Simulated Office Work Research Articles

Development of Air Ventilation Garments with Small Fan Panels to Improve Thermal Comfort

Air ventilation garments (AVGs) are reported to be effective in improving thermal comfort in hot environments in previous research. The purpose of this study was to develop AVGs with small fan panels and examine their cooling performance. Three AVGs equipped with more, much smaller sized ventilation fans were developed, including FFV (ten small fans all located on the front body), BBV (ten small fans all located on the back body), and FBV (six small fans located on the front body and four small fans located on the back body). Another garment, without ventilation fans but with the same structure and textile material, was made as a reference garment (CON). The cooling performance of the four garments was examined through subject trials in a moderately hot environment of 32 °C and 60% relative humidity. Simulated office work with 70 min of sedentary activity was performed. The results showed that the physiological indexes of the mean body skin temperature, the mean torso skin temperature, and the heart rate in the three AVG scenarios were significantly lower than those in the CON condition (p < 0.05). Thermal sensation, thermal comfort, and wetness sensation were also improved when wearing the three AVGs (p < 0.05). No significant difference was displayed among the three AVGs on the whole body and the whole torso (p > 0.05) due to the similarity of the air velocity created by the fan panels. A significant difference was found on the local torso skin, with FFV significantly reducing the chest and the belly skin temperature, and BBV significantly reducing the scapula and the lower back skin temperature (p < 0.05). This study indicates that the AVGs with the small fan panels were effective in reducing heat strain and improving thermal comfort, and thus are recommended for use in hot environments.

Perceived Air Quality and Productivity in the Office Building

Problems of perceived quality of the environment find its reason especially when monitoring performance and productivity of work. Thus, verification of the degree of environmental quality impact on employee performance comes into consideration. The results of two independent studies involving 50 subjects, and using similar procedures and blind exposures have shown that increasing the air quality (by decreasing the pollution load or by increasing the ventilation rate, with otherwise constant indoor climate conditions) can improve the performance of simulated office work (text typing, addition and proof-reading). Performance testing was performed in the open space office of an office building at three air exchange intensities: n1 = 0.5 h−1, n2 = 1.5 h−1 and n3 = 2.5 h−1. Other physical environmental parameters that could have affected the assessors’ performance were maintained in the range: indoor air temperature θai = 22 - 24 °C, relative air humidity φai = 40 - 60%, air velocity vai ≤ 0.25 m.s−1, noise level load L = 40 - 50 dB (A), daylight - diffuse radiation component. The present results document the productivity benefits of providing good indoor air quality and indicate that providing indoor air of a higher ventilation level will increase productivity.

Personal CO2 cloud: laboratory measurements of metabolic CO2 inhalation zone concentration and dispersion in a typical office desk setting.

Inhalation exposure to pure and metabolic elevated carbon dioxide (CO2) concentration has been associated with impaired work performance, lower perceived air quality, and increased health symptoms. In this study, the concentration of metabolic CO2 was continuously measured in the inhalation zone of 41 subjects performing simulated office work. The measurements took place in an environmental chamber with well-controlled mechanical ventilation arranged as an office environment. The results showed the existence of a personal CO2 cloud in the inhalation zone of all test subjects, characterized by the excess of metabolic CO2 beyond the room background levels. For seated occupants, the median CO2 inhalation zone concentration levels were between 200 and 500 ppm above the background, and the third quartile up to 800 ppm above the background. Each study subject had distinct magnitude of the personal CO2 cloud owing to differences in metabolic CO2 generation, posture, nose geometry, and breathing pattern. A small desktop oscillating fan proved to be suitable for dispersing much of the personal CO2 cloud, thus reducing the inhalation zone concentration to background level. The results suggest that background measurements cannot capture the significant personal CO2 cloud effect in human microclimate.

