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Prevention of noise-induced impairment of hearing: a team effort
of a variety of tasks. However, it would appear that this form of display demands more of the operator's attention than other forms of indication. Finally it is pointed out that a number of additional problems relating to numerical displays are in need of investigation.
1.3.53(54004)
Smith, F., Lott, D., and Cronnel, B. The effect of type size and case alteration on word identification.
American Journal o f Psychology, 1969, 82. 2, 2 4 8 - 2 5 3 216 subjects searched for words in passages of text, some of which were printed in normal upper or lower case, others with alternate letters in upper and lower case or with alternate letters varying in size. The numbers of words identified in a given time for the varying conditions support the experimental hypothesis that the relative size of alternate letters, rather than the alternation of case, accounts for differences between conditions. The results were taken as supporting the view that alternative sets of features for the same letter sequence are treated as functionally equivalent and that readers identify words by (1) discriminating these feature sets and (2) integrating them for identification of the word as a whole.
Auditory processes 1.3.54(53022)
Griffiths I. D. and Langdon, F. J. Subjective response to road traffic noise
Journal o f Sound and Vibration, 1968, 8. 1, 1 6 - 3 2 A study consisting of acoustic measurements at fourteen sites in the London area and 1 200 interviews dealing with the effects of noise conditions prevailing at each of these sites has been carried out with the object of developing acceptability criteria for traffic noise from roads in residential areas. Dissatisfaction with the noise conditions, as expressed by residents at each of these sites, was related to sound levels in such a way that it was possible to predict the median level of dissatisfaction at each site by the use of a measure taking into account the mean sound levels exceeded for 90 and 10% of the sampling periods throughout a whole day, which it is proposed to call the Traffic Noise Index (T.N.I.) Predictions made on the basis of either 10 or 90% levels alone were considerably less accurate than those
178
AppliedErgonomics June 1970
made on the basis of the combined measure. Individual dissatisfaction scores correlated poorly with physical measures. This finding is believed to be the result of wide individual differences in susceptibility to and experience of noise, as well as in patterns of living likely to be disturbed by noise. Attempts to allow for these factors were unsuccessful. Disturbance of various activities was shown to be related to noise levels and the increasing extent of this effect with worsening of noise conditions was used to validate the scale of dissatisfaction.
1.3.55(53023) Griffiths, I. D. A note on the traffic noise index and the equivalent sound level
Journal of Sound and Vibration, 1968, 8. 2, 2 9 8 - 3 0 0 Recent Continental work has suggested the use of a complex method, the "equivalent sound level", in the physical assessment of noise-nuisance. Work at the Building Research Station on traffic noise has led to the development of a simpler index closely related to residents expressed dissatisfaction with their traffic noise conditions. The paper compares the two methods as predictors of dissatisfaction.
1.3.56(53024)
Sutton, P. Design of a noise specification for process plant
Journal o f Sound and Vibration, 1968, 8. 1, 3 3 - 4 3 This paper reviews noise in relation to the design of petroleum and chemical process plant. The selection of design noise criteria is considered with particular reference to community noise. The problems in drafting and applying a practical plant noise specification are discussed, and areas where further research is needed are identified. The subject is dealt with from the viewpoint of the practical design engineer.
