Rob Campion of the Window & Glass Association NZ touches on the importance of ensuring your windows, doors and glazing comply with the Building Code, and how to tell.
So, how does a building inspector, or anyone for that matter, know that the windows and doors delivered and installed on your site have been designed, tested and constructed in a manner that will be compliant with the building consent and, therefore, the Building Code?
And do they have sufficient information to sign them off as compliant?
The simple answer is to check the labels and markings required by the applicable sections of the Code. Unlike our cars, the labels and badges tend to be a little more subtle, but they’re there, or at least they’re supposed to be!
These labels and markings are an important part of knowing that your windows, doors and glazing are as they’re supposed to be, and that they meet the structural, durability and safety requirements of a home built in Aotearoa.
The New Zealand Building Act 2004 and the New Zealand Building Code demonstrates its awareness of the importance of compliant window and door products for the weathertightness and structural performance of the exterior envelope.
When it comes to establishing on site the compliance of windows and door frames, section 12 of Clause B1 refers directly to NZS 4211 — Specification for the Performance of Windows, as does paragraph 9.1.10 of Clause E2.
NZS 4211:2008 has recently been updated — but not yet cited — as TS 4211:2022, and renamed as the Specification for the classification of windows.
The new version continues with a section devoted to the labelling of all production windows, and provides a template and set of parameters for the label, for consistency, and to aid with inspections.
The new label (right) has some subtle differences to the previous editions, but still contains information on the supplier and, most importantly, it indicates the Standard the prototype of the system has been tested to, the wind zone rating, and the air infiltration class achieved.
It is the air infiltration class that varies from the 2008 Standard, but that is a topic for a future discussion.
The labels are typically adhered to the left-hand jamb of opening sashes within the hardware cavity for windows, to the jamb adjacent the top hinge for hinged doors, and to the edge of the leading stile for sliding doors.
The new Technical Specification, rather than New Zealand Standard, includes additional label templates for units tested to E2/VM2, referred to as EM7, and for units outside of the generic wind zones, requiring Specific Engineering Design or SED.
In the case of the latter, a test report number is inscribed onto the label for reference.
Glazing must be permanently marked for compliance with two differing situations. For some years now, we’ve been marking our glazing to indicate its compliance for safety with the NZBC — primarily clauses B1 and F2, each referring to NZS 4223.3:2016.
Glass is a fragile and dangerous building component when broken, and strict regulation has been put in place, through these documents, to ensure the ongoing safety of a building’s occupants.
To help easily identify safety, whether toughened or laminated glass has been used in the many locations where it is required, and appropriate, panes are required to be etched with a stamp, including information about the supplier, the type and thickness of the glass, and the Standard to which the glass is deemed to comply (below).
For Insulated Glass Units(IGUs), more commonly referred to as double or triple glazing, Clause B2 requires that each unit be marked to identify the manufacturer or supplier, the year of its manufacture as a minimum, and that it complies with NZS 4223.2:2016.
This marking is not quite as easy to find as the safety stamp, as it is usually printed on the spacer bar between the two panes of glass making up the IGU (below).
The identification of windows and glazing that comply with the New Zealand Building Code is important, and is growing.
With the introduction of Clause H1 updates, the need to understand the make of the IGUs will be important not only to the BCA signing off its thermal compliance, but also to the home owner who might need to replace a pane in the future.
This final piece of the H1 implementation puzzle is still being finalised but is underway, and is equally as important as the existing frame and glazing labelling.
In short, ensure your windows are labelled, and labelled appropriately!
If you have any questions contact your local glass supplier, or come directly to the Association.