A comparison of trunk biomechanics, musculoskeletal discomfort and productivity during simulated sit-stand office work

Sedentary office work has been shown to cause low back discomfort and potentially cause injury. Prolonged standing work has been shown to cause discomfort. The implementation of a sit–stand paradigm is hypothesised to mitigate discomfort and prevent injury induced by prolonged exposure to each posture in isolation. This study explored the potential of sit–stand to reduce discomfort and prevent injury, without adversely affecting productivity. Twenty-four participants performed simulated office work in three different conditions: sitting, standing and sit–stand. Variables measured included: perceived discomfort, L4–L5 joint loading and typing/mousing productivity. Working in a sit–stand paradigm was found to have the potential to reduce discomfort when compared to working in a sitting or standing only configuration. Sit–stand was found to be associated with reduced lumbar flexion during sitting compared to sitting only. Increasing lumbar flexion during prolonged sitting is a known injury mechanism. Therefore, sit–stand exhibited a potentially beneficial response of reduced lumbar flexion that could have the potential to prevent injury. Sit–stand had no significant effect on productivity.Practitioner Summary: This study has contributed foundational elements to guide usage recommendations for sit–stand workstations. The sit–stand paradigm can reduce discomfort; however, working in a sit–stand ratio of 15:5 min may not be the most effective ratio. More frequent posture switches may be necessary to realise the full benefit of sit–stand.

High indoor CO2 concentrations in an office environment increases the transcutaneous CO2 level and sleepiness during cognitive work

ABSTRACTThe purpose of this study is to perform a multiparametric analysis on the environmental factors, the physiological stress reactions in the body, the measured alertness, and the subjective symptoms during simulated office work. Volunteer male subjects were monitored during three 4-hr work meetings in an office room, both in a ventilated and a non-ventilated environment. The environmental parameters measured included CO2, temperature, and relative humidity. The physiological test battery consisted of measuring autonomic nervous system functions, salivary stress hormones, blood's CO2- content and oxygen saturation, skin temperatures, thermal sensations, vigilance, and sleepiness. The study shows that we can see physiological changes caused by high CO2 concentration. The findings support the view that low or moderate level increases in concentration of CO2 in indoor air might cause elevation in the blood's transcutaneously assessed CO2. The observed findings are higher CO2 concentrations in tissues, changes in heart rate variation, and an increase of peripheral blood circulation during exposure to elevated CO2 concentration. The subjective parameters and symptoms support the physiological findings. This study shows that a high concentration of CO2 in indoor air seem to be one parameter causing physiological effects, which can decrease the facility user's functional ability. The correct amount of ventilation with relation to the number of people using the facility, functional air distribution, and regular breaks can counteract the decrease in functional ability. The findings of the study suggest that merely increasing ventilation is not necessarily a rational solution from a technical-economical viewpoint. Instead or in addition, more comprehensive, anthropocentric planning of space is needed as well as instructions and new kinds of reference values for the design and realization of office environments.

Active workstation allows office workers to work efficiently while sitting and exercising moderately

ObjectiveTo determine the effects of a moderate-intensity active workstation on time and error during simulated office work. MethodsThe aim of the study was to analyse simultaneous work and exercise for non-sedentary office workers. We monitored oxygen uptake, heart rate, sweating stains area, self-perceived effort, typing test time with typing error count and cognitive performance during 30 min of exercise with no cycling or cycling at 40 and 80 W. ResultsCompared baseline, we found increased physiological responses at 40 and 80 W, which corresponds to moderate physical activity (PA). Typing time significantly increased by 7.3% (p = 0.002) in C40W and also by 8.9% (p = 0.011) in C80W. Typing error count and cognitive performance were unchanged. ConclusionsAlthough moderate intensity exercise performed on cycling workstation during simulated office tasks increases working task execution time with, it has moderate effect size; however, it does not increase the error rate. Participants confirmed that such a working design is suitable for achieving the minimum standards for daily PA during work hours.

A ventilation cooling shirt worn during office work in a hot climate: cool or not?

