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Frequently Asked Questions - Chairs

WHAT FEATURES MUST AN ERGONOMIC CHAIR HAVE?

There are five features that make a chair ergonomic:

  1. Seat height
  2. Seat depth
  3. Armrest height
  4. Backrest height
  5. Backrest  tension.

Required standards for an ergonomic chair (According to BIFMA, 2004):
Seat width: shall not be smaller than 450mm.
Seat height: Standard seat height shall be adjustable by at least 90mm within the ranges of 400mm to 560mm.
Seat depth: Shall adjust by at least 50mm and all include the range from 420mm to 460mm.
Armrest height: Armrest shall adjust by at least 50mm and including ranges from 190mm to 240mm. 
Backrest height: Standard backrest ranges between 450mm and 550mm. High back should be 75mm greater than the standard backrest.
Backrest angle: The backrest-to-seat angle range shall be from 93-113 degrees. When reclining, the occupants feet need to remain flat on the floor. 
Recline/tilt mechanism: Synchro mechanism or knee tilt mechanism. 
Lumbar support: The height of the lumbar support shall fall within the range of 150mm to 250mm above the seat.

WHAT IS THE DIFFERENCE BETWEEN THE HUMANSCALE LIBERTY / SMART / WORLD CHAIR?

The frame composition differs between the chairs. 

  • The World chair has a total weight of 14kg and the frame is made from Polypropylene. 
  • The Liberty chair has a total weight of 18.3kg and the frame is made from Aluminium. 
  • The Smart chair has a total weight of 15.4kg and the frame is made from Aluminium. 
  • The noticeable difference is that the World chair has a mesh seat, and Liberty / Smart   chairs both have foam seats, but they all have mesh backrests.
  • Fewer parts and components are used to assemble the World chair.
  • The shape of these chairs differ aesthetically.

WHAT CHAIRS ARE AVAILABLE IN STOCK AND OFFER THE SHORTEST LEAD TIME?

All ‘standard chairs’ are available and in stock in Johannesburg and Cape Town, with a lead time of 1 to 2 weeks. 

WHAT IS A ‘STANDARD CHAIR’?

WORLD CHAIR STANDARD OPTIONS:

-   Black World chair with Inhale (black) Oxygen fabric seat pan and carbon Monofilament mesh back rest. 

-   White World chair with Revive (light grey) Oxygen fabric seat pan and white Pinstripe mesh back rest. 

-   White World chair with Verdant (green) Lotus fabric seat pan and white Pinstripe mesh back rest. 

-   Grey World chair with Tranquil (dark grey) Oxygen fabric seat pan and carbon Monofilament mesh back rest. 

LIBERTY CHAIR STANDARD OPTIONS: 

-   Graphite (black) Aluminium frame with Inhale (black) Oxygen fabric seat pan and carbon Monofilament mesh back rest. 

 

SMART CHAIR STANDARD OPTIONS:

-   Graphite (black) Aluminium frame with Inhale (black) Oxygen fabric seat pan and carbon Monofilament mesh back rest.

 

FREEDOM CHAIR STANDARD OPTIONS: 

-   Graphite (black) Aluminium frame with Inhale (black) Oxygen fabric seat pan, backrest and headrest. 

 

 

WHAT FABRIC OPTIONS ARE AVAILABLE?

Various fabric options to choose from within the Oxygen and Lotus range. 

 

Oxygen fabric: Composed of 90% Wool and 10% Nylon, Oxygen is a lightweight

fabric with high abrasion resistance and stretch properties. Oxygen is a Second Nature branded climate neutral upholstery fabric with sleek, tailored appearance available in various fresh shades. A 100 000 Martindale cycles (rub count). 

Lotus fabric: Water-repellant and easy to clean. The ideal textile for healthcare and hospitality environment. A soft to touch texture with 350 000 double rubs (rub count). 

 

 

ARE HUMANSCALE CHAIRS AVAILABLE IN LEATHER AND WHAT ARE THE OPTIONS?

The Humanscale Freedom can accommodate a full set of leather cushions (backrest, seat pan, headrest and arm pads). 

The Humanscale Liberty and Smart chairs can accommodate leather seat cushions. 

The Humanscale World chair does not accommodate leather options. 

 

 

WHAT ARE THE VARIOUS FRAME COLOUR OPTIONS? 

World chair has three frame colour options: black, grey and white.

Liberty chair has the option of graphite, silver/grey and polished aluminium frame. 

Smart chair has the option of graphite, silver/grey and polished aluminium frame. 

