Organisations need to understand what resilience means for the buildings they inhabit or own. Here are some of the issues for an organisation to consider as it works through the challenges ahead.
Since the Christchurch earthquakes, New Zealand organisations have been reviewing the resilience of the buildings they operate in. But resilience for buildings involves more than robust construction – it includes links with the operational planning of the organisations that occupy them.
Steps to understanding
Start by asking some questions to get a wider understanding of your building’s context:
- Does your organisation own the building it occupies or is it a tenant?
- Do you occupy one building or several, and are they in the same location or geographically spread?
- Is the surrounding environment vulnerable to earthquakes and other hazards – consider neighbouring buildings, key access routes and infrastructure services?
How important is your building to you?
The concept of importance levels for different buildings is embedded in our design codes, with a high-occupancy building such as a theatre designed to higher performance standards than one with low occupancy.
Similarly, buildings that support critical post-disaster functions, such as hospital operating theatres, are assigned an importance level that requires they are both standing and usable afterwards.
These importance levels provide a broad hierarchy of societal performance objectives for buildings.
Organisations, particularly those with several buildings, should create performance objectives for their own premises. Look at how each building is used. How often are people inside and what equipment is there? How time-critical are the operations conducted in the building – would being out of action for a few hours, a few weeks or a few months be a problem? How easy would it be to relocate if required?
Weighing up the risks
When engineers assess buildings, they often focus on the %NBS – the capacity and performance of the building as a percentage of an equivalent new building built to today’s Building Code.
However, this is a very broad metric, and organisations need to be savvier at understanding how their buildings are likely to perform in a major event. Talk of earthquake-proof buildings is a misnomer, as any building will fail if the forces are great enough.
There are several key questions to ask:
- What are the life-safety risks associated with how the building might fail – will people be killed or injured?
- Will the building remain functional afterwards – it might not look pretty, but could people go back in and use the building?
- How long would it take to repair the damage – is it likely to be a quick fix or a demolish-and-replace job?
Depending on the design, some buildings may perform well on one or two of these criteria but poorly on the others. It is important to understand the level of the event at which functionality can become impaired and the safety of lives a concern.
Develop a plan to progressively improve the resilience of your organisation’s building stock. Not every building needs to be serviceable after an event – in many cases, simply getting people out unharmed is a sensible objective.
Think about your building’s resilience as an investment rather than a compliance decision. What would it cost your organisation if a particular building became inaccessible for the foreseeable future?
Business continuity considerations are not just for hospitals and critical infrastructure organisations. Manufacturing organisations where equipment is hard to move and to replace at short notice and organisations that deliver time-critical services may see their business wiped out if they don’t plan for such eventualities.
However, organisations spread across several locations may be able to temporarily relocate capacity and may be less concerned with building resilience beyond Code expectations.
A few other things to consider…
Also consider the non-structural elements of your building. Does it have heavy ceiling tiles or large items of furniture that create safety risks? Is equipment properly secured?
Are you likely to be left with a major repair bill and downtime due to damage to fixtures and fittings, such as wall linings or lighting or heating systems? Consider the resilience of the infrastructure services supplying your premises – a multi-storey building isn’t much use without power or water.
Think about the neighbourhood and what could prevent you and your staff accessing your building, even if it is undamaged. How well are the building’s contents protected? Is your basement storing valuable records or equipment that could be water damaged?
Also think about the different scenarios that could make your building unusable. Often, we focus on hazards that we have recently experienced. Think about where your building is located and other hazards it may be exposed to – are these risks increasing because of climate change or how the neighbourhood is developing?
Review your tenancy agreement
Building tenants that suffer damage can find themselves in a difficult position. Unlike owner-occupiers, tenants have little control over the time and way in which any damage is repaired.
After the Christchurch earthquakes, many tenants found themselves shut out and poorly informed about the future of their premises. Delays in the start of repairs rendered some business interruption policies ineffective, and organisations found themselves locked into tenancy agreements for premises that they no longer wished to occupy.
Any organisation that rents or leases a building should ensure that there are clauses in their agreement covering how the situation will be handled if the building is damaged or becomes inaccessible or unusable for any reason.
The time when a lease is signed is essentially the only opportunity to sort out these issues, so this is when it is important to get as much information as possible about the likely performance of the building.
