UPDATES TO GLAZING IN BUILDINGS STANDARDS NZS 4223
The complete set of Standards NZS 4223.1 to NZS 4223.4 Glazing in buildings, have all been amended or replaced. Given that only the old versions are cited in the NZBC Acceptable Solutions, the question arises when would it be preferable to use the new versions? And what should you do when specifying? Also, as manifestations are sometimes required by NZS 4223.3, we look at exactly what manifestations are.
Old and New Standards
The set of Standards NZS 4223 Glazing in buildings, have all been amended or replaced as follows:
|Old Standard ||New Standard |
|NZS 4223.1:2008 - Glazing in buildings - Glass selection and glazing ||NZS 4223.1:2008 A1 - Glazing in buildings - Glass selection and glazing |
|NZS 4223.2: 1985 - The selection and installation of manufactured sealed insulating glass units ||NZS 4223.2: 2016 - Glazing in buildings - Insulating glass units |
| NZS 4223.3: 1999 - Glazing in buildings - Human impact safety requirements |
| NZS 4223.3: 2016 - Glazing in buildings - Human impact safety requirements |
| NZS 4662.4: 2008 Glazing in buildings - Wind, dead, snow and live action |
| NZS 4662.4: 2008 A1 - Glazing in buildings - Wind, dead, snow and live action |
According to Standards NZ the major changes involve closer alignment with the NZBC AS's and VM's, and correcting errors identified in the old Standards. The old Standards are modified by NZBC B1/AS1 Structure, part 7.0 Glazing and NZBC F2/AS1 Hazardous building materials, part 1.0 Glazing. The new Standards are not cited in the NZBC and therefore are not modified by the NZBC, however they seem to have addressed the previous modifications, by either meeting or exceeding those requirements.
As the new Standards have corrected errors and they seem to meet or exceed NZBC requirements, Masterspec has decided, for Health and Safety reasons, to update the use of these old Standards to the new Standards. Glass is classified as a hazardous substance by the NZBC, therefore for health and safety it is advisable to use the highest, up to date and correct standard as the basis of design and installation.
All affected Masterspec sections now use the new Standards although they are an Alternative Solution because the NZBC Acceptable Solutions cites the old versions. However, as they meet or exceed the requirements of NZBC B1/AS1 and NZBC F2/AS1, this should not be a major issue.
If there is a need to revert to the old versions, some clause guidance notes indicate the old version references where applicable to make it easy to convert back. Other clauses that only refer to a Standard generally will not require changes. If you do use the old versions don't forget to add the year to the Standard in the DOCUMENTS clause, as a Standard without a year is automatically regarded as the latest published version.
Bathroom, Ensuite, and Spa Rooms
This is one area where the new Standard meets and exceeds the requirements of the old Standard modified by NZBC F2/AS1. NZS 4223.3: 2016, 8.0 Bathroom, Ensuite, and Spa Rooms, has a number of differences to the NZBC, for instance the Standard requires safety glass within 2000mm of the floor, whereas NZBC F2/AS1, in some cases, only requires safety glass within 1500mm of the floor.
Regardless of which method of compliance you use it pays to check your design for glass type, location and thickness.
Manifestations for Glass
What is manifestation? This is a question we get asked quite often.
NZS 4223.3:2016 defines Manifestation as, "Marking of glazing to make it visible”. Masterspec only use the term in relation to permanent, post construction markings, so as not to confuse them with temporary marking used during construction which Masterspec call "indicators" (indicating only the presence of glass).
NZS 4223.3:2016 2.2 Manifestation (making glass visible), requires a manifestation if glazing can be mistaken for a door way or an unimpeded path of travel. The Standard provides a number of parameters for deciding when and where they will be required. The size of glass panel, location and type of transoms, transparency of glass, etc, are all parameters which affect the need for manifestations.
Manifestations are generally not mandatory for housing (detached, multi-unit, group dwellings) clause 2.2.3.
Manifest can be a range of decorative effects, but are frequently opaque or translucent vinyl, stripes, decals or logos.
The major difference between the old and new Standards is the manifest zone height above the floor varies between NZS 4223.3:1999 (303.1.2) 700mm (upper edge) to 1000mm (lower edge), and NZS 4223.3:2016 (2.2.5) centreline 800mm to 1200mm (800mm exactly for early childhood centres). The manifestation band must be at least 20mm high in all cases, but not necessarily horizontally continuous.
As we are writing this article the breaking media news (pun intended) is that frameless toughened glass balustrades without specific rails may be outlawed by MBIE possibly as soon as June 1st. We have seen no official details at this point so it is not known if this is true and what the actual affects might be. Anecdotally we understand Auckland Council are issuing warnings that toughened glass balustrades without hand rails may soon not be allowed. We will keep you posted on progress.
Read the article at radionz.co.nz