(dis)comfort questionnaires

Many questionnaires

There are many questionnaires on comfort and discomfort each having their own advantages and disadvantages. Also, the application field and the usage in different design stages have influence on the preference for a questionnaire. For instance the selection of a questionnaire in an exploration phase, where humans have much time to think about options might differ from the one which has to be completed every 10 minutes in a specific testing situation.

Experts’ opinion

In a recent study, 55 experts that visited the International Comfort Conference in 2019 gave their opinion on (dis)comfort questionnaires that are mentioned in the scientific literature. The paper is accepted for publication the journal Work and has the title PCQ: Preferred Comfort Questionnaires for Product/Service Design. The authors are: S Anjani, M Kühne, A Naddeo, S Frohriep, N Mansfield, Y Song and P Vink. In this new paper, we highlight some major outcomes related to (dis)comfort in seat studies and the total environment, though the research covers more application fields such as hand/tool handle design and feet leg studies.

Seat comfort

The most useful questionnaires for seat studies in the early design phase seems to be the seat elements questionnaire published by Van Veen et al (2015). 55% of the 55 experts were in favour of this questionnaire. It consists of 11 questions.  For studying prototypes two questionnaires were suitable. The two that were mentioned most are: the postural comfort method by Corlett & Bishop (1976) (55% favoured for this one) and again the method of Van Veen et al (2015) (64%). For comparing two products both the Corlett & Bishop (1976) and Van Veen questionnaire were favoured, but another one was added: The Mansfied two-stage method described by Sammonds et al. (2017). For evaluating an end product the Van Veen et al (2015) and Sammonds et al. (2017) method were again chosen.

The Van Veen et al. (2015) questionnaire used a 9-point Likert scale for the answers and the 11 questions are:
1.How much would you like to have this seat?
2. How do you assess the comfort of this seat?
3. How do you evaluate the overall comfort of the backrest?
4. How do you evaluate the overall comfort of the seat pan?
5. Does this seat assist your physical well-being?
6. How do you like the mobility of the seat pan?
7. How do you like the mobility of the backrest?
8. How do you like the overall mobility of the seat?
9. How do you like the support of the seat pan?
10. How do you like the support of the backrest?
11. How do you like the overall support of the seat?

In the Corlett & Bishop (1976) questionnaire the participant has to rate discomfort in different body parts at the following body map:

Some authors use a scale for different levels of discomfort per body part.

The Sammonds et al. (2017) questionnaire consists of two stages (see figure below). First the scores for the body parts have to made and then the overall discomfort has to be scored.

Environmental comfort

The most useful questionnaires for environmental comfort in the early design phase could not clearly be defined. All scores were below 50%. Perhaps this might not be so relevant as for various environmental factors guidelines are available. For studying prototype environments, comparing two environments and evaluating environments the Multi factorial methods – cross modal matching ISO 20882 was favoured by 64% of the 55 experts.  This method is not freely available and can be bought from International Organization for Standardization (ISO). Two methods also mentioned for all situations are the ‘simple comfort score’ (used for instance by De Lille, et al, 2016) and the method to measure auditory comfort of Fields et al. (2001).

The method of Fields et al. (2001) is specific for one aspect of the environment and is well described in this paper. The method of the Lille et al (2016) is asking participants to rate their comfort on a scale from 1-10. (1=no comfort at all and 10=extreme comfort). She asked that several times during the flight and could see the pattern in different phases of the flight.

Great 6 month progress discussed at consortium meeting in Nottingham

Last week our second consortium meeting took place at Nottingham Trent University. We have been working on the ComfDemo project for six months now.

Some members made the journey to Nottingham in a turboprop aircraft and were able to take inflight measurements. The findings were analyzed and discussed with the experts attending the meeting. We learnt that more research and refinement is needed with regards to our methods. We realized for instance that the frequencies and amplitudes of vibration and sound measured using the jacket will need augmenting with precision measurements. This puts requirements on each type of sensor we use as well as the positioning of the sensors. Placing the sensors directly onto the human body is most realistic for measuring personal thermal comfort levels. However in order to get more accurate readings on vibration levels it seems that the sensors need to be located on the cabin floor.

