Report on the Review of the Building Code: 6 Key findings and recommendations
6.1 Summary of findings
In summary, the review found that:
1. the Building Code largely complies with and meets the requirements of the Building Act 2004, but does not adequately address some areas
2. the Building Code does not adequately set performance standards for buildings to ensure that:
- people who use buildings can do so safely and without endangering their health, with respect to:
- protection from hot surfaces and substances (in certain circumstances)
- sanitation requirements for water to address potential health issues that could arise from the use of raw water and greywater
- having warm, dry homes that are energy- efficient
- protection from excessively loud alarms to avoid possible hearing damage
- construction that is consistent with the requirements of the Hazardous Substances and New Organisms Act 1996
- they have attributes that contribute appropriately to the health, physical independence and wellbeing of the people who use them, with respect to:
- space
- connection to the outdoors
- noise control
- access to communal facilities for people with disabilities
- people who use a building, can escape from it if it is on fire
- buildings are designed, constructed, and can be used in ways that promote sustainable development, with respect to:
- the energy used over the whole lifecycle of a building
- efficient use of materials, water, waste
- the durability of building materials and building elements
3. some parts of the Building Code are not stated in sufficient detail to provide clear guidance on the performance standards that buildings must meet to ensure compliance with the Building Code
4. the additional requirements of the 2004 Act can be incorporated into the Building Code with relatively minor amendments
5. some refinements to the structure of the Building Code would improve the usability of the Code for a wider range of users
6. Compliance Documents are relied on by a large percentage of the sector for guidance and technical specificity (which the Department must recognise).
6.2 Recommendations on the Building Code structure
It is recommended that the Building Code be set out as follows.
- Section 1 - General: containing the general principles for building performance, the performance framework for buildings, and requirements for maintenance and durability.
- Section 2 - Structural performance: containing the requirements for the integrity and stability of buildings against the events and physical conditions they may be subjected to.
- Section 3 - Fire and emergency safety: containing the requirements to safeguard people (including firefighters) and neighbouring property against fire and other related hazards, prevent the spread of fire, and provide means of escape from fire and other emergencies.
- Section 4 - Features for wellbeing and physical independence: containing requirements for the wellbeing and physical independence of people, including access, space, noise control, light and connection to the outdoors.
- Section 5 - Environment: containing requirements for a healthy and appropriately comfortable environment for people, including moisture, indoor air quality, indoor temperature, and control of moisture from internal and external sources.
- Section 6 - Safety of users: containing requirements for the safety of users and protection from the risks of injury encountered by people in and around buildings.
- Section 7 - Sanitation: containing requirements to safeguard people from illness caused by exposure to human or domestic waste, by consumption of contaminated water, and by inadequate facilities for personal hygiene, laundering and food preparation.
- Section 8 - Resource efficiency: containing requirements for the efficient use of resources for buildings including materials, energy, water and waste.
6.3 Recommendations on the scope of the Building Code
It is recommended that:
- objective statements be retained in the Building Code and be amended to clearly align with the new purposes of the Act
- the following objectives and functional requirements define the scope of the Building Code.
Objectives
- Safety: to limit the probability that, as a result of the design, construction, use or demolition of the building, a person in or adjacent to the building will be exposed to an unacceptable risk of injury.
- Health: to limit the probability that, as a result of the design, construction, use or demolition of the building, a person in or adjacent to the building will be exposed to an unacceptable risk of illness.
- Wellbeing: to limit the probability that, as a result of the design, construction, use or demolition of the building, a person in or adjacent to the building will be exposed to an unacceptable loss of wellbeing.
- Physical independence: to limit the probability that, as a result of the design, construction, use or demolition of the building, a person in or adjacent to the building will be exposed to an unacceptable
loss of physical independence.
- Sustainable development: to promote sustainable development.