1.3.57(53027)
McCann, P. H. The effects of ambient noise on vigilance performance
Human Factors, 1969, 11. 3, 251-256 The effects of continuous noise versus intermittent noise on subjects performing an audiovisual checking task were examined. Although there
was no difference between the effects of the two kinds of noise o n total errors, intermittent noise produced a larger number of omission errors than did continuous noise. There were no differences in overall vigilance performance between male and female observers. There was a decrement in performance with time-at-work typically found in other vigilance studies. 1.3.58(53030)
Cohen, A. Noise effects on health, productivity, and well-being
Transactions of the New York Academy of Sciences, 1968, 30. 7, 910-918 High noise levels injure the receptor cells of the organs of corti. Noiseinduced hearing loss is a major health problem in industry. Hearing safeguards are handicapped by disagreement on criteria for safe levels. Noise may also impair other systems which are susceptible to stress, such as speech reception, performance on vigilance tasks, and visual and tactile perception. Effects of noise on well-being, apart from disruption of sleep, depend on psychological factors in response to noise. Noise annoyance varies directly with intensity, pitch, randomness in time, and movement of noise source. Attempts are being made to construct an annoyance index for sounds. (52 ref.) 1.3.59(54120) Weston, H. R. Prevention of noise-induced impairment of hearing: a team effort
Ergonomics Society o f A ustralia & New Zealand. Sixth Annual Conference, Aug. 1969 The author points out the importance of sincere leadership from the highest levels of management, continual supervision and a combined effort by many sections if a hearing conservation scheme is to be successful. A realistic approach to this complicated problem is suggested. Prevention in the buying stage is stated as a most important factor in reducing occupational deafness. A noise specification for buying and design is suggested. Reference is made to reduction of noise, the need for close consultation between the acoustic specialist and plant personnel, practical difficulties which are overlooked by well meaning enthusiasts and some reasons for failure when attempting reduction by enclosure. An illustration is given of
an enclosure which achieved a useful reduction without interfering with the operation of the machine. It is suggested that enclosures can be used more extensively in industry with a combination of technical advice and operation know how; but they may be complicated and often futile. Hearing protection is discussed as a 'last resort' but nevertheless a most essential part of hearing conservation. Some of the reasons are given why managements fail to gain employee co-operation and acceptance of ear protection. The need for motivation of all concerned is pointed out and there are some suggestions in this respect.
Body mechanics, anthropometry, physiology and motor performance
1.3.60(54126)
53-60
Silbert, E. Aircraft noise and development c o n t r o l - t h e policy for Gatwick airport
Town Planning Institution Journal, 1969, 5 5 . 4 , 149-152; abstr. in Building Science Abstracts. Describes a planning policy for the Gatwick area specifically in relation to aircraft noise, based on official estimates of future aircraft noise, and on answers to a subjective noise rating questionnaire. The area has been divided for development purposes into three noise zones, and it is proposed that separate communities serving the airport should be sited a short distance from it, leaving the airport itself surrounded by open countryside. 1.3.61(54137)
Flugrath, J. M. Modern Day Rock-and-Roll Music and Damage-Risk Criteria
Journal o f A coustical Society of America, 1969, 45. 3, 704-711 Ten rock-and-roll dance bands were recorded in one dance hall catering to teenagers. 100 level measurements for each linear, A-weighted, C-weighted, and octave bands 500, 1000, 2000 and 4000 Hz were computed for analysis of variance, average level, and standard deviation for the ½-h recording of each dance band. The spectrum of rock-and-roll music was found to peak at 2000 Hz, and C-weighted minus A-weighted (C - A) values were found to be approximately 1. The standard deviations of sound-level measurements and octave-band measurements were found to be quite small, indicating that amplified rock-and-roll music can be considered as a form of 'steadystate' sound if many measurements over time are averaged. It was found that the average levels of several of the
dance bands exceeded both 'equalenergy' and 'average-level' damagerisk criteria.
but neither of these effects was differential for the two t r e a t m e n t groups. 1.3.64(54233)
1.3.62(53109)
Srivastava, S. S. et al. Load carriage by infantry soldier: criteria for assessment of physiological and psychological fatigue Defence Science Journal, 1968, 18. 2,
Attempts were made to evolve criteria for assessing the physiological and psychological fatigue at the end of a given task in field studies pertaining to load carriage. Fifteen tests, physiological and performance in nature, including assessment of blood pressure, respiration rate, pulse rate, erythrocyte sedimentation rate, eosinophil count, Harvard Step Test, energy expenditure during work, motor reaction, Cancellation Test, target hitting, and weight discrimination were administered to eight t w e n t y - t h i r t y year old subjects. Results revealed a consistently progressive fall in eosinophil count with increasing levels of fatigue. The pulse recovery index which was a measure of the rate of pulse recovery after exercise, was lower with higher levels of fatigue. All the other tests in their present form were found unsuitable as fatigue tests.
