TAPPI/ANSI T 549 om-25 is a TAPPI test method for determining the static and kinetic coefficient of friction (COF) of uncoated writing and printing paper using a horizontal plane arrangement, with paper sliding against itself.
COF results from this method are commonly used to evaluate sheet handling and feeding behavior in printing, copying, and other sheet-transport processes where consistent separation and controlled slip are critical. If you need help aligning your test setup to a customer or internal requirement, talk with our team about your application.
Coefficients of static and kinetic friction of uncoated writing and printing paper by use of the horizontal plane method (TAPPI/ANSI T 549 om-25)
TAPPI/ANSI T 549 om-25 focuses on friction behavior between two paper surfaces (paper-on-paper) for uncoated writing and printing grades. It defines how to generate static and kinetic COF values using a horizontal plane method and a controlled sliding action.
This standard is frequently referenced when paper runnability depends on balancing sheet separation (avoiding double-feeds) with smooth transport through feeders, nips, guides, and downstream converting operations.
Quick definition
Document type: Test method.
What it measures: Static COF (starting friction) and kinetic COF (sliding friction) for uncoated writing and printing paper, measured as paper sliding against itself on a horizontal plane.
Typical use: Comparing lots, grades, or process conditions to support consistent feeding, stacking, and sheet transport performance.
What this standard covers
This method describes a horizontal plane procedure where one paper specimen is held on a flat test surface and the other is attached to a moving element (commonly a sled or carriage). The test system measures the resisting force during the start of motion (static) and during sliding at a controlled condition (kinetic), then reports COF as a ratio based on the normal force and measured resistance.
The method is intended for paper-on-paper friction measurements. If the requirement is for packaging materials or other substrate pairings, a different TAPPI approach may be more appropriate.
Why this standard matters in testing
COF is a practical indicator of how easily sheets will start to move and continue to slide relative to each other. In real production environments, that behavior affects feeding reliability, sheet separation, and transport consistency.
Because friction is sensitive to surface condition, handling, and the way contact is applied, aligning the fixture style and instrument control to the cited edition is important when COF limits appear on purchase specs, print-shop requirements, or QC release criteria.
Common materials, product types, or applications covered
Common materials: Uncoated writing papers and uncoated printing papers where paper-on-paper slip behavior is relevant.
Common applications: Copier and printer feed performance, press infeed behavior, sheet stacking and singulation, and runnability comparisons between production lots or suppliers.
Common test or verification workflow
A typical workflow is to condition and prepare representative paper specimens, mount one specimen to the horizontal plane and the other to the moving element, and run a controlled slide to capture both the peak force associated with motion start (static friction) and the force level during sustained sliding (kinetic friction). Results are then summarized for the required directions or orientations when the end-use is direction-sensitive.
Common outputs: Static COF and kinetic COF values used for comparison to internal targets, customer limits, or historical performance baselines.
Equipment commonly used for this standard
TAPPI/ANSI T 549 om-25 typically points to a coefficient-of-friction test setup that can produce a controlled horizontal sliding motion and measure tangential force accurately.
Common equipment families: Horizontal-plane COF testers; friction sled/plane fixtures; force measurement via a load cell or calibrated force gauge; drive/control hardware that maintains a consistent sliding condition; specimen cutting and handling tools appropriate for paper.
Practical buying considerations: Fixture geometry and contact condition, control of travel and motion, repeatable specimen clamping, and data capture that can report both static and kinetic behavior in a way that matches how your requirement cites the method.
If you are comparing fixture styles or need a quotation for a complete COF station (instrument, fixture, and software), you can request pricing for a configuration matched to your lab workflow.
How to read this designation or revision
TAPPI/ANSI: Indicates the document is published by TAPPI and also approved as an American National Standard.
T 549: The TAPPI test method number.
om: “Official Method” in TAPPI’s test method classification.
-25: The year designator associated with the cited edition (2025). Because equipment setup and reporting expectations can be edition-sensitive, match the exact suffix shown in the requirement.
Related standards, methods, or frameworks
COF requirements are often specified using different methods depending on the material type and the intended end-use. TAPPI/ANSI T 549 om-25 is focused on uncoated writing and printing papers using a horizontal plane method.
Packaging-material friction: TAPPI’s COF approach for packaging materials is commonly handled under a different TAPPI method (inclined plane), and the measurement sequence used there may not match the first-slip approach used in T 549.
Get help selecting a T 549 COF testing setup
If you need a COF tester and fixture package that aligns with TAPPI/ANSI T 549 om-25 and your specific paper grade and throughput needs, request a detailed quote and include the COF targets, specimen size constraints, and whether you need static, kinetic, or both.