AUSTRALIAN GRADING STANDARD

Transcription

1 AUSTRALIAN GRADING STANDARD Timber Hardwood Grade Description MARKET TIMBERS 471 Somerville Rd Brooklyn VIC 3012, Australia Tel: Established Suppliers to Australia's leading builders, architects and designers.

2 Australian Grading Standards The grades specified in Australian Grading Standard are primarily based on the features and desired aesthetic appearance. Each piece of hardwood product shall be graded on the face, back, edges and ends, as appropriate, in accordance with the requirements of this Standard, sawn or milled to ordered dimensions, and within the tolerances appropriate to the product. The grading names in Australian Grading Standard are not intend to indicate a ranking of quality. For some applications and species, an increasing proportion of features may make a product more desirable rather than less. 1. Select Grade Providing a floor where the feature present or natural discolouration will not dominate the appearance of the floor, this timber flooring is classified as select grade. Select grade has the least number of natural features such as gum veins and pin holes. MARKET TIMBERS provides select grade timber flooring with limited variation in natural characteristics. All our products have been carefully selected and graded, floorboard by floorboard, to ensure that it meets strict quality standards. 2. Medium Feature - Standard Grade depending on the species, features will vary and in some instances boards meeting high feature grade may only appear moderately featured. It should be note that the difference in appearance between a Select Grade floor and a Medium Feature Standard Grade can be quite significant whereas the difference in appearance between a Medium Feature Standard Grade floor and a High Feature Grade floor can be quite small. Providing a floor that may have significantly more character than a Select Grade floor, it is classified as standard grade. Standard grade has a moderate amount of natural features. To some degree this will depend on the features present in a particular species. In one species gum veins may naturally be prevalent while in another there may be few gum veins but past borer activity may be more prevalent. Therefore, this grade can be expected to have greater character than Select Grade, and contain an increased amount of gum vein, past borer activity, knots and natural discolouration. MARKET TIMBERS provides meadium feature - standard grade timber flooring with interesting and distinctive variations and markings, to enhance the look of a timber floor and give it a unique character as individual signature. 3. High Feature Grade High Feature Grade is also known as Rustic Grade. Providing a floor that contains boards with similar features to Medium Feature Standard Grade but where the length of features such as gum veins may be longer and past borer activity more frequent. Again MARKET TIMBERS provides high feature grade timber flooring with unique natural features. Although high feature grade has always been considered the cheapest grade, it is now becoming more popular due to the beauty of its natural look. Modern techniques in the finishing of these floors make them aesthetically stunning. 471 Somerville Rd Brooklyn VIC 3012, Australia Tel:

3 Natural Features of Timber Hardwood MARKET TIMBERS 1. Knots 3. Grains The grains in back sawn timber piece have mixed direction that can include cathedrals, crowns or swirls along the face of the board. According to the specifications in AS/NZS , the measurement of the grain is to determine the slope. General grain slope calculation is given by a/b. Knots are the remnants of branches that have been captured by the growing trunk of the tree. The size of the knots is defined as the width which is measured between lines parallel to the length of the timber piece with the knot. 2. Holes The size of the holes is measured when they appear on the surface of the timber. In the above figure. x refers to the width of the hole. and y refers to the length of the hole. In timber industry, the term grain means the general direction of wood fibres relative to the length of the timber piece. Grain also refers to the direction, size, arrangement, appearance, or quality of wood fibres. There are straight grains, irregular grains, wavy grains, and etc. The most common grain variation is the pattern of the growth rings on the surface, which is determined by the ways the timber is cut. The most two common cutting methods include Quarter sawn (left) and Back sawn (right). The grains in quarter sawn timber piece are relatively straight, even and parallel running along the board. 4. Gum Veins and Gum Pockets Gum Veins and gum pockets are common characteristics in most hardwoods. They are the build-up of resin or tree sap and can be easily identified by their colour difference on the same timber piece. The centre of gum veins, generally white in color, has very few wood fibres and is soft in texture. As moving towards the edges of the gum veins, the colour becomes darker and the amount of wood fibres increases.

