9.5 Type 3 recommendations to investigate and collaborate on possible performance requirements

Type 3 recommendations are recommendations to investigate and collaborate on possible performance requirements that are conceptual at this stage. They require development and collaboration with the sector before they could be considered for approval for consultation as amendments to the Building Code.

9.5.1 Resource efficiency

Part of the purpose (section 3) of the Building Act is 'to promote sustainable development', and the principles (section 4) include the need to facilitate:

• the efficient use of energy, energy conservation and the use of renewable sources of energy in buildings
• the efficient and sustainable use in buildings of materials and material conservation
• the efficient use of water and water conservation in buildings
• the reduction in the generation of waste during the construction process.

It is recommended that assessing the resources used by buildings through the carbon dioxide (CO2) emissions associated with their construction, operation, maintenance and demolition be investigated. This could include specifying a maximum design annual CO2 emission using a metric yet to be developed.

Operating energy is the only resource that the Building Code addresses. The Building Code attempts to limit the energy used for operating new buildings on a day-to-day basis by requiring designers to address energy efficiency. It sets limits on the design energy for heating housing, and has insulation requirements for residential and commercial buildings, energy efficiency requirements for domestic water heating systems, and requirements for the efficiency of lighting in commercial buildings.

The Building Code does not account for the energy used over the whole lifecycle of a building. Energy is used in the construction, operation, maintenance and demolition of the building, and is used directly or indirectly to produce and transport building materials.

The Building Code has no requirements for the efficient use of materials, minimising waste from construction and demolition, or conserving water or using it more efficiently.

In consultation, there was support for suggested objectives for conservation and efficient use of materials, and for addressing environmental impacts throughout the life of materials, although there was concern that this might be difficult to implement. There was also support for addressing waste minimisation.

The Department looked at ways to incorporate performance-based requirements for:

• the efficient use of materials
• promoting the use of recycled and sustainable materials
• minimising construction and demolition waste.

If included in the Building Code, any such requirements would need to be assessed when a building consent was sought and/or a subsequent code compliance certificate issued on completion of the building work. Direct requirements, such as setting limits on water consumption, could be impractical and expensive to administer effectively. The proposed approach looks at indirectly achieving outcomes in these areas.

The Department considered two significant questions on how the Building Code could address resource efficiency.

• How can the Building Code address the resources used during the whole life of the building?
• Is energy the best measurement or would something else be more appropriate?

For a complete picture of resource efficiency, the whole life of a building should be considered, including the resources used in the construction, operation, maintenance and demolition of the building, and the energy used directly or indirectly to produce building materials - a lifecycle assessment.

Burning fossil fuels (gas, coal, oil) to generate electricity and using gas, coal or wood directly for heating produce CO₂ emissions, which contribute to the greenhouse gases linked with climate change. CO₂ emissions can therefore be considered to more directly measure the impacts of using resources than energy: it is the CO₂ emissions associated with the generation and use of energy that are unsustainable because of their contribution to climate change, rather than energy use itself.

CO2 emissions are proposed, rather than other greenhouse gas emissions, because CO₂ is the most significant greenhouse gas associated with buildings, and established criteria for assessing the CO₂ associated with various forms of energy used in buildings already exist.

Lifecycle assessment can be used to assess the CO₂ emissions associated with a building for the whole of its life. This could consider:

• emissions used on a day-to-day basis to run the building
• emissions that arise from the materials used to construct and maintain the building
• emissions arising from the construction, maintenance and demolition of the building.

One-off CO2 emissions, such as the CO₂ emissions associated with building materials, could be divided up over the design life of a building. The designer would need to consider what the optimum intended life for the building would be.

For the purpose of assessing the ongoing CO₂ emissions associated with operating a building, some assumptions about how buildings would be used need to be made. For example, if the Building Code had a requirement that the building should be able to maintain indoor air temperature within a particular range, then the CO₂ emissions would be assessed on that temperature range (regardless of whether the building users actually operated the building to those conditions).

Another activity which creates CO₂ emissions is in supplying drinking water and removing storm water and wastewater. The CO₂ emissions come from the energy used to treat raw water and pump it around distribution networks. Embodied CO₂ emissions are also associated with the network infrastructure. Assessing the CO₂ emissions from water could facilitate water efficiency without prescribing specific solutions. It could also help to promote rainwater harvesting and use of non-potable water where people's health would not be compromised.

If CO₂ emissions could be practically assessed, the Building Code could set limits on annual CO₂ emissions, on the basis of a design value, not an actual in-use value. The annual maximum design CO2 emission could be set at different levels for different types of buildings so that they were designed and constructed to be more environmentally and economically sustainable.

