Understanding ‘nil to low’ and ‘low to moderate’ intensity
Either ‘nil to low’ or ‘low to moderate’ intensity of occupation and passage – people either in or near the building – is required for earthquake-prone buildings (EPB) to be eligible for an exemption.
These terms are defined in Schedule 4 of the Building (Specified Systems, Change the Use, and Earthquake-prone Buildings) Regulations 2005. While they allow for different building uses, each has low consequences for life safety.
Schedule 4 is available on the NZ Legislation website.
Buildings must have all the required characteristics has further information about these life safety consequences and the other building features needed for an exemption.
When the definitions of 'nil to low' and 'low to moderate' intensity apply
The table below summarises the definitions of ‘nil to low’ and ‘low to moderate’ intensity.
| Number of people in or near the building/part* | How long and how often people are present | |||
| Always short duration, infrequent | Always short duration, may be frequent | Sometimes/always more than short duration, infrequent | Sometimes/always more than short duration, frequent | |
| Very low** | Nil to low | Nil to low | Nil to low | Low to moderate |
| Low | Nil to low | Nil to low | Nil to low | (neither category applies) |
| Sometimes / always more than low | Nil to low | Low to moderate | Low to moderate | (neither category applies) |
| Key: * If no one is ever present in or near the building or part for any length of time, the intensity is ‘nil to low’ ** Defined in the regulations as “1 or a number close to 1” |
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The following information summarises these definitions and gives some possible examples. The examples are illustrative only – territorial authorities will consider each case individually.
Examples of nil to low intensity
Either: Nil
Example: Disused building that no one goes in or near.
Or: Always low numbers for short durations (but may be frequent).
Example: Isolated building; only visitor is a caretaker twice a month for a routine inspection (generally lasting about half an hour).
Example: Old warehouse used to store sports equipment over summer. During the season around 10 people go in every second day for short periods.
Or: Always low numbers, sometimes/always more than short durations, and always infrequent.
Example: Old warehouse in a small town only used occasionally (by five musicians for band practice for a few hours each month).
Or: Sometimes/always more than low numbers, always short durations, and always infrequent.
Example: Small rural unreinforced masonry church used for occasional services, which around 50 people generally attend for an hour and a half.
Examples of low to moderate intensity
Either: Always low numbers, short durations, and frequent.
Example: Disused building but a few people walk past frequently.
Or: Always low numbers, sometimes/always more than short durations, and frequent. (Note: The regulations state that the number of people staying/nearby for more than a short time “is always 1 or a number close to 1”.)
Example: Lighthouse accessed daily by one person for five hours.
Or: Sometimes/always more than low numbers, sometimes/always more than short durations, and infrequent.
Example: Old warehouse that seats 100 people. The building is used four times a year for drama club productions, which each last around three hours.
Or: Frequently more than low numbers but always for short durations.
Example: Weekly church service in rural location, only attended by 12–15 people. Someone also mows the lawns around the building every month or so.
Considering intensity of occupation and passage
The consideration of how many people use the building (intensity of occupation) could take into account:
- formal arrangements such as tenancy and lease agreements, meeting and maintenance schedules and the like
- any other information available such as whether a building is regularly used as a shelter, as a tourist attraction, for access to facilities etc.
Considering how many people are near the building (intensity of passage) could be more qualitative. It could take into account how close people would pass this building (eg the distance of any footpath to the earthquake-prone building or part). It should also consider how far building elements could fall onto the road if the building were to collapse.
Buildings that a number of people walk close to and often are NOT likely to be considered either nil to low, or low to moderate intensity. This could include buildings very close to:
- shops, offices, schools, other service buildings
- bus stops, train stations, tourist centres
- key walking routes; eg on the way to shops or schools.
Buildings that a number of people drive close to and often are NOT likely to be considered either nil to low, or low to moderate intensity. This could include buildings very close to:
- key traffic routes used regularly by vehicles including public transport
- areas where high concentrations of vehicles build up, such as busy intersections.