Abstract
The Business and Institutional Furniture Manufacturers Association published a new educational seating standard in 2012. (See the sidebar for BIFMA details.) Discussions during the development of this standard included the anthropometrics of children. These discussions showed that the large anthropometric databases available for children are outdated and do not represent the current student population. The standard was finalized following receipt of input from ergonomists on how children’s sizes have changed, but it does not cover the ergonomic design of seating for children. A current large-scale anthropometric data set for children would have been beneficial in developing loads in the standard as well as in recommending sizes for educational furniture.
Despite the relative lack of children’s anthropometric data, this standard is a critical step toward better accommodation of their educational needs.
On November 2, 2012, the American National Standards Institute (ANSI) approved the newly developed safety and performance standard for educational seating: ANSI/BIFMA X6.1-2012: Educational Seating – Tests. The Business and Institutional Furniture Manufacturers Association’s (BIFMA) Seating Subcommittee worked diligently to create this new industry consensus standard using several test methods from existing ANSI/BIFMA seating standards as a basis. ANSI/BIFMA X6.1-2012 involved the development of several unique tests relevant to the educational environment, including tests for educational products, such as convertible benches, chair desks, and backpack hooks (BIFMA International, 2012).
We were on the committee that promulgated the standard and, as such, were uniquely positioned to contribute human factors/ergonomics (HF/E) knowledge and approaches to its creation, which we describe in this article.
Background and Development
Although BIFMA had several variations of chair standards dating from 1974, there was no specific test standard for classroom seating. The educational seating standard was initiated in 2008 and put to a member vote by 2011. This period may seem like a long time to gain industry consensus on methods and specifications necessary for this type of standard, but it is typical of the lengthy process of defining and refining an entire branch of manufacturing within the furniture industry.
This particular standard defines specific tests, laboratory equipment, conditions of test, and recommended minimum levels to be used in the test and evaluation of the performance, durability, and structural adequacy of educational seating. The standard does not cover things such as user comfort, academic performance, and ergonomic features such as adjustment ranges. Although designers in the United States have included that type of information for adult office workers in the ANSI/HFES 100-2007 standard and the BIFMA G1-2013, we have not yet developed a similar standard for school furniture.
ANSI/BIFMA X6.1-2012, as is the case with most standards, starts with a scope, definitions, and general information about tests, terminology, and types of chairs to be covered. In general, it covers seating products normally used in schools and colleges: stacking chairs, tablet-arm chairs, chair desks, stools, cafeteria tables with attached seating, and convertible bench/tables. Tests included in the standard are related to different components of the chair; for example, the backrest (i.e., strength and durability), chair base, tilt mechanism (if applicable), seat (i.e., impact), stability (will it tip over too easily?), arms (strength and durability), casters, leg strength, footrest, and tablet arm (if applicable). Indexes in the standard include explanations of how to create the materials needed for testing, along with some of the more unique tests that came up during the standard’s development.
Consensus Process
When building consensus among many subject matter experts, a common technique used to keep the process moving is, first, to employ the larger group of 30 to 40 people to clearly define a set of needs related to an area of the standard and, second, have a smaller group of agreed-upon experts meet separately to research, clarify, and write a specific test or test definition. The size variations between small and large educational seating settings are too vast to allow a one-size-fits-all approach to testing. As such, definitions of what products in the market generally look like must be evaluated against size ranges of children who are likely to use those products.
After agreement is reached on what the users will look like, efforts are made to use extremes in that population to build in safety factors. Assumptions also had to be made to simulate 10 years of use during a typical 180-day school year to develop the number of cycles for which to test a chair in a controlled lab environment.
Because the standard involves performance measures, it is critical to understand not just who will use the product but also how they are likely to use and abuse it. For example, it is likely that a child will lean back in a chair on the two rear legs. Agreeing that educational seating should be designed to discourage bad outcomes from this behavior was the first step. Deciding how to “qualify” a chair as acceptable in this effort was an entirely different challenge.
An example of something the group did not take on is the possibility that a “plus-size” teacher might step onto the seat to reach something. Although this might happen, it is beyond the scope of “reasonable use,” so the standard team felt it did not fit into the scope of the standard. That said, an ANSI/BIFMA team spent the past few years developing the X5.11-2015 Large Occupant Office Chair Standard to help address the growing need for larger-capacity seating and how to test those products that claim to be up to the task. This standard was approved by ANSI on January 5, 2015.
The HF/E Connection
The most significant HF/E-related discussions came to focus on anthropometry databases, with concerns about the effect of obesity on the size of children and how these changes affect the structural design and testing of the products covered by the standard.
Research for the type of information needed in this standard came from sources such as the CAESAR anthropometric database (Harrison & Robinette, 2002); NHANES (combined data set for the years 2005–2008; Centers for Disease Control and Prevention, 2003–2008); BS EN 1729-2:2006 (British Standards Institution, 2007); Molenbroek, Kroon-Ramaekers, and Snijders (2003); regional anthropometric data from Benden (2011–2013); CHILDATA (June 1995; Norris & Wilson, 1995); sizing of current educational seating on the market; and peer-reviewed papers on use and proprietary industry experience based on internal testing and warranty experience. When using the NHANES (2005–2008) data sets, all persons older than 22 years were deleted from the subject pool, as were all pregnant girls. Percentiles for height and weight were calculated for the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles for both girls and boys and then compared with age and level/grade for students.
