Myrtle

Density Notes

Seasoned density is based on moisture content of 12%. Unseasoned density is an approximation as it depends on the moisture content at the time of measurement. Measured kg/m3.

Durability Notes

Species Specific Notes: Termite resistance of heartwood: Not resistant. Sapwood is susceptible to Lyctid Borer.

Myrtle has good durability for decorative, architectural and structural applications internally but is not recommended for external use.

The in-ground durability of heartwood is low. Refer to AS 5604-2005 Timber - Natural durability ratings.

Durability is defined as the inherent resistance of a timber species to decay, or to insect or marine borer attack. All references to durability refer to the heartwood only. A scale of low to high - durability class 4 = low (0-5yrs); 3 = (5-15yrs); 2 = (15-25yrs) ; 1 = high (25yrs+) - has been adapted for in-ground durability.

Fire Notes

Average Specific Extinction Area is determined by the volume of smoke measured over the mass loss of the tested sample per test carried out in accordance with ‘Cone Calorimeter Test’ AS/NZS 3837. It is measured in units of m2/kg.

Bushfire Attack Level (BAL): Naturally bushfire-resisting timbers are those with inherent bushfire-resisting properties. Some species have been tested and a number are in the process of being tested. Resistance is measured by BAL. BAL-12.5: Ember attack, BAL-19: Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 12.5 and 19 kWm3, BAL-29: Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 19 and 29 kWm3.

Critical Radiance Flux measures the radiant (heat) energy required to sustain burning. It is used in Australia to regulate floor coverings. The requirements are set out in BCA Specification C1.10a, providing CRF values for floor coverings based on Class of building, the location within the building (general use or use in fire isolated exits) and whether or not the building is sprinkler protected or not. CRF is measured in kW/m2.

Smoke Development Rate is the speed at which smoke increases as determined by testing flooring materials in accordance with AS ISO 9239.1. The rate is expressed in terms of percent/minutes. For buildings not protected with a sprinkler system, a maximum smoke development rate of 750 percent/minute applies.

EFH Ingnitibility is a measure of the tendency of a material to ignite measured on a scale of 0-19. An index of 0 indicates that the material did not ignite during the 19 minutes that the test takes. An index of 19 indicates that the material ignited in the first minute.

EFH Smoke-Developed Index is a measure of the concentration (measured by optical density) of smoke a material emits as it burns. It is based on an arbitrary scale of 0 to 10. The higher the index, the greater the hazard from smoke is likely to be.

EFH Spread-of-Flame Index is a material's propensity to burn rapidly and spread flames based on a scale of 0 to 10 where 0 means that the materials will not cause flames to reach the ceiling and 10 indicates that the material could be expected to cause flames to reach the ceiling of a room within 10 seconds of ignition.

Fire Properties Group Number: is rated from 1-4 - 1 (Non-Combustible), 2 (Reasonably Non-Combustible), 3 (Slightly Combustible), 4 (Combustible).

Joint Notes

The joint group is a classification of the strength of a species in joint design. The values are from 1 (very high strength) to 6 (very low strength).

Mechanical Notes

Modulus of Rupture (MOR) is a measure of maximum stress which timber can momentarily sustain when loaded slowly and continuously as a beam. Measured in MPa.

Modulus of Elasticity (MOE) is of importance in determining the deflection of a beam under load, the greater the stiffness, the less the deflection. Measured in GPa.

Maximum Crushing Strength, also referred to as compression strength, measures the ability of the timber to withstand loads applied on the end grain. Measured in MPa.

Impact provides the Izod value, which is the energy taken in joules (J) to fracture the timber.

Toughness is a measure of timber’s ability to resist shocks and blows, and is synonymous with impact strength. It is measured in Nm.

Hardness refers to the Janka hardness test and is a measure of timber’s resistance to indentation. This value is as listed on the CSAW website.

Movement Notes

Radial and tangential movement is the percentage of dimensional change for each 1% moisture content change between about 3% moisture content and the fibre saturation point for the particular species. Between (FSP) 25% and 5%MC. Figures are approximate.

Shrinkage Notes

Species Specific Notes: Before reconditioning: Radial shrinkage is 3%, Tangential shrinkage 6.5%

Tangential shrinkage is the measure of the percentage reduction in dimension from the unseasoned to 12% moisture content condition. Radial shrinkage is perpendicular to the growth rings, it is shrinkage in the direction towards the centre of the tree. Measurement is % value. Green to 12%MC. Figures are approximate.

Strength Notes

Strength groups are given for unseasoned (S1-S7) and seasoned (SD1-SD8) timber in accordance with AS 2878. S1 and SD1 yield the highest strength and stiffness whereas S7 and SD8 yield the lowest.

Stress Notes

Species Specific Notes: Structural grade Myrtle is not commonly available.

A stress grade is defined in AS 1720 as the classification of timber for structural purposes by means of either visual or machine grading. The stress grade indicates the basic working stresses and stiffnesses to be used for structural design purposes. Measured in MPa.