Building’s %NBS just part of the issue
New Zealand has a legacy problem of older building stock that will take time to remedy. While it might be desirable for every building your organisation occupies to be optimally resilient, this isn’t going to occur overnight.
Evacuating a building at 5 minutes’ notice when getting an engineer’s report that says it is less than <33%NBS is not usually the required response. It is important to understand the contributing factors to the low rating and what the consequence of failure may be before making a decision.
Sometimes, the fact that a building is simply earthquake-prone may not be as concerning as discovering that it has a critical vulnerability that might cause catastrophic collapse in a much larger earthquake.
Health and safety legislation does not require a workplace to be a zero-risk environment but it does require that organisations develop a plan for how to make that workplace as safe as practically possible.
Involve staff in decision-making and come up with staged solutions for dealing with any earthquake-prone buildings your organisation uses. For example, if there is one part of a building that is particularly vulnerable, staff might have ideas for how to adjust operations so that it is rarely occupied or undertake temporary works to offer protection in the case of a failure.
In 1997, the University of Berkeley in the US acknowledged that many of its buildings were earthquake-prone and likely to collapse in a major earthquake. Facing a retrofit bill of up to US$1.2 billion, it developed a staged retrofit programme over 20–30 years.
Knowing that, in the interim, the university would be occupying earthquake-prone buildings, it decided to be open in talking about the risks. At the start of each semester, they talked to classes about earthquake preparedness, gave information about the risks of earthquake-prone buildings and answered questions.
Importantly, Berkeley demonstrated it was addressing the problem and has maintained staff and student engagement throughout.
If the University of Berkley can deal with this situation in one of the most litigious countries in the world, surely we can in New Zealand. The key is to demonstrably work on improving our resilience and not just leave it as tomorrow’s problem.
Don’t simply rely on insurance
One of the biggest lessons from the Canterbury earthquakes is that reliance on insurance is not necessarily the right answer. While it helps that a lot of insurance payouts are flowing into the local economy, over time, the premium payments will balance this, and the same cover, terms and conditions may not be available.
A combination of mitigation of lower-level risk and then using insurance as a top-up for disasters may be more cost-effective than simply insuring for every event.
Fully involve any consultants you use
Any advisers engaged for engineering aspects or business continuity planning should have a good appreciation and understanding of the range of issues covered, and you should brief them on your specific context and needs.
For example, a structural engineer may address %NBS or the design of a new building as if the Building Code is the only requirement to be met. But the Building Code is not focused on a business’s priorities – it is there to protect life safety and to minimise risk of damage to adjacent properties. Buildings that are equally Code compliant may perform completely differently in terms of business continuity objectives.
The brief an organisation gives to consultants should reflect this. If a building must be operational after an earthquake, this should be stated. It may not require that the building be designed for the same importance level as an emergency facility, but it might lead to building form or materials being used that are more damage resistant. At the least, the cost impact of this should be investigated.
Changes on several fronts
Considering these issues in an organisation’s planning is timely in the current environment where changes are occurring in both regulatory and technical environments for buildings and earthquakes.
On the regulatory side, the Building Act (Earthquake-Prone Buildings) Amendment Bill has been introduced. While there is no change to the threshold level defined for an earthquake-prone building, the intention to have all commercial and large residential buildings assessed within 5 years of the Bill’s passage is putting the spotlight on the performance of buildings in earthquakes.
At the end of 2013, WorkSafe New Zealand sought to clarify health and safety requirements and earthquake-prone buildings by issuing a position statement for employers and owners on dealing with earthquake-related hazards.
This indicates that the Health and Safety in Employment Act does not seek to impose requirements for a building’s earthquake resilience at a higher standard than the Building Act.
At a technical level, the New Zealand Society for Earthquake Engineering in conjunction with the Structural Engineering Society and New Zealand Geotechnical Society will update their 2006 guidance document on assessing the seismic performance of existing buildings.
Destructive testing of 1- and 2-storey timber-framed buildings in 2013 by BRANZ for the Ministry of Education and Housing New Zealand Corporation has clearly shown these types of buildings have a much greater resilience than indicated by traditional engineering calculations.
www.resorgs.org.nz/Resources/resources-for-business.html where the booklet Shut Happens is of particular interest.
Articles are correct at the time of publication but may have since become outdated.