The aim of the study was to identify whether a ventilation cooling shirt was effective in reducing heat strain in a hot climate. Eight female volunteers were exposed to heat (38 °C, 45% relative humidity) for 2 h with simulated office work. In the first hour they were in normal summer clothes (total thermal insulation 0.8 clo); in the second hour a ventilation cooling shirt was worn on top. After the shirt was introduced for 1 h, the skin temperatures at the scapula and the chest were significantly reduced (p < 0.05). The mean skin and core temperatures were not reduced. The subjects felt cooler and more comfortable by wearing the shirt, but the cooling effect was most conspicuous only during the initial 10 min. The cooling efficiency of the ventilation shirt was not very effective under the low physical activity in this hot climate.

Assessing the effect of indoor environmental quality on productivity at office work

Abstract In a real environment makes it very difficult to evaluate the effect of a single parameter on human productivity, mostly because many of them are present at the same time and act together on each occupant. This study is aimed at investigation of selected office building to determine the presence of polluting agents such as volatile organic compounds, particulate matters and carbon dioxide and to assess the perceived productivity by office occupants. Occupants performed simulated office work consisting of three tasks in three office spaces. The mean values of total volatile organic compounds were in line with those found in other studies; taking into account the guideline value suggested by Molhave (200 μg.m-3). Mean values of PM10 mass concentrations exceeded the indoor limit value (50 μg.m-3) by 62.7% in office 1 and by 46.49% in reception. Concentrations of carbon dioxide in monitored office spaces were under the recommended concentration according to Pettenkofer (1800 mg.m-3).

Workplace productivity and individual thermal satisfaction

This study examines the relationship between individual thermal satisfaction and worker performance. Field measurements and a questionnaire survey were conducted within an organization participating in the COOL BIZ energy conservation campaign. A subjective experiment was also conducted in a climate chamber with eleven Japanese male subjects, testing five scenarios combining operative temperature (25.5 °C and 28.5 °C), clothing (with and without suits), and cooling items (desk fan, air-conditioned shirt, mesh office chair). From the individual analysis, actual air temperature in the COOL BIZ office was poorly correlated with self-estimated performance, whereas perceived thermal satisfaction correlated well with self-estimated performance (R2 = 0.944, p < 0.001). The results of the subjective experiment indicate that performance during simulated office work (i.e. multiplication and proof reading tasks) increased with greater individual thermal satisfaction (R2 = 0.403 and 0.464, p < 0.001). The finding that perceived thermal satisfaction of occupants is reflected in objective measurement of office work performance has practical implications for the evaluation of thermal satisfaction in real offices as a means to boost workplace productivity.

Wearable ECG Recorder with Acceleration Sensors for Monitoring Daily Stress

A small and light-weight wearable electrocardiograph (ECG) device with three accelerometers (x, y, and z axis) was developed for prolonged monitoring of everyday stress. It consists of an amplifier, a microcomputer with an analog/digital converter, a tri-axial accelerometer, and a memory card. Four parameters can be sampled at 1 kHz for a maximum of 27 h with the default battery and a 1 GB memory card. An algorithm for the reliable and clear detection of R wave peaks of ECG was also developed for accurate heart rate variability (HRV) analysis. The algorithm reduces ECG motion artifacts induced by body movements. Off-line data processing includes autonomic nervous system (ANS) activity bi-spectral analysis and the application of the tone-entropy method to HRV data. The availability of the system was tested through simulated office work and three-day monitoring. Both short-term and circadian rhythms of ANS activity were clearly observed. The experimental data verifies the functionality of the proposed system.

