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The density of American red oak at 12% moisture content averages around 700 kg/m³. This means that in areas up to and including BAL-19 red oak can be used for window joinery, door frames and the framing surrounding any glazing that is less than 400 mm from an adjacent surface. In areas up to BAL-19, AS 3959 permits any timber with a density of 650 kg/m³ or greater in these locations. Window joinery and framing more than 400 mm above an adjacent surface can be any species of timber. This regulation is based on the principle that the mode of bushfire attack in BAL-12.5 and BAL-19 is primarily accumulation of embers and burning debris at the base of walls. Hence the restriction on timber closer than 400 mm to adjacent ground, decking or similar horizontal surface. 

It is surprising that reclaimed timber is not offered in a stress graded condition. Grading rules for recycled timber are available on our website and can be downloaded free of charge via this link https://www.woodsolutions.com.au/system/files/Recycled_Products_Structuralproducts_0.pdf. Span tables can also be downloaded once the grade is known. It will be necessary to know the species of timber before it can be graded, but presumably suppliers can provide this information. Regarding a person to provide a stress grading service, Timber Training Creswick provides training in visual stress grading and should be able to put you in touch with people in your area who have completed their courses. TTC has a website here https://timbertrainingcreswick.com.au/about/. 

Whether timber would achieve a 1-hour fire rating depends on the size and density of the species of timber. Our Technical Design Guide #06, titled Timber-Framed Construction – Sacrificial Timber Construction Joint, explains how to use timber's charring properties. A copy can be downloaded free of charge from our website via this link https://www.woodsolutions.com.au/publications, or a hard copy can be purchased here https://www.intertekinform.com/en-au/search/standard/?searchTerm=WS06&productFamily=STANDARD&q=WS06. The construction details in our Technical Design Guide #06 are valid for any species of timber with a density not less than 470 kg/m³. TDG #06 is based on Australian Standard 1720 Part 4: Fire resistance for structural adequacy of timber members. To calculate the charring rate (c) in millimetres per minute the formula in AS 1720.4 is:

²

Where = timber density at 12% moisture content in kg per cubic metre

For example, the charring rate of pine with a density of 550 kg/m³ would be 0.4 + 0.26 = 0.66 mm/min. A dense hardwood would 'char' more slowly. A structural design check is required to make sure the residual section would continue to carry the load after a 1-hour period.