Solar Panel Installation in the NT

Transcription

1 Solar Panel Installation in the NT Over the last 4 years, Heiner Structural Engineering Consultancy (HSEC) has assisted its clients with over 500 solar installations in the NT. HSEC has become one of the leading experts for engineering and certifying solar installations in cyclonic regions and more specifically, the NT. As a result of the destruction of Darwin in 1974, by Cyclone Tracey, the Northern Territory has some of the tightest building regulations in the world. In addition, solar installations have never been specifically regulated, resulting industry to be shoe-horned into existing regulations. This has meant that the solar industry falls under 4 different regulatory authorities. These are; NT Worksafe Power and Water NT Department of Land and Planning Services NT Building Act Clean Energy Council of Australia Under the Department of Lands and Planning Services NT Building Act, NT registered practitioners are required for both building certification and structural engineering, which HSEC can provide. We can also provide expert advice in complying with NT building Act. However, we are not experts in dealing with NT Worksafe, Power and Water or the Clean Energy Council of Australia, and as such, cannot assist with their regulations. We recommend contacting the Solar Energy Industries Association INC (SEIA) for further information regarding these bodies and their requirements to work in the NT. They can be contacted at NT@seia.org.au and have regular meetings in Palmerston about once a month.

2 Definitions: Section 40 Design: Building Permit: Occupancy Permit: Tier 1 building control zone: Tier 2 building control zone: Deemed to comply manual: Cyclonic Zone: An engineering design certificate provided to the NT building act by an NT registered engineer to certify that the drawing meets current Australian standards and law. There are multiple types, but in this case, all that matters is having a structural engineering version A bundle of documents including a certificate provided by an NT Registered Certifier to the building allowing legal start of construction works. As per the NT building act, no works in building control areas can commence without one. The section 40 design certificate forms part of this package. A certificate provide by an NT Registered Certifier at the end of the job that certifies that all works have been undertaken as per the NT building Act. This certificate is provided by the certifier to the NT building board, and issued to the client. Zones that require a building permit and occupancy permits to undertake any building works. Currently there are 3 in the NT, Darwin, Alice Springs and Lake Bennett. The NT building control zone limits can be found on this website, by turning on the Building Control Areas filter under Land Administration and Admin Interests. Zones that require only a building permit undertake any building works. No occupancy permit is required. Currently there are 18 in the NT, including within 500m of a major highway. Further information can be found at The DTC listing is a list of manufactured products that have been deemed to comply with Australian Standards in the cyclonic zones of the NT by the NT government. Further information can be found at: This is an area as per AS1170.2: Wind actions. This area covers all buildings within 50km of the coastline.

3 Solar arrays installed on existing buildings fall under 2 Building advisory committee notes, BAC and BAC and 2 building notes, 81 and 83. Installation requirements depend on the type of building for the installation and where the installation is. At this stage, all commercial and apartment blocks buildings require a building permit / occupancy permit. For domestic houses and sheds, the requirements depend on whether the array is being installed in a cyclonic zone or whether it is in an NT building control zone. Domestic housing and sheds Region Zone Requirements Cyclonic Inside the Building Control Zone Building Permit Occupancy Permit (Tier 1 zone only) Cyclonic Outside of Building Control Zone No require for building permit Non-Cyclonic Inside the Building Control Zone No building permit is required if: Installer is CEC accredited Panels are CEC accredited The building is less than 5 years old. OR The roof can be approved by a registered certifier, builder or structural engineer. Non-Cyclonic Outside of Building Control Zone No require for building permit Complicating the matters further, there is an exemption to the requirement of a building permit in cyclonic regions in the event that; The PV panels and mounting rails are referenced in the DTC Manual The installer is accredited with the CEC The panels are accredited with the CEC The roof is structural sound by either; o A building permit was issued after 1 January 2007, or o The rood is sound as certified by a NT registered certifier, builder or structural engineer. At this stage, we do not recommend attempting this route. There is currently only 1 panel approved under the DTC standards, the Auxin panel (DTC/M/539). This DTC has been written in such a way that only a roof of rare dimensions will satisfy its provisions. In addition, it is within our experience that it is very difficult to obtain a DTC, both in expense and time, with a number of companies failing. Even if the panel is approved by the Building Advisory committee, you will only be able to install the panels on new buildings (post 2007) without the engineering anyway. Therefore we deem the exercise to be not financially viable at this stage for a small market such as Darwin.

