My Observations of the Office Chair ANSI/BIFMA X 5.1 Standard.
One standard used in the design and testing of office chairs is the American National Standards Institute/BIFMA X 5.1 standard. This standard caters for a range of expected sizes that an adult may be, however in general and in my opinion does not really cater for the smaller sized adult or the bigger sized adult or the wider sized adult.
So it is not really surprising to discover that many small compact office chairs may not actually follow the Office Chair ANSI/BIFMA X 5.1 2017 Standard as these specifications may be too severe for the smaller sized adult who also weighs less.
The Office Chair ANSI/BIFMA X 5.1 2017 Standard includes a weight limit of 275 pounds. This was based on the weight of the 95th percentile adult male which when the ANSI/BIFMA X 5.1 2017 Standard was being developed was around 275 pounds.
What does 95th percentile adult male weight mean?
Loosely speaking, 95 per cent of the adult male population in the United States weighed 275 pounds or less according to the United States CDC/NCHS, National Health and Nutrition Examination Survey of 2007-2010 (Source: pdf file at the CDC website).
Again loosely speaking, 5 per cent of the adult male population in the United States weigh more than 275 pounds according to the above mentioned survey.
In case, you are wondering, 95 per cent of the adult female population in the United States weighed 251 pounds or less according to the above mentioned survey.
Of course, some different race, ethnicity and age categories within different groups weigh more than this overall result for “All racial and ethnic groups”, both for adult males and for adult females. And some weigh less.
The previous version of this standard was based on a weight of around 250 pounds. With the revised weight limit of 275 pounds, this means that weight related tests now have to withstand successfully the heavier weight in order to pass these weight related tests.
The tests in this standard are intended to assess the performance of new products only. They are not intended to assess a product that has been in use.
Source: BIFMA website
I do find this interesting. It suggests to me that an office chair manufacturer would still claim that they are compliant with the ANSI/BIFMA X 5.1 Standard if they were manufacturing/marketing that particular office chair model prior to the 2017 version of the standard “kicking in”.
What about other human measurements?
From what I can see and understand, the Office Chair ANSI/BIFMA X 5.1 2017 Standard only seems to be “seriously” interested in the human weight measurement.
Just because 95% of the United States adult male population are below 275 pounds does not mean that 95% of the United States adult male population can sit comfortably in a chair that passes the Office Chair ANSI/BIFMA X 5.1 2017 Standard. Just saying.
Weight is important however so are other human measurements. If office chairs had standard sizes applied worldwide, that would help buyers to buy office chairs, even if there was overlap between the different office chair sizes as people come in all sizes.
Of course, it is up to the office chair manufacturer to determine which standards that they follow if any. However many organisations and many people when purchasing products or services may specify a standard. For those organisations or those people if a product or service does not have that standard, they are excluded from further consideration. This then “persuades” manufacturers and sellers to ensure that their products or services obtains “certification” to these standards.
However if manufacturers or sellers mention in their specifications or in their advertising materials or in their marketing materials or in any other materials that the chair follows certain standards they should in my opinion be very clear about which standards and which levels.
The Office Chair ANSI/BIFMA X 5.1 2017 Standard does not refer to specific human seat width measurements although the Office Chair ANSI/BIFMA X5.11 Large Occupant Standard does. I understand that this particular standard has a similar scope to ANSI/BIFMA X5.1 with the following main differences:
- It uses a 400 pound male as the basis for its test loads
- And the seat width must be 22 inches or greater to be tested to this standard
I do think that both these standards should include more actual human measurements in their specifications. There are office chairs that may pass the BIFMA tests however have a narrow seat width that many adults will not be able to sit into. Just saying.
I have noted compact small office chairs with a narrow seat width of 18.5 inches. Any person with a clothing hip size of between 35″ and 36″ may find this particular chair to be a very tight fit and may not really be able to fit into it comfortably. And of course, then there is also the weight factor which also needs to be considered.
I have also noted compact small office chairs where the seat width is not specified. The width of the package may be specified however it is not really possible to estimate the seat width. Many compact small office chairs purchased online are of course self assembly. So people buy the chair, assemble it and then find out that the chair is not suitable but because they assembled it they can’t return it for a refund. That hurts.
I have noticed specifications for office chairs which includes a statement something like the following “all the accessories of this office chair have passed the test of BIFMA, which is a guarantee for your personal safety. The chair can bear the weight of 250 pounds”. I have noticed that the “date first available” included in Amazon Product Information details being more than 2 years after the Office Chair ANSI/BIFMA X 5.1 2017 Standard was introduced. These are in my view technically new chair models and in my view to claim that “all the accessories of this office chair have passed the test of BIFMA … The chair can bear the weight of 250 pounds” is misleading as the Office Chair ANSI/BIFMA X 5.1 2017 Standard clearly specifies that the weight limit is 275 pounds.
Many people purchasing office chairs may have some sort of checklist that the chair most fulfill and “passing BIFMA” may be one of them. Which weight limit do the office chairs you are purchasing have to satisfy? I would think that if you are buying for yourself, you would take some measurements, including height, hip size and weight measurements and take it from there. If you are buying chairs for a business, you would I assume go with the newer ANSI/BIFMA X 5.1 2017 Standard, as that would be the safer thing to do as you have no idea the sizes of people who may use the chair in the future.
I assume office chairs that are truly Office Chair ANSI/BIFMA X 5.1 2017 Standard compliant to be more expensive than chairs that technically are somewhere between the ANSI/BIFMA X 5.1 2011 Standard and the ANSI/BIFMA X 5.1 2017 Standard.
Many office chairs for instance are manufactured in China and used in the United States. Due partly to different sizes of people in China and in the United States, and to different standards, it is very important in my view that the expected people to use the office chairs are measured to make it more likely that the office chairs are able to be used for their intended purpose over the expected lifetime of the office chairs. However, you can’t measure people who are not employed by the business yet. This is where having very clear chair sizing standards would help.
Office chairs have an expected lifetime with normal disclaimers. BIFMA have an Office Chair ANSI/BIFMA X 5.1 2017 Standard and an Office Chair ANSI/BIFMA X5.11 Large Occupant Standard. Maybe they need an Office Chair ANSI/BIFMA Small Occupant Standard as well. Just saying.