Review of application of thermal manikin in evaluation on thermal and moisture comfort of clothing

Abstract

The thermal manikin is a complicated, delicate, and expensive tool, which could simulate the heat exchange between environment and human body and measure the evaporative resistance and thermal insulation of clothing. This study reviewed the application of thermal manikin in evaluation on thermal and moisture comfort of clothing and the thermal manikin through three aspects namely traditional thermal manikin, thermal regulation manikins, and numerical thermal manikins. Several typical manikins (Newton, Coppelius, SAM, Walter, Ruth, and Wenda) were described, and the features, application fields, measurement principles, and research status of thermal manikin were demonstrated. Finally, the development trends of thermal manikin were proposed. Not only would this work promote the further development of the thermal manikins themselves and the innovation of relevant technologies but also provide valuable information for the development and design of relevant products.

Keywords

Thermal manikin thermal insulation evaporative resistance perspiration heat transfer review

Introduction

The history of thermal manikins has been given formerly by Holmer^1,2 and Wyon.³ There are over 100 thermal manikins all over the world. The use and research of manikins have been developed for more than 70 years, which are used to analyze the thermal interface between ambient environment and human body.

The first single segment copper thermal manikin was built by the US Army during the 1940s.⁴ A few of this type of thermal manikins is still used. The thermal manikin was divided into several independent segments which could be flexibly controlled and provided independent temperature distribution information during the development process of thermal manikin due to the need of more detailed data.

The early thermal manikins are static and standing which provide limited information. Due to which, manikins were produced with joints which could allow manikin to be movable. This dry manikin can only measure the thermal insulation of clothing. An important step forward happened with the appearance of sweating thermal manikin that could provide more valuable information about heat transfer by evaporation. Nowadays, most thermal manikins could realize perspiration and movable postures.

The thermal manikin had a diversified development such as female thermal manikin^2,5–7 and models by Chao; breath thermal manikin; baby thermal manikin,^8–13 head thermal manikin; and all kinds of thermal manikins.^14–19.

In general, the revolution of thermal manikins could be classified into four generations. The first generation is non-perspiration and not movable thermal manikin;^20–22 the second generation cannot sweat, but they could simulate sweating by utilizing wetted skin.^23–26 This generation is still used by Havenith from Britain, Holmer from Sweden, and McCullough from USA; some manikins could be movable, some of them are static; and the third generation is sweaty and movable thermal manikins, such as “Newton” from USA, “Walter” from Hong Kong,²⁷ “SAM” from Switzerland,²⁸ “Coppelius” from Finland,²⁹ “Taro” from Japan,³⁰ “Kem” from Japan;³¹ and the latest or the fourth generation is the thermal regulation manikin with function of thermal regulation namely the third-generation thermal manikins couple with thermal physiological models.

This study would review the thermal manikin through three aspects, namely traditional thermal manikins, thermal regulation manikins, and numerical thermal manikins. Several typical manikins (Newton, Coppelius, SAM, Walter, Ruth, Wenda) were introduced, and the features, application fields, measurement principles, and research status of thermal manikin were demonstrated. Finally, the future trends of thermal manikin were proposed. Not only would this work promote further development of the thermal manikins themselves and the innovation of relevant technologies but also provide valuable information for the development and design of relevant products.

Traditional thermal manikins

The features and application areas of thermal manikin

The role of thermal manikin is to measure the impact of the ambient environment on human body including thermal radiation and heat transfer through human body surface contact. The thermal manikin is an accurate and reliable tool² for the assessment of thermal factors as well as the delicate, expensive, and complicated tool, but it has lots of useful features. The thermal manikin could measure the heat loss of human body due to thermal convection, conduction, and radiation. The whole or local heat fluxes as well as evaporative resistance and thermal insulation of clothing could also be measured by thermal manikin, which could imitate the heat exchange between environment and human body.