Because the NHANES data included only height and weight data, we also reviewed historical anthropometric data from CHILDATA (Norris & Wilson, 1995), which is a compilation of anthropometric studies of children around the world. Of specific interest were anthropometric measurements (for example, hip breadth, buttock-to-popliteal length, and popliteal height) that would help in identifying what seat height/width would be applicable for children and provide input on the design of the bag that would hold the load that would be in the seats or dropped into seats during testing. The CAESAR (Harrison & Robinette, 2002) data were used to identify where the anthropometric data for children younger than 22 years old overlapped with anthropometric data for adults.
Select furniture companies provided measurements of some of their current educational furniture and the grades of children who typically use it. The ages for these grades were then identified to determine if the anthropometric measurements for children of the ages that typically use the chairs matched the current chair sizing (see Figures 1 through 4).
Current industry practice: Height (in.) 5th percentile female and 95th percentile male.
Proposed industry practice: Height (in.) 5th percentile female and 95th percentile male.
Current industry practice: Weight (lbs) 5th percentile female and 95th percentile male.
Proposed industry practice: Weight (lbs) 5th percentile female and 95th percentile male.
The compilation and comparison of all these data helped the team conclude that without a recent anthropometric database of children’s measurements, it was not possible to make recommendations on changes to the sizes of chairs for children. Ultimately, the decision was made to use seat heights and children’s weight to group the chairs into three sizes that would be used in the standard (see Table 1). The anthropometric data also were the basis for recommendations regarding the loads for tests and the dimensional criteria for the bag that would hold the test loads.
Chair Sizes
Note. Reprinted with permission of the Business and Institutional Furniture Manufacturers Association.
Conclusion
The successful completion and approval of ANSI/BIFMA X6.1-2012: Educational Seating – Tests shows that including ergonomists on BIFMA standards committees allows for the furthering of HF/E issues and more informed standards. It also clearly identified the need for a more current anthropometric database of children in North America that includes more than just height and weight. Such a database would enable ergonomists to provide more up-to-date data that designers and manufacturers of children’s products could use to achieve a better fit of their products with the intended population.
Matt Reed (Reed & Ebert-Hamilton, 2012) at the University of Michigan’s Transportation Research Institute has been collecting anthropometric data on children ages 4 to 11 for use in the automotive industry. At present he has collected data on 162 children and recently presented his child anthropometry approaches using depth cameras and body shape models (Park, J. Lumeng, C. Lumeng, Ebert, & Reed, 2014). It is hoped that this data collection effort will continue to measure children as well as expand to ages 12 to 18 and then be made available for use by industries other than just automotive.
Mark Benden (2011–2013) and his team at Texas A&M have also collected anthropometric data on more than 500 children in relation to school furniture that they hope to publish in the next 2 years. Most recently the team released ergonomics details on posture and comfort for children in school furniture with design implications for obese children (Benden, Pickens, Shipp, Perry, & Schneider, 2013).
BIFMA is the not-for-profit trade association for business and institutional furniture manufacturers. Since 1973, BIFMA’s role has been to sponsor the development and refining of current and future standards, educate on their importance and application, and translate their necessary complexity into more easily understood and implemented formats. BIFMA also monitors the state of the industry, serves as a forum for member cooperation and collaboration, interacts with international counterparts, and advocates for regulatory conditions that foster value and innovation. Copies of the new standard are available from BIFMA (https://bifma.org/secure/orderform.html).
Discussion
Current school furniture design is greatly influenced by the following:
Lack of ergonomics design guidelines for educational furniture: A current large database of children’s anthropometric measurements is needed to develop this.
One-size-fits-all approach: Schools often purchase the same size chair for all grades despite the availability of several sizes from manufacturers.
Cost: Schools often lack the financial resources to spend a lot on furniture, so low-cost, nonadjustable furniture is predominant in most schools.
Design for custodial staff: In many cases, the design of seating is based on stacking and cleaning requirements.
We also know that children become more restless and inattentive with prolonged sitting. The increase in inattention and restlessness could be attributed to the novelty of the task or even the design of the furniture. Teachers want better classroom management, better student engagement, and, ultimately, improved learning. Although dynamic workstations may reduce disruptive behavior problems and increase students’ attention or academic behavioral engagement by providing them with a different method for completing academic tasks (e.g., standing) that breaks up the monotony of seated work, such workstations would still need to be sized to appropriately fit the current student population.
However we proceed, new approaches for designing school furniture should be in harmony with children’s natural habits, tendencies, engagement, and sizes. Now that we have a standard for testing structural issues related to school furniture, perhaps it is time to develop a standard for classroom furniture ergonomics.