TAPPI T231

Introducing TAPPI T231 – Industrial Physics

TAPPI T 231 is the industry‑recognized method for determining the zero‑span tensile strength of pulp and paper. This test measures the intrinsic strength of individual fibers by eliminating the influence of fiber length and bonding, giving mills and laboratories a direct view of fiber integrity.

Zero‑span testing is one of the most sensitive indicators of pulp quality. It helps mills detect process drift, evaluate incoming fiber, and understand how refining, bleaching, or contamination affects sheet strength long before issues appear on the paper machine.

What TAPPI T231 Covers

TAPPI T231 outlines procedures for measuring wet and dry zero‑span tensile strength using specialized clamping and loading systems. Key elements include:

• Preparing handsheet or strip samples
• Clamping fibers at zero span to isolate intrinsic fiber strength
• Measuring wet and/or dry tensile force
• Calculating fiber strength values for process control and quality evaluation
• Ensuring consistent sample conditioning and testing parameters

The method applies to:

• Pulp evaluation
• Fiber‑strength benchmarking
• Refining and process‑control studies
• Recycled‑fiber assessment
• R&D and quality‑control laboratories

TAPPI T 231 provides a direct, reliable measure of fiber strength — one of the most important predictors of runnability and sheet performance.

Where TAPPI T231 Is Used

This standard is widely used across pulp, paper, and fiber‑based industries:

• Pulp mills and integrated paper mills
• Recycled‑fiber operations
• Tissue, packaging, and printing‑paper producers
• Independent and mill‑based laboratories
• R&D, process‑optimization, and troubleshooting teams

It supports both routine QC testing and deeper fiber‑quality investigations.

Why Zero‑Span Testing Matters

Understanding fiber strength is essential for:

• Preventing web breaks and lost production time
• Detecting process drift before quality declines
• Evaluating refining, bleaching, and fiber‑mix impacts
• Benchmarking incoming pulp quality
• Improving sheet strength, bonding, and runnability

Zero‑span tensile testing is one of the fastest ways to see whether your fiber is strong enough to run — before you find out the hard way on the machine.

Testing solutions for TAPPI T231

One product from the Industrial Physics portfolio aligns directly with TAPPI T231’s focus on fiber‑strength evaluation:

Technidyne Pulmac Automated Z‑Span™ Fiber Strength Tester

The Automated Z‑Span™ Tester measures fiber strength before quality slips. Load handsheet or strip samples onto the feed tray, and the system automatically runs up to 24 wet and/or dry zero‑span tests in a single sequence. Results appear on the touchscreen within minutes and export directly to a PC database for trending and record keeping.

The Z‑Span™ Tester generates fiber‑quality numbers sensitive to fiber strength, fiber length, bonding potential, and fiber alignment — the variables that determine whether your sheet holds together on the machine. Routine testing helps mills detect process changes early, adjust before quality drops, and avoid costly web breaks.

Industrial Physics also offers deep knowledge resources on pulp evaluation, including guidance on standard methods such as TAPPI T275 and broader pulp‑quality insights to help you get the most from your Z‑Span™ system.

Your Global Test and Measurement Partner for TAPPI T231

Industrial Physics supports pulp and paper producers with the tools and expertise needed to evaluate fiber strength in line with TAPPI T231. From automated zero‑span testing to fiber screening, contaminant detection, and handsheet preparation, we help ensure your fiber is strong, stable, and ready for production.