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Key: test item, instrument name, total nonvolatile migration, gravimeter, moisture permeameter

Product

Water Vapor Transmission Tester for Building Materials - Cup Method

W-B-31-F-1
Focusing on packaging and material testing technology, we are committed to quality control in industries such as healthcare, pharmaceuticals, food, packaging, textiles, and new materials. Our products are widely used in enterprises, testing institutions, universities, and research institutes.

Category:

Permeation Analyzer

Water Vapor Transmission Rate Analyzer

WVTR Tester- Gravimetric Method

Water Vapor Transmission Tester for Building Materials - Cup Method

Overview

The LabStone W-B-31-1 is a professional Cup Method Water Vapor Transmission Tester engineered specifically for thick-section building materials. It accurately measures the water vapor transmission rate (WVTR), permeance, permeability, and moisture flux density of thermal insulation, waterproofing membranes, gypsum boards, and concrete slices.

By integrating both the Desiccant Method (Gain) and Water Method (Loss) in a single unit, it provides comprehensive data to support building energy efficiency analysis and moisture control design in compliance with international standards including ASTM E96, EN 13859-1, EN 1931, and EN ISO 12572.

Function:

Determining water vapor transmission rate, permeability characteristics of materials and containers.

Suitable for: Film, sheet, container, and construction material of plastic, textile, leather, and metal.

Test Principle：

The instrument utilizes the Gravimetric Cup Method:

A test cup is filled with either a desiccant (for Desiccant/Gain Method) or distilled water (for Water/Loss Method).

The specimen is sealed over the mouth of the cup using the hot wax edge-sealing technique.

The sealed cup is placed in a temperature- and humidity-controlled chamber. The system maintains a constant humidity differential across the specimen, driving vapor transmission.

A high-precision analytical balance periodically weighs the cup. The rate of mass change is used to calculate the water vapor transmission properties of the material.

Compliant Standards:

ASTM E96 / E96M-22 - Standard Test Methods for Water Vapor Transmission of Materials

EN 13859-1 - Flexible sheets for waterproofing - Definitions and characteristics of underlays - Part 1: Bitumen sheets for roof waterproofing

EN 1931 - Geosynthetics - Determination of water vapour transmission properties of flexible barriers

EN ISO 12572 - Hygrothermal performance of building materials and products - Determination of water vapour transmission properties

GB/T 17146-2015 - Test method for water vapor transmission performance of building materials

GB/T 21332-2008 - Determination of steady-state moisture transmission properties of thermal insulation materials for building

QB/T 2411-2020 - Test method for water vapor transmission rate of plastic film and sheeting - Cup method

Key Features

Dual-Mode Integration: Supports both Desiccant Method (Gain) and Water Method (Loss) in one system, allowing for complementary verification of results.

Heavy-Duty Construction: Specifically designed for building materials with thicknesses up to 150 mm. The robust Hot Wax Edge-Sealing ensures zero leakage and eliminates edge-flow errors common with thick samples.

Ultra-High Precision: Measurement error as low as 0.05 g/m²·24h. The high-resolution balance (1 mg) and temperature control (±0.1°C) ensure data stability over long test durations.

Fog-Free Humidification: Utilizes pure steam injection directly into the test chamber. Unlike ultrasonic humidifiers, this prevents water droplet fallout ("false penetration") that can skew results.

Uniform Environmental Field: Dual-plane spiral airflow ensures exceptional homogeneity of temperature, humidity, and wind speed across all test stations.

No Special Room Required: Built-in environmental control eliminates the need for a costly constant-temperature/humidity laboratory. Test data remains unaffected by ambient fluctuations.

Automatic Desiccant Regeneration: The system includes an automatic dryer and desiccant regeneration cycle, reducing manual maintenance.

Balance Protection: Patented thermal insulation and moisture-proof technology safeguards the high-precision balance, extending its service life.

Data Integrity (Optional): Optional GMP Computerized System Module provides user management, audit trails, and electronic signatures to meet 21 CFR Part 11 requirements.

Technical Specifications

Parameter	Specification
Measurable Range (WVTR)	0.05 ~ 10,000 g/m²·24h
Test Accuracy	≤ 0.05 g/m²·24h
Moisture Flux Density	5.8×10⁻¹⁰ ~ 1.2×10⁻⁴ kg/(s·m²)
Balance Capacity	620 g
Balance Readability	1 mg
Temperature Range	10 ~ 50 °C
Temperature Accuracy	±0.1 °C
Humidity Range	5% ~ 95% RH
Humidity Accuracy	±1% RH
Air Velocity	0.02 ~ 0.5 m/s (0.02 ~ 0.3 m/s optional)
Test Area	50 cm² (custom sizes available)
Max. Sample Thickness	≤ 150 mm
Air Supply	> 0.3 MPa (User-provided)
Power Supply	AC 220V ±10%, 50Hz
Power Consumption	< 2000 W

Standard Configuration

Main testing unit (host)

Test computer with professional software

Air dryer

Wax-sealing permeable cups (quantity per model)

Calibration weights

Sample cutter

Optional Configuration

GMP Computerized System Module (User management, Audit trail, Electronic signature)

User-Provided Items

Compressed air source (> 0.3 MPa)

Distilled water

Desiccant

Application Industries & Scenarios

Building Materials Manufacturing

Insulation Boards: QC testing of XPS, EPS, rock wool, and glass wool boards per EN ISO 12572.

Waterproof Membranes: Testing bitumen and synthetic roofing membranes per EN 13859-1.

Gypsum & Fiber Cement Boards: Evaluating moisture resistance of interior wall panels.