4 The width of the gum vein and gum pocket shall be measured on the surface of the timber and the length shall be measured along the timber piece. The depth shall be measured at 90 o to the surface on which it appears. 5. Checks and Splits Checks and splits of timber refer to the appearance of cracks in wood. As timber dries out over time, checks and splits are likely to appear. There are different types of cracks in timber as illustrated in the figure below, surface check (a), normal check (b), internal check (c) and split (d). The width (w) of the check is measured on the surface of the timber piece perpendicular to the longitudinal direction of the check. The length (x) of the split and the length (y) of the check are measured parallel to the length of the timber piece. In Australian Grading Standard, it is considered inappropriate to include internal checks as part of the grading rules since they cannot always be seen by the grader. 6. Want, Wane and Sapwood The sapwood of a tree is the youngest wood in a tree s trunk and is located in the outermost rings. All wood that exists in a tree either currently is or was once sapwood until it reaches a certain age. Sapwood is generally in comparison with heartwood that is the older wood that is deeper in the trunk of the tree and close to the center. Sapwood is also called living wood because it is the wood that conducts water from the roots underground to the leaves in the branch. Not only does sapwood Wane refers to the presence of bark or lack of wood from any cause on the edge or corner of a piece of timber. Want refers to the absence of fiber on the edge of timber.

5 MARKET TIMBERS APPENDIX SUMMARY TABLES OF GRADE DESCRIPTIONS (Informative) The summary of the descriptions given in Tables 1 and 2 is not exhaustive and does not take the place of the requirements set out in this Standard. Reference should be made to the appropriate Sections of Australian Grading Standard for a complete description of the grades. TABLE 1 SUMMARY OF NON-PERMISSIBLE FEATURES Surface SELECT GRADE (SEL) MEDIUM FEATURE GRADE Standard (MF) HIGH FEATURE GRADE (HF) Any surface Enclosed termite galleries Heart shakes Enclosed termite galleries Heart shakes Enclosed termite galleries Heart shakes Shakes Shakes Shakes Cross-fractures, crossshakes Cross-fractures, crossshakes Cross-fractures, crossshakes Splits Splits Splits End splits End splits End splits Decay, primary rot Decay, primary rot Decay, primary rot Lyctid-susceptible sapwood Lyctid-susceptible sapwood Lyctid-susceptible sapwood Any exposed surface Loose knots Loose gum veins Gum pockets, latex pockets Overgrowth of injury Knot checks Want and wane Loose knots Want and wane Mechanical damage Stain other than natural discolouration and discolouration of sapwood due to preservatives Want and wane Mechanical damage Stain other than natural discolouration and discolouration of sapwood due to preservatives Sticker marks Mechanical damage Sticker marks Stain other than natural discolouration and discolouration of sapwood due to preservatives Sticker marks

6 Feature Tight knots and any associated voids; individually or in aggregate in any 1 m of board length TABLE 2 SUMMARY OF PERMISSIBLE FEATURES IN HARDWOOD PRODUCTS SELECT GRADE (SEL) Not exceeding 15 mm or 1/4 of the surface on which it occurs MEDIUM FEATURE GRADE Standard (MF) On exposed surfaces Not exceeding 40 mm or 1/3 of the surface on which it occurs HIGH FEATURE GRADE (HF) Not exceeding 50 mm or 3/8 of the surface on which it occurs Loose Knots Not permitted Not permitted As for holes As for holes Holes (borer, non-enclosed termite galleries and other) (a) Length Not exceeding the lesser of 15 mm or 1/4 of the surface on which it occurs (b) Width Exceeding 2 mm not permitted Not exceeding 2 mm o Boards of width up to and including 50 mm 2 holes per 100 mm 4 holes per 900 mm o Boards of width over 50 mm up to and including 100 mm 5 holes per 100 mm 10 holes per 900 mm o Boards of width over 100 mm 8 holes per 100 mm 16 holes per 900 mm Not exceeding the lesser of 40 mm or 1/3 of the surface on which it occurs Exceeding 3 mm not permitted Not exceeding 3 mm o Boards of width up to and including 50 mm 8 holes per 100 mm 12 holes per 900 mm o Boards of width over 50 mm up to and including 100 mm 16 holes per 100 mm 24 holes per 900 mm o Boards of width over 100 mm 24 holes per 100 mm 36 holes per 900 mm Not exceeding the lesser of 50 mm or 3/8 of the surface on which it occurs Exceeding 10 mm, not permitted. Exceeding 3 mm and not exceeding 10 mm not more than 3 in any 1 metre length of board Not exceeding 3 mm o Boards of width up to and including 50 mm 8 holes per 100 mm 12 holes per 900 mm o Boards of width over 50 mm up to and including 100 mm 16 holes per 100 mm 24 holes per 900 mm o Boards of width over 100 mm 24 holes per 100 mm 36 holes per 900 mm Concealed surface grade for SEL, MF and HF grades On concealed surfaces Not exceeding 1/3 of the surface on which it occurs; and Not within 3 mm of any exposed surface Exceeding 10 mm o loss of cross-section at any position in the length of the board not exceeding 1/5 of the cross-section; and o Not within 3 mm of any exposed surface Exceeding 3 mm and not exceeding 10 mm loss of crosssection at any position in the length of the board not exceeding 1/5 of the cross-section Not exceeding 3 mm unlimited Slope of grain Not exceeding 1 in 8 Not exceeding 1 in 8 Not exceeding 1 in 8 Not exceeding 1 in 8 (continued)