The thermal manikin is mainly used in two fields. One field is the determination of clothing thermal properties^32,33. The other field is the evaluation on the effects of thermal environment which especially could assess the whole or local heat transfer in the complex environment such as plane, aircraft, vehicle, HAVC system, and so on.

Development progress of thermal manikin

Table 1 was modified from Wyon,³ Holmer,² and Nilsson³⁴ illustrated that every new manikin appeared with the improvement of technologies and methods. This study would choose six typical thermal manikins for detailed introduction.

Table 1.

The development progress of thermal manikins.

No.	Segmentation	Series	Material	Regulation	Posture	Country & year
1	1-segment	COPPERMAN	Copper	Analog	Standing	USA, 1942
2	11-segments	ALMANKIN	Aluminum	Analog	Standing	UK, 1964
3	Radiation manikin	CEPAT400	Aluminum	Analog	Standing	France, 1972
4	16-segments	HENRIK2	Plastic	Analog	Movable	Denmark, 1973
5	16-segments	CHARLIE	Plastic	Analog	Movable	Germany, 1978
6	16-segments	SIBMAN	Plastic	Digital	Sit, stand	Sweden, 1980
7	19-segments	VOLTMAN	Plastic	Digital	Sitting	Sweden, 1982
8	36-segments	ASSMAN	Plastic	Digital	Sitting	Sweden, 1983
9	19-segments	TORE	Plastic	Digital	Movable	Sweden, 1984
10	7-segments	CLOUSSEAU	Plastic	Analog	Standing	France, 1980
11	sweating manikin	COPPELIUS	Plastic	Digital	Movable	Finland, 1988
12	female manikin	NILLE	Plastic	Comfort	Movable	Denmark, 1989
13	33 + 3-segment	HEATMAN	Plastic	Multi	Sitting	Sweden, 1991
14	1 segment sweating	TARO	Copper	Digital	Standing	Japan, 1992
15	breathable manikin	NILLE	Plastic	Multi	Movable	Denmark, 1996
16	26-segments sweating	SAM	Plastic	Digital	Movable	Switzerland, 2001
17	1-segment sweating	WALTER	Breathable fabric	Digital	Movable	Hong Kong, 2002
18	26-segments	TOM	Copper	Digital	Movable	USA, 2003
19	1-segment	not available	Windproof fabric	Digital	Movable	USA, 2003
20	126-segments	ADAM	Porosity metal	Digital	Movable	USA, 2003
21	17 segments sweating	KEM	Porosity material	Digital	Movable	Japan, 2004
22	Sweating manikin	NEWTON	Wicking skin with water tubes	Digital	Movable	USA, 2005
23	Thermoregulatory sweating manikin	NEWTON	Wicking skin with water tubes	Digital	Movable	USA, 2009
24	Female sweating manikin	WENDA	Breathable fabric	Digital	Movable	USA, 2016
25	Baby sweating manikin	RUTH	Wicking skin with water tubes	Digital	Movable	USA, 2017

Newton thermal manikin

Thermal manikin Newton was manufactured by Measurement Technology Northwest in the United States. Newton was designed and complied with ISO and ASTM standards. The outer shell of Newton is made of carbon-epoxy thermal conductive materials and Newton is articulated, which could present the motion of each joint and various human body postures. The neck and wrists of Newton could choose to add joints.

The sweating system of Newton based on a matrix of fluid ports and a removable fabric skin layer. There are lots of sweating holes that the water flow from to the dry fabric skin layer. The skin can maintain 100% saturation through the control of computerized water amount. In this manikin, the surface of the manikin was divided into many segments, in which temperature and heat flux could be controlled independently.

There are many segments of Newton thermal manikins which could be customized as required. This model uses a 32-segment Newton thermal manikin. Newton thermal manikin system was controlled by ThermDAC software, which advanced in faster transient response and greater application ambient range.

Newton thermal manikins are all over the world for the moment. Some researchers investigated the proficiency of Newton tests in the different labs. The same clothing was tested by the same Newton manikin in the four different countries or regions labs. The findings demonstrated that the precision of Newton is high and the deviation is small, which also contributed to the worldwide discussion on standardized studies of evaporative resistance of clothing.

