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National Wood Burner Performance Review: Phase 2

Executive Summary

1 Introduction

2 Methodology

3 Test Results

4 Conclusions

Appendix 1: Review Protocol

1 Introduction

The purpose of the review was to ascertain compliance and provide information to consumers, retailers and installers on the products they purchase and install.

The review was conducted by the Ministry for the Environment in partnership with Environment Canterbury and Nelson City Council. The review was carried out in two phases:

• Phase 1: involved testing the design of 35 wood burners in-store

• Phase 2: involved testing the design, emissions and efficiency of 10 (purchased) wood burners.

This report describes the process and the results of Phase 2 of the performance review. The report for Phase 1 of the review is available at:

http://www.mfe.govt.nz/publications/air/national-wood-burner-review-jun07/index.html.

1.1 National environmental standards for air quality

The Resource Management (National Environmental Standards Relating to Certain Air Pollutants, Dioxins and Other Toxics) Regulations 2004 were promulgated on 6 September 2004. For the purposes of this report, these regulations will hereafter be referred to as “the NES for air quality”.

The NES for air quality requires that from 1 September 2005 all new wood burners installed on properties less than two hectares must have a discharge of less than 1.5 grams of particles for each kilogram of dry wood burnt, and a thermal efficiency at least 65 per cent as tested under a specified standard. Under the Resource Management Act 1991 responsibility for enforcing the NES for air quality is devolved to regional councils and unitary authorities.

Under the NES for air quality, a wood burner is defined as:

(a) a domestic heating appliance that burns wood; but

(b) does not include -

i. an open fire; or

ii. a multifuel heater, a pellet heater, or a coal burning heater; or

iii. a stove that is -

(A) designed and used for cooking; and

(B) heated by burning wood.

The NES for air quality does not apply to burners installed in properties over two hectares. This means that it is not illegal to manufacture or sell non-compliant burners in New Zealand, provided they are not sold for installation in properties smaller than 2 hectares. It is however, illegal to sell or advertise that a wood burner meets the NES for air quality if it does not.¹

1.2 New Zealand regulatory context

Currently in New Zealand, wood burners are authorised for installation by either Environment Canterbury or Nelson City Council in accordance with the rules in their respective regional plans.² The Ministry publishes burners authorised by these councils on a national list for the benefit of consumers, retailers, district, city and regional councils in the rest of New Zealand.

To be authorised, a burner must be tested in accordance with required test methods and then physically checked and approved by Environment Canterbury or Nelson City Council. The required test methods are:

• Australian/New Zealand Standard AS/NZ 4013:1999, Domestic solid fuel burning appliances – Method for determination of flue gas emissions, and

• Australian/New Zealand Standard AS/NZ 4012:1999, Domestic solid fuel burning appliances – Method for determination of power output and efficiency.

During the authorisation process burners are physically inspected and documentation for the burners is reviewed. This documentation includes installation and operating instructions, design drawings, and manufacturing design tolerances. In addition, the appliance is checked to ensure there are no parts that are likely to fail during in-home use, or be easily modified by the owner, and labelling is checked to ensure it is correct and meets Environment Canterbury or Nelson City Council requirements.

Environment Canterbury requires that burners have a maximum particle emission of less than 1.0 g/kg and Nelson City Council requires emissions to be less than 1.5 g/kg.³ To avoid duplication the two councils have agreed that any burners authorised by Environment Canterbury (ie, that emit less than 1.0 g/kg) are also adopted by Nelson City Council. Nelson City Council authorises burners that emit between 1.0 and 1.5 g/kg.

The Ministry for the Environment (the Ministry) publishes a list of all wood burners authorised by both Environment Canterbury and Nelson City Council on their website – this is called the ‘authorised list’.

Other burners, with test results that meet the NES for air quality requirements but that have not been authorised, may exist. While these burners may comply with the NES for air quality there is no independent verification that the burner being sold is the same as that which was tested. There has further been no assessment of the burner design to avoid issues such as tamperability or in-home failure.

Previously, the Ministry published a ‘tested list’ on their website. Burners on the tested list had a test certificate demonstrating their emissions and efficiency met the NES when tested in accordance with AS/NZS 4012/4013. However, burners on the tested list had not been authorised by Environment Canterbury or Nelson City Council. Following the poor results of Phase 1 of this review, the tested list was removed from the Ministry’s website. Now wood burners must go through the independent and rigorous ‘authorisation’ process before they are published on the Ministry’s website as compliant with the air quality standards.

Local authorities in New Zealand only grant building consent for wood burners they are satisfied meet the NES for air quality. The Ministry for the Environment strongly recommends that councils only approve burners that are listed on the Ministry’s website.

1.3 The performance review (Phase 1 and 2)

In April 2006, the Ministry began a national performance review of wood burners under the NES for air quality.

Environment Canterbury and Nelson City Council are national leaders in regulating wood burners. It was, therefore, appropriate for the review to be carried out in partnership with these councils. The Ministry provided the funding for the project, with Environment Canterbury and Nelson City Council providing considerable resources in kind (staff with relevant expertise in the authorisation of low-emission wood burners).

Phase 1 – Design verification

Phase 1 involved design verification on 35 randomly selected wood burners. Design verification testing is a physical inspection of a burner for comparison with its original design as described in the emissions and efficiency test report. All burners were checked in-store by an independent engineer with verification undertaken in accordance with a review protocol (further details in Section 2).

Overall, Phase 1 of the performance review found poor compliance. Only 37 per cent of burners passed, while 54 per cent of burners failed the performance review. In addition, 9 per cent of results were undetermined ie, it could not be determined whether the burners passed or failed.

Phase 2 – Design verification, emissions and efficiency tests

Phase 2 of the review incorporated design verification as well as full emissions and efficiency testing of 10 randomly selected wood burners.

The 10 burners were purchased by Environment Canterbury and Nelson City Council (five each). The burners were then submitted to an accredited laboratory for design verification and emissions and efficiency testing in accordance with the required test methods. Emissions and efficiency testing was carried out to determine compliance with the NES for air quality.

Emissions and efficiency testing was contracted to two laboratories currently accredited with International Accreditation New Zealand as follows:

• Spectrum Laboratories (for the Yunca Finz)

• Applied Research Services (for the remaining nine burners).

The inclusion of Spectrum Laboratories was to provide (limited) inter-laboratory accreditation. The results of this aspect of testing have been made available to International Accreditation New Zealand.

1.4 Industry input

Before the introduction of the NES for air quality, the wood burner industry was not regulated for emissions in most areas of New Zealand (ie, there were no emission limits other than the voluntary limits present in AS/NZS 4013:1999). Therefore, it was expected that compliance issues could arise in the review.

It was important that such a review provide transparency and fairness to the industry. The Ministry met with the New Zealand Home Heating Association (NZHHA) executive and manufacturers in April 2006 to outline the intention to carry out a performance review. At that time a date for the review was not specified. The industry therefore had no warning, other than general notice, that a review would be undertaken at some stage in the next two years.

The Ministry extended the opportunity for NZHHA to provide technical input into the design of the review. The NZHHA formally endorsed the review and offered their support by providing:

• co-operation in requesting retailers make burners in retail showrooms available for inspection (design verification testing only)

• co-operation in requesting member manufacturers make test reports available

• informing all members (particularly retailers) of the upcoming review

• technical input into the design of the review protocol.

In addition to this, a sub-committee was set up to develop a protocol to govern the performance review (discussed in more detail in Section 2).

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