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Sweating Guarded Hotplate TF129

4.8 (5 reviews)

Sweating Guarded Hotplate, or thermal resistance tester is a laboratory testing system used to test the thermal resistance properties(ability to persist a heat flow) of textiles for clothing, the purpose of thermal testing is to make sure the end products are comfortable to wear during sweating conditions, or to check the ability to protect from heat.

This type of sweating-guarded hotplate is also used in testing the thermal resistance and water-vapor resistance of medical textiles like face masks and protective clothing.



Thermal resistance range: 0.002-2 .0 m²·K/W, Resolution: 0.0001 m²·K/W
Evaporative Resistance range: 0-1000 m²·Pa/W, Resolution: 0.001m²·Pa/W
Repeatability: ≤ ±2%
Test plate temperature range: 0℃ ~ 35℃, adjustable, accuracy: ±0.2℃
Air velocity: 0 ~ 1 m/s, adjustable, accuracy: ±1%
Sample thickness: 0~50 mm
Test plate area: 254 mm x 254 mm


StandardsISO 11092, ASTM F1868, GB/T 11048
Power110/220 V, 50 Hz
Weight62 Kg
Dimensions770 mm x 670 mm x 430 mm

TESTEX – a professional textile testing instrument supplier – Sweating Guarded Hotplate TF129 is on sale, contact us to get a detailed price quote.

What is the Sweating Guarded Hotplate?

Sweating Guarded Hotplate is the most professional, stable, and advanced Thermal and Evaporative Resistance test instrument in the world.

The sweating guraded hotplate with a separate design for each component. Altogether, it mainly consists of an automatic water supply system, wind speed stabilisation system, test mainframe, and climate chamber. It can automatically adjust the height of the hotplate according to the thickness of the test sample and so ensures that the air-speed sensor is 15mm above the hot plate.

It offers Windows-based software. Connect the main machine inside the chamber to the software by Wi-Fi, so operators may control and monitor the testing in the office.

An advanced Temperature & Humidity Chamber is offered with the machine.

Note: this instrument needs a customized PC.

Textile – Test standards for thermal resistance and water-vapour resistance

  • GB/T 11048: Testing of thermal resistance and water-vapour resistance under steady-state conditions – sweating guarded hotplate test method
  • ISO 11092: Textiles – Physiological effects – Measurement of thermal and water-vapour resistance under steady-state conditions (sweating guarded hotplate test)
  • ASTM F1868: Standard test method for thermal and evaporative resistance of clothing materials using a sweating hot plate

This sweating guarded hotplate (often referred to as the “skin model”) described in this international standard is intended to simulate the heat and mass transfer processes which occur next to human skin. This test method is suitable for all types of textile fabrics, but also for coating, leather and multi-layer composites.

Terms and definitions

thermal resistance, unit: m2·K/W

Rct: the temperature difference between the two faces of a material divided by the resultant heat flux per unit area in the direction of the gradient.

water-vapour resistance, unit: m2·Pa/W

Ret: water-vapour pressure difference between the two faces of a material divided by the resultant evaporative heat flux per unit area in the direction of the gradient.

water-vapour permeability index

  • imt: ratio of thermal and water-vapour resistances in accordance with the following formula
  • imt = S * Rct / Ret
  • S = 60 Pa/K

water-vapour permeability

  • Characteristic of a textile material or composite depending on water-vapour resistance and temperature in accordance with the following formula
  • Wd = 1 / (Ret·ΦTm)
  • Where ΦTm is the latent heat of vaporization of water at the temperature Tm of the measuring unit, equals, for example, 0.627 W·h/g at Tm = 35℃.

How to test thermal resistance and water-vapour resistance?

Place the specimen on the electrically test plate which is kept at a constant temperature by the test plate, its surrounding heat shield and the protective plate at the bottom, so that the heat from the test plate can only be dissipated through the specimen.

For the determination of thermal resistance, the heat flux through the test sepcimen is measured after steady-state conditions have been reached.

For the determination of water-vapour resistance, an electrically heated porous plate is covered by a water-vapour permeable but liquid-water impermeable membrane. Water fed to the heated plate evaporates and passes through the membrane as vapour, so that no liquid water contacts the test sample. With the test sample placed on the membrane, the heat flux required to maintain a constant temperature at the plate is measure of the rate of water evaporation, and form this the water-vapour resistance of the test specimen is determined.

Features of Sweating Guarded Hotplate TF129

High practicality

Individually designed system for easy control. The height of the hotplate can be automatically adjusted according to the thickness of the sample. Besides, it ensures that the air-speed sensor is 15mm above the hotplate, making for a more realistic testing environment.

Remote monitoring

It provides windows-based software and connects to the host computer in the test chamber, so the operator can control and monitor the test situation from the office.

More reference value of test results

A complex, specially designed environment to ensure the strictest control and monitoring of air temperature, air velocity, relative humidity, etc. This results in more objective and realistic testing of samples.