Coppelius thermal manikin

The earliest sweating thermal manikin which was based on high moisture absorption fabric to simulate sweating through spraying the water to the fabrics was manufactured by Goldman.³⁵ The real sweating thermal manikin Coppelius did not appear until 1980s which was invented by Meinander³⁶ with horniness foamed plastic. The shoulders, elbows, buttocks, and knees of Coppelius thermal manikin were mounted on fake joints for the freedom of movement and various postures of the manikin. A computerized micro-valve system was used to control the water distribution for simulating thermal manikin sweating which encompassed 187 sweating glands and maintaining the moisture of the skin.

The skin of Coppelius thermal manikin consists of two layers. They are the outer microporous membrane which transmits water in vapor but not in liquid form and the inner non-woven material, which spreads the water to the internal surface. The manikin surface produces heat and vapor similar to the human skin owing to the supplied water which would be evaporated by the heating system. The manikin maximum amount of water supply is 200 g m⁻² h⁻¹ in the moderate sweating level.

The main function of Coppelius is to determine the dry heat loss and wet heat loss of clothing by measuring the quantity of water supplied and the weight added to the garment before and after the test. There are two Coppelius manikins in use at present. One is located in VTT Laboratories in Tampere of Finland. The other is located in North Carolina State University.

SAM thermal manikin

The SAM thermal manikin, whose full name is Sweating Agile thermal Manikin, was built on the basis of Coppelius thermal manikin by Richards and Mattle³⁷ and Mattle²⁸. SAM was made of foamed plastic-mixed aluminum powder, which increased the thermal conductivity of manikin and lead to uniform perspiration. Besides, SAM could use two-axis linkage mechanism which compelled limbs motion and simulated human walking with all kinds of nimble postures. The internal skeleton of thermal manikin is suspended from a weight system and manikin was covered by 26 outer shells. Each shell can be heated independently and equipped with sensors. The thermal manikin concludes 125 sweating holes which distributed over the whole body surface to simulate human sweating. The internal micro valves was used to simulate the vapor and liquid sweating which adjusted sweating speed ranging from 0 to 4l m⁻² h. However, there are few literatures about the evaporative resistance and thermal insulation of clothing which are tested by SAM thermal manikin.

Walter thermal manikin

The Walter movable fabric thermal manikin was developed by Fan and Chen.²⁷ Walter is the first sweating manikin which is made of water circulation system and waterproof and vapor permeable fabrics in the world. Walter simulates sweating through waterproof and vapor permeable fabric, which monitors the dynamic changes of water vapor in real time through a high-precision balance under the basis on development of SAM, instead of measuring the mass change of clothing to calculate the amount of water evaporation. According to literature research, Walter is the only fabric thermal manikin which can measure the dynamic experimental data in the world for the moment and give the evaporative resistance and thermal insulation of clothing for two important parameters during one measurement.

The system of Walter consists of water circulation system, manikin walking system, water supply system, and data measuring and recording system.³⁸ The water circulation system of Walter can distribute the heated water from the center of the manikin to the whole manikin body. The temperature of each manikin body part is determined by the velocity of water flow which is controlled by internal micro water valves.³⁹

The Walter joint of shoulders, elbows, hips, and knees are controlled by a four-bar crank mechanism which allowed manikin to walk like Newton, Coppelius, and SAM. Since Walter is a fabric sweating thermal manikin, it is not convenient for walking. A motion joint is added between the thighs and the body to make the manikin move more like a real person with the maximum speed of 4 km/h.

Wenda female thermal manikin

Thermal manikins of male shape are widely used for the moment. Male thermal manikins have been often used to assess the thermal comfort of women’s garments. However, the findings may be inaccurate because of the differences in body shape between men and women, which may lead to obvious differences in sweating accumulation and heat response.