Another aspect is the maximum heating or cooling needed to keep the indoor temperature within a particular temperature range. Insufficient heating would mean the temperature would never reach the target temperature, regardless of how long a heater was on for. But a bigger heating source than necessary would place excessive demand on power generation and transmission systems.

It is proposed that buildings be designed and constructed so that the heating or cooling (ie, the power) calculated to maintain indoor temperatures within the comfort range when modelling annual or lifetime energy demands in buildings is less than a specified level.

If this approach could be implemented practically, it would mean that a designer could choose the most effective and economical means of limiting CO₂ emissions for a building for the whole of its lifecycle through, for example, choice of materials, construction methods, systems for running the building and strategies for demolition.

Because this approach would take account of the emissions from materials and resources used for construction, maintenance and demolition as well as the CO₂ emissions used to run a building, it could address several of the sustainable development objectives of the legislation.

Assessing CO₂ emissions in this way, and other proposed changes, would form an integral part of the Building Code. For example:

• Under the General section it is recommended that designers demonstrate that a building will meet the requirements of the Building Code for the building's intended life. Considering resource efficiency in the context of building life could deter designers from specifying materials and systems that require frequent replacement. Dividing the emissions from construction over the period of the intended life could deter designers from specifying a short intended life.
• Considering resource efficiency together with the proposal under Environment that the temperature in residential buildings would need to be able to be kept within a range of temperatures could ensure that designers install appropriate heating systems that are also energy-efficient to run.
• Sanitation requirements facilitate the use of raw (untreated) water where appropriate.

This proposal would also link closely with the recently announced New Zealand Energy Efficiency and Conservation Strategy, which aims to: maximise energy efficiency and renewable energy; promote sustainability; improve quality of life; and drive economic transformation in business. The strategy also aims to save 5 to 6 million tones of CO₂ emissions per year by 2025 and the Building Code would contribute to this reduction.

The incorporation of a CO₂ emissions measure in the Building Code may be considered an ambitious approach.

• The assessment of emissions associated with the materials (known as 'embodied emissions') and construction of buildings would be a new measure in building codes internationally and there are differing approaches to its assessment. Further work would be needed to propose a suitable methodology.
• Analysing the environmental impacts of buildings through their whole lives from construction through to demolition (known as 'lifecycle analysis') is also relatively new and there are differing approaches to its assessment. Again, further work would be required to propose a suitable methodology.
• Work is required to determine how to assess the CO₂ emissions associated with various forms of energy and different construction materials so that designers and regulators have the information they need to apply this approach.
• This concept uses complex ideas and is technically difficult. Further work to develop this concept would draw on expert input. Detailed consultation would also occur as part of this process.

9.5.2 Fire safety

'Fire safety' refers to safeguarding people and neighbouring property against fire and other related hazards, preventing the spread of fire and providing means of escape from fire and other emergencies.

The Building Code sets out performance requirements for fire and emergency safety design, but these are not quantified. The Compliance Documents have not provided specific requirements to fire engineers about performance requirements, design scenarios or design fires. This has led to inconsistent interpretations about the implied requirements of the Building Code, and disputes about the safety of fire designs for proposed buildings. The performance requirements for multi-storey residential buildings, and the provisions for means of escape, have been the subject of several determinations by the Department.

It is recommended that specifying fire design scenarios and performance requirements to be taken into account when designing for fire safety be investigated. These would be in line with the structural design process that specifies events and physical conditions on the structural performance of buildings such as wind, earthquake and snow.

Under the framework the Building Code would:

• specify performance requirements for fire design
• specify fire design scenarios and design fires that must meet performance requirements
• define fire design scenarios including:

Specified fire scenarios would provide examples of the types of fire a building might be required to withstand. They would be developed to ensure all the elements of building design currently regulated in the Compliance Documents would continue to be addressed in a performance- based design.

The proposed approach would permit flexibility and innovation in design, but ensure a more consistent outcome for fire safety.

9.5.3 Features for wellbeing and physical independence

9.5.3.1 Space

The Building Code includes provision for space for activity in access routes, kitchens, laundries, and space for activity, furniture, sanitary and mobility aids in aged care facilities only. There are no requirements for space in other types of buildings.

Consultation threw up considerable comment that the Building Code should ensure sufficient space in dwellings (in particular, apartments) for occupants to be able to move with ease in their dwelling, and to be able to move furniture into and out of their dwelling. This was commonly expressed by specifying a minimum size for an apartment.

The Department has also heard considerable support for the concept of universal design, but also comments questioning the practicability of some measures and the effect on affordability of housing.

The 2007 discussion document did not propose 'universal design' for all housing, but did propose a 'design furniture' standard as a means of achieving space and accessibility. Some submitters took this to mean a standard for furniture, which was not intended, and the expression 'performance standard for space and accessibility' is used to clarify the intent in this report.

