NYX WVH Water Vapor Absorption Tester for Textile and Leather Materials

Overview

The NYX WVH Water Vapor Absorption Tester is a dedicated gravimetric instrument engineered for standardized evaluation of water vapor permeability and absorption behavior in flexible sheet materials—particularly leather, coated textiles, synthetic membranes, and composite laminates used in personal protective equipment (PPE), footwear, and work gloves. It operates on the principle of controlled vapor exposure under static, saturated conditions: a precisely dimensioned test specimen is sealed over the open mouth of a metal test cup containing 50 mL of distilled water. The assembly is conditioned at a defined ambient temperature (typically 23 ± 2 °C) and relative humidity (50 ± 5 % RH) for exactly 8 hours. The mass gain of the specimen—measured before and after exposure using an external analytical balance (0.1 mg resolution recommended)—quantifies its capacity to absorb water vapor from the headspace. This method reflects real-world physiological stress scenarios where moisture management directly impacts wearer comfort, thermal regulation, and barrier integrity.

Key Features

• Modular test rack configurations: Selectable 3-, 6-, or 8-position stainless steel support frames for parallel multi-sample evaluation—enabling statistically robust replicate testing per batch.
• Dedicated precision cutting dies: Includes four interchangeable circular dies (Φ35 mm, Φ43 mm, Φ56 mm, and Φ85 mm) machined to ±0.05 mm tolerance, ensuring consistent sample area and edge geometry across material types and standards.
• Standard-compliant test cups: Deep-drawn stainless steel cups with precisely defined inner diameters and vertical sidewalls—designed to minimize edge effects and ensure uniform vapor flux distribution across the specimen interface.
• Sealing interface optimized for low-permeability substrates: Dual O-ring groove design on cup flange accommodates both rigid and semi-flexible specimens without compression-induced microcracking or seal leakage.
• Non-electronic, passive architecture: Eliminates calibration drift, software dependency, or firmware updates—ensuring long-term measurement stability and traceability aligned with GLP laboratory practices.

Sample Compatibility & Compliance

The WVH system supports flat, non-porous, and semi-permeable sheet materials up to 3 mm thickness and minimum tensile modulus of 1.5 MPa. Compatible substrates include bovine/cattle leather, chrome-tanned glove leather, PU- and PVC-coated fabrics, neoprene laminates, and microporous polyurethane membranes. All mechanical dimensions—including cup geometry, die tolerances, and rack spacing—conform strictly to dimensional requirements specified in EN ISO 20344:2011 (Section 6.7), ISO 17699:2005 (Section 4.2), and GB/T 12624–2009 (Section 6.5). The test protocol satisfies the regulatory verification pathway for Category II and III PPE under EU Regulation (EU) 2016/425 and aligns with ASTM F1868–22 (Water Vapor Transmission Rate—Part B: Upright Cup Method) for comparative benchmarking.

Software & Data Management

The WVH is a hardware-only platform requiring no embedded firmware or proprietary software. Data acquisition and reporting are performed externally using laboratory-grade balance interfaces (RS-232 or USB HID) and validated spreadsheet templates or LIMS-integrated worksheets. Raw mass values (pre- and post-test), environmental logs (temperature/humidity), operator ID, and sample metadata are recorded manually or via barcode-scanned entry to satisfy audit trails required under ISO/IEC 17025:2017 Clause 7.5 and FDA 21 CFR Part 11 (when paired with compliant electronic record systems). Calibration certificates for supporting balances must be maintained per ISO 9001:2015 Section 7.1.5.

Applications

• Quality control of finished glove leathers prior to cut-and-sew assembly—verifying compliance with EN 420:2009 moisture absorption limits (≤10 mg/cm²).
• Comparative R&D screening of hydrophilic vs. hydrophobic surface treatments on textile laminates intended for breathable safety footwear.
• Batch release testing for medical-grade surgical glove materials per QB/T 4024–2010 Annex A.
• Stability assessment of moisture-barrier coatings after accelerated aging (e.g., 72 h at 70 °C per ISO 14373).
• Root-cause analysis of field complaints related to glove clamminess or liner delamination in high-humidity industrial environments.

FAQ

Is an analytical balance included with the WVH system?
No. A Class I analytical balance with ≥0.1 mg readability and ISO/IEC 17025-accredited calibration is required but supplied separately.
Can the WVH be used for testing non-leather materials such as Tyvek® or ePTFE membranes?
Yes—provided the material forms a continuous, defect-free barrier over the cup aperture and meets minimum stiffness requirements to maintain seal integrity during the 8-hour test cycle.
Does the system meet FDA or EU MDR requirements for medical device testing?
The WVH itself is not a medical device; however, its methodology and dimensional compliance support biocompatibility and performance testing per ISO 10993-12 and EN ISO 13485:2016 Annex C when integrated into a validated QMS.
What environmental monitoring is required during testing?
Ambient temperature must be stabilized at 23 ± 2 °C and relative humidity at 50 ± 5 % RH for the full duration—verified using NIST-traceable sensors logged at 15-minute intervals.
Are replacement cutting dies available for custom diameters?
Yes. NYX offers CNC-machined custom dies (tolerance ±0.03 mm) upon request with lead time of 10 working days.