The first female manikin Nille was built at the Danish University of Technology in 1989,² which was produced by plastic and divided into several segments whose temperature could be controlled independently. This female manikin has one additional function: simulating breathing, which is useful to indoor environment quality assessment. Another female thermal manikin Maria was invented by Silva and Coelho⁵ later, which was made of glass and polyester shells and covered by a strip of nickel wire. After that, a 16-segment female thermal manikin Diana was manufactured by Konarska et al.^6,7 However, all above female thermal manikin cannot simulate sweating, which is of great importance to human thermal comfort.

The female sweating thermal manikin Wenda was created by Chao. The design concept of Wenda comes from fabric sweating thermal manikin Walter, which is similar with a medium-sized Chinese female adult with a B cup breast size. Wenda simulates sweating through waterproof and vapor permeable fabric skin as same as Walter. This fabric skin which is a three-layer laminated fabric consists of a tricot knitted nylon backing fabric as the inner layer, a strong nylon woven fabric as the outer layer and a middle layer of a microporous polyteyrafluoroethene Gore-Tex membrane, which has more than 1.4 billion tiny pores at every square centimeter. The pore diameter of membrane is about 200 nm, which is more than 700 times larger than a vapor molecule, but almost 20,000 times smaller than a drop of liquid water. Therefore, the fabric skin can allow water vapor transmission, but it can also prevent liquid water from passing through.

Ruth baby thermal manikin

The research data of infants in current literature are very limited. The only literature sources are acquired about baby heat loss in the incubators which results from baby thermal manikin.⁴⁰ The early baby thermal manikin based on simplified geometry manikins.⁸ However, recent investigations focus on dry heat loss from baby thermal manikin which is similar to anthropomorphic infant-sized manikins.^9,10 Due to ethical consideration, experiments cannot be performed on living babies, which would impose risk to the infant body. Thus the idea of baby thermal manikin which was used to study the heat exchange between infant and environment came into being. Therefore, there were lots of studies which investigated the thermal status of infant,^41–45 measured the thermal insulation of baby clothing^46–48 and diapers.^49–51

The baby thermal manikin Ruth was developed by Measurement Technology Northwest in 2017. Ruth is divided into 11 segments, which resembles a 9-month-old infant with similar size. The baby thermal manikin consists of precise temperature sensors and a thermally conductive carbon-epoxy shell with internal heater elements. Spherical ball joints are equipped at the neck, shoulders, and hips, with single-flexure joints at the knees and elbows. Cable connections are at the eyes to minimize any interference with the clothing being measured. The baby thermal manikin Ruth also includes skin sweating system, which takes advantage of a matrix of pores over the active surface of the baby thermal manikin coupled with computerized fluid delivery and a wicking fabric skin layer to distribute water over the surface of the baby thermal manikin. However, the measurement results of the baby thermal manikin Ruth and open published literature have not been seen so far.

Measurement principle of thermal manikin

There are two basic forms of human body heat dissipation: wet heat loss driven by humidity gradient and dry heat loss driven by temperature gradient. The total heat dissipation of human body is the sum of dry heat loss and wet heat loss. Therefore, the important factors affecting the thermal and moisture comfort of clothing are the moisture permeability of clothing and the thermal insulation performance of clothing, which is called the evaporative resistance and thermal insulation of the clothing. Thermal resistance is defined in terms of “Clo” value. Its definition was put forward by Gagge from Yale University in 1941, which resembled the thermal insulation of clothing dressed by a healthy adult who felt comfortable and seated in a room temperature of 21°C, indoor relative humidity of less than 50%, and wind speed of no more than 0.1 m/s. Sweat evaporates on the surface of the skin and passes through the clothing to the environment. The resistance to this vapor transmission is called the evaporative resistance of clothing. The concept of thermal resistance has been proposed, which facilitates the evaluation of thermal and moisture comfort of clothing transform from abstract heat and moisture transfer model to quantitative value.

