ASTM E337 Humidity Measurement Testing by Psychrometer (Wet & Dry Bulb)
The object of this test method ASTM E 337-02 is to provide guidelines for the construction of a psychrometer and the techniques required for accurately measuring the humidity in the atmosphere. Only the essential features of the psychrometer are specified.
TRUSTED BY
- Overview
- Scope, Applications, and Benefits
- Test Process
- Specifications
- Instrumentation
- Results and Deliverables
ASTM E337-02 Humidity Measurement Overview
ASTM E337-02 describes a standard test method for measuring humidity using a psychrometer by determining wet-bulb and dry-bulb temperatures. This method is widely used to accurately evaluate atmospheric moisture conditions in controlled and ambient environments.
Humidity plays a critical role in material performance, environmental control, and industrial processes. This standard provides a reliable and straightforward approach for determining relative humidity from temperature differences measured with a psychrometric setup.
Scope, Applications, and Benefits
Scope
ASTM E337-02 outlines procedures for determining relative humidity using wet- and dry-bulb temperature measurements. It evaluates:
- Relative humidity (%)
- Wet-bulb temperature
- Dry-bulb temperature
- Moisture content in the air
Applications
- HVAC and environmental monitoring
- Material testing laboratories
- Meteorological measurements
- Industrial process control
- Storage and preservation environments
Benefits
- Provides accurate humidity measurement
- Simple and cost-effective method
- Suitable for field and laboratory use
- Supports environmental control systems
- Ensures compliance with testing standards
ASTM E337-02 Humidity Test Process
Instrument Setup
Psychrometer is prepared with dry-bulb and wetted wick on the wet-bulb thermometer.
1Air Exposure
The instrument is exposed to airflow (natural or forced) to stabilize readings.
2Temperature Measurement
Wet-bulb and dry-bulb temperatures are recorded after equilibrium is reached.
3Calculation
Relative humidity is calculated using psychrometric charts or equations.
4ASTM E337-02 Humidity Technical Specifications
| Parameter | Details |
|---|---|
| Applicable Environment | Ambient air, laboratories, industrial and field conditions |
| Temperature Range | Typically 0°C to 50°C |
| Measured Outputs | Relative humidity (%), wet-bulb and dry-bulb temperatures |
| Airflow Requirement | Adequate ventilation or air movement for accurate readings |
Instrumentation Used for Testing
- Psychrometer (sling or aspirated type)
- Thermometers (wet-bulb and dry-bulb)
- Distilled water (for wet-bulb wick)
- Airflow source (fan or natural ventilation)
- Psychrometric charts or calculation tools
Results and Deliverables
- Relative humidity (%)
- Wet-bulb and dry-bulb temperature readings
- Environmental condition assessment
- Moisture content evaluation
- Compliance reports
Frequently Asked Questions
It measures relative humidity by determining wet-bulb and dry-bulb temperatures using a psychrometer, allowing calculation of atmospheric moisture content for environmental monitoring, laboratory testing, and industrial process control under standardized conditions.
A psychrometer is an instrument consisting of wet-bulb and dry-bulb thermometers used to measure humidity by comparing temperature differences, which indicate the amount of moisture present in the air under specific environmental conditions.
Wet-bulb temperature reflects the cooling effect of evaporation and is essential for determining humidity, as the difference between wet- and dry-bulb temperatures directly correlates with the moisture content of the surrounding air.
It is used in HVAC systems, laboratories, meteorology, and industrial environments to monitor and control humidity levels, ensuring proper environmental conditions for materials, processes, and human comfort across various applications.
The method provides reasonably accurate humidity measurements, typically within ±2–5% relative humidity, depending on proper instrument use, airflow conditions, calibration, and environmental stability during measurement.
Why Choose Infinita Lab
for Electron Energy Loss
Spectroscopy (EELS)?
At the core of this breadth is our network of 2,000+ accredited labs in the USA, offering access to over 10,000 test types. From advanced metrology (SEM, TEM, RBS, XPS) to mechanical, dielectric, environmental, and standardized ASTM/ISO testing, we give clients unmatched flexibility, specialization, and scale. You are not limited by geography, facility, or methodology – Infinita connects you to the right testing, every time.
Looking for a trusted partner for Electron Energy Loss Spectroscopy (EELS) Testing?
Send query us at hello@infinitlab.com or call us at (888) 878-3090 to learn more about our services and how we can support you.
Request a Quote
Submit your material details and receive testing procedures, pricing, and turnaround time within 24 hours.
Quick Turnaround and Hasslefree process
Confidentiality Guarantee
Free, No-obligation Consultation
100% Customer Satisfaction
