18.104.22.168 Dimensional Requirements
In school children, there is a conflict between the natural tendency to unrestricted physical movement and the need to maintain a seated position for a longer period of time (Troussier et al. 1999). Headache, knee pain, back pain and attention deficit are among the most common adverse effects of prolonged sitting (Drozynska 1997; Krutul 2004a; Snijders et al. 1995). In order to reduce these negative effects, education programmes in schools contain many forms of physical activation for students. The actions undertaken in this area only minimise the effects of erroneous furniture design. In order to completely solve problems connected with the functionality of school furniture, more effort should be put into creating innovative rules of furniture design. More attention must be devoted to the proper, ergonomic design of school furniture.
Diversity in designing should, therefore, take into account and promote solutions that not only improve the figure, but also ensure freedom and mobility of both children and furniture (Molenbroek 1994).
Due to the complexity design problems, innovative solutions for school furniture should arise in multidisciplinary teams composed of orthopaedic doctors, rehabilitation experts, teachers, psychologists, constructors, technologists, environmentalists, economists and of course designers (Fig. 3.26).
Only such a team is able to develop the values of factors responsible for optimum shapes and constructional solutions of furniture. Figure 3.27 shows the most important parameters affecting optimal design of school furniture.
Differences in the height of Polish children (boys and girls) aged from 7 to 12 years (elementary school) amount to 30 cm on average, while in children between 13 and 15 years (middle school youth) only 12 cm. Therefore, due to this variation of height of children at a similar age, and living both in Poland as well as in other countries of the European Union (Drozynska 1997; Jarosz 2003; Nowak 1993), when designing school furniture, it is necessary to answer the following questions: which measuring system best fulfils the needs of this population of users, for which project is it being done and which dimensions of the body should be measured in a population of children representing one class in order to find the best recommendations. The requirements in the scope of equipping school with furniture
Fig. 3.27 Parameters that influence optimal design of school furniture
intended for didactic rooms are specified in the norms PN-EN 1729-1:2007 and PN-90/F-06009. Tables and chairs should be marked with a label that specifies using a digit symbol or colour (Tables 3.12 and 3.13) and the furniture size. Marking furniture enables teachers to organise individual children easily to their proper benches and chairs. In this case, three important rules must be considered:
• Before inserting furniture to the teaching room, they need to be marked by a number of colours corresponding to the proper scope of a child’s height,
• Pairs folded from benches (tables) and chairs should have an identical feature,
• In each room, there should be furniture having at least three-dimensional characteristics.
The younger the child, the less the developed bone structure, and it is more important to adopt the correct posture during school activities. This posture is significantly shaped by the chair and table; therefore, when designing school furniture, seven primary criteria must be taken into account, which are illustrated in Fig. 3.28.
1. The backrest of the chair should stiffly support the back at the height of the lumbar region, below the shoulder blades.
2. The height of the front edge of the table must correspond to the height of the bottom surface of the bend forearm in a position when the arm is placed vertically.
3. To guarantee freedom of movement, the distance between the edge of the table and pupil’s body needs to be determined, as well as the distance between the lumbar support and the seat.
4. Distance between the lower surface of the table and the thigh must be ensured.
5. The part of the shank near the knee cannot put pressure on the front edge of the seat.
6. A clear space between the back part of the calf and front edge of the seat must be taken into account.
7. The foot must rest on the floor. The seat and table height should be adjusted to the thickness of the shoe sole, around 2 cm.
An example set of school furniture is shown in Fig. 3.29. It allows freedom of movement of the child both while listening (Fig. 3.29a), writing (Fig. 3.29b) and reading (Fig. 3.29c).
The results of anthropometric studies of children and adolescents at school age served to develop the optimal dimensions of school furniture, which are contained in the norms (EN 1729-1:2007; PN-ISO 5970:1994; PN-90/F-06009;
PN-90/F-06010.01; PN-90/F-06010.05; PN-88/F-06010.02; PN-88/F-06010.03), and the principles of dimensioning have been illustrated in Fig. 3.30.
All these standards define the requirements for school tables and chairs, describing the dimensions, angles, furniture class, required identification markings and colours, adapted to the average values of height of European children.
Fig. 3.28 Preferential points to dimensioning school tables and chairs
The requirements for seats are the following basic characteristics:
• The surface of the seat should be situated horizontally. It is recommended also to tilt it towards the backrest up to the value of -5°+5°,
Fig. 3.29 A set of school furniture allowing the child freedom of movement while a listening, b writing, c reading
• The surface of the seat cannot be flat. It is recommended to use a bend at the front and back edge, so that the radius of rounding the front edge was significantly greater than the radius of rounding the rear edge,
• The depth of the seat should be adjusted in such a way that the distance between the edge of the worktop and the body’s trunk amounts from 5 to 10 cm, and
• the backrest supporting the back should have roundings and be tilted from the vertical by 5°-20°.
The requirements for tables are as follows:
• The worktop surface of the table for one pupil cannot be smaller than 60 x 50 cm,
• The worktop of the table should have the possibility of tilting from the horizontal by 0°-20°, and
• The space under the worktop is to ensure the ability to store schoolbags or other equipment of the pupil, not limiting freedom of movement in any way.
The standards do not specify the forms of design, construction, technology and
quality of materials; however, this data must be specified by the manufacturer of