Newton (N) in Gas Struts: Force Rating & Load Capacity Explained

The unit Newton (N) indicates the extension force of the piston rod in a gas strut. This physical value defines the load capacity of the fitting and determines which flap weight can be reliably opened and held open at a specific flap height. An incorrect N rating leads to the furniture flap dropping down or jamming.

What exactly does the Newton specification on gas struts mean?

A gas strut (technically also called a gas spring) consists of a cylinder and a movable piston rod. The nitrogen gas hermetically sealed and compressed inside the cylinder creates constant internal pressure. This pressure results in the extension force, which is measured in Newtons. As soon as the flap is released, this force pushes the piston rod outward and lifts the front.

Technically important: A gas spring is not a door damper for a soft-close mechanism. Whilst a buffer merely brakes a movement and absorbs kinetic energy, the gas spring actively generates force to lift and statically hold loads. Roughly converted, 10 N corresponds in vertical practice to roughly the lifting force for 1 kg of weight. However, because furniture flaps rotate on hinges, the lever effect must strictly be included in the calculation.

Typical values and standards for furniture flaps

In furniture construction, the force of the struts is standardised to allow straightforward allocation to common flap formats. The standard spectrum usually ranges from 50 N to 150 N.

A flap fitting for heavy fronts, for instance made of solid wood or thick MDF boards, requires significantly more power due to the higher dead weight. This is where gas struts for heavy flaps are used. These components provide extension forces of 200 N, 250 N, 350 N or in exceptional cases up to 500 N. The stroke (the maximum extension distance of the piston rod in mm) often remains identical to weaker models; only the gas pressure inside the cylinder is higher.

Calculation and selection of the correct load capacity

Selecting the exact matching N rating is like balancing a beam scale: The force of the strut must precisely counteract the torque of the flap.

If the strut is dimensioned too weakly (e.g. 60 N for a heavy solid wood front), the flap sags down. If it is too strong (e.g. 250 N for a light chipboard front), the flap shoots up uncontrollably, can hardly be closed, and the hinges will tear out of the carcass over time.

Three factors are decisive for determining the required Newton rating:

1. Weight of the flap: Including all attachments such as a furniture handle or profiles.
2. Height of the flap: The height determines the length of the lever arm. A 600 mm high flap requires more force than a 300 mm high flap of the same weight.
3. Opening angle: Depending on the hinge type (usually 75°, 90° or 110°), the centre of gravity of the open front changes.

Installation and interaction with other fittings

To prevent warping of the wooden front and to distribute the load evenly across the cabinet carcass, gas struts are fundamentally installed in pairs (left and right). Fixing to the side panels and to the inside of the flap requires drilling distances precise to the millimetre. These distances define the operating angle and ensure that the piston rod is fully retracted when closed.

The strut always works in conjunction with the upper concealed cup hinges. To secure the round or oval mounting plates to the carcass and front, wood screws and furniture screws with a diameter of 3.5 mm or 4 mm are used. For very light flap constructions, a mechanical flap stay without gas pressure can alternatively be used.

Related terms

• Stroke: The working travel of the piston rod in mm (difference between retracted and extended state).
• Extension force: The power output of the gas spring specified in N.
• Concealed cup hinge: The concealed hinge that forms the pivot axis of the flap.

Related categories

• Gas struts
• Gas struts for heavy flaps
• Flap fittings