Functional requirements
The objectives of this Building Code are achieved by buildings or their elements having features that:
Section 1 - General
- limit impacts from events and physical conditions to tolerable levels
- meet Building Code requirements for the intended life of the building
Section 2 - Structural performance
- maintain structural integrity, remain stable and do not collapse under the effects of foreseeable events and physical conditions throughout the life of the building, including during construction and demolition
Section 3 - Fire safety
- limit the risk of an accidental fire or explosion occurring
- limit the risk of fire or explosion impacting areas beyond its point of origin
- limit the risk of fire safety and other emergency systems failing to function as expected
- limit the risk of people being delayed from moving to a place of safety during a fire or other emergency
- limit the risk of firefighters or other emergency services personnel being delayed in or impeded from assisting in evacuation and performing firefighting operations
- limit the risk to firefighters or other emergency services personnel during evacuation and firefighting operations
- limit the risk of adverse effects to other property1
- limit the risk of the release of stored hazardous substances in a fire
- limit the risk of injury due to exposure to high levels of sound from alarm systems
Section 4 - Features for wellbeing and physical independence
- facilitate access to, within and from the building by all people, including people with disabilities
- facilitate access to facilities and services by all people, including people with disabilities
- facilitate connection to the outdoors
- provide space for personal activities
- limit exposure to noise originating from a source within the building
- limit exposure to noise transmitted from a source outside the building
Section 5 - Environment
- limit the risk of unwanted moisture indoors from moisture originating outside the building
- limit the risk of unwanted moisture indoors from moisture originating within the building
- limit the risk of water overflow penetrating to an adjoining property
- limit the risk of illness or loss of wellbeing caused by indoor air contaminants
- limit the risk of illness or loss of wellbeing caused by thermal conditions
- limit the risk of illness or loss of wellbeing caused by internal moisture
Section 6 - Safety of users
- limit the risk of injury due to slipping, falling, drowning or collision
- limit the risk of injury due to inadequate lighting
- limit the risk of injury due to exposure to hot surfaces and substances
- limit the risk of injury due to hazardous agents on site
- limit the risk of injury or illness due to exposure to hazardous substances
Section 7 - Sanitation
- facilitate the sanitary disposal of wastewater
- facilitate the sanitary disposal of solid waste
- facilitate the safe disposal of industrial liquid waste
- facilitate personal hygiene
- facilitate laundering
- facilitate hygienic food preparation
- facilitate cleaning in commercial and industrial buildings
- limit the risk of contamination of water supply systems
- limit the risk of consuming contaminated water
- limit the growth of legionella in heated water
- limit the risk of illness from greywater
Section 8 - Resource efficiency
- facilitate the conservation and efficient use or reuse of energy
- facilitate the conservation and efficient use or reuse of water
- facilitate the conservation and efficient use, reuse, or disposal of materials.
6.4 Recommendations on the performance requirements of the Building Code
6.4.1 Type 1 recommendations to amend the Building Code to clarify performance requirements
It is recommended that the Building Code be amended:
- to clarify that variability and uncertainty are to be taken into account, and an overall safety level must be achieved
- to clarify that lighting and other helpful devices (in addition to signs) are to be provided in buildings (except detached dwellings, or within household units of multi-unit dwellings) to identify, for people, including people with disabilities:
- escape routes
- emergency-related safety features
- potential hazards
- accessible routes and facilities for people with disabilities
- to use the expression wastewater in place of foul water
- to be specific about where sanitation facilities are to be available, ie:
- toilets and hand-washing facilities are to be available where people live or are accommodated, work, or consume food or drink on the premises
- showering or bathing facilities are to be available where (other than ancillary buildings, outbuildings and back-country huts):
- people live or are accommodated
- people engage in active recreation
- children under five are supervised or educated
- to clarify that 'sufficient number' means the time to queue for a toilet, on average, is less than one minute (which is the basis of the present Acceptable Solution)
- to be specific about where laundering facilities are to be available, ie, in:
- detached dwellings or separate household units that accommodate three or more people
- early childhood centres
- group dwellings
- aged care facilities
- multi-unit dwellings
- camping grounds
- by deleting reference to workcamps (for laundering and food preparation facilities).
6.4.2 Type 2 recommendations to consult on proposals to change performance requirements
It is recommended that amendments to the Building Code and related Compliance Documents be prepared for consultation on proposals:
- to include in the Building Code a statement of these general principles:
- effects on adjacent buildings: a building or building work should not cause adjacent buildings to be affected by any of the design events that impact on buildings
- disproportionate consequences: the failure of an element or system should not result in a consequence disproportionate to the event or physical condition that caused the failure
- consequences of failure: building elements should be constructed in a way that makes due allowance for the consequences of failure
- effects of uncertainties: building elements should be constructed in a way that makes due allowance for the effects of uncertainties arising from design and construction processes, including variations in the properties of building materials, workmanship, site conditions and the demands on buildings
- that designers consider the events and physical conditions stated in Table 1 (see Appendix 3)
- that buildings be designed and constructed to avoid surface water (flood) with a 1 percent annual exceedance probability (AEP) entering them
- that buildings be classified into performance groups according to Table 2 (see Appendix 3)
- that performance group 4 and 5 buildings (see Table 2 in Appendix 3) be designed and constructed to withstand tsunami where a tsunami risk has been identified in District Plans
- that a table of tolerable impacts related to events and physical conditions and performance groups be introduced to the Building Code
- that the design of buildings must be such that there is at least 90 percent confidence that buildings will meet the applicable tolerable impact requirements, according to the performance group and range of events to be considered
- that all buildings must meet the 'Insignificant' tolerable impact requirement for physical conditions that could affect buildings all the time
- that a building must be designed, constructed and capable of being maintained to provide confidence that it will comply with the performance requirements of the Building Code throughout its life
