Determinations issued
Determination 2008/23
The refusal to issue a code compliance certificate for the installation of an oil-fired appliance
The matter for determination
The application arose from the territorial authority's refusal to issue a code compliance certificate for the installation of an oil-fired water boiler ('the appliance') because it had not been provided with certain test certificates to show that the appliance complied with a particular Australian Standard. The building owner applied for the determination.
The building work and the submissions
The appliance provided heated water to heat a house througha radiant floor heating system.
The territorial authority said it would not accept the installation of any product that could not be proven to comply with Australian Standard AS 1691: 1985 Domestic Oil-fired Appliances - Installation.
The owner said AS 1691 was an installation standard, and not a design standard. The owner provided a copy of a certificate showing that the appliance was certified under British Standard EN267: 1999 Forced Draught Oil Burners. Definitions, Requirements, Testing, Marking. The owner had used the certification to obtain approval for the appliance from the appropriate authority, the Environmental Risk Management Authority (ERMA).
Discussion
In the absence of a specific sub-mission on the matter, it appeared the territorial authority was principally concerned about whether the appliance itself had been tested to the appropriate Standard, and whether the testing met the requirements of the Acceptable Solution C/AS1.
Clause C1 of the Building Code is only concerned with the safe installation of such appliances. Paragraph 9.3.2 of C/AS1 modifies AS 1691 by removing the requirement that an installer is to ensure that the appliance itself complies with another Standard (AS 1960: SAA Domestic Oil-fired Appliances Safe Design Code).
The compliance of the appliance itself is the responsibility of ERMA, which has recognised that certification under EN267 is equivalent to certification under AS 1690. The appliance was therefore one approved by ERMA for its intended use in the owner's house.
The appliance manufacturer had provided the installation instructions to the installer that specified safe distances between the appliance and adjacent combustible materials. It was understood the appliance had been installed and the territorial authority had raised no specific objections about the installation.
Conclusion
The determination concluded that the decision by the territorial authority to refuse to issue a code compliance certificate because the appliance had not been tested to AS 1690 was incorrect. The appliance had been tested and certified using a recognised testing Standard and had been approved for use by the appropriate authority.
In the absence of any specific submission to the contrary, it was accepted that the appliance had been installed in accordance with the manufacturer's instructions.
The decision
It was determined that the territorial authority's decision to refuse to issue a code compliance certificate was reversed.
Determination 2008/35
The Code compliance of a house in which injected foam wall insulation has been installed
The matter for determination
The application arose from the territorial authority's decision to issue a notice to fix in respect of foam insulation that had been injected into the cavity behind the brick veneer of an existing single-storey house. The notice to fix required the foam to be removed and the cavity to be reinstated. The matter to be determined was whether the foam, as installed in the cavity, complied with the Building Code. The owner applied for the determination.
The installation of the foam was not consented. The determination also considered faults that were found with the consented work done on the house. However, that aspect of the determination is not discussed here.
The building work
The building is an existing single-storey house, which was subject to some alterations and additions, including plastering the existing brick-veneer. The brickwork was plastered and then painted with an acrylic paint system. A close-boarded deck was constructed next to the house as part of the consented work (this was found to trap moisture near the junction of the concrete foundations and lower walls).
The territorial authority granted a building consent and a code compliance certificate for the additions and alterations. However, the consented work did not include the foam insulation, which was installed near the end of construction. The foam was provided to increase the thermal performance of the house and was installed by the local franchisee of a company that operated nationwide.
The foam is a urea-formaldehyde foam and was injected, as a viscous liquid, into the existing brick cavity where it expanded and set. There was no building paper to the timber framing and the foam filled the depth of the timber framing in addition to the cavity, resulting in a foam layer that was approximately 150 mm thick. The house was considered to have some low risk weathertightness features and it was subject to extreme wet and windy weather conditions and high humidity levels.
The territorial authority issued a notice to fix that required the owner to remove the foam and reinstate the cavity behind the brickwork.
Assessment methodology
The determination considered the following aspects.
- The effect of installing the foam into the brick cavity.
- An internal study of New Zealand and overseas literature on the use and effectiveness of the foam.
- The arrangements between the local franchisee and the national company, quality assurance, installation techniques, and the size of the national operation. General aspects of the foam's ability to comply with the Building Code were also considered.
- A detailed inspection of the building was completed plus a second inspection after six months to see whether the moisture levels detected in the walls during the first inspection had changed over time.
- Whether the installation of the foam was considered building work and whether it was exempt from the need for a building consent.
The effects of installing the foam to the brick cavity
The original single-skin brick veneer formed a rain screen that prevented any moisture penetrating the brickwork from coming into contact with the timber framing. Any moisture that did penetrate the brickwork was stopped from going further by the drained and ventilated cavity. The brickwork was readily able to absorb and dissipate moisture.
The injection of the foam significantly modified the brick veneer cladding system because:
- there is no longer a drained and ventilated cavity between the brick and the timber frame
- the plaster and paint to the brick veneer means any moisture in the brickwork cannot now dissipate to the outside. Also, moisture cannot escape from the brickwork to the interior because the cavity has effectively been removed.
The internal study
The foam has been used with a high degree of success and there have been few failures reported. The few failures that had been reported were due to rain penetration from pre-existing defects in the existing cladding. In the United Kingdom, the foam was most commonly installed in the cavity between double skin brick walls. The outer skin of brick is often not exposed to the combinations of wind and rain that affect New Zealand buildings.