Personal cooling with phase change materials to improve thermal comfort from a heat wave perspective

The impact of heat waves arising from climate change on human health is predicted to be profound. It is important to be prepared with various preventive measures for such impacts on society. The objective of this study was to investigate whether personal cooling with phase change materials (PCM) could improve thermal comfort in simulated office work at 34°C. Cooling vests with PCM were measured on a thermal manikin before studies on human subjects. Eight male subjects participated in the study in a climatic chamber (T(a) = 34°C, RH = 60%, and ν(a) = 0.4 m/s). Results showed that the cooling effect on the manikin torso was 29.1 W/m(2) in the isothermal condition. The results on the manikin using a constant heating power mode reflect directly the local cooling effect on subjects. The results on the subjects showed that the torso skin temperature decreased by about 2-3°C and remained at 33.3°C. Both whole body and torso thermal sensations were improved. The findings indicate that the personal cooling with PCM can be used as an option to improve thermal comfort for office workers without air conditioning and may be used for vulnerable groups, such as elderly people, when confronted with heat waves. Wearable personal cooling integrated with phase change materials has the advantage of cooling human body's micro-environment in contrast to stationary personalized cooling and entire room or building cooling, thus providing greater mobility and helping to save energy. In places where air conditioning is not usually used, this personal cooling method can be used as a preventive measure when confronted with heat waves for office workers, vulnerable populations such as the elderly and disabled people, people with chronic diseases, and for use at home.

난방환경에서 온(溫)맵시 착용에 따른 생리적 반응 및 주관적 감각

This study tests the performance of the recommended winter dress OnMapsi for an office worker through the analysis of skin temperature changes according to the heating environment. We tested and compared the effects of with/without undergarments for 4 male subjects in an artificial-climate chamber with two air temperatures of <TEX>$19^{\circ}C$</TEX> and <TEX>$22^{\circ}C$</TEX>, <TEX>$50{\pm}10%$</TEX> R.H. During the 60 minute experiment that simulated office work, the subjective feelings (that included thermal, humidity and comfort sensation, and skin temperature) were measured at equal intervals. The results show that the forehead and chest skin temperatures were not affected by air temperature or clothing type, while the hand and foot skin temperatures were affected at <TEX>$0.3-0.9^{\circ}C$</TEX> depending on clothing type and <TEX>$1.9-2.2^{\circ}C$</TEX> depending on air temperature. The mean skin temperature was decreased by the experimental time pass more with regular formal wear than with OnMapsi. The second experiment located the ambient temperature in which subjects wearing OnMapsi show equal skin temperaturesto those without undergarments at <TEX>$22^{\circ}C$</TEX>. Therefore it is possible to decrease heating temperatures to <TEX>$18-21^{\circ}C$</TEX> in the office for winter OnMapsi wear that produces a skin temperature and thermal sensation that is the same as those at <TEX>$22^{\circ}C$</TEX>.

Instantaneous changes in heart rate regulation due to mental load in simulated office work

The cardiac regulation effects of a mental task added to regular office work are described. More insight into the time evolution during the different tasks is created by using time-frequency analysis (TFA). Continuous wavelet transformation was applied to create time series of instantaneous power and frequency in specified frequency bands (LF 0.04-0.15 Hz; HF 0.15-0.4 Hz), in addition to the traditional linear heart rate variability (HRV) parameters. In a laboratory environment, 43 subjects underwent a protocol with three active conditions: a clicking task with low mental load and a clicking task with high mental load (mental arithmetic) performed twice, each followed by a rest condition. The heart rate and measures related to vagal modulation could differentiate the active conditions from the rest condition, meaning that HRV is sensitive to any change in mental or physical state. Differences between physical and mental stress were observed and a higher load in the combined task was observed. Mental stress decreased HF power and caused a shift toward a higher instantaneous frequency in the HF band. TFA revealed habituation to the mental load within the task (after 3 min) and between the two tasks with mental load. In conclusion, the use of TFA in this type of analysis is important as it reveals extra information. The addition of a mental load to a physical task elicited further effect on HRV parameters related to autonomic cardiac modulation.

