance, durability, and ergonomic factors. These latter factors include tool weight, grip comfort, noise, and vibration. Gulfstream Aerospace Corporation was able to evaluate all the ergonomic issues using in-house expertise with the exception of vibration. Because vibration analysis requires specialized equipment, methodology, and expertise, Gulfstream Aerospace Corporation requested the assistance of NIOSH through the Health Hazard Evaluation Program. The NIOSH scientists visited Gulfstream Aerospace Corporation on February 21 - 24, 1995. During this visit, the team provided hand-arm vibration (HAV) training for about fifteen Gulfstream Aerospace Corporation employees. Managers, supervisors, engineers, buyers, nurses, technicians, and industrial hygienists attended the HAV training. The NIOSH team devoted the remainder of the visit to collecting data on several pneumatic hand-held power tools. The main objective of the data collection was to compare the vibration acceleration levels of various tools used under identical working conditions. III. BACKGROUND Gulfstream Aerospace Corporation is a non-union aerospace company that designs and manufactures private jet airplanes which are sold to both domestic and foreign customers. Gulfstream Aerospace Corporation employs nearly 4000 workers of which nearly 1000 are assigned to manufacturing and assembly operations. Almost all of the workers use pneumatic hand-held power tools at some point during a typical work day. There are an estimated 10,000 air-driven tools located throughout the plant, including bucking bars, buffers, drills, palm sanders, rivet guns, routers, sanders, and screw guns. Gulfstream Aerospace Corporation purchases these tools from several different manufacturers. A goal of the safety staff at Gulfstream Aerospace Corporation is that their buyers purchase tools designed in accordance with ergonomic principles. The tools tested in this investigation include tools from the following manufacturers: Aro, Chicago Pneumatic, Deutsch, Dotco, Ingersoll-Rand, Sioux, and U.S. Tools. Page 3 - Health Hazard Evaluation Report No. 94-0425 IV. EVALUATION CRITERIA A. Hand-Arm Vibration (HAV) In general, vibration is the study of mechanical oscillations of a dynamic system. Frequency, displacement, velocity, and acceleration are four parameters that characterize vibration. Usually, frequency and acceleration are the two quantities that draw the most concern. The vibration data in this report is graphed as acceleration versus frequency in a log-log plot. The motion of a vibrating system is periodic. This means the motion is repetitive, creating a definite cycle or period. Frequency is the inverse of the period (1/T, where T is the period) and has units of Hertz (Hz) or cycles per second. Acceleration levels have the International System of Units (SI) of m/s2 or units of gravity (g's) and are vector quantities that characterize the amplitude and direction of vibration. Vibration is an ergonomic stressor seen in a number of industries. For example, forestry, electronics, automobile, aerospace, shipbuilding, mining, transportation, road construction, trucking, and even dentistry all are industries that involve vibrating hand-held tools and/or vehicles. Occupational vibration exposure is classified as either whole-body vibration (WBV) or HAV, the latter sometimes referred to as segmental vibration. Occupational WBV usually involves industrial vehicles, public transportation, or vibrating platforms. The vibration enters through the worker’s feet and/or seat. In comparison, HAV is produced by power tools that are either electric, pneumatic, or hydraulic. Drills, impact hammers, polishers, buffers, rivet guns, sanders, grinders, routers, and nut runners are all examples of common power tools found in industry that expose workers to HAV. B. Hand-Arm Vibration Syndrome The health effects from over-exposure to HAV is hand-arm vibration syndrome (HAVS). Basically, HAVS involves circulatory, neurological, and musculoskeletal disturbances. Victims experience vasospasms which reduce the blood flow in the fingertips and cause the fingers to turn white or blanch. These attacks are triggered by cold temperatures. Sufferers may also experience numbness, tingling, and sensitivity threshold shifts after years of HAV exposure. These disturbances are caused by damage to the sensory nerves in the hand and arm and are more permanent than circulatory disturbances.1 Finally, some musculoskeletal problems can be attributed to HAV. Fatigue is the most prevalent issue and is probably Page 4 - Health Hazard Evaluation Report No. 94-0425 linked to the neurological sensitivity threshold shift which may cause workers to unintentionally and unnecessarily over-grip the tool. Scientists and physicians are continuously improving screening and monitoring techniques