Masonry Magazine October 2002 Page. 36
Purchasing
DECISIONS
WOULD WOOD WORK?
The concept of Laminated Veneer Lumber (LVL) for scaffolding planks makes a lot of sense in many applications. But what about traditional solid wood planks? Have we moved beyond wood for planking or is there still life left in our old friend?
The standard solid wood plank for scaffolding is the Dense Industrial 65 (D165) sold by supply companies, distributors and directly from the manufacturers. One of the latter is Kennison Forest Products, Sulphur, La., Dick Kennison, president and CEO of the company, claims, "In over 30 years of experience with D165, we have had no reports of plank failure when the plank is cared for properly while not in use. The life of D165 scaffold plank is as long or longer than its laminated counterpart and D165 is lighter in weight. In addition, D165 costs as much as 20 percent less than laminated plank."
Good arguments in keeping solid wood on your scaffold. But Kennison isn't done extolling the virtues of solid wood. "Dense Industrial 65, while suitable for all uses, actually excels in wet or very humid conditions because solid sawn wood doesn't absorb moisture as readily as laminated plank."
And both, of course, are OSHA and ANSI certified for use on scaffolding, meeting or exceeding published standards. As Kennison says, "Both are graded and/or tested for all uses. However, we feel the integrity of solid sawn D165 is easier to maintain."
Yes, it's basically a matter of preference but when you look at all the factors, D165 should win out according to those who cut lumber for a living.
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As mentioned previously, only a few manufacturers specifically produce LVL scaffold plank. They have developed the proper veneer grade combination to optimize the strength of the product when it's to be used "on flat" as a scaffold board as compared to "on edge" as a beam.
All legitimate LVL scaffold plank manufacturers should have an in-house quality control program outlining procedures for proof-testing scaffold plank. They should be testing every plank to ensure strength properties are adequate to carry the load capacities as specified by the American National Standards Institute (ANSI) and observed by OSHA.
In addition, ANSI standard A10.8-2001 specifies "all laminated plank shall bear the seal of an independent, nationally recognized inspection agency certifying compliance with the design criteria."
In other words, all producers must have an outside third-party agency that is accredited by the National Evaluation Service (NES), to regularly monitor the manufacturers' quality control program and testing procedures. Essentially, qualified IVL scaffold plank producers go the extra mile to mechanically test their product under watchful eyes. To date, solid lumber plank mills merely visually grade their planks and attempt to pull out boards that do not appear to be up to standards.
Upon acceptance, each qualified LVL scaffold plank is identified with an ink stamp bearing the following information:
* SCAFFOLD PLANK
* Brand Name-i.e., Master Plank; Microllam; TecLam
* Inspection agency logo or name
* Manufacturer's name
* ANSI
* OSHA
Finally, manufacturers will typically machine a slight radius (or bevel) on plank edges to minimize splintering and seal coat the plank ends to minimize moisture absorption and end checking. Technically advanced
With laminated veneer lumber, the normal defects found with wood, such as knots, are dispersed throughout the entire plank. When properly produced, it is an extremely homogenous product with predictable strength properties superior to solid lumber plank.
As noted earlier, LVL manufacturers try to differentiate their product from their competitors by using different wood specie (for example, spruce, southern pine or Douglas fir). Since each wood species has a different density, the species of choice, combined with the veneer grade lay up pattern, directly relates to the strength properties of the finished product.
In addition, the chosen wood species also correlates to the physical handling weight of the LVL. plank itself. Therefore, it is crucial that you study the allowable span tables of each brand of LVL plank being considered to ensure you chose the right product for your application and scaffolding equipment.