Occupant Responses and Office Work Performance in Environments with Moderately Drifting Operative Temperatures (RP-1269)

Fifty-two experimental subjects (50% female) were seated in a climate chamber and exposed to operative temperature ramps with different slopes, directions, and durations during two related experiments. The first experiment covered a temperature range of 22°C–26.8°C (71.6°F–80.2°F) and subjects wore light clothing (0.5 clo). The operative temperature was increased in rates of 0.6 K/h (1.1°F/h) (for 8 h), 1.2 K/h (2.2°F/h) (for 4 h), 2.4 K/h (4.3°F/h) (for 2 h), and 4.8 K/h (8.6°F/h) (for 1 h), respectively. In one session, subjects were exposed to a constant temperature of 24.4°C (75.9°F) (for 4 h). The second experiment covered a temperature range of 17.8°C–25°C (64°F–77°F), and subjects wore heavier clothing (0.7 clo). Temperature ramps of 0.6 K/h (1.1°F/h) (for 8 h), 1.2 K/h (2.2°F/h) (for 6 h), 0.6 K/h (−1.1°F/h) (for 8 h), and −1.2 K/h (−2.2°F/h) (for 6 h) and exposure to a constant temperature of 21.4°C (70.5°F) (for 6 h) were examined. Subjects assessed their thermal sensation, acceptability of the thermal environment, perceived air quality, and intensity of sick building syndrome (SBS) symptoms. Subjects' performance was measured by simulated office work, including tasks such as addition, proofreading, reading and comprehension, and text typing. Results of the experiments showed that even moderately changing operative temperature ramps were sensed by sedentary subjects when exposure times exceeded 4 h. No significant effects on SBS symptoms related to local irritation of mucous membranes were found, while intensity of headache, concentration ability, and general well-being were significantly affected in most of the ramps. Linear dependence of perceived air quality on operative temperature was noted. No significantly consistent effects of individual temperature ramps on office work performance were found.

Effect of Using a Treadmill Workstation on Performance of Simulated Office Work Tasks

Although using a treadmill workstation may change the sedentary nature of desk jobs, it is unknown if walking while working affects performance on office-work related tasks. To assess differences between seated and walking conditions on motor skills and cognitive function tests. Eleven males (24.6 +/- 3.5 y) and 9 females (27.0 +/- 3.9 y) completed a test battery to assess selective attention and processing speed, typing speed, mouse clicking/drag-and-drop speed, and GRE math and reading comprehension. Testing was performed under seated and walking conditions on 2 separate days using a counterbalanced, within subjects design. Participants did not have an acclimation period before the walking condition. Paired t tests (P < .05) revealed that in the seated condition, completion times were shorter for mouse clicking (26.6 +/- 3.0 vs. 28.2 +/- 2.5s) and drag-and-drop (40.3 +/- 4.2 vs. 43.9 +/- 2.5s) tests, typing speed was greater (40.2 +/- 9.1 vs. 36.9 +/- 10.2 adjusted words x min(-1)), and math scores were better (71.4 +/- 15.2 vs. 64.3 +/- 13.4%). There were no significant differences between conditions in selective attention and processing speed or in reading comprehension. Compared with the seated condition, treadmill walking caused a 6% to 11% decrease in measures of fine motor skills and math problem solving, but did not affect selective attention and processing speed or reading comprehension.

Work-induced pain, trapezius blood flux, and muscle activity in workers with chronic shoulder and neck pain

Pain, trapezius microcirculation, and electromyography (EMG) were recorded during 90min of simulated office work with time pressure and hand precision demands in 24 full-time working subjects with chronic shoulder and neck pain. The responses were compared with those of a reference group of 28 healthy subjects without pain. Pain intensity was rated on a visual analogue scale. Intramuscular blood flux was measured by laser-Doppler flowmetry (LDF) and muscle activity by surface EMG bilaterally in the upper trapezius. Pain increased during the work task, and the increase was larger in women than in men and in the reference group. Muscle activity was low: <4% of EMG during maximal voluntary contraction. LDF showed elevated intramuscular blood flux above baseline throughout the work task in both groups and during recovery in the pain group. Pain in the active side correlated positively with blood flux in the pain-afflicted subjects and negatively in the reference group. In conclusion, office work induced pain, and trapezius vasodilation that did not return to resting values during recovery. These data show that pain is associated with trapezius vasodilation but not with muscle activity. Interaction between blood vessels and nociceptors may be important in the activation of muscle nociceptors in people with chronic shoulder and neck pain. Pain-afflicted people may benefit from breaks spaced at shorter intervals than those needed by pain-free subjects when working under time pressure.