Stable and reliable data processor

Optional PC software is available for a variety of functions, displaying all real-time data. For example, remote control and creation of test reports, automatic calculation of thermal resistance, water vapour resistance (evaporation resistance)

In addition, it can record various indicators. For example, the water vapour permeability index, insulation values, heat loss, display of measurement results and dynamic curves.

Applicable to common international standards

Built-in programmable test procedures to meet the requirements of relevant ASTM, GB/T, ISO, and other standards.

Why Choose TESTEX  Sweating Guarded Hotplate TF129

Strictly meet standards:

All data for TF129 meet the standard parameters, for example, ISO 11092 and ASTM F1868.

Consistency with international third-party laboratories:

The test data are comparable to the test results obtained by well-known international third-party laboratories.

High reproducibility:

Whether is the same set of samples, or different machines of the same model, after multiple tests, the results are consistent.

Longer service life:

TESTEX makes prototypes and then subjects them to rigorous reliability testing in a variety of environments to ensure achieve the expected service life.

Longer service life

For all the Sweating Guarded Hotplates manufactured by TESTEX, before mass production, prototypes are made and required to pass the strict Reliability Test. This means testing under challenging conditions such as high and low temperatures, high speeds, and high loads to ensure an expected service life of no less than 8 years.

User-friendly transparent warranty policy

Textile testing machines, 14 months free warranty (12 months normal warranty time + 2 months shipping time). Besides, all spare parts, have 3 months free warranty.

We provide full life-cycle support for sweating guarded hotplate TF129. So feel free to contact our service team with any questions you may have.

5 reviews for Sweating Guarded Hotplate TF129

  1. jack ding

    This is the big investment for our lab, but it worth it, make our testing smooth and efficient

  2. Adelaide Graham

    It’s worthy.

  3. Mabel Electra

    Works perfectly, instruction manual was easy to read and understand.

  4. Kyle Thompson

    That is very stable, and I like to communicate with professional staff like Lily.

    • testextextile

      Thanks. All staffs in TESTEX are professional.

  5. Fanny Windsor

    The guarded hot plate apparatus price is reasonable and help us a lot.Recommend !

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Why We Need the Thermal Resistance Test?

When people wearing clothes in cold or hot climates, the temperature of clothing, especially close-fitting, varies with the temperature of the skin. People should choose suitable clothes to ensure comfort, or at least in adverse weather conditions to protect the human body. The heat transfer property of fabric can ensure the comfort of clothing, for example, the clothing with high thermal resistance has a better function of preventing cold, while the clothes with low thermal resistance can give a cool feeling. Therefore, testing the thermal resistance of fabrics has an important reference for improving people's clothing comfort.

Thermal Resistance Test Principle

The sweating guarded hot plate instrument produced by our company adopts the constant temperature method. Place the sample to be tested on an electric hot plate which has good thermal insulation at all the other surfaces. Transfer heat to an electric heating plate so that it reaches constant temperature state, and test the heat needed to maintain the constant temperature of the electric heating plate. This method has been adopted by ASTM as the standard number ASTM D1518.

Sweating Guarded Hot Plate Test Method

Assemble the instrument, install SGHP software according to instructions, connect with thermal resistance instrument through network signal, and prepare for the test.

The RCT0 test is used to express the basic parameter of a machine. The value of Rct0 will be used to calculate the final RCT value of a sample. Rct0 test should be done when the machine stopped for a long time or the environment changed great.

Cut the sample as 50 cm x 50 cm, and pretreat it according to the standard requirements. Place the treated sample on the surface of the test area. If the thickness of the sample is more than 1 mm, then adjust the height of the wind speed sensor so that the height between the sample and the sensor is about 15 mm. According to the standard requirements to set the temp and humidity and then start the test until the testing environment is stable. Record the test results and calculate the final RCT values of the sample.

Daily Maintenance

1 Keep the machine clean: Clean the surface of the test plate and the dust of the air of exhaust grid by using the towel.
2 If the Ret test is finished and another Ret test will be run in next day, then open the safety cover and open the door of the conditioning chamber, the water will be evaporated from inside of the machine, and prolong the service life of the machine.
3 If the conditioning chamber will not be used for a long time, please drain off the water of the conditioning chamber.


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    Q: Does the chamber have the option - control humidity?

    A: No, it is not equipped with this option.


    Q: At what humidity ranges is the machine able to run?

    A: The machine is not equipped with control humidity, but Temperature & Humidity Chamber can meet your needs, with its humidity range of 25%~85% R.H.


    Q: What advantages does the machine have?

    A: 1. It can contact with WIFI.

    1. The thermal resistance and Temperature & Humidity Chamber can be used separately. And other suppliers combine the two machines into one. They must be used together.

    2. Our Temperature & Humidity Chamber is made by a professional factory, which is more accurate. The ITS (Intertek testing service) bought this machine from a famous company, whose price is triple than ours. The test results from this machine are not precise because the machine is made by the company himself. Finally, he turned to us and bought a new one. We only do what we are good at.

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