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D4431-92 – Standard Test Method Technical Guide
📋 Scope and Classification
ASTM D4431-92 provides a comprehensive framework for specifying paper hand towels intended for industrial and institutional use. It covers two classes, five types, and four styles, accommodating both virgin and recycled fiber content (see Annex X1.2). The standard requires orders to specify the class, type, style, and dispenser type (Section 5).
| 🟦 Feature | 📏 Code | 📐 Description |
|---|---|---|
| Class | A | Bleached or Semibleached (One-ply) |
| Class | B | Natural (One-ply implied) |
| Type | 1, 2, 3 | One-Ply |
| Type | 4 | Two-Ply |
| Type | 5 | Two-Ply, Double Delivery |
| Style | I | Singlefold |
| Style | II | Multifold (Wide and Narrowfold) |
| Style | III | C-Fold |
| Style | IV | Roll (Perforated or Unperforated) |
Specific definitions for folded formats are provided in Section 3. A narrowfold is defined as 2¾ in. (70 mm) or less in folded depth, while a widefold exceeds 2¾ in. (70 mm).
🔬 Test Methods and Physical Requirements
The standard mandates specific physical properties, measured according to established ASTM and TAPPI methods. Conditioning of samples must follow Practice D 685 or TAPPI T 402 to ensure accurate, reproducible results.
| 🟦 Required Property | 🎯 Test Method | ⚡ Key Standard |
|---|---|---|
| Grammage (Weight) | TAPPI T 410 | Weight per unit area |
| Dry Tensile Strength | D 828 / T 404 / T 494 | Constant rate of elongation |
| Wet Tensile Strength | TAPPI T 456 | Performance when wet |
| Water Absorption | TAPPI T 432 | Absorbency of bibulous papers |
| Brightness | TAPPI T 452 | Directional reflectance at 457 nm |
⚠️ Safety Hazard Caveat: Per Section 1.4, the safety caveat pertains specifically to the test method portion (Section 9) of this specification. Users must establish appropriate safety and health practices prior to testing.
🧪 Material Composition and Compliance
Fiber content, including the percentage of recycled fiber, is not rigidly fixed by this specification. Section 6 explicitly requires the fiber and recycled fiber content to be mutually agreed upon between the buyer and the seller. This allows maximum flexibility for procurement while maintaining the performance benchmarks established by the physical test methods. Terminology relating to these materials is defined in ASTM D 1968.
💡 Ordering Advice: When placing an order under this specification, always specify the exact Class, Type, Style, and design of the intended dispenser. Failing to specify these parameters may result in towels that are functionally incompatible with the target dispensing equipment.
❓ Frequently Asked Questions
🔍 What distinguishes Class A from Class B towels?
Class A towels are bleached or semibleached (one-ply), providing a higher brightness and whiter appearance. Class B towels are natural (unbleached) and typically have a lower brightness value.
💡 Does the standard allow for recycled content?
Yes. The scope explicitly covers virgin, recycled, and recycled content paper products (Section 1.2). The specific percentage of recycled fiber is determined by agreement between the buyer and the seller per Section 6.
⚡ Which test method measures wet strength?
Wet tensile breaking strength is measured by TAPPI Standard T 456. Dry tensile strength can be measured using ASTM D 828 or TAPPI T 404 / T 494.
📌 What are the exact fold depth dimensions for Style II?
© 2026 TNLab — This article is a technical interpretation for reference only. The original standard as published by ASTM International takes precedence.