Effect of Using a Treadmill Workstation on the Performance of Simulated Office Work Tasks

Effect of Using a Treadmill Workstation on the Performance of Simulated Office Work Tasks

The Combined Effects of Many Different Indoor Environmental Factors on Acceptability and Office Work Performance

Ninety-nine young-adult subjects of both genders were randomly assigned to four groups. One group performed simulated office work for two hours in a set of poor environmental conditions, with overhead fluorescent lighting, recorded traffic noise from a busy street, 27°C (80.6°F) operative temperature, supply air polluted by emissions from linoleum, recorded open office noise, and almost no daylight. The realistic annual cost of improving each of the six conditions was estimated and expressed as a percentage of the total sum of the cost of improving conditions. The modifications included improved lighting, barely audible traffic noise, operative temperature of 22°C (71.6°F), clean air, quiet, and a daylit view out. A second group briefly experienced all 12 conditions and individually selected the improvements they preferred, up to a 50% budget. A third group of subjects was randomly paired with each of the subjects from the second group, and each pair was exposed to the conditions selected by the second-group subjects. A fourth group was exposed to fully-improved (100% budget) conditions. Significant improvements in subjective assessment occurred at higher budget/individual choice levels, and the self-reported performance of office tasks improved, although measured performance could not be shown to differ significantly between treatment groups.

Effect of humidity on human comfort and productivity after step changes from warm and humid environment

Subjective experiments were conducted to evaluate the effects of humidity on human comfort and productivity under transient conditions from hot and humid environment to thermally neutral condition. Two climate chambers, “Chamber 1” and “Chamber 2”, adjoined each other were used for this study. Subjects were exposed to 30 °C/70%RH air in Chamber 1 for 15 min with 2.0 met of metabolic rate. Then they moved into Chamber 2, where 4 humidity conditions, 30, 40, 50 and 70%RH were examined. Air temperature was adjusted to keep SET* constant at 25.2 °C for all conditions. Subjects were exposed in Chamber 2 for 180 min performing 2 kinds of simulated office work. Positive effects of low humidity on subjective pleasantness were found under transient condition at low humidity due to more evaporation from human body, while no significant difference in thermal sensation and humidity sensation among 4 relative humidity levels was obtained. Subjective performance was found to be at the same level under all conditions. However, subjects reported to be more tired at 70%RH after humidity step change.

Experimental Determination of the Limiting Criteria for Human Exposure to Low Winter Humidity Indoors (RP-1160)

Thirty subjects (17 female) were exposed for five hours in a climate chamber at 22°C (71.6°F) to clean air at 5%, 15%, 25%, and 35% RH. A comparable group was similarly exposed to air polluted by carpet and linoleum to the 35% RH condition and to 18°C, 22°C, and 26°C (64.4°F, 71.6°F, and 78.8°F) at an absolute humidity equal to 15% RH at 22°C (71.6°F). They performed simulated office work to ensure that they kept their eyes open and reported sick building syndrome (SBS) symptom intensity on visual-analogue scales. Nine objective tests of eye, nose, and skin function were applied. Subjective discomfort, though significantly increased by low humidity, was slight even at 5% RH. More rapid blink rates were observed at 5% than at 35% RH (P < 0.05), and tear film quality as indicated by the Mucous Ferning Test deteriorated (P < 0.05) at low humidity (5%, 15%) and at the highest air temperature 18°C, 22°C > 26°C (78.8°F). Low humidity was found to have reduced the rate of performance of three office tasks by 3%–7%.