1.3.63(53276)
Johnson, E., Smith, S, and Myers, T. I. Vigilance throughout seven days of sensory deprivation
Psychonomic Science 1968, 11.8, 293-294 Sixty volunteer Naval enlisted men participated in a study of 7-day individual isolation. F o r t y subjects lived in small, dark, quiet rooms with little to do (sensory deprivation; SD) The other twenty served in a live-inthe-lab control group with ad lib access to lights, recreational materials, and intercom conversation with another control if mutually desired. SD subjects were significantly superior to controls in signal detection performance on an auditory vigilance task administered after 25, 73 and 145 hours of treatment. Both within- and between-sessions performance decrements over time were observed,
Simpson, R. E. and Bolton, C. B. An anthropometric survey of 200 RAF and RN aircrew and the application of the data to garment size rolls
Royal Aircraft Establish me nt Technical Report 67125, Jul. 1968 An anthropometric survey of limited scope was undertaken in October and November 1966, involving 200 Royal Air Force and Royal Navy aircrew. The forty four measurements taken on each subject were mainly those used in the drafting of patterns for the RAE experimental range of aircrew functional garments. The acquired data have been tabulated and presented primarily for functional clothing size purposes. Tables and graphs are also included which give the data in a form suitable for use in aircrew work-space studies etc. Comparisons are made between specimen garment size-rolls for the 200 subjects based on chest girth/torso hoop, chest girth/stature and weight/ stature as control parameters. An analysis of the data supports the recommendation that size-rolls for one-piece garments in which a good torso fit is essential should be based on two direct body measurements, such as chest girth and torso hoop, rather than include one or more indirect measurements like weight or stature in the control parameters. The data indicate that if one-piece garment torso fit is not important it is better logistically to use chest/ stature or weight/stature as controls for garment sizing. Suggestions are made regarding measuring techniques and procedures which should prove useful in a larger scale survey which is recommended. 1.3.65(54238)
Frankenhaeuser, M., Post, B., Nordheden, B., and Sjoeberg, H. Physiological and subjective reactions to different physical work loads
Perceptual and Motor Skills, 1969, 28.2, 343-349 Catecholamine excretion, cardiovascular functions, and subjective effort were studied in 10 healthy male subjects in a control condition and in three experimental sessions in each of which 5 successive 6-min. tests of either 150,450, or 750 kpm/min., were performed on a bicycle ergometer. Catecholamineexcretion rates remained close to control levels at the lower work loads,
Applied Ergonomics June 1970
179
1.3.53(54004)
Smith, F., Lott, D., and Cronnel, B. The effect of type size and case alteration on word identification.
American Journal o f Psychology, 1969, 82. 2, 2 4 8 - 2 5 3 216 subjects searched for words in passages of text, some of which were printed in normal upper or lower case, others with alternate letters in upper and lower case or with alternate letters varying in size. The numbers of words identified in a given time for the varying conditions support the experimental hypothesis that the relative size of alternate letters, rather than the alternation of case, accounts for differences between conditions. The results were taken as supporting the view that alternative sets of features for the same letter sequence are treated as functionally equivalent and that readers identify words by (1) discriminating these feature sets and (2) integrating them for identification of the word as a whole.
Auditory processes 1.3.54(53022)
Griffiths I. D. and Langdon, F. J. Subjective response to road traffic noise
Journal o f Sound and Vibration, 1968, 8. 1, 1 6 - 3 2 A study consisting of acoustic measurements at fourteen sites in the London area and 1 200 interviews dealing with the effects of noise conditions prevailing at each of these sites has been carried out with the object of developing acceptability criteria for traffic noise from roads in residential areas. Dissatisfaction with the noise conditions, as expressed by residents at each of these sites, was related to sound levels in such a way that it was possible to predict the median level of dissatisfaction at each site by the use of a measure taking into account the mean sound levels exceeded for 90 and 10% of the sampling periods throughout a whole day, which it is proposed to call the Traffic Noise Index (T.N.I.) Predictions made on the basis of either 10 or 90% levels alone were considerably less accurate than those
178
AppliedErgonomics June 1970
made on the basis of the combined measure. Individual dissatisfaction scores correlated poorly with physical measures. This finding is believed to be the result of wide individual differences in susceptibility to and experience of noise, as well as in patterns of living likely to be disturbed by noise. Attempts to allow for these factors were unsuccessful. Disturbance of various activities was shown to be related to noise levels and the increasing extent of this effect with worsening of noise conditions was used to validate the scale of dissatisfaction.
