Heavy Duty Office Chairs
Heavy-Duty Office Chairs Built for Bigger Bodies and 24/7 Workplaces
Most office chairs aren’t built for every body or every environment. They can feel small, unstable, or weak, leaving you shifting uncomfortably, worrying about safety, and losing focus on the work that matters.
Heavy-Duty Chairs Solve Two Distinct Challenges:
a. Continuous Use in 24/7 Environments
Control rooms, call centres and other high-demand settings require chairs that can endure 24/7 use. Our heavy-duty chairs are engineered with reinforced components and tested for long-lasting performance, so teams can rely on them day and night without fear of failure or downtime.
b. Support for Bigger Bodies
If you are a larger individual, you need more than a standard office chair. A wider, deeper seat and robust construction provide stability, comfort and confidence during your working day, so you can focus on your work without discomfort or distraction.
Whether your priority is 24/7 durability or accommodating a larger body, our heavy-duty chairs deliver safety, support and peace of mind, so you can concentrate on the work that matters, not your chair.
Categories
Firefly Ergonomic Office Chair
Alya Ergonomic Office Chair
Heathrow 24/7 Heavy Duty Chair
R8950 incl VATWhat is a Heavy-Duty Office Chair?
Our heavy-duty chairs are engineered using high-strength materials, reinforced frames, upgraded gas lifters, and high-quality swivel mechanisms, ensuring they can endure heavier weights and extended use while preserving both comfort and structural integrity.
“When a standard office chair is deployed in a heavy duty environment, two common outcomes typically emerge. Either the chair’s performance and longevity suffer, or it might unexpectedly fail, potentially resulting in injury.”
Components used for Heavy Duty Office Chairs
1. The Base Set
a. Castors or wheels
Our heavy duty office chairs all have large diameter castors as they have a higher load carrying capacity.
For example, 60mm diameter castors have a higher carrying capacity than 50mm ones and they are more manoeuvrable.

b. The 5-Star base
5-Star bases are made either from aluminium, glass reinforced nylon, or formed steel tubing.
- Aluminium bases have a very high weight carrying capacity and can be recycled. For this reason, most of our heavy duty office chairs have aluminium 5-star bases.
- Bases made from nylon with glass fibre reinforcing have become extremely popular. With the correct design structure, quality nylon, and a 30% glass fibre reinforcement filling, nylon bases are a good choice for heavy duty office chairs. These bases provide excellent strength and are flexible enough to move easily over slightly uneven floors.
- Bases welded together from steel tubing are known to fail along weld lines. Such failures usually occur without warning and may result in injury. For this reason, none of our heavy duty chairs have a welded steel base.
c. Gas lifter
The gas lifter allows you to raise and lower the seat height of the chair. It also acts as a ‘damper’ to cushion the impact when you first sit down. Gas lifters should be manufactured in accordance with a specific international design standard, for example DIN EN 16955-2017. If they are, they will carry the applicable mark or logo as well as a Class Rating. Our heavy duty chairs have a Class 4 gas lifter which has a higher load rating than the standard Class 3 found on most office chairs.
2. The swivel mechanism on heavy duty office chairs
The mechanism enables you to adjust the movement of the seat and backrest. Adjustments include the angle of the seat and backrest, the depth of the seat (important for taller individuals), the seat height, and the tilt tension.
The strength of the office chair mechanism in a heavy duty environment is vital. To ensure that the mechanism is suitable, all our heavy duty chairs have mechanisms that have been strength tested by SABS or BIFMA.
The mechanism on Karo’s Heathrow chair was tested and certified by the SABS in 2005. The procedure involved cycling a weight of 200kg on the mechanism 300 000 times!

3. The Seat on heavy duty office chairs
Seats for chairs used in a 24/7 environment need to be strengthened to “carry the load”. Normal or standard office chair seats are not designed for a heavy duty application.
Common materials used for the seat base are plywood, polypropylene or nylon. A seat suitable for a heavy duty chair needs thicker plywood with more laminations. Heavy duty seats made from polypropylene or nylon require additional structural webs or steel reinforcement.
The Ortho2XL chair has an extra large seat and backrest to accommodate people with a larger frame.
4. The Backrest of heavy duty office chairs
For any office chair, the backrest support structure is not as heavily stressed as the seat. Upholstered plywood backrests do not normally require additional reinforcement, while polypropylene shells typically have standard web reinforcements. If the chair has a mesh backrest like the Alya and Firefly, the supporting frame should be made of a good quality, glass fibre reinforced nylon. Other plastics are simply not strong enough for heavy duty applications.
When do you need a Heavy Duty Office Chair?
Heavy duty office chairs are the preferred choice for:
- 24/7 applications like a call centres or control rooms, or
- Larger individuals who require a chair that can support their frame.