Developing the perfect comfort model is not going to be easy. In order to measure the factors that influence comfort levels during a flight we need to keep the questionnaires short. They have to be completed several times during a flight, at specific stages. In order to not miss any data the right (amount of) questions have to be asked, at the right time.  

Inflight we measured sound levels above 80dB. In the environmental chamber at NTU we listened to several turboprop recordings being played at different dB levels. We took into account that perception in the chamber is not in line with quantitative measurements because context influences perception. However at a certain level the volume and level of discomfort was experienced as too high.  

The oxygen level, temperature and humidity were set to a level comparable to the climate in Tokyo in the summer. We will use this chamber again at a later stage to calibrate our measurement equipment.

During the meeting we also discussed the ethical issues surrounding data processing. We talked about personal data protection and which data we are legally allowed to collect from our participants. We are well aware that an important part in this process is informing our participants on what happens with their personal data. The project is running according to planning and the consortium seems to work as a great team with complimenting skills that are invaluable for the completion of this challenging project.

The consortium worked six months on this project and had their second meeting. Some members of the ComfDemo took a turboprop flight on the way to this ComfDemo meeting. On the way to the meeting inflight measurements were taken and discussed with the experts during the meeting. It showed that more research and refinement of the measurement is necessary. For instance, the frequencies and amplitudes of vibration and sound were not accurate enough. The location of the sensor is also very important. Putting the sensors on the human body is close to comfort, but on the cabin floor is better for recording the real vibration. dB measurements showed levels above 80 dB.

The ComfDemo consortium members listened to several turboprop recordings played at different dB levels in the environmental chamber of NTU. It was noted that the perception in the chamber is different from quantitative measurements as the context plays a role, but of course at a certain level the volume was experienced too high.  

The oxygen level, temperature and humidity were set to a level comparable to Tokyo as some candidates for the Olympic games were training in the room. We will use this room to calibrate our measurement data later.

We also discussed ethical issues, like which data are we allowed to measure of persons at different flights and how should we inform participants.

The project is running according to planning and we found out that we really have the right partners for tackling this challenge. We also agreed that it isn’t easy to make the perfect comfort model and measure the comfort influencing factors during a flight. The questionnaires should not be too long if you complete it several times during the flight and at the same time we don’t want to miss data. Measuring is challenging not only for the position of the sensors, but also regarding the requirements for each sensor.

Smell experiment in research fuselage

Part of the project is the construction of a comfort model including all relevant factors, and defining the best way to measure them. In order to discover this, several experiments will be carried out on separate comfort factors or different comfort factors together, in order to reveal their interrelation. One of those experiments on the relation between smell and comfort, was carried out at the Boeing 737-500 aircraft fuselage available at TU Delft, as depicted above.

ComfDemo Kick-off retrospective

In the beginning of September, a 2-day kick-off meeting was organised with all consortium partners together in the Hague and Delft. After a short round of introductions and presentations of what each partner will contribute and would like to get out of the project, topic manager Fraunhofer provided the partners with some more insights on the aim of the call: enhancing human centered cabin design by enabling prediction and verification of human comfort on different levels (distant, close and touching the body). All presentations together instantly sparked some in-depth discussions about the touch points between the partners, opportunities and approach for the project.

The next day, more in-depth presentations and discussions on the separate work packages followed, as well as a presentation of the first version of the comfort measuring jacket. Follow-up appointments between partners were scheduled and after a short visit to the Flying V interior concept at TU Delft and a nice dinner, all partners went home feeling satisfied about the successful start.  

International Comfort Congress 2019

The International Comfort Congress of 2017 was a big success with more than 60 papers covering all aspects of comfort science with application across multiple sectors.  Many delegates asked the organisers for a follow-up conference and so it was organized again on August 29-30 2019 in Delft. At the congress we shared studies, theories and technologies for road vehicle and aircraft seats, transport systems interiors, bed comfort, comfort models, and more.  We aimed to exchange the latest knowledge, and stimulate ideas cross-sector and between industry and researchers.

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