Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D1758-06 – Standard Test Method Technical Guide
📐 Specimen Geometry and Types
ASTM D1758-06 defines two test methods based on stake size. Method A uses 3/4-in. square stakes for accelerated testing, while Method B employs nominal 2-by-4 in. stakes for longer-term evaluations. The preferred wood is sapwood of southern pine (Pinus spp.) with 6 to 10 rings per inch, free of knots and excessive cross-grain.
| 🟦 Feature | 📐 Method A | 📐 Method B |
|---|---|---|
| Specimen Size | 3/4-in. square stakes | Nominal 2-by-4 in. stakes |
| Primary Use | Quick comparative results | Quasi-service long-term tests |
✅ Specification: Southern pine sapwood with 6–10 growth rings per inch ensures consistent material quality for comparative testing.
⚙️ Test Procedure and Plot Requirements
The test involves impregnating stakes with preservative at various retentions and exposing them in field plots. Plots must be in warm humid climates with fertile, fallow, uniform soil. The presence of wood-destroying fungi and subterranean termites must be verified by pretest exposure of untreated samples. Vegetation is controlled manually or mechanically, without chemicals. When reusing ground, stakes must be spaced at least 150 mm (6 in.) from previous locations.
⚠️ Important: No fertilizers or chemicals may be applied during the test, and plots must be protected from fire, predators, and pilferage. The plot must be large enough to permit future stake installation expansion.
📊 Evaluation and Condition Index
Stakes are inspected periodically and graded for decay and termite attack severity. An index of condition is calculated from these grades to express preservative effectiveness. Results are reported periodically and at test termination, following the guidelines in Section 12 of the standard.
| 🎯 Inspection Parameter | ⚡ Description |
|---|---|
| Decay Severity | Grade based on degree of fungal damage observed |
| Termite Attack | Grade based on severity of termite activity |
❓ Frequently Asked Questions
🔍 What wood is preferred for test stakes?
Sapwood of southern pine (Pinus spp.) with 6 to 10 rings per inch, free of knots.
💡 Why use warm humid climates for test plots?
To accelerate fungal and termite activity, enabling faster evaluation of preservative performance.
⚡ What is the minimum spacing for reused ground?
At least 150 mm (6 in.) from any previous stake location to avoid interference.
📌 Can vegetation be controlled with chemicals?
No, only manual or mechanical controls are permitted to prevent contamination of the test.