Architectural Design & Engineering

Building Envelope Design: Providing WVTR data for hygrothermal simulations (e.g., WUFI) to prevent condensation and mold growth.

Green Building Certification: Supporting LEED, BREEAM, and China Green Building Star evaluations.

Infrastructure & Civil Engineering

Geosynthetics: Testing geomembranes and landfill liners per EN 1931.

Tunnel & Subway Construction: Validating waterproofing barriers in underground environments.

Cold Chain & Agriculture

Cold Storage: Testing insulation panels for walk-in freezers and refrigerated warehouses.

Greenhouse Coverings: Evaluating vapor barriers in agricultural tunnels.

Third-Party Testing & R&D

Accredited Laboratories: Issuing test reports compliant with ASTM, EN, and ISO standards.

Material Science: Researching new breathable membranes and smart insulation materials.

Frequently Asked Questions (FAQ)

Q1: Which European standards are supported?

A: The W-B-31/61-F-1 fully supports EN 13859-1 (roofing membranes), EN 1931 (geosynthetics), and EN ISO 12572 (insulation materials). These are the primary standards required for CE marking and UKCA compliance in the European Economic Area.

Q2: What is the advantage of the "Hot Wax Edge-Sealing" method?

A: For thick building materials (up to 150 mm), mechanical clamping often fails to prevent edge leakage. Hot wax creates a hermetic, flexible seal around the specimen perimeter, ensuring that all vapor passes throughthe material rather than leaking around the edges. This is critical for obtaining accurate WVTR values on thick substrates.

Q3: Why doesn't this instrument require a constant-temperature/humidity room?

A: The instrument features a fully enclosed, self-contained environmental chamber with precision PID control for temperature and fog-free steam injection for humidity. It actively controls the microclimate around the test cups, isolating them from ambient lab fluctuations. This saves significant capital expenditure on facility upgrades.

Q4: When should I use the Desiccant Method vs. the Water Method?

A: Desiccant Method (Gain): Used when simulating conditions where moisture migrates from the environment into a dry structure (e.g., exterior wall sheathing in humid climates). Water Method (Loss): Used when simulating conditions where moisture escapes from a wet structure to a dry environment (e.g., interior basement walls). Running both provides a complete picture of material behavior.

Q5: Can this instrument test geotextiles and geomembranes?

A: Yes. The instrument is fully compliant with EN 1931 for determining the water vapor transmission properties of flexible polymeric barriers used in civil engineering and landfill applications.

Function
Determining water vapor transmission rate, permeability characteristics of materials and containers.
Suitable for: Film, sheet, container, and construction material of plastic, textile, leather, and metal.
Principle
Method: water method, upright cup and inverted cup supported.
Water filled into test cup; mount the specimen on test cup and place it into test chamber; the temperature, the relative humidity and the wind speed inside test chamber are controlled to appointed value; the water vapor pressure difference between the outer and the inner of test cup will drive the water vapor permeating the specimen, the test cup’s weight will decrease; weighing the test cup and calculate the permeability characteristics of the specimen.
Standards
GB/T 1037、YBB 00092003、ASTM E96、ISO 2528、GB/T 17146、GB/T 12704、GB 19082、GB/T 21332、QB/T 2414、TPPI T464、ASTM D1653、YY0471.2、DIN 53122。
Characteristics
- Conplies to Standards of China, USA, ISO Strictly;
- Test error attenuates to zero and the maximum error can be estimated;
- Patented permeable cup: No plastic on the exterior of the cup(to avoid water absorption), non-slip design (no distortion of the sample), reliable sealing.
- Temperature and Humidity: The temperature is controlled by the TEC module and the humidity is controlled by dried air automatically;
- Uniform airspeed: Double-plane spiral circulation air, uniform airspeed, humidity field, and temperature field.
- Patent balance protector: moisture-proof, heat-proof and erosion-proof to protect the analytic balance;
- Air Dryer: the desiccant is re-dried automatically and its replace period is about 6 months;
- Work environment: indoors without constant temperature or humidity requirement (low cost), the test result is independent from the environment.
- Automatic：no mechanical knob; one button to test; terminating test and saving data automatically;
- Self-diagnosing：diagnosing when power-on and avoiding working within faults;
- Software: graphical, all-time, and all-element monitoring and recording, multi-format reports;
- Data security: conform to requirements of the GMP “computerized system”.

Specification

Name	Parameter		Name		Parameter
Measure Range	Film: 0.05~10,000 g/m²•24h Container: 0.0002-30 g/pkg•24h		Measure Error		Fim: 0.05 g/ m²•24h Container: 0.0002 g/pkg•24h
Balance Range	210 g		Balance Resolution		0. 1 mg
Temperature Range	15-45 ℃		Temperature Error		±0.3 ℃
Humidity Range	5% -50%		Humidity Error		±2% RH
Airspeed	0.03 - 2.5 m/s（stepless speed regulation）		Air Pressure		>0.3 MPa
Test Area	33 cm²（Other areas can be customized）		Specimen Thickness		<3 mm
Specimen Weight	<180 g		Custom Cup Height		<150 mm
Power Supply	AC220V /110V ;50/60Hz		Power Consumption		<2 kW
Model	Model
	STW-8/030-G	STW-8/040-G	STW-8/60-G	STW-8/080-G
Specimen Count	3	4	6	8
Size (L×B×H) mm	873× 700× 688
Net Weight	70 kg		79 kg

Configuration: Principal machine, computer, air dryer, professional software, test cupes, Correction weight(200g), Specimen Sampler.
Optional: GMP Software module, asphalt-seal cup.
Self-Supply: Compressed air, distilled water.

Keywords:

WVTR Permeation Tester - Gravimetric Method

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