1.3.55(53023) Griffiths, I. D. A note on the traffic noise index and the equivalent sound level
Journal of Sound and Vibration, 1968, 8. 2, 2 9 8 - 3 0 0 Recent Continental work has suggested the use of a complex method, the "equivalent sound level", in the physical assessment of noise-nuisance. Work at the Building Research Station on traffic noise has led to the development of a simpler index closely related to residents expressed dissatisfaction with their traffic noise conditions. The paper compares the two methods as predictors of dissatisfaction.
1.3.56(53024)
Sutton, P. Design of a noise specification for process plant
Journal o f Sound and Vibration, 1968, 8. 1, 3 3 - 4 3 This paper reviews noise in relation to the design of petroleum and chemical process plant. The selection of design noise criteria is considered with particular reference to community noise. The problems in drafting and applying a practical plant noise specification are discussed, and areas where further research is needed are identified. The subject is dealt with from the viewpoint of the practical design engineer.
1.3.57(53027)
McCann, P. H. The effects of ambient noise on vigilance performance
Human Factors, 1969, 11. 3, 251-256 The effects of continuous noise versus intermittent noise on subjects performing an audiovisual checking task were examined. Although there
was no difference between the effects of the two kinds of noise o n total errors, intermittent noise produced a larger number of omission errors than did continuous noise. There were no differences in overall vigilance performance between male and female observers. There was a decrement in performance with time-at-work typically found in other vigilance studies. 1.3.58(53030)
Cohen, A. Noise effects on health, productivity, and well-being
Transactions of the New York Academy of Sciences, 1968, 30. 7, 910-918 High noise levels injure the receptor cells of the organs of corti. Noiseinduced hearing loss is a major health problem in industry. Hearing safeguards are handicapped by disagreement on criteria for safe levels. Noise may also impair other systems which are susceptible to stress, such as speech reception, performance on vigilance tasks, and visual and tactile perception. Effects of noise on well-being, apart from disruption of sleep, depend on psychological factors in response to noise. Noise annoyance varies directly with intensity, pitch, randomness in time, and movement of noise source. Attempts are being made to construct an annoyance index for sounds. (52 ref.) 1.3.59(54120) Weston, H. R. Prevention of noise-induced impairment of hearing: a team effort
Ergonomics Society o f A ustralia & New Zealand. Sixth Annual Conference, Aug. 1969 The author points out the importance of sincere leadership from the highest levels of management, continual supervision and a combined effort by many sections if a hearing conservation scheme is to be successful. A realistic approach to this complicated problem is suggested. Prevention in the buying stage is stated as a most important factor in reducing occupational deafness. A noise specification for buying and design is suggested. Reference is made to reduction of noise, the need for close consultation between the acoustic specialist and plant personnel, practical difficulties which are overlooked by well meaning enthusiasts and some reasons for failure when attempting reduction by enclosure. An illustration is given of
an enclosure which achieved a useful reduction without interfering with the operation of the machine. It is suggested that enclosures can be used more extensively in industry with a combination of technical advice and operation know how; but they may be complicated and often futile. Hearing protection is discussed as a 'last resort' but nevertheless a most essential part of hearing conservation. Some of the reasons are given why managements fail to gain employee co-operation and acceptance of ear protection. The need for motivation of all concerned is pointed out and there are some suggestions in this respect.
Body mechanics, anthropometry, physiology and motor performance
1.3.60(54126)
53-60
Silbert, E. Aircraft noise and development c o n t r o l - t h e policy for Gatwick airport
Town Planning Institution Journal, 1969, 5 5 . 4 , 149-152; abstr. in Building Science Abstracts. Describes a planning policy for the Gatwick area specifically in relation to aircraft noise, based on official estimates of future aircraft noise, and on answers to a subjective noise rating questionnaire. The area has been divided for development purposes into three noise zones, and it is proposed that separate communities serving the airport should be sited a short distance from it, leaving the airport itself surrounded by open countryside. 1.3.61(54137)
Flugrath, J. M. Modern Day Rock-and-Roll Music and Damage-Risk Criteria
Journal o f A coustical Society of America, 1969, 45. 3, 704-711 Ten rock-and-roll dance bands were recorded in one dance hall catering to teenagers. 100 level measurements for each linear, A-weighted, C-weighted, and octave bands 500, 1000, 2000 and 4000 Hz were computed for analysis of variance, average level, and standard deviation for the ½-h recording of each dance band. The spectrum of rock-and-roll music was found to peak at 2000 Hz, and C-weighted minus A-weighted (C - A) values were found to be approximately 1. The standard deviations of sound-level measurements and octave-band measurements were found to be quite small, indicating that amplified rock-and-roll music can be considered as a form of 'steadystate' sound if many measurements over time are averaged. It was found that the average levels of several of the
dance bands exceeded both 'equalenergy' and 'average-level' damagerisk criteria.
