However, not all seismic assessments are created equal, and understanding their differences is crucial.
An Initial Seismic Assessment (ISA) offers a broad indication of a building’s expected performance. It considers factors such as the type and date of construction, local seismicity, ground conditions, and building usage. While useful as a first step, an ISA may result in an inflated %NBS (New Building Standard) score, giving an overly optimistic view of the building’s seismic resilience. The Ministry of Business, Innovation and Employment (MBIE) guidance recommends that an ISA should typically be followed by a Detailed Seismic Assessment (DSA).
A Detailed Seismic Assessment with a limited scope can be even more misleading. Such a report targets specific building elements rather than the whole structure, potentially disguising the true quality of the asset. Importantly, the client, not the engineer, determines the extent and scope of the evaluation. A limited-scope DSA often looks identical to a full DSA to the untrained eye, making it a “wolf in sheep’s clothing.” This approach can also inflate the %NBS score, creating risks for future insurability, financing, and tenant retention.
Is an inflated %NBS score good? Perhaps if you are selling, as it paints an optimistic picture of the asset’s quality. However, if a thorough assessment later reveals a lower %NBS, it can lead to serious consequences. For example, in the Oyster v MSC case, a subsequent DSA with a lower %NBS led a blue-chip tenant to cancel their lease.
For strategic and actionable seismic advice, consider reaching out to gridlinenz for a conversation and a coffee. We’re here to help you achieve your goals.