The earliest sweating thermal manikin which applied the theory of two-steps measurement principle⁵² under the basis of above theory was developed for quantifying the thermal and moisture comfort of clothing by Goldman.³⁵ After that, many researchers studied intensively sweating thermal manikin. Fan constructed a movable sweating thermal manikin Walter and proposed the theory of one-step measurement principle for the precision improvement of measurement results.²⁶

The theory of two-steps measurement principle is as follows. The first step: the dry heat loss and wet heat loss of clothing are measured by dry thermal manikin; and the second step: the total heat loss of thermal manikin is measured under the same experiment conditions as the first step. The evaporative resistance of clothing is calculated through the sweating thermal manikin taking advantage of the computational formula of evaporative resistance. Such measurements have been proved inaccurate by experiments because of the two assumptions. First, it is necessary to assume that the dry heat loss of the dry thermal manikin is equal to the dry heat loss of the wet thermal manikin. Second, the relative humidity of the wet thermal manikin skin should be assumed to be 100%, which leads to the increase of the thermal insulation and the decrease of the evaporative resistance.

The sweating thermal manikin Walter uses the theory of one-step measurement principle. The amount of perspiration of manikin is equal to the quantity of water supplied by the manikin, and the amount of perspiration varies with the change of clothing, which can be obtained directly by the data collection system of the manikin. The skin of Walter sweating thermal manikin is in direct contact with the water inside the manikin, and the relative humidity of the skin is 100%. Therefore, the thermal insulation and evaporative resistance of clothing can be measured through sweating thermal manikin Walter by one step, which has repeatability and high accuracy.

There are three methods of sweating for thermal manikin currently. The first method is that pre-wetted fabric skin is put on the manikin; the second method is that a constant amount of water supply is delivered to the surface of the skin by adjustment; the third method is sweating fabric thermal manikin which is full of water and produced perspiration through waterproof and breathable fabric skin. The evaporative resistance and thermal insulation of the same clothing was tested on the thermal manikin through three different sweating methods by Gao. The findings demonstrated that the deviation of thermal insulation was small, and the deviation of evaporative resistance was very large, and the evaporative resistance of clothing measured on Newton is 44.5% lower than the evaporative resistance measured on Walter.⁵³

Thermal regulation manikin

The manikin which is controlled by thermal physiological regulation models is called thermal regulation manikin. The traditional thermal manikin does not have the function of thermal physiological regulation. There is a deviation of skin temperature between human body test and thermal manikin test due to the shivering and vasodilation thermal response of human body in order to adapt to the temperature change in the environment. In addition, most traditional thermal manikins cannot simulate or predict the skin temperature and core temperature of human body simultaneously.

The thermal regulation manikin can simulate complex physiological human thermal response such as shivering, vasomotion, and sweating in order to adapt to temperature changes in the environment. The thermal regulation manikin includes a thermal manikin which is controlled by a thermal physiological regulation model using a feedback loop. The thermal manikin is programmed to respond to the thermal environment as a real human being in the above method.

There are many thermal regulation manikins during the past development process. The first thermal regulation manikin Adam was developed for the American National Renewable Energy Laboratory, which was controlled by a thermal physiological regulation model.⁵⁴ However, some studies showed that the deviation of predicted skin temperature and core temperature was much large.^55,56 Another single-sector thermal regulation manikin Torso^57–59 was developed at the Swiss Federal Laboratories for Materials Science and Technology, which was coupled with thermal physiological regulation model of Fiala and colleagues.^60–62 Although the single thermal regulation manikin did not have large deviation, the single-sector torso resembled a human body limited the accuracy and precision of experimental results. A multi sector thermal regulation coupled with the same thermal physiological regulation model, which could accurately predict the change of skin surface temperature and the heat loss of human body in dynamic environment.^37,63

At present, the commercial thermal regulation manikin Newton is more mature, which is composed of thermal manikin Newton and a thermal physiological regulation model and comfort model.^64,65 Despite there are still some disadvantages in the thermal regulation manikin, such as about the verification of the thermal regulation model, the prediction precision of thermal regulation manikin is increasing with the thermal physiological regulation model and the continuous performance improvement of thermal regulation manikin. The thermal regulation manikin has expanded the application area of the traditional thermal manikin, which can also be used in the fields of meteorology, environmental engineering, urban climate and clinic, and so on.