Freedom chair has the option of graphite and polished aluminium frame. 

 

 

WHAT DOES THE WARRANTY/GUARANTEE COVER? 

Humanscale ergonomic seating has a 15 year warranty on all structural moving parts/structure of the frame; 10 year warranty on the gas cylinder and 5 year warranty on all high-ware parts (arm pads, casters, fabric and mesh). 

 

 

DO HUMANSCALE CHAIRS HAVE BACK LOCKING MECHANISMS?

Humanscale seating does not have black locking mechanisms. The body is designed to move and a back locking mechanism hinders this ability. When one is seated in a static posture for a long duration, this often leads to back discomfort. The ability to move/recline in your seat will encourage circulation within your body which will reduce discomfort. 

 

 

DOES A MESH BACK OFFER SUFFICIENT LUMBER SUPPORT?

Not all mesh backrests offer sufficient lumbar support. You will notice that many chairs with a mesh back have an arm extending/pressing against the mesh in the lumber area. This is there to give you more support. Humanscale chairs do not have this arm pushing against the mesh as the chairs have a patented mesh backrest that consists of three panels. This design, along with the contour of the frame, gives you all the lumber support you need. It also provides support through all the angles of recline. 

 

 

WHY IS IT IMPORTANT FOR A CHAIR TO HAVE ADJUSTABLE ARMRESTS?

We all have different arm lengths/anthropometric dimensions. Adjustable armrest heights will ensure everyone will be able to use the armrests at the optimal height. 

 

 

ARE THE CHAIRS AVAILABLE WITH VARIOUS CYLINDER HEIGHTS?

We have the following cylinder heights available:

Low                -          95mm

Standard       -          130mm

Tall                  -          135mm

High                -          205mm with foot ring

 

 

WHEN WOULD I NEED TO LOOK AT A CHAIR WITH A HEADREST? I.E. WHAT IS THE FUNCTION OF THE HEADREST?

If you are setting for long hours a day and need the extra neck support and if you have numerous screens. The Freedom Headrest features a dynamic support that cradles the head and neck during recline, but remains neutral when in upright positions. 

 

WHAT IS THE OPTIMAL RECOMMENDED SEATED HEIGHT?

Seat height is different for everyone. The ideal seated height is when your feet are flat on the floor and your hips are slightly higher than your knees. There should be an angle slightly greater than 90 degrees between your thighs and torso. 

 

 

WHAT IS THE BENEFIT OF SEAT DEPTH ADJUSTABILITY?

Seat depth adjustability is the ability to be able to increase or decrease the seat pan length. Not everyone has the same seat depth. Shorter individuals will need a shorter/smaller seat pan and  taller individuals will need a longer/larger seat pan. There should always be a 2-5cm gap between the back of your knees and the front of the seat pan to eliminate any pressure. Pressure behind your knees will limit/reduce blood circulation to your feet. 

 

 

WHAT IS THE OPTIMAL SEATED ANGLE I SHOULD MAINTAIN WHILE WORKING?

We have been told that sitting at 90 degrees is the best seated posture however the optimal seated posture should be more recline, 100-110 degrees. The more recline you are seated, the less unequal pressure is applied on your intervertebral discs. When you are seated upright (90 degrees) or lean forward, you flatten your spine and this creates more unequal pressure on the intervertebral discs. 

 

 

HOW DO I SET THE TENSION OF THE CHAIR?

There is no tension set lever on the Humanscale chairs. Humanscale chairs have a weight sensitive recline mechanism therefore it will support your body in any recline position.

 

 

HOW SHOULD I POSITION MY ARMRESTS WHEN WORKING AT A DESK?

Most individuals place their armrests too low as they want to sit closer to the desk. However, if you don’t use your armrests, you have constant muscle activity in your neck and shoulders to maintain a typing, arm position. This often leads to muscular discomfort. It is recommended that you place the armrests at desk height and if your feet are not flat on the floor, then it is recommended that you use a footrest.  

 

 

WHAT ARE CASTERS?

An undriven wheel that is attached to the bottom of a larger object to enable that object to be moved. Casters are used in numerous applications, such as office chairs.

 

 

WHAT ARE GLIDES?

These small discs are attached to the bottom of a chair's legs, allowing the chair to “glide” over floors with some force.

 

 

WHAT TYPE OF CASTERS ARE USED FOR WOODEN FLOORS / TILES / CARPETED FLOORS?

Wooden floor - soft casters

Tiled floor - soft casters 

Carpeted floor - hard casters