Fiber Porosity
High pressure liquid permeability testing quantifies the resistance of paper structures to gas or fluid movement during vacuum processes. The pts-rh 021/97 standard defines the technical methodology for assessing this air permeability across standardized samples of industrial packaging paper. This measurement determines how substrate density interacts with coating absorption rates during the converting stage.
Manufacturers apply this protocol to verify consistent porosity levels when producing multi-layered barrier boards.
Resistance Calibration
Air flow rate through a given surface area provides the primary unit for quantifying the barrier performance of fibrous substrates. The pts-rh 021/97 protocol establishes fixed atmospheric pressure gradients to prevent flow turbulence from invalidating the resulting data. Precision remains a function of maintaining strict humidity controls within the laboratory chamber during the observation period.
Variations in moisture content within the paper fibers distort the measured permeability value by swelling or shrinking the structural voids. Converting lines rely upon these readings to calibrate vacuum cups and suction belts that manipulate finished stock at high speeds. Stable flow rates ensure the material moves through printing presses without losing registration due to sheet deformation or uneven drying.
Production Boundary
Mechanical integrity of the specimen requires that the sample remain free from surface creases or internal delamination before testing commences. Laboratory staff examine the sheet structure to confirm that no manufacturing defects introduce artificial leakage paths into the flow measurement. Such testing protocols stop applying once the material undergoes lamination or wax saturation because these processes alter the base physical properties of the fiber.
These readings confirm that the porosity profile meets the performance specifications required for industrial high speed production environments.