Numerical thermal manikin

Numerical thermal manikin is a virtual thermal manikin which is based on computational fluid dynamics (CFD) simulation software. The geometric model is obtained by scanning the real thermal manikin by three-dimensional laser. Then the software processed the virtual thermal manikin in blocks and grid and coupled with the thermal physiological regulation model. CFD simulation has provided an effective and simple way to study the physiological response and heat transfer in various environments. In the past few decades, CFD has become a useful tool with numerical thermal manikin for calculating the heat exchange between the human body and the surrounding environment in the virtual environment.

Several researches coupled the CFD with thermal physiological regulation model to study thermal comfort, physiological response, and heat transfer.^66–72 Some researchers utilized the numerical thermal manikin with a simple geometry, which coupled a two-node thermal physiological regulation model and could not predict the thermal physiological responses of individual body segments. Cropper coupled CFD and multi-node thermal physiological regulation model to confirm the skin temperature of human body, but the difference between simulated and experiment results was not analyzed.⁷⁰ Zhu⁷¹ proposed a coupling system to assess the skin temperature distribution and heat transfer around the human body, but the maximum deviation between simulated skin temperature and experimental results was up to 2.9°C.

Voelker and Alsaad⁷³ proposed a method to simulate microclimate around human body by coupling CFD solver to UCB thermal comfort model. Yang simulated the thermal behaviors and heat transfer of nude human body by coupling thermal physiological regulation model and CFD.⁷⁴ However, his study focused on nude human body, and the influence of clothing on heat and mass transfer is not taken into account. The heat and moisture of clothing layers should be considered to evaluate the thermal comfort and thermal stress in future research.

The wide use of numerical thermal manikin depends on the purpose of the user and the performance of the computer. Numerical thermal manikin further expands the application breadth and depth of traditional thermal manikins and thermal regulation dummy. At present, numerical thermal manikin is not fully developed, and there is a great room for improvement.

Future development trend of thermal manikin

Body part thermal manikin

The present thermal manikin can only measure the total evaporative resistance and thermal insulation of clothing which represent the whole body heat transfer information. It could be necessary to calculate the local evaporative resistance and thermal insulation of clothing. Local thermal resistance could truly express the thermal insulation performance of clothing covering part of the body, determine the local comfort of clothing, and further promote the structure design and fabric materials selection of functional clothing. Besides, the traditional thermal manikin is not suitable for measuring the heat and moisture transfer of local small part products (such as hats and gloves). Therefore, the birth of body part thermal manikins is promoted, such as head thermal manikin.

A two-zone head thermal manikin has been intensively studied for investigating heat transfer properties of different kind of headgear, which was transformed from a fake head in a shop window manikin.^14–17 After that, a new segmentation of the head surface have been proposed for building a new nine-zone head thermal manikin (Measurement Technology Northwest, USA, 2012).¹⁹ There would be more body part thermal manikins which are created in the future.

With fast cooling system

Human beings have thermoregulation functions and can be cooled by a series of thermoregulatory responses when they suffer a hot environment. However, most thermal manikins cannot simulate the rapid decrease of body temperature when environments change from hot environment to normal or low temperature environment because of lacking of fast cooling system. With the development of science and technology, the thermal manikin will gather more new technologies, which is more similar to the real person.

Smart thermal manikin

The existing thermal manikins are suspended and cannot be kept on their backs and have a seat alone, which leads to the limit of their application. In future, thermal manikin should become more intelligent, which can stand alone, sit and supine through the wireless operation of laptop or mobile phone. The smart thermal manikin is not only used indoors but also can be flexibly applied outdoors.

