Optio BSF70 HI Bi-fold Door


Folding and Sliding Doors


Welcoming, stunning, practical.

An intelligent combination of form and function, our highly versatile and market-leading Bi-fold sliding door system gives you maximum control over the style and operation of the doors.

Multiple panels can be added to accommodate the design specifications of your building, with the option to open in or out as required. The system also boasts a unique flush line pop-out handle that allows for square flush stacking panels when doors are fully open.

Now with the option to use our Quik Clip for faster installation. 

The BSF70 HI performance, achieves impressive U-values of 1.4 Uw with double glazing and 1.1 Uw with triple glazing.

BSF70 HI Data sheet

Click this link to access the NBS Chorus page for this product and specify it for your project:


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Design features

  • Certified under the Secured By Design scheme
  • Tested to PAS 24
  • Unique, pop-out handle that allows for maximum door opening and panels to stack square
  • Four stainless style rollers to ensure smooth and consistent operation


  • Chamfered and square bead options
  • Glazing 28mm – 44mm
  • Available in a range of opening configurations
  • Available with heavy duty rollers; BSF70 HI HD
  • Available in a range of single or dual colour and anodised finishes
  • QuiK Clip bead available with 28mm glazing
  BSF70 BSF70 HD
U value W/m²K (Double glazing) : 1.6 W/m²K 1.6 W/m²K
U value W/m²K (Triple glazing) : 1.4 W/m²K 1.4 W/m²K
Air tightness (Pa) : Class 4 (600 Pa) npd
Water tightness (Pa) : Class 9a (600 Pa) npd
Wind load (Pa) : Class AE2400 (2400 Pa) npd
Certifications : Q-mark npd
Air permeability : Class 4 (600 Pa)
Water resistance : Class 9a (600 Pa)
Security PAS 24 : X npd
Opening : Open in and open out Open in and open out
2-2-0 : X X
3-3-0 : X X
3-2-1 : X X
4-4-0 : X X
4-2-2 : X X
4-3-1 : X X
5-5-0 : X X
5-3-2 : X X
5-4-1 : X X
6-6-0 : X X
6-3-3 : X X
6-4-2 : X X
6-5-1 : X X
7-7-0 : X X
7-4-3 : X X
7-5-2 : X X
7-6-1 : X X
Size limits
Max Vent Weight : 100 kg 130 kg
Sightline (Head) : 110mm 110mm
Sightline (Cill) : 130mm 130mm
Sightline (Jamb) : 110mm 110mm
Sightline (Meeting Stile) : 140mm 140mm
Max sash width (mm) : 1200 1200
Max sash height (mm) : 3000 2400
Frame dimension : 70 mm 70 mm
Dual color option : X X
Multi-point locking : X X
Glazing options : Internal bead Internal bead
Glazing thickness : 24mm - 40mm 24mm - 40mm
U value W/m²K (Double glazing) : 1.4 W/m²K
U value W/m²K (Triple glazing) : 1.1 W/m²K
Wind load (Pa) : Class E2400 (2400pa)
Certifications : X
Size limits
Max glass thickness (mm) : 40mm
Max sash width (mm) : 1200mm
Max sash height (mm) : 2400mm std/ 3000mm
Frame dimension : 70mm
Dual color option : X
Multi-point locking : X