7 Feature Tight gum veins SELECT GRADE (SEL) Not exceeding o surface width measured across the feature, 2 mm o individual length, 250 mm o aggregate length, 1/2 the length of the piece MEDIUM FEATURE GRADE Standard (MF) On exposed surfaces Quartersawn surface width measured across the feature, not exceeding 5 mm Backsawn o extent across face unlimited o surface width measured across the feature not exceeding 60 mm o individual length not exceeding 1 m o depth not exceeding 2 mm Loose gum veins Not permitted Not intersecting an end Surface width measured across the feature not exceeding 3 mm Agg. length not exceeding 1/5 of the length of the piece Gum pockets, latex pockets and overgrowth of injury Not permitted Surface width measured across the feature, not exceeding10 mm Length not exceeding 50 mm Backsawn depth not exceeding 2 mm HIGH FEATURE GRADE (HF) Quartersawn surface width measured across feature, not exceeding 5 mm Backsawn o extent across face unlimited o depth not exceeding 2 mm Not intersecting an end Surface width measured across the feature, not exceeding 3 mm Agg. length not exceeding 1/5 of the length of the piece Surface width measured across the feature, not exceeding 15 mm Length not exceeding 75 mm Backsawn depth not exceeding 2 mm Concealed surface grade for SEL, MF and HF grades On concealed surfaces Quartersawn surface width measured across feature, not exceeding 5 mm Backsawn o extent across face unlimited o depth not exceeding 5 mm Not intersecting an end Surface width measured across the feature, not exceeding 3 mm Agg. length not exceeding 1/5 of the length of the piece Length not exceeding 300 mm Quartersawn surface width measured across the feature, not exceeding 30 mm Backsawn depth not exceeding 5 mm Knot checks Not permitted Width not exceeding 2 mm Width not exceeding 3 mm Width not exceeding 5 mm Checks other than internal (Note 1) Stain (Note 2) Natural discolouration Other discolouration including sticker marks Width not exceeding 1 mm Individual length not exceeding 250 mm TABLE 2 (continued) Width not exceeding 2 mm Individual length not exceeding 250 mm Width not exceeding 2 mm Slight (Note 3) Unlimited Unlimited Unlimited Not permitted Not permitted Not permitted Unlimited Black speck (Note 2) Slight (Note 3) Unlimited Unlimited Unlimited Width not exceeding 3 mm

8 Feature Non-Lyctid-susceptible sapwood (which includes appropriately treated sapwood) SELECT GRADE (SEL) MEDIUM FEATURE GRADE Standard (MF) On exposed surfaces HIGH FEATURE GRADE (HF) Unlimited Unlimited Unlimited Unlimited Burls Unlimited Unlimited Unlimited Unlimited Hobnails Want, wane and mechanical damage NOTES: No significant colour variation unlimited Significant colour variation, width measured at right angles to board not exceeding 15 mm TABLE 2 (continued) No significant colour variation unlimited Significant colour variation, width measured at right angles to board not exceeding 40 mm Unlimited Concealed surface grade for SEL, MF and HF grades Unlimited On concealed surfaces Not permitted Not permitted Not permitted Width not exceeding 1/3 of the width of the surface on which it occurs Aggregate length not exceeding 300 mm Not within 3 mm of any exposed surface 1 Timber products purporting to comply with this Standard are graded visually. Some features such as internal checks cannot always be seen by the grader; therefore, it is considered inappropriate to include internal checks as part of the grading rules. After further profiling of the timber (often by another party), the previously unseen internal checks may be revealed on the surface of the newly profiled product. When this occurs, they should be assessed as checks other than internal because they are now on the surface. Internal checks are not considered acceptable in some products and care should be exercised during drying to limit their occurrence. 2 When it is intended to apply a paint or similar pigmented finish to a product, then discolouration, stain or black speck need not be limited when agreed between the purchaser and supplier. 3 The interpretation of the word slight will depend on the species being graded. The word slight has been used, even though it is subjective, because of the difficulty in describing what is a small or trifling amount of a feature, which may create a visual impact on the product. The visual impact of colour variation within a board will depend on a number of factors. A slight feature is considered not to have a large impact on the overall appearance. For example, a floor with considerable color variation between heartwood and sapwood may tolerate greater discolouration in some boards without affecting the overall appearance of the floor. In other instances where the timber is predominantly of one colour (particularly of a lighter tone), the contrast created by a small amount of discolouration within a board will heavily impact on the overall appearance and should not be considered slight.