Peter Nickel

Sensitivity and Diagnosticity of the 0.1-Hz Component of Heart Rate Variability as an Indicator of Mental Workload

We investigated whether the 0.1-Hz component of heart rate variability (HRV) allows one to discriminate among levels of mental work stress induced by different types of tasks (diagnosticity) as well as among those induced by different levels of difficulty (sensitivity). Our 14 participants were presented 14 tasks of the Advisory Group for Aerospace Research and Development Standardized Tests for Research with Environmental Stressors battery in a repeated-measures design. Sufficient sensitivity was obtained for a discrimination between work and rest, but we found no support for a more fine-grained sensitivity. Concerning diagnosticity, only the grammatical reasoning task could be discriminated from all other tasks, indicating for this task a level of mental strain comparable to rest, which was in contrast with the results both for perceived difficulty and performance. We propose that HRV is an indicator for time pressure or emotional strain, not for mental workload, given that it seems to allow discrimination between tasks with and without pacing. Application of this research argues against using HRV as a measure of mental and especially cognitive workload, particularly where system safety or occupational risks may be at stake (e.g., when evaluating operator tasks or interface design in control room operations).s

Evaluation of presentation of information for process control operations

In an experimental process control simulation study two operators performed monitoring and control operations including safety critical tasks that required parallel processing of information distributed over different functional mimic displays. The assignment of mimic displays to Visual Display Units (VDUs) was experimentally varied by allowing one or two VDUs for mimic presentation. The study revealed no evidence for differences in task performance during normal process control operations. During abnormal operations, however, detrimental effects both on performance and work load were observed. Having only one VDU available for mimic display revealed either a lower level of performance (time for fault management) and/or a higher level of emotional work strain. It is concluded that decisions on the number of VDUs necessary for effective and efficient process control must refer to the tasks to be performed and the presentation of information necessary for a safe, effective and efficient task performance under critical, but not only normal conditions.

Development of an Online Checklist for the Assessment of Alarm Systems and Alarm Management in Process Control

In the past, poorly designed alarm systems and inadequate alarm management contributed to the emergence of critical events with partially serious consequences. Based on the experience gained from these incidents, guidelines were created with recommendations for the design of alarm systems and alarm management. A comprehensive checklist has been developed to analyze the current design quality of alarm systems and alarm management and has been used in various control rooms across different branches of industry in Germany. Using the checklist, design deficiencies can be identified and action needs can be derived. So far, the results also show systematic differences in the application of the checklist between individual assessors and between groups of assessors.

BASS 4: a software system for ergonomic design and evaluation of working hours

OBJECTIVE To extend an existing computer programme for the evaluation and design of shift schedules (BASS 3) by integrating workload as well as economic aspects. METHODS The redesigned prototype BASS 4 includes a new module with a suitable and easily applicable screening method (EBA) for the assessment of the intensity of physical, emotional and cognitive workload components and their temporal patterns. Specified criterion functions based on these ratings allow for an adjustment of shift and rest duration according to the intensity of physical and mental workload. Furthermore, with regard to interactive effects both workload and temporal conditions, e.g. time of day, are taken into account. In a second new module, important economic aspects and criteria have been implemented. Different ergonomic solutions for scheduling problems can now also be evaluated with regard to their economic costs. RESULTS The new version of the computer programme (BASS 4) can now simultaneously take into account numerous ergonomic, legal, agreed and economic criteria for the design and evaluation of working hours. CONCLUSIONS BASS 4 can now be used as an instrument for the design and the evaluation of working hours with regard to legal, ergonomic and economic aspects at the shop floor as well as in administrative (e.g. health and safety inspection) and research problems.

Ergonomics Analysis of Alarm Systems and Alarm Management in Process Industries

A study dealing with human factors and ergonomics in the design of alarm systems and alarm management in the process industries was conducted at 15 workplaces for control room operators across different branches of industry in Germany. The results show that none of the systems under investigation fulfilled all the design recommendations derived from relevant literature, guidelines or standards. Thus, the results indicate an increased risk potential for incidents. Need for action to improve alarm systems and alarm management has, inter alia, been found particularly necessary with regard to alarm prioritization, consideration of operator performance limits, instructions on alarm handling and system support, continuous improvement processes as well as systematic training concepts and operator training concerning the alarm system and alarm handling. Results also suggest that there is still a lack of design improvements, as has already been documented in former research reports on critical incidents.

The Design of Alarm Systems and Alarm Management - An Empirical Investigation from an Ergonomic Perspective

This paper reports results of a study dealing with the ergonomic design quality of the alarm system and alarm management in 15 process control systems from different sectors of industrial production. Based on available guidelines and ergonomic evidence, a checklist was designed and applied to these systems to test for compliance with these guidelines. The results show that there is a great deal of non-compliance with the requirements, leading to severe impairments of process safety. The main areas of design deficiencies have been found in the lack of prioritization of alarms, a lack of action guides in the presentation of alarms, lack of continuous improvement of the alarm system, a lack of systematic training concepts and training of alarm handling. Feeding back the results to the companies involved clearly showed that they were looking for help in dealing with these problems.

Bildschirmarbeit in Leitwarten — Teil 2: Untersuchungen zur Umsetzung von ergonomischen Gestaltungsanforderungen

Kurzfassung: Bildschirmarbeit in Leitwarten (einschließlich Kontrollräumen und Überwachungszentren) fällt zweifelsfrei unter den Anwendungsbereich der Bildschirmarbeitsverordnung. Jedoch lassen sich bereits vorliegende Handlungsempfehlungen für eine ergonomische Gestaltung von Bildschirmarbeit im Büround Verwaltungsbereich nicht ohne weiteres auf den Leitwarten-Bereich übertragen. Ziele eines von der Bundesanstalt für Arbeitsschutz und Arbeitsmedizin initiierten und geförderten Projektes sind daher zum einen eine Bestandsaufnahme der Arbeitsbedingungen an derzeitigen Arbeitsplätzen mit Bildschirmarbeit in unterschiedlichen Leitwarten und zum anderen die Entwicklung von Gestaltungsempfehlungen für eine ergonomische Gestaltung von Bildschirmarbeit in Leitwarten in den Bereichen Industrie und Dienstleistung. Schlüsselwörter: Bildschirmarbeit, Leitwarte, Evaluation, Gestaltungszustand.

Bildschirmarbeit in Leitwarten — Teil 1: Entwicklung einer Checkliste zur Überprüfung von ergonomischen Gestaltungsanforderungen

Kurzfassung: Bildschirmarbeit in Leitwarten (einschließlich Kontrollräumen und Überwachungszentren) fällt zweifelsfrei unter den Anwendungsbereich der Bildschirmarbeitsverordnung. Jedoch lassen sich bereits vorliegende Handlungsempfehlungen für eine ergonomische Gestaltung von Bildschirmarbeit im Büround Verwaltungsbereich nicht ohne weiteres auf den Leitwarten-Bereich übertragen. Ziele eines von der Bundesanstalt für Arbeitsschutz und Arbeitsmedizin initiierten und geförderten Projektes sind daher zum einen eine Bestandsaufnahme der Arbeitsbedingungen an derzeitigen Arbeitsplätzen mit Bildschirmarbeit in unterschiedlichen Leitwarten und zum anderen die Entwicklung von Gestaltungsempfehlungen für eine ergonomische Gestaltung von Bildschirmarbeit in Leitwarten in den Bereichen Industrie und Dienstleistung. Schlüsselwörter: Bildschirmarbeit, Leitwarte, Checkliste, Evaluation.