Seismic rating of Government Office Accommodation update
In October last year we asked agencies to provide details on the seismic rating of their office accommodation, and public facing sites from existing assessments. This information has now been collated and covers all buildings within the office accommodation portfolio.
The Government Office Accommodation portfolio comprises some 919,680m2 of office and public interface space, in 585 buildings throughout New Zealand. These buildings provide accommodation for 51,798 public servants across all 62 agencies included in the property functional leadership mandate.
Seismic assessments – the requirements
The assessments quantify seismic performance/behaviour as a rating. Compared with the minimum required by the building code for new buildings, this provides a measure of the expected performance from a life safety point of view. It is expressed as a percentage of the standard achieved from application of the building code requirements, or % New Building Standard (NBS).
The % NBS rating reflects the lowest rating of any part of a building. This means that only specific parts of the building may pose an actual risk in the case of a seismic event.
| Seismic grade | A+ | A | B | C | D | E |
|---|---|---|---|---|---|---|
| Percentage of New Building Standard (%NBS) | >100 | 80-100 | 67-79 | 35-66 | 20-34 | <20 |
| Life safety risk description | Low risk | Low risk | Low to Medium risk | Medium risk | High risk | Very high risk |
Portfolio status
Across the portfolio of 585 buildings, 363 have received an assessment for seismic performance against these technical guidelines. 333 of these buildings are above 67% NBS which is the minimum level recommended by the New Zealand Society of Earthquake Engineers. The two buildings rated ‘high risk’ and ‘very high risk’ have been vacated.
| Seismic grade | A+ | A | B | C | D | E | Total |
|---|---|---|---|---|---|---|---|
| Buildings with a seismic rating | 26 | 238 | 69 | 28 | 1 | 1 | 363 |
Of the 222 buildings that do not have an NBS assessment, 146 have been assessed by agencies using a risk-based approach. This type of assessment considers factors such as, the age of the building in relation to changes in the building code, type of construction and number of floors. 36 buildings (just over 6% of the portfolio) have not yet been assessed.
| Seismic grade | NBS assessment completed (awaiting outcome) | Risk Assessment | Unrated | Total |
|---|---|---|---|---|
| Buildings without a seismic rating | 40 | 146 | 36 | 222 |
Priorities for the next 12 months include:
- Review those buildings without a NBS rating to determine whether a NBS rating is required
- Review seismic assessments to ensure that the assessment has captured all potential building vulnerabilities
- Improve the seismic rating of buildings as leases expire and new leases are entered into.