- that the designer should state an 'intended life' for a building and demonstrate that it is expected to meet the requirements of the Building Code for that time. An 'intended life' of at least 100 years will be required where the building or building work has 'permanent' effects on other property2
- that the Building Code incorporate the physical conditions likely to affect the performance of a building over its intended life, as in Table 2 (see Appendix 3)
- that building designers clearly show how the physical conditions that affect buildings have been considered and allowed for
- that building designers state the frequency of maintenance or replacement of building systems and how this should be done, to satisfy the building consent authority that the proposed maintenance and replacement arrangements are practicable and a viable means of achieving compliance for the life of a building
- that information about maintenance be included in the documentation provided in a building consent application, to make it available to future building owners
- that a performance framework as described above be applied to the requirements for structural performance requiring the designer to consider:
- the physical conditions that affect the structural performance of the building
- the chances of an event occurring
- the performance group of the building
- the impacts that can be tolerated for a range of circumstances
- that the Building Code be amended to clarify the requirements for addressing concurrent events and physical conditions
- that, for all buildings where alarms used for evacuation are required, the audible signal in a place of safety be not more than LAmax 100 dBA at any normally accessible point in the room at a height of 1.8 m, or no more than 15 dBA greater than the ambient noise, whichever is the greater
- that:
- at least one access route with features for people with disabilities be provided in multi-unit dwellings
- common spaces in multi-unit dwellings be accessible
- where shared facilities for access, parking provisions and sanitary facilities are provided in buildings, they should be accessible for people with disabilities (inclluding shared laundry facilities at hostels, motels and multiunit dwellings, required only for camping grounds at present)
- that, for residential buildings and teaching spaces:
- insulation against airborne noise be based on 80 percent population satisfaction (PPS)
- (likely to satisfy 80 percent of the population)
- insulation against impact noise be based on 80 PPS
- that the reverberation time (expressed in seconds for specific teaching spaces) be specified
- that the maximum design levels for the most common contaminants of indoor air be as set out in Table 3 (see Appendix 3)
- that:
- the maximum relative humidity in occupied spaces not exceed 70 percent for more than six hours a day in habitable spaces
- the time required for condensation on surfaces in occupied spaces (eg, bathrooms) to evaporate must be limited to less than three hours
- that:
- the maximum relative humidity in occupied spaces not exceed 70 percent for more than six hours a day in habitable spaces
- the time required for condensation on surfaces in occupied spaces (eg, bathrooms) to evaporate must be limited to less than three hours
- that access to surfaces or substances of a temperature higher than 50ºC (except for cooking elements) be restricted in early childhood centres, schools, aged care facilities, care facilities for people with disabilities, and hospitals
- that the temperature of heated water leaving the outlet of personal hygiene facilities be less than 50ºC (to avoid the likelihood of scalding)
- that construction requirements for buildings used for storing or using hazardous substances be consistent with the requirements of the Hazardous Substances and New Organisms Act 1996 (HSNO Act)
- that for commercial and industrial buildings, multi-unit dwellings and detached dwellings where there is no independent access or private open space at ground level, space must be provided for safe, hygienic storage before collection of waste and recyclable waste, and access for collection
- that:
- where shared laundry facilities are provided in buildings (eg, multi-unit dwellings, motels, camping grounds) they must be suitable for use by people with disabilities
- that space and facilities for the hygienic use and storage of cleaning equipment be provided in commercial and industrial buildings
- that:
- terminology be changed from potable to drinking water (and correspondingly, from non-potable to non-drinking water)
- water supplied at outlets of fixtures (including laundry tubs) and appliances intended for human consumption, utensil washing, food preparation, oral hygiene and personal washing meet the health quality requirements of the New Zealand Drinking Water Standard 2005
- that:
- raw water that is supplied from springs, bores and tank rainwater may be used for laundry, toilet flushing or irrigation
- raw water used for these purposes is to have low risk to human health from direct contact
- the level of microbial indicators is not to exceed 10 E.coli /100ml
- raw water supplied at outlets of fixtures and appliances intended for human consumption, utensil washing, food preparation, oral hygiene and personal washing, is to meet the health quality requirements of the New Zealand Drinking Water Standard 2005
- that water pipes with non-drinking water be continuously identified
- that:
- greywater may be re-used within a building to flush toilets
- the level of pathogens in greywater stored for re-use as measured by microbial indicators must be less than 1 E.coli/100ml
- the quality of stored greywater must be monitored and the system maintained as a specified system
- greywater may used for subsoil irrigation where that is permitted under the Resource Management Act 1991
- greywater directly distributed for subsoil irrigation does not need to be treated.
6.4.3 Type 3 recommendations to investigate and collaborate on possible performance requirements
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
- 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
- specifying that buildings be designed and built to allow space for 'household activity and access' be investigated
- 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,3 and no less than a set level on a 'connection to the outdoors' scale, be investigated.
6.5 Recommendations for implementation
It is recommended that a programme of staged releases of changes be followed.
It is recommended that Compliance Documents affected by changes to the Building Code be amended and released concurrently with changes to the Building Code.
It is recommended that the development of an Acceptable Solution for Housing be investigated. This could provide details for typical house construction for designers, builders and building consent authorities, and be applicable to about 80 percent of the house construction in New Zealand.
It is recommended that the release of changes to the Building Code and Compliance Documents be accompanied by a comprehensive sector education programme.
It is recommended that guidance be provided to designers, builders and building consent authorities by way of Compliance Documents (and other information) to minimise the impact on compliance costs.
It is recommended that designers have both guidance on features that improve the general accessibility and adaptability of buildings, and some possible solutions.