Percentages in Office Chair Design Drawings
The percentages involved in office chair design drawings are mainly determined based on different percentiles of human body measurement items, as detailed below:
Seat height: Typically designed according to the 50th percentile of leg length. The 50th percentile, or median, means that half of the people have leg lengths shorter than this value, and the other half have leg lengths longer than this value. Designing the seat height based on the 50th percentile of leg length ensures that most people can have their feet naturally touch the ground when using an office chair, facilitating operations such as using a keyboard and mouse. It also helps maintain correct sitting posture, reducing physical fatigue and injuries caused by improper posture.
Seat width: Designed based on the 85th percentile of hip circumference. The 85th percentile indicates that 85% of people have hip circumferences smaller than this value, and 15% have hip circumferences larger than this value. Using the 85th percentile of hip circumference to design seat width is primarily to accommodate people with larger body sizes, ensuring they have sufficient space for their hips when sitting, preventing them from feeling cramped and uncomfortable, and thereby improving comfort and satisfaction during use.
Armrest height: Designed according to the 50th percentile of shoulder width. The advantage of this design is that it allows most people to naturally place their forearms on the armrests, reducing the burden on the arms and preventing arm soreness and fatigue caused by prolonged suspension. At the same time, an appropriate armrest height also helps maintain body balance and stability, enhancing sitting comfort.
Backrest height: Designed based on the 50th percentile of trunk forward inclination angle. The trunk forward inclination angle is an important indicator reflecting the angle between the trunk and the vertical direction when a person is sitting. Designing the backrest height according to the 50th percentile of the trunk forward inclination angle enables most people to maintain a comfortable sitting posture during movement or work, providing good support for the back, reducing tension and fatigue in the back muscles, and preventing the occurrence of back diseases.
Backrest width: Designed according to the 50th percentile of the distance between the back's concave point and the shoulders. This design ensures that the backrest width conforms to the body characteristics of most people, providing an appropriate support area for the back, allowing the back to rest comfortably on the backrest, and enhancing the stability and comfort of the sitting posture.
