Grading Rules for Eastern Red Cedar
By Brian Bond -Speech delivered at ACA Annual Convention Oct 2005
Printed in The Cedar Leader Apr-Jun 2006
Lumber grades, just what are they and what do they do for you when
buying or selling lumber? When determining the value of lumber, you
could just apply a price given the volume or board footage
available. For example, a 4-inch wide board that is five-feet long
would have 2 board feet (See: How to determine surface measure and
board footage) multiply this by the price per board foot and you
have the total price. However, the value of a board is typically
based on more than just how much wood there is. The quality of the
board must also be taken into account. Quality may have to do with
the number of knots or how much heartwood is contained in a board.
Grading rules allow some value to be placed on the quality of the
piece of lumber. They also allow for consistency and uniformity
between a buyer and seller of lumber.
Grading rules are usually based either on the predicted strength or
how much usable material is available for further manufacturing,
such as in making furniture or moldings. Visual appearance grading
rules are based on the defects that are visible on the surface of
the lumber that would reduce its usefulness in further manufacturing
processes. For example, in most hardwoods, knots are considered a
defect that must be removed before the remaining wood can be used.
The more knots, the lower the grade.
Standardized grading rules provide consistency between producers and
loads of material. A manufacturer of furniture must know that each
time a certain grade lumber is purchased and run through the plant
that given the same part sizes the same yield will be obtained. If
there were no grading rules, then the furniture manufacturer would
not know how much lumber to buy or how to estimate the cost of
producing the furniture.
Are grading rules required for red cedar lumber? Some would argue
that, yes, we must have consistency of product to have reproducible
production yields and costs. Others might argue, no, it allows for
an individual to maximize profit within his/her specific market.
Proprietary grading rules are those that you develop yourself,
specific to your market. They are based on what quality aspects you
or your customer value rather than those accepted as an industry
standard. Industry standard grading rules are usually developed by a
trade association and are agreed upon by all those participating in
the association. Should industry standard grading rules be used or
should you design your own proprietary grading rules? To truly
answer this question one should ask the following questions:
1) Does your market require the use of standardized grading rules?
2) Would proprietary grading rules allow you to capture and hold
onto a specific market?
3) Would proprietary grading rules limit your market and cause you
to lose customers not familiar with your grading techniques?
Standardized grading rules already exist for eastern red cedar. The
National Hardwood Lumber Association (NHLA) located in Memphis,
Tennessee developed a set of rules for red cedar. There are only two
grades defined by the NHLA for aromatic red cedar: No. 1 Common and
Better and No. 2 Common, which are presented in Table 1. The rules
specify the minimum width and length of board required to meet a
certain grading specification. For example, a No. 1 Common board
must be wider than 3 inches; however, in a load of purchased lumber
25% can be 3 inches. Each board graded as No.1 Common must have
enough cuttings 3 inches wide by 2 feet long or 2 inches wide by 3
feet long to make up 66-2/3 clear volume in the board. A cutting is
a portion of a board obtained by cross-cutting, by ripping, or both
that must not contain wane, loose pith, rot, or shake. There is no
limit to how many of the cuttings are permitted. These grades will
accept sound knots, white streaks and firm, tight pith in the
cuttings. Figure 1 displays a board with two cuttings. Boards are
graded on the poorest visible side. The total amount of sapwood in
cuttings may not exceed one sixth the heartwood side. The amount of
sapwood is unlimited on the reverse side.
Let's go through an example of how to apply the NHLA grade rules for
an eastern red cedar board. In Figure 1, a four inch wide by ten
foot long board is displayed showing the worst face. This board was
cut to 1-inch thickness so its volume would be (4" x 10')/12 x 1" =
3 board feet. Since the board is 4-inches wide, it meets the minimum
width requirement for a No. 1 Common board. Since it is 10-feet
long, it exceeds the minimum length required. There are two
potential cuttings in this board, one is 3-inches wide by 5-feet
long and the other is 2-inches wide by 4-feet long. Each of these
cuttings meets the minimum size requirements for a No.1 Common
board. If we total the amount of cutting units, there are 24 cutting
units (15 units + 9 units = 24 units total). To obtain 66-2/3% of
clear cuttings we need 24 cutting units (Surface measure x 8 as
specified by the rules). This board contains enough yield to make
the No. 1 Common grade.
Do the NHLA grading rules represent the needs of your customer and
the markets that you do business in? If not, then you will be
required to develop your own proprietary grading rules. For eastern
red cedar, I would expect these rules to contain information about
minimum board widths and lengths, heartwood percentages, and
acceptable number of tight and loose knots in the grading face.
Expert knowledge of your customer's needs will assist you in
developing the grade specifications and price differences.
Grading rules are needed to assist buyers and sellers of cedar
lumber in determining the value of the material as well as provide
consistency in the product. Currently, the National Hardwood Lumber
Association provides some standardized grading rules for red cedar;
however, you may find that they to not meet your customers needs. If
you or your customers have different needs, then you will have to
develop proprietary grades to meet their needs.
For more information on the National Hardwood Lumber Grading Rules:
National Hardwood Lumber Association
6830 Raleigh-LaGrange Road
Memphis, TN 38184-0518
Phone: (901) 377-1818
Email: info@nhla.com
Website: www.natlhardwood.org
|