but neither of these effects was differential for the two t r e a t m e n t groups. 1.3.64(54233)
1.3.62(53109)
Srivastava, S. S. et al. Load carriage by infantry soldier: criteria for assessment of physiological and psychological fatigue Defence Science Journal, 1968, 18. 2,
Attempts were made to evolve criteria for assessing the physiological and psychological fatigue at the end of a given task in field studies pertaining to load carriage. Fifteen tests, physiological and performance in nature, including assessment of blood pressure, respiration rate, pulse rate, erythrocyte sedimentation rate, eosinophil count, Harvard Step Test, energy expenditure during work, motor reaction, Cancellation Test, target hitting, and weight discrimination were administered to eight t w e n t y - t h i r t y year old subjects. Results revealed a consistently progressive fall in eosinophil count with increasing levels of fatigue. The pulse recovery index which was a measure of the rate of pulse recovery after exercise, was lower with higher levels of fatigue. All the other tests in their present form were found unsuitable as fatigue tests.
1.3.63(53276)
Johnson, E., Smith, S, and Myers, T. I. Vigilance throughout seven days of sensory deprivation
Psychonomic Science 1968, 11.8, 293-294 Sixty volunteer Naval enlisted men participated in a study of 7-day individual isolation. F o r t y subjects lived in small, dark, quiet rooms with little to do (sensory deprivation; SD) The other twenty served in a live-inthe-lab control group with ad lib access to lights, recreational materials, and intercom conversation with another control if mutually desired. SD subjects were significantly superior to controls in signal detection performance on an auditory vigilance task administered after 25, 73 and 145 hours of treatment. Both within- and between-sessions performance decrements over time were observed,
Simpson, R. E. and Bolton, C. B. An anthropometric survey of 200 RAF and RN aircrew and the application of the data to garment size rolls
Royal Aircraft Establish me nt Technical Report 67125, Jul. 1968 An anthropometric survey of limited scope was undertaken in October and November 1966, involving 200 Royal Air Force and Royal Navy aircrew. The forty four measurements taken on each subject were mainly those used in the drafting of patterns for the RAE experimental range of aircrew functional garments. The acquired data have been tabulated and presented primarily for functional clothing size purposes. Tables and graphs are also included which give the data in a form suitable for use in aircrew work-space studies etc. Comparisons are made between specimen garment size-rolls for the 200 subjects based on chest girth/torso hoop, chest girth/stature and weight/ stature as control parameters. An analysis of the data supports the recommendation that size-rolls for one-piece garments in which a good torso fit is essential should be based on two direct body measurements, such as chest girth and torso hoop, rather than include one or more indirect measurements like weight or stature in the control parameters. The data indicate that if one-piece garment torso fit is not important it is better logistically to use chest/ stature or weight/stature as controls for garment sizing. Suggestions are made regarding measuring techniques and procedures which should prove useful in a larger scale survey which is recommended. 1.3.65(54238)
Frankenhaeuser, M., Post, B., Nordheden, B., and Sjoeberg, H. Physiological and subjective reactions to different physical work loads
Perceptual and Motor Skills, 1969, 28.2, 343-349 Catecholamine excretion, cardiovascular functions, and subjective effort were studied in 10 healthy male subjects in a control condition and in three experimental sessions in each of which 5 successive 6-min. tests of either 150,450, or 750 kpm/min., were performed on a bicycle ergometer. Catecholamineexcretion rates remained close to control levels at the lower work loads,
Applied Ergonomics June 1970
179