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Performance of Triple Glazed Sliding Doors

IFT certification from the Rosenheim Institute...

When it comes to triple glazed sliding door performance values, you can’t beat the minimal windows® 4+.

This sliding door system enables architects to create; larger, taller and more thermally efficient sliding glass doors with triple glazing. However, the impressive innovations of this system can now go even further. 

The successful and improved performance IFT certification from the Rosenheim Institute for burglar resistance and sound insulation widen the applications of these minimally framed doors. 

With this system you can create large sliding doors with tested sizes up to 4.5m high and 12m² for each sliding glass paneIt’s important to remember that these are the maximum sizes the triple glazed sliding door has been tested to. 

When considering other factors such as the wind load in the area, larger sizes can be achieved, we’ve installed systems up to 6m tall!

juliet balcony with sliding glass door and glass balustrades
triple glazed slim sliding doors in luxury home

Are Triple Glazed Sliding Doors Secure?

When it comes to triple glazed sliding door performance in terms of security, our system has been tested to both the high European standards and UK standards, surpassing all requirements 

The burglar resistance ‘WK’ (Widerstandsklasse) designations were replaced with ‘RC 2’ (resistance class) for the UK market and the minimal windows® 4+ sliding door has successfully met the criteria for frame, fittings and glazing for RC2. 

Compliance with class RC 2 automatically includes compliance with class RC 2 N, both classes are mentioned in the test report. The RC 2 certification for minimal windows® 4+ enables architects to create a secure slim framed sliding glass door which is also aesthetically pleasing and can be incorporated into many unique designs. 

In terms of ‘Burglar Resistance’, the triple glazed sliding door performance is exceptional, and the system was tested to EN 1627 to ensure protection against forced entry. 

If you are looking for a sliding glass door with PAS 24 certification, our minimal windows Sliding Door is the first sliding glass door in the UK to have passed the testing as a door for PAS 24. 

triple glazed floor to ceiling slim sliding doors with flush threshold
modern glass home extension with triple glazed, oversized sliding glass doors from minimal windows

Triple Glazed Sliding Door Performance: Weather Testing

Wind Load

Wind load refers to the amount of pressure caused by wind that the glass must be able to resist

The triple glazed minimal windows® 4+ sliding door system offers exceptional sliding door performance values alongside super contemporary design.  

Due to the triple glazing, these sliding doors provide impressive insulation to retain a comfortable internal living space, especially during strong winds. 

With structural glass bonded into high quality aluminium framing profiles, our triple glazed sliding door performance in unparalleled.  

In terms of the wind load for triple glazing sliding doors, the minimal windows 4+ system achieves C5 to EN12210, tested to +/- 4500Pa wind pressure to TAS 202. 

Air Permeability

Air Permeability refers to the amount of air that is able to travel through a window or door system in its closed position 

A large part of this is ensuring where the glass and the frame meet is bonded securely. Systems that using glazing bead to secure the glass in place are not only less secure but will also allow more air through. 

The minimal windows triple glazed sliding door performance in terms of air permeability is excellent, with the system undergoing rigorous testing and achieving Class 4 to EN12207. 

Water Resistance

Building Regulations Approved Document A details many aspects of building construction that should be considered in line with its location and positioning in the landscape.  

This means that different locations around the Uk will have different requirements when it comes to triple glazed sliding door performance in regard to wind loading.  

At the maximum tested sizes, our 4+ triple glazed sliding door achieved a wind load of E1050 to EN12208, tested with 3.4 litres/ m² / min to TAS 202.  

This is not always needed, and the minimal windows 4+ sliding door was actually specified on a project in central London where due to the low wind loading in the area the doors could be installed a nearly 6m tall.  

triple glazed sliding door performance values
slim framed sliding glass door in London

Triple Glazed Sliding Door Performance: Sound Insulation

The improvement in sound reduction is a significant innovation especially useful for urban projects close to busy roads or transportation.  

The minimally framed sliding glass doors were tested with a brush seal and demonstrated a sound reduction index of 43 decibels.  

This is a key factor for Passivhaus standards and modern urban planning enabling these minimal sliding doors to be incorporated into numerous sustainable home designs. 

Lastly the ongoing endurance test shows no signs of wear on the frame with 34,610 complete opening cycles. This test enables us to prove durability and quality of minimal windows® system allowing us to provide a high quality product as well as guarantees. 

The minimal windows® 4+ sliding-fix construction (4,190 x 2980 mm) were tested for sound insulation. 

pool glazing by an indoor swimming pool with large triple glazed sliding glass doors
minimal windows 4+ triple glazed oversized sliding glass doors by an indoor pool in a luxury home in the countryside

Triple Glazed Sliding Door Endurance Test

The large sliding doors (3,100 x 4,000 mm and a weight of 993 kg per leaf) are currently being tested at our own premises – showing no signs of wear on the carriage and rail system or on the drive with the KELLER MOT2000. 

The endurance test is presently continuing 

  • RC 2 “Increased protection for normal housing security” 
  • Sound Reduction Index of 43dB 
  • 34,610 complete opening cycles 

This increased testing puts our minimally framed sliding glass doors – minimal windows® 4+ – to the test and the results prove their incredibly high quality and the impressive technologies used within the fabrication process. 

minimal windows® have been used on numerous contemporary home offices in gardens, providing the all-important separate space for work using large minimal framed sliding glass doors at the forefront of the design. 

slim sliding glass doors in a rear extension in midlands traditional house
thermally broken triple glazed ultra-slim sliding glass doors

Triple Glazed Sliding Door Thermal Performance

To show the thermal performance of a glazing system, a combination of a value will be shown as Uw, and it is measured in Watts per metre squared Kelvin, shown as W/m2K. 

The lower the number the better, as this number represents how much heat energy is able to pass through the glazing system.  

Our minimal windows 4+ triple glazed sliding doors can reach Uw values as low as 0.8 W/m2K, with an average Ug value of 0.6 W/m2K. 

This will have to be calculated on a project by project basis as factors such as the size of the door and glass specification can affect this. 

minimal windows 4+ oversized sliding doors in a commercial venue
traditional wedding venue in Newbury with triple glazed steel look sliding doors

Does Triple Glazing Improve Energy Efficiency?

Triple glazed doors improve the energy efficiency of a home as with the extra insulating gas cavity, extra glass pane and deeper thermally broken frame profile, the system achieves higher thermal efficiency levels than double glazed sliding doors.  

All minimal windows glazing systems are manufactured with a low e coating as standard, something many glaziers charge extra for, to allow the systems to achieve unparalleled thermal performance values. 

With updates to Approved Document L of the UK Building Regulations which came into effect in June 2022, there is now a larger emphasis on sustainable home design and creating a thermally efficient building envelope.  

A huge part of this will be down to the glazing, and we have already started to see an increase in the use of triple glazing for high-end residential and commercial projects.  

double height oversized slim sliding doors with ultra-minimal framing
three pane double height sliding glass door with minimal aluminium framing in a double height kitchen-diner

Hurricane Tested Sliding Glass Doors

Our triple glazed sliding door performance exceeds all expectations, even undergoing hurricane testing and again, surpassing all requirements.  

The hurricane resistance testing involved cyclic wind pressure loading tested to 3510Pa in accordance with TAS 203. This makes the minimal windows 4+ system ideal for any areas with a high wind load, such as coastal facing properties.  


For more information on triple glazed sliding door performance values, contact the minimal windows team today.