American hardwood lumber grading Q&A series

By Bob Sabistina, grading consultant to the American Hardwood Export Council

The Grading Rules for North American hardwood lumber were established 100 years ago by the National Hardwood Lumber Association (NHLA), which is now headquartered in Memphis, Tennessee. I have been writing a series of articles, answering a variety of questions pertaining to the application of those grading rules. This month’s article answers some of the questions I have received over the past few months. These questions come from all over the world, as the American Hardwood Export Council (AHEC) has been distributing these articles from Europe to Asia.

We recently purchased some 8/4 No. 2 Common red oak. When the shipment arrived we noticed that the boards were heavily checked. Upon asking our supplier about this, he said the lumber qualifies for No.2B Common and that he could ship this, since I ordered No. 2 Common under the NHLA grading rules. We are a chair manufacturer and use this material for our solid legs. I have always bought No. 2 Common and have never had this problem before. Have the rules changed?

The NHLA rules have not changed and this has been included in the rules for around 20 years. However, this does need to be changed. First of all, let me explain that there are actually two grades of No. 2 Common, consisting of No. 2A Common and No. 2B Common. You have been receiving No. 2A Common, which requires 50% clear cuttings and this works well in your manufacturing of chairs. No. 2B Common is not often used grade in species such as oak, hard maple and cherry because it simply requires that the board have 50% sound cuttings, to produce something that you might use for the frame of an upholstered sofa, for example. The No. 2B Common grade is more often used with lower value species such as tulipwood, cottonwood, or soft maple.

The short answer to a long explanation is that when No. 2 Common is specified, it can contain both No. 2A and No. 2B Common. I would say that if this is the first time you know of this happening you are fortunate. In future, the best way to prevent this from happening again is to make sure you always specify No. 2A Common, when ordering No. 2 Common and when you need clear cuttings.

We are receiving a number of quotes for hardwood lumber and notice the words green tally on some and net tally on others. Are there multiple tally methods and, if so, which is the one we should specify?

There is a difference between a green tally and net tally of anywhere between 7-10% depending on the species and supplier. You should also see the same difference in price if everything else matches up, such as origin of species, quality, and grading. The green tally is the actual measurement of the lumber before it goes into the dry kiln to be dried. When going through the drying process the lumber will naturally shrink in volume from about 7-10%. If the lumber is then measured after the drying process, this is the net tally. The net tally is the actual kiln dried footage that you receive. If I were a buyer, purchasing kiln dried lumber, I would always go for the sure thing and purchase on the net tally. If you want to convert between one tally and the other, you must know the percentage of shrinkage your supplier is using. So just ask.

I am in Germany and had an enquiry for 'mosaic grade' cherry and hard maple. Have you ever heard of this specification?

I have not heard of this 'mosaic grade'. If I were to venture a guess, I would say it could be a type of patterned hardwood flooring using one or both of those species. There is no 'mosaic grade' in the NHLA rule book. It could also be a local grade for some musical type pattern on these two species like straight grain, or curly grain, both of which hard maple and cherry can be sorted for. If any reader can shed more light on this, I would be most grateful.

I know you have covered this, but I cannot find the article, so, will you please explain the Prime grade that I keep getting quotes for.

Prime was created years ago by exporters as a substitute for the FAS grade. Originally a lot of shippers could not send the Standard NHLA FAS grade because it allowed too much wane (bark or lack of wood) on the board. The rules allow up to ½ the length of the FAS board to have wane. As long as the minimum clear cutting percentage was 83⅓%, the board met the FAS requirements. For export shipments this was a problem, as bark in some species cannot leave the United States. Therefore, export shippers would re-edge the lumber to eliminate the wane. This, in turn, caused some boards to fall below the minimum size width needed for the FAS grade; thus the birth of Prime - a virtually square edged board that might fall below the 6 inch width required to meet the FAS grade. Today, with the expansion of US hardwood exports, a lot of shippers are creating new ways to set their lumber apart from their competitors. Prime can have different meanings from one shipper to the next, so it is my advice to talk with the supplier and get his or her specifications. For some species it might be a colour sort, for others a width and length sort. The most important thing in any successful relationship with your lumber supplier is an open dialogue.

NOTE: I have moved to China and am setting up an office in Shanghai for the NHLA. I will continue to work closely with AHEC and conduct seminars with them throughout the world. It was thought that being in Asia would bring me closer to the market. If you are interested in any on the job training, please send me an e-mail. I appreciate the questions I receive which make these articles possible. Contact me at: bshardwoods1@yahoo.com
American Hardwood Export Council

The American Hardwood Export Council (AHEC) is the leading international trade association for the US hardwood industry, representing the committed exporters among US hardwood companies and all the major US hardwood product trade associations. AHEC concentrates it efforts on providing architects, specifiers, designers and end-users with technical information on the range of species, products and sources of supply.
AHEC produces a full range of technical publications which are available free of charge by visiting www.ahec-europe.org or by faxing (44) 20 7626 4222.

For more press information, please contact:
Lucy Peacock (lucy.peacock@ahec.co.uk), American Hardwood Export Council, tel. 044-20-7626 4111, fax 044-20-76264222.