SPF (spruce-pine-fir) pallet lumber
SPF (spruce-pine-fir) is Uniform Standard species class 13, a low-density softwood group. It is the lightest of palletdesign.ai's five species at about 3.24 lb per board foot green and 2.3 kiln dried including nails, with a conservative allowable bending stress of 850 psi, so SPF pallets are light but need larger sections for heavy or racked loads.
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What SPF is
SPF stands for spruce-pine-fir, a trade group of light softwoods sawn mainly in Canada and the northern US. The Uniform Standard's class 13 (SPF) is broad. It includes balsam and subalpine fir, eastern hemlock, baldcypress, eastern white, jack, lodgepole, ponderosa and red pine, redwood, pitch and pond pine, the spruces and western red cedar. All are in the low-density sort group.
SPF is commonly sold as kiln-dried dimension lumber, so SPF pallets tend to use standard sizes: 2x4 stringers at 1-1/2 x 3-1/2 in, and 1x4 or 1x6 deckboards at 3/4 in thick.
Key properties
| Property | Value |
|---|---|
| Species class | 13 (SPF and similar softwoods) |
| Sort group | Low density, softwood |
| Engine weight factor, incl. nails | 3.24 lb/bd ft green, 2.3 lb/bd ft KD19 |
| Published PDS calibration | 13.9 bd ft pallet: 45 lb green, 30 lb at 12% moisture |
| Engine allowable bending stress | 850 psi |
| Engine price assumption | $800 per MBF (green, standard grade) |
The price per MBF is palletdesign.ai's default cost assumption for green, standard-grade stock, not a market quote. The bending stress is the conservative allowable value palletdesign.ai uses for indicative checks, not a design value from a grading agency.
The green weight factor is calibrated against a published PDS sheet for an SPF pallet.
What SPF does to a pallet
For a GMA-style 48 x 40 stringer pallet (13.5 board feet):
| Mixed hardwood | SPF | |
|---|---|---|
| Weight, green | about 59 lb | about 44 lb |
| Weight, KD19 | about 39 lb | about 31 lb |
| Lumber cost at engine default | about $9.45 | about $10.79 |
SPF's allowable bending stress is about 23% lower than mixed hardwood's, so the same design checks about 23% weaker in palletdesign.ai's indicative beam check, a conservative screen rather than a rating. SPF pallets usually make up the strength difference with bigger sections, such as 1-1/2 in wide stringers and 3/4 in decks. The palletdesign.ai 42 x 42 template, for paint, telecom and chemical loads, is built in SPF with 1-1/2 in stringers.
Typical uses
- Light to medium loads where pallet weight matters: export, air freight, manual handling.
- Clean, dry pallets for food, pharmaceutical and retail programs, since SPF is commonly kiln dried.
- Retail supply chains: the example PDS analysis on Home Depot's supplier site is an SPF pallet. Home Depot is documented as excluding species classes 7 and 14, not class 13, but confirm with the current vendor guide.
Limits to know
- Lower nail holding and strength than dense species. Use the right nails and enough section.
- Repairs: the Uniform Standard's repair rules restrict low-density classes, including class 13, to interior deckboards.
- Racking: check any racked SPF design carefully, especially across the width, where only the top deck spans the beams. See racking pallets.
Nails for SPF
Annularly threaded (ring shank) nails are recommended for most softwoods and low-density species, which covers SPF. The per-joint count still follows the Uniform Standard by board width: 2 nails per joint up to 5-1/4 in, 3 up to 7 in and 4 up to 8 in. See pallet nails.
Specifying SPF
| Field | Example |
|---|---|
| Lumber mix | Species class 13 (SPF), Standard &BTR, 100% |
| Moisture at manufacture | KD 19% |
| Stringers | 1-1/2 x 3-1/2 in actual (2x4) |
| Fasteners | Annularly threaded, length and wire diameter stated |
For heavier SPF designs, consider 3/4 in deckboards and a fourth stringer before switching species.
How palletdesign.ai uses SPF
Choose SPF in the lumber settings or name it in your request. The engine applies the lighter weight factors, the $800 per MBF price assumption and the 850 psi allowable stress for indicative rack checks. If a racked SPF design fails the indicative check, the designer suggests stronger options such as more or deeper stringers or a denser species.
Questions
- What does SPF mean in pallets?
- Spruce-pine-fir, a group of light softwoods. The Uniform Standard classes it as species class 13 in the low-density sort group.
- How much does an SPF pallet weigh?
- A GMA-style 48 x 40 in SPF pallet weighs about 44 lb green and about 31 lb kiln dried, by palletdesign.ai's weight factors.
- Are SPF pallets strong enough for racking?
- They can be, with larger sections, but SPF is weaker than dense species: palletdesign.ai assumes 850 psi against 1,100 psi for mixed hardwood. Confirm racked capacity with a PDS analysis or test.
Related
- Pallet lumber: species, grades and moisturePallet lumber is cut-to-size hardwood or softwood stock specified by species class, grade and moisture. Mixed hardwood, oak, SYP, SPF and Douglas fir lead.
- Southern yellow pine (SYP) pallet lumberSouthern yellow pine (SYP, species class 22) is a dense, strong pallet softwood: about 4.45 lb per board foot green, 3.4 kiln dried, 1,300 psi in the engine.
- Hem-Fir pallet lumberHem-fir is a western softwood, Uniform Standard species class 12, in the low-density sort group. Use annular nails and confirm its properties with the mill.
- 42 × 42 pallet42 × 42 in (1067 × 1067 mm) pallet specs with drawings: stringer pallet 55 lb, block pallet 91 lb, skid 71 lb. Nail counts, board feet and parts lists for each build.
- Pallet nails: types, sizes and how manyPallet nails are usually 2 to 3 in helical or annular threaded nails, 11 to 12-1/2 gauge. A GMA 48 x 40 uses 84 nails: 2 or 3 per joint by board width.
- Pallet lumber moisture contentPallet lumber moisture content drives weight, shrinkage, mold and nail holding. Kiln drying to 19% (KD19) cuts a GMA pallet from about 59 lb to about 39 lb.
Sources
- NWPCA Uniform Standard for Wood Pallets (2012), Annex B species classes and Table 7 sort groups
- The Home Depot example PDS analysis (v3.35, SPF)
- PalletOne, Choosing the best pallet nails
- palletdesign.ai engine defaults (calc.ts, capacity.ts)