Our ceilings are designed using the USG Generic seismic design guide and have the following assumptions and limitations:
Building in which ceiling is installed
• Building must be located within New Zealand
• Building must be no more than 40 metres tall
• Building must not be Building Importance Level 4 having unique requirements for "post-disaster" functionality (e.g. some hospital areas, police station) - refer to AS/NZS 1170 for a full definition
• For perimeter fixed ceilings, continuous nogging must be provided at the same level as the perimeter angle trim along all fixed edges of the ceiling (a continuous concrete or block masonry wall/beam is also acceptable)
• The support structure (including nogging, associated wall/bulkhead, and building superstructure) must be solid and stiff enough to carry the seismic bracing loads from the ceiling without suffering any damage. A Qualified Structural Engineer must confirm this
Ceiling & Services
• Rivet strengths allow for use with 6 and 10mm Teg Tabs and no Teg Tabs (refer to Seismic Force Calculator)
• End connections must be detailed as shown in the design
• Maximum tee spacing must be 1200mm in any direction
• Ceiling must be non-trafficable
• Ceiling must be non-structural (ceiling system does not provide structural stability to the building, e.g. acting as a ceiling diaphragm)
• Install and fix all lay-in ceiling panels with correct hold-down clips in full conformance with USG specifications. Where point accessibility is required, nominate unclipped panels with a visual marker ego-coloured sticker/board pin etc.)
• Ceiling weight must include ceiling tiles, suspension grid, lighting, any other services, and insulation if laid
on the grid
• Individual ceiling tiles must not weigh more than 7.5kg. All items weighing more than 7.5kg must be supported independently from the ceiling (including some luminaires and air conditioning cassettes etc.) unless covered by a specific engineering design (SED)
• All interior partition walls must be supported independently from the ceiling (including independent horizontal restraint to the top of the wall), or their weight must be included in the ceiling seismic mass calculations, including specific consideration of the seismic load on each ceiling tee (obtain specific advice from a structural engineer)
• All evacuation and life safety systems must be supported independently from the ceiling and must be likely to
remain functional even if the roof collapses
• There must be no other reason why ceiling movement/damage or falling tiles would cause an unusually high hazard or injury (e.g. cause release of hazardous substances/organisms, damage to electrical reticulation).
• Ceilings must be installed in accordance with: AS/NZS2785; AWCI Code of Practice and manufacturer installation guides
• Perimeter-fixing rivets must be aluminium. No substitution is permitted
Key Technical and Engineering Assumptions
• Standard design, unless otherwise stated, is based on a 10mm seismic clearance. If more is required, this needs to be specifically requested and priced for
• Unless your quotation specifically states that it is designed for a Serviceability Limit State(SLS), the designs and quotation will be for an Ultimate Limits State(ULS).
• Annual probability of exceedance for design earthquake is 1/25 (for serviceability level earthquake)
• The ceiling ductility is assumed to be μ=1.25 (for serviceability level earthquake)
Producer Statements and Warranties
• The cost of your quotation does not cover the cost of obtaining a PS1 (Design), PS2 (Design review) and PS4 (Construction review) producer statements; however, these can be obtained based on the quoted design at an extra charge. If a PS1 design is required for the project and this was not available to us at the time of tender, then any additional or upgraded components and their associated labour will also be charged as an extra
• We are able to supply you with a PS3 (construction) or warranty documents at no additional charge to the quoted price. These are supplied on request only.
