Main focus when specifying windows for high-rise buildings
There are two key factors that needs to be considered when specifying windows and doors on high-rise apartment blocks.
The first and most important is safety in operation and the second is weather performance.
Glazing Strategy
At the early stages of design, the decision on how windows are to be cleaned, maintained and re-glazed needs to be addressed. This decision really boils down to whether the proposed strategy is an external or an internal one.
If an external strategy is chosen, this means the use of special plant, such as roof-top mobile access equipment and/or abseilers for example.
If an internal strategy is chosen, then the design and choice of window is critical. There are various types of hinges/operation of windows on the market that allows cleaning the external pane of glass from the inside. These include – top-hung reversing, horizontal pivot, vertical pivot, side swing reversing and side guided, all of which open out. Then there are inward opening windows – side hung and tilt & turn.
Of all the above types of operation the safest by far, in our opinion, is with an inward opening window, such as the side hung or tilt and turn. The reason being is that any cleaning, maintenance or re-glazing is carried out safely within the apartment room.
Cleaning
With outward opening windows there can always be an element of having to lean out to operate the windows and if hinge mechanisms have not been regularly maintained they can become “sticky” and difficult to operate, especially if they are quite large. This has a risk, in that the occupant may have to reach out a long way to try to pull the window shut.
Other potential issues with outward opening windows on high-rise buildings is with the wind. When opening a window outward, particularly large side hung or side swing windows, the sash can be caught by a strong gust of wind, acting like a sail on a boat. The forces applied by such a gust could even lead to the sashes being ripped off the hinges.
The use of fixed lights on high-rise buildings will always cause an issue on an internal cleaning strategy, in that there will always be a need to lean out of an adjacent opening window to clean them. Therefore, these should be limited in size, so that the occupants do not have to lean very far to clean them.
Re-glazing
When it comes to re-glazing from inside, this can only be done if windows have internal beads or can be opened into the room and safely re-glazed from inside.
Please be aware, some internally beaded windows still require the glass to be moved outside the building, turning at an angle to bring it back in, which can be a risk, particularly on large panes.
Our Recommendations
At Idealcombi we always recommend the use of our Futura+i inward opening tilt and turn windows and matching fixed sashes. The tilt function allows you to vent the room while the turn function allows the window to be cleaned safely from inside the building, or if necessary be re-glazed safely. The fixed sashes are all capable of being safely re-glazed from the inside.
The key function on the tilt and turn handle means that children cannot open the window in turn function, if the key has been removed.
Balcony Doors
In respect to doors leading onto balconies on high-rise buildings there is also the appropriate operation to consider.
Outward opening doors will have the same potential issue as outward opening windows, when it comes to high winds, but to a higher degree as a door is bigger and heavier than a window, so the forces are much higher.
The safest door operation for high-rise is either sliding doors or inward opening doors.
At Idealcombi we have a wide choice of sliding doors and inward opening doors that can be considered.
Window Performance for High-Rise Buildings
Due to greater wind pressure on high-rise buildings it is essential that all doors and windows are tested to high weather performance. If possible, the wind loadings for the building should be ascertained so that the performance of the windows and doors can be checked through, against independent test certificates that they meet the requirements in respect to air, wind and water.
It is also essential that calculations are produced in respect to the installation, so that the correct fixings can be used.
At Idealcombi all our systems have been independently tested and meet a very high performance standard (Click image to see example). On all our large high-rise projects we will provide a full design drawings package with structural calculations for wind loading and installation (See below for example).
I hope the above has answered some or all of your questions.
If you have further questions, in regard to specifying windows for high-rise buildings, feel free to get in touch on JRH@idealcombi.com or request a meeting.
Thank you for reading.
James Hutchins
Managing Director
Idealcombi UK