The formaldehyde gas released as the foam cures is an irritant to some people, the extent of which differs from person to person. The use of the foam was banned in Canada in 1980 on account of reports of homeowners suffering ill effects from formaldehyde. However, no such ban appears to have been imposed in the United Kingdom or in Europe.
The installer and general aspects of Code compliance
There are 12 active franchises operating throughout the country and each franchisee operates as an independent contractor. The national company organises conferences, training programmes, and ongoing off-site training on a compulsory basis. There is a standardised tendering and monitoring procedure, including job record sheets. Each franchise is monitored twice each year and is required to submit job records and samples of foam for testing. The company claimed to have carried out about 9,000 installations spanning a period of about 25 years up to the present.
The determination considered the foam to be durable. It was not susceptible to the agents that commonly cause degradation of other building materials nor was it exposed to UV light that can degrade some plastics.
Combinations of some factors affected the weathertightness risks to retrofitted external walls, particularly where there were defects in the walls exposed to wind-driven rain. The foam did generally improve the thermal resistance of the walls that contributed to achieve the requirements of both Building Code Clauses E3 and H1. There was the risk of condensation forming within the wall cavity, but this could occur regardless of the type of insulation used.
The curing foam gives off formaldehyde gas. The company recommended increased rates of ventilation for the first four weeks following installation of the foam. The company provided test data from studies carried out in 1981 that showed gas levels 30 days after installation that were well within safe levels given in a Department of Labour publication.
The inspections
The determination noted that a cubic metre of foam contains approximately 40 litres of water that results from the production of the foam itself and that dissipates from the foam as it cures. The foam to the external walls is 150 mm thick, which means a large volume of water was present in the foam as it was installed. Foam samples were taken at four levels at one location, which showed much higher levels of moisture at the lower levels. Permeability tests indicated that water can easily percolate downwards through the foam.
People in the house experienced irritation when the samples were being taken and tests indicated that wet foam was still producing irritants.
Air tests for formaldehyde were also carried out in several rooms of the house and high readings were found in areas that were not well ventilated.
The dissipation of water from the foam was made difficult as the brickwork was now impervious to water. Impervious internal finishes had also been installed, and the close-boarded deck had limited ventilation at the junction of the concrete foundations and lower walls. It is believed the wet, and therefore uncured, foam was still giving off irritants but that this would diminish once the foam dried. High ventilation rates should be maintained until this was achieved.
The moisture content of the timber framing was also tested and high readings were found at lower levels. A second inspection was completed six months after the first readings were taken to see whether the moisture content to the timber had changed over time. The moisture content had dropped near to an acceptable level, indicating that the foam was also drying. It was recommended that ventilation of the exterior junction of the foundations and the wall be improved, as the limiting effects of the close-boarded deck were still evident.
Was the installation of the foam 'building work', and was it exempt from the need for a building consent?
Section 7 of the Building Act says 'building work' means work 'for, or in connection with, the construction, alteration, demolition, or removal of a building; . . .'. It was concluded that the installation of the foam insulation was building work that altered the house and must therefore be building work as defined in section 7 of the Act.
Schedule 1 of the Act does not specifically mention foam insulation. However, paragraph (k) of Schedule 1 provides that a territorial or regional authority may allow building work to proceed without the need for a building consent subject to conditions concerning Code compliance or safety. Paragraph (k) should only be invoked after consideration of the nature and type of the building work concerned.In relation to this building, the view was taken that the installation of the foam should have been included as part of the consented work, and was therefore not exempt from the need for a building consent. While the foam cannot be subject to a code compliance certificate, because it was unconsented work, it was eligible to receive a certificate of acceptance if considered to be Code-compliant.
Conclusion
It was concluded that the house did comply with Building Code Clauses E3 Internal moisture and H1 Energy efficiency. However, because of a combination of the moisture injected with the foam, and inadequate ventilation, the house did not comply with Clauses B2 Durability, E2 External moisture and F2 Hazardous building materials.
There is evidence that the brick walls, with the right conditions, will eventually comply with Clauses B2 and E2. The modification of the close-boarded deck to allow better ventilation would assist this. The continuing presence of formaldehyde in the building was a concern, taking into account the time the foam has been in place.
However, it was acknowledged that with adequate ventilation and the passing of time, this would also comply.
While the determination concluded that the decision of the territorial authority to issue the notice to fix requiring the removal of the foam was incorrect, it was recommended that any new notice to fix should not be enforced until a full spring and summer season had passed. This would confirm whether or not the foam insulation and adjacent framing and linings had dried out to acceptable levels and the formaldehyde present had dissipated.
The use of the foam was not appropriate in all situations and the company needed to make its franchisees aware of the product's limitations. The injection of foam into particular walls would alter the performance of the wall with respect to other Building Code Clauses in addition to Clause H1. It was recommended that the company revise its procedures around the injection of the foam into brick cavities.
The decision
It was determined that the foam did not comply with Clauses B2, E2 and F2 of the Building Code. The decision of the territorial authority to issue the notice to fix requiring the removal of the foam from the cavity behind the brick veneer was reversed.
To read all the determinations in summary or in full, go to: www.dbh.govt.nz/determinations