The solutions that enable a performance standard for space and accessibility to be met could remove the need for one of the more difficult aspects of future adaptability, where doorways and corridors need to be widened. The performance standard could require doorways and corridors to be wide enough to meet the needs of people with physical disabilities, particularly wheelchair users, without further modification.

The proposals mean a minimum size for apartments would not need to be specified. A performance standard for space and accessibility would give designers the flexibility and incentive to make efficient use of space while ensuring residential buildings would provide adequate space for occupants to move around and use them to their expectations.

Further work would be required to assess whether it is feasible to introduce a performance-based standard for space and accessibility and how this would work in practice.

It is recommended that specifying that buildings be designed and built to allow space for 'household activity and access' be investigated.

9.5.3.2 Light and connection to the outdoors

Connection to the outdoors arises from a complex combination of physical conditions, such as availability of natural light, access to views of the natural or built environment, views of the immediate outdoors, natural ventilation, views of the approaches to the building, and access to outdoors areas.

The Building Code has natural light requirements (30 lux at floor level for 75 percent of the standard year)¹³ for habitable spaces in housing, old people's homes and early childhood centres. These buildings are required to provide adequate openings for natural light and visual awareness of the outside environment.

Ways of addressing connection to the outdoors through different combinations and types of availability of both natural light and views of the outdoors for particular spaces in buildings are being considered.

A rating scale of qualitative measures (Table 5, see Appendix 3) is proposed for connection to the outdoors, incorporating the following features.

• Natural light and direct sunlight
• Proximity to adjacent buildings
• Visual awareness of the sky
• Visual awareness of the ground
• Visual awareness of the neighbourhood

This would be a new type of performance measure for the New Zealand Building Code, but this tool has been used internationally in the management, performance and serviceability of buildings and building-related facilities.

This tool would allow designers flexibility, particularly on restricted sites, while still ensuring building users had adequate connection to the outdoors. For example, limited views could be offset with good access to daylight.

Windows potentially provide solutions to a number of the Building Code requirements, including many of the requirements for connection to the outdoors. If the level of natural lighting was sufficient for general lighting, then that could be taken into account in the assessment of design annual CO₂ emissions for resource efficiency (see 'resource efficiency' above). Natural ventilation provided by opening windows could similarly qualify for the assessment of design annual CO₂ emissions.

More work is required to develop:

• a 'connection to the outdoors' rating scale
• a design tool(s) that allows design professionals and regulators to assess their building against the rating scale.

It is recommended that specifying that all habitable spaces should achieve no less than 30 lux of natural light at floor level for 75 percent of a standard year,14 and no less than a set level on a 'connection to the outdoors' scale be investigated.  

9.5.4 Buildings with cultural, historical or heritage value

The Building Act 2004 recognises the need to facilitate the preservation of buildings with significant cultural, historical or heritage value. Heritage buildings are identified through statutory processes by the New Zealand Historic Places Trust and local authorities. There are no unique provisions for these buildings in the Building Code.

Under the Building Act, any alterations to buildings, including heritage ones, must comply as nearly as is reasonably practicable with the Building Code in relation to means of escape from fire and to access and facilities for people with disabilities. Buildings must also continue to comply with the other provisions of the Building Code to at least the same extent as before the alteration. This provision allows for waivers or modifications to Code compliance to ensure the unique nature and characteristics of heritage buildings are maintained if a building is altered.

The Building Act also refers to the importance of recognising any special traditional and cultural aspects of the intended use of a building. New buildings with cultural and traditional uses - for example, wharenui, churches, temples and mosques - must, like all buildings, meet the performance requirements of the Building Code. The performance requirements should achieve health, safety, wellbeing, physical independence and resource efficiency without compromising the traditional or cultural value of the building.

In consultation, a distinction was made between heritage or historic buildings, and new buildings with a cultural purpose. It was considered that new buildings should be required to fully meet the Building Code requirements, while heritage and historic buildings may require special dispensation. For heritage and historic buildings, the current waiver or modification approach provides the flexibility needed to address the unique nature of these buildings case by case.

It is proposed to develop Compliance Documents, including Acceptable Solutions, specifically for heritage or historic buildings to assist with decision-making.

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12 Other property means any land or buildings, or part of any land or buildings, that are not held under the same allotment; or not held under the same ownership; and includes a road.

13 Other property means any land or buildings, or part of any land or buildings, that are not held under the same allotment; or not held under the same ownership; and includes a road.

14 For the purposes of determining natural light, the standard year is the hours between 8 am and 5 pm each day with an allowance for daylight saving.