Herman Miller Test Lab

The Toughest Seat In The House

The many ways the Test Lab at Herman Miller stresses out its chairs.

Deep in the heart of Portal Mill, our UK headquarters and manufacturing facility, is a hidden but critical department rarely visited by customers and shrouded in mystery. Join us as we lift the lid on the Herman Miller Test Lab.

For over 70 years, we’ve been putting our chairs (and desks, and accessories) through their paces. We test not only to international and global standards but also to our own internal standards, using higher loads and increased repetitions to ensure that our 12-year warranty stands up to its claim on every product we engineer. And when we introduce products so innovative that industry standards don’t yet exist, our team of engineers often lead the way by creating tests to thoroughly evaluate performance and quality over time. We estimate that 50 percent of the tests performed in our facilities are not conducted by any of our competitors.

Our chair testing process comprises six core stages:

The Million Cycle Test

This test replicates 12 years of continuous use, 24 hours a day, covering the equivalent of how a chair gets used over the course of 3 shifts. It includes the Load Test, which involves dropping a weight onto the seat, and the Backrest Durability Test, in which the backrest is fully reclined under force. Both mimic customers sitting down and reclining multiple times a day, over a prolonged period. All our chairs go through this rigorous process, which takes nearly 4 months to complete.

The Drop Test

Separate from the Load Test, a 130kg weight is dropped into the seat from 150mm four times ⁠-⁠ twice at a functional load and twice at a higher load while the chair is at its highest and lowest settings.

The Dual Arm Test

We've all been guilty of using the arm rests to push ourselves up and out of a chair, putting weight and pressure on them. The Dual Arm Test applies uneven pressure on each arm 60,000 times to replicate that activity 10 times a day, 5 days a week for over 20 years. Only when both arms are still structurally sound and fully functioning do they pass the test.

The Swivel Test

Swiveling can be stressful ⁠-⁠ maybe not for those of us spinning round, but certainly for the castors and base of the chair. In the Swivel Test, over 60,000 spins are carried out in each direction to simulate all the swivels a chair may need to perform.

The Shock and Humidity Test

As we’ve expanded our offering across the globe, it became apparent that we needed to factor in different climates, as well as the physical transport of goods from our main manufacturing site in the UK to mainland Europe. This resulted in the Shock and Humidity Test and the Transportation Test.

This test takes place over 3 weeks, exposing our products to temperature extremes of –18°C up to 60°C and a shock humidity of 48°C at 80% humidity (rather them than us!).

The Transportation Test

During the Transportation Test, our chairs and desks are boxed and dropped six times onto various faces, edges, and corners before undergoing a test journey to Scotland and back, putting our packaging in the spotlight to ensure it can withstand anything thrown at it.

The tests above only relate to the finished article. There’s also a plethora (estimated at over 2000) of tests that are carried out on raw materials and individual components. Notable additions include tests for the recent introduction of more sustainable and environmentally friendly water⁠-⁠based glues, which help us move away from more traditional substances while still ensuring they are fit for our purpose and will withstand wear over time.

Chris Owen, European Conformance and Testing Manager, said, “We test to the 95th percentile of European consumers, taking into account multiple requirements to meet the needs of citizens in our European markets. Our custom-built test labs enable us to run testing 24/7 for many months at a time. By carrying out such thorough testing, we not only ensure that quality is consistent, and our products will stand the test of time, but we also use it as an opportunity to learn, refine our designs, and develop new materials to help better our products in the future.”