4 Engineering Requirements for Installs Under the NT building Act, NT registered engineers can approve all structural works. This is up to the discretion of the engineer, and their interpretations of the relevant Australian Standards and Building Codes. In addition, a major requirement of registration in the NT is having professional indemnity insurance. This discretion, interpretation and insurance requirements lends itself to slight variations of approvals by different engineers due to their evaluation of risk and interpretations. It is also incumbent on the engineer to ensure all materials are fit for purpose, whether by testing or calculation. Due to the complexity of the materials used within the solar installation combined with the relative youth of the industry, this has lent itself to the requirement that the majority of panels and rails will require physical testing. HSEC maintains a list of previously approved panels and rails. By using any of these panels or rails, the engineering on the system is straight forward and simple. If you are looking to use a rail or panel system beyond our list, a test report will be required, or we can provide such testing. Please be aware that the testing requirements for the NT cyclonic wind zone will likely be far beyond the typical testing of solar panels, with a minimum of about 5.4kPa applied to rear of the panel for domestic uses. Assuming your panel and rail system is approved by us, you can then start looking at clients and specific jobs. We can easily approve the majority of buildings in the NT with a few exceptions. Please be aware that we will not be able to approve any solar arrays on pre cyclone Tracey roofs, without a reroof to post Tracey standards. In addition, we have not seen a system that meets our standards to affix to concrete tie or Aluminum tile roofs. Between the tie down requirements, the existing cyclonic ties, the small batten sizes and weatherproofing issues, we believe there is too much risk of problems and significant costs arising from this work. Finally, the lightweight cold formed shed industry has been involved in a race to the bottom for price for the last years. In our opinion, this has resulted in a number of buildings that do not meet current Australian Standards. Therefore, we can only approve these buildings on a case by case basis. Engineering requirements: Assuming your rail and panel have been approved by HSEC, all you will need to provide for each job is a roof plan, with a quick sketch of the layout of the panels, number of panels, and a note of which rail and panel models you wish to use for the job. We will then issue a section 40 design for your array, with notes on which screws to use and spacing between them.

5 Building Permit requirements: Building certification for solar panels is a routine exercise. Assume the building is a legal structure, with either a certificate of occupancy or a lawful letter, and the engineering works, a building permit can be issued. Documentation required for a building permit are: Application of building permit (attached) With sections 1,2,3,5 and 8 filled out as best you can. A site plan of the whole allotment with an indication of which building will have solar installed on it. Section 40 certificate of design from engineer We will require payment of outstanding fees before we will provide you with the building permit. Install Requirements As per AS1170.2, solar panels can be installed at an absolute minimum of 200mm of the edges. Ridge lines also have this minimum distance, assuming the roof pitch is greater than 10degrees. Valleys and ridges less than 10 degrees do not have any minimum requirement. However, due to gable overhangs on timber trusses, and the batten spacing requirements on the roof edges, we recommend that you use a 700mm minimum edge distance, which will cover all situations. We can, if required on a specific case, approve less than 700mm, but for the sake of less mistakes, we recommend staying with the 700mm. Screw spacings and sizes are provided on the s40 drawings, but sufficient to say: Batten type Spacing Type Metal Roof Batten 200 max centers M6.5 screw Steel Purlin 500 max centers 14G Tek Screw Timber Roof Batten 200 max centers with 2m of edge, 14G type 17 35mm min Concrete Roof 400 max centers in internal zone Spacings depend on rail, but up to 1000mm Embedment M12 chemset bolt with 125mm Min Embedment Occupancy Permit requirements: As soon as the building permit is issued, you are legally allowed to start building. After construction is complete, we will require an inspection on the works, please normally allow 24 hours notice. Assuming that your works comply with the details for the building permit, an occupancy permit can be started. To finalize your occupancy permit, we will require Electrical Certificate Building Declaration Occupancy Permit Application After the Occupancy permit has been issued, we will provide it to both the building board and the client. At this stage, the job is finalized and a legal structure.