Large Open-plan Office Research Articles

Particle Emission Characteristics of Office Printers

In modern society, printers are widely used in the office environment. This study investigated particle number and PM2.5 emissions from printers using the TSI SMPS, TSI CPC 3022, and 3025A TSI P-Trak and DustTrak. The monitoring of particle characteristics in a large open-plan office showed that particles generated by printers can significantly (p = 0.01) affect the submicrometer particle number concentration levels in the office. An investigation of the submicrometer particle emissions produced by each of the 62 printers used in the office building was also conducted and based on the particle concentrations in the immediate vicinity of the printers, after a short printing job, the printers were divided into four classes: non-emitters, and low, medium, and high emitters. It was found that approximately 60% of the investigated printers did not emit submicrometer particles and of the 40% that did emit particles, 27% were high particle emitters. Particle emission characteristics from three different laser printers were also studied in an experimental chamber, which showed that particle emission rates are printer-type specific and are affected by toner coverage and cartridge age. While a more comprehensive study is still required, to provide a better database of printer emission rates, as well as their chemical characteristics, the results from this study imply that submicrometer particle concentration levels in an office can be reduced by a proper choice of the printers.

The Effect of Adaptation Levels and Daylight Glare on Office Workers' Perception of Lighting Quality in Open Plan Offices

A series of post occupancy evaluation (POE) studies have been carried out as part of the research for a M. Phil (Architecture) degree at the University of Sydney. The aim of the studies was to isolate causes of dissatisfaction within the large open plan office environment. It was hypothesized that the adaptation level would be a significant influence on peoples' perceptions of their visual environment. The outcomes from laboratory based research had indicated that situations where the mean adaptation levels were greater than 30 to 40 cd/m2 would be judged bright and well lit. The outcomes from the POE studies disagreed with these findings and mean adaptation levels in excess of 100 cd/m2 were associated with conditions judged to be dim, gloomy and inadequately lit. There seems a possibility that daylight glare from windows destabilized the visual function and set adaptation levels that caused well illuminated spaces to appear inadequately lit. Implications for lighting design are raised and the need for ongoing research is identified.

Prediction of the speech intelligibility index behind a single screen in an open-plan office

Improved acoustical privacy is the principal goal of the acoustical design of open plan offices. As the replacement of the Articulation Index (AI), the Speech Intelligibility Index (SII) can be used as a single-number measure of the speech privacy in open-plan offices. In this paper, a mathematical model of the speech propagation over single screens in a large open-plan office space is presented. The calculated effects of the office parameters, such as the screen height, ceiling and floor absorption, etc. on the SII behind the screen are discussed and are compared with measured results. To facilitate the practical use of the model, an empirical correction is derived from a wide range of ceiling tiles to provide values of the effective sound absorption of typical suspended ceilings in open offices. Compared to measured results, SII can be predicted with an RMS error of 0.03.

An experimental study of OFDM at 5.25 GHz in an office environment

Orthogonal frequency-division multiplexing (OFDM) has received considerable interest as a means for delivering broadband data in highly dispersive wireless channels. Here we present the design, implementation, and performance of an OFDM system operating at 5.25 GHz, which provides 20 Mbits/s in an office environment. From propagation measurements, we describe a design methodology for determining the key parameters of the OFDM system, such as the number of subcarriers and the size of the guard period. The performance of the system is evaluated using experimental data obtained from a typical large open-plan office. Using a transmit power of +7 dBm, the OFDM system is capable of operating in a highly cluttered environment, providing usable error rates up to a range of 20 m. The importance of error control coding is shown, and we empirically derive the degree of correctability required to achieve packet failure rates of <1% from the cumulative distribution of errors per packet.

Movement under emergency lighting: the effects of changeover from normal lighting

This paper considers how people's ability to move over an escape route is affected by different procedures for changing from normal room lighting to emergency lighting. The experiment took place in a large open plan office at two emergency lighting illuminances, 0.16 lx and 0.012 lx. The changeover to emergency lighting was either instantaneous or involved a 5 second period of darkness before the emergency lighting came on, as is allowed by BS 5266. The subjects were instructed either to move as soon as the emergency lighting came on or to wait until they felt able to move unhesitatingly over the escape route. The time taken to leave the office, the manner of movement and subjects' opinions of the conditions were all recorded. They showed that movement was faster, smoother and easier at 0.16 lx than at 0.012 lx, for all conditions. When the subjects moved immediately the emergency lighting came on, having a 5 second period of darkness allowed more rapid, steadier movement with fewer collisions once movement started. However, the total time taken to leave the room was slightly longer than if the subjects moved immediately following an instantaneous changeover. Allowing the subjects to wait until they felt able to move unhesitatingly, ensured smooth steady movement but the total time taken at 0.012 lx was much longer than if the subjects started to move immediately after the changeover. Estimates of the state of adaptation of the visual system following a step change in luminance provide a plausible explanation of all these results.

Movement under emergency lighting: the effect of illuminance

This paper describes an investigation carried out in a large open plan office with the aim of identifying the illuminance necessary for rapid, safe movement under emergency lighting conditions. In the experiment, the times taken for each subject to cover an escape route were measured. The manner in which the subjects moved was observed and their opinions of the conditions were noted. This data was collected from sixty subjects in all, twelve at each illuminance condition. The subjects were not familiar with the office and were of working age. From the data collected it is concluded that at a mean illuminance of 0.2 lx, people experience some difficulty in moving quickly and unhesitatingly over the escape route. At a mean illuminance of 1 Ix there is no difficulty in moving smoothly and steadily over the escape route at a speed similar to that achieved under the normal room lighting. These results suggest that the present emergency lighting criterion of a minimum illuminance of 0.2 Ix is only reasonable if it is indeed treated as an absolute minimum. They also indicate that it would be useful to adopt a mean illuminance of 1 Ix on the escape route as an additional emergency lighting criterion. Three subsidiary experiments were carried out to explore the effects of age, familiarity with the office and group movement rather than individual movement. These subsidiary experiments showed that these factors made little difference to the subject's ability to move under the emergency lighting. Therefore the conclusions reached for the main experiment also apply to older people of working age, to those who are familiar with the space and to people moving in small groups.

Noise and performance

I was interested in M Bryan's results (Physics Bulletin February 1973) on the effects of noise on mental performance. The printing and publishing industry covers a wide range of noisy environments from the hectic 'creative chaos' of the large open-plan offices where editorial staff put together national newspapers to the shattering din of the press hall.