Wider application range of ambient temperatures

The thermal manikin is often used to assess the thermal properties of clothing and related products under normal temperature. However, the thermal manikin approximated a real person, which has better to suit all kinds of environments. Fu et al.⁷⁵ evaluated the effects of water and radiation on thermal protection performance of firefighting clothing under low-level thermal radiation by using thermal manikin. The experiment results provided a comprehensive understanding of the thermal and moisture transfer of clothing under low-level thermal radiation and multiple sweating rates. Havenith studied the effects of thermal radiation on the heat loss of Newton thermal manikin at different wind speed. However, the thermal radiation flux is 0.325 and 0.45 kW/m² which is very low, and it does not discuss the thermal protection performance.⁷⁶ The thermal properties of some extremely cold garments are tested, which require that the thermal manikin is in a very low temperature environment, and the sweating system inside the thermal manikin may be frozen. The ambient environment application of thermal manikin will be widely broaden in future.

Non-uniform perspiration

At present, most thermal manikins make uniform perspiration. The human body sweats heavily after strenuous exercise, and the amount of sweat is different in different parts of human body. The sweat amount of armpit, chest, and back is usually more, but the sweat amount of limbs is less. A sweating thermal manikin should be developed in order to more accurately measure the evaporative resistance and thermal insulation of clothing in the future, where the sweating intensity similar to that of a real person namely non-uniform perspiration. The skin of thermal manikin Walter is made of high-strength breathable fabric. Different sweating skin special fabrics should be produced based on the test data of real persons. Different special skin fabrics should be used to make different parts skin of human body so that thermal manikin can simulate unevenly sweating at different parts in the same experimental conditions environment. Shi et al.⁷⁷ daubed silica gel on the back of Walter’s fabric skin, which can also simulate uneven sweating.

Standardization of measuring principles and methods

There are all kinds of thermal manikins all over the world. The evaporative resistance and thermal insulation of the same clothing are different caused by the same measuring principle under the same experimental conditions environment, which affected the research of thermal and wet comfort of clothing. There are three modes to measure the thermal insulation of clothing by thermal manikin: constant heat flow, constant skin temperature, and thermal comfort adjustment. In the same way, there are also three methods for calculating thermal insulation of clothing: serial model, parallel model, and global model. The standard for measuring thermal insulation of clothing by thermal manikin is ASTM F 1291, ISO9920 2007 and ISO15831 2004. However, there is only one standard ASTM F2730-10 for testing the evaporative resistance of clothing, which only describes the size, test conditions and procedures of the thermal manikin and does not confirm the method of thermal manikin sweating. Therefore, different thermal manikins can apply different methods to simulate sweating, and there is no clear rule about the setting of sweating amount. Therefore, the experiment results of different national thermal manikin are quite different around the world. The measurement principle and testing method of thermal manikin need to be further standardized in future, and the experiment results of different thermal manikins are more comparable.

Conclusion

The thermal manikin is the accurate and reliable tool for assessment of thermal factors as well as the delicate, expensive, and complicated tool, and it has lots of useful features. The thermal manikin could measure the heat loss of human body due to thermal convection, conduction, and radiation. The whole or local heat fluxes as well as evaporative resistance and thermal insulation of clothing could also be measured by thermal manikin, which could imitate the heat exchange between environment and the human body.

This article reviewed the thermal manikin through three aspects, namely traditional thermal manikin, thermal regulation manikins, and numerical thermal manikins. Several typical manikins (Newton, Coppelius, SAM, Walter, Ruth, Wenda) were described, and the features, application fields, measurement principles, and research status of thermal manikin were demonstrated. Finally, the future development trends of thermal manikin were proposed. In the future, there would be more body part thermal manikins; the thermal manikin with fast cooling system will gather more new technologies, which is more similar to the real person; thermal manikin will become more intelligent, which can be operated and controlled by laptop or mobile phone, the smart thermal manikin is not only used indoors but also can be flexibly applied outdoors; the ambient environment application of thermal manikin will be widely broaden; the thermal manikin can simulate unevenly sweating at different body parts, which more actually measured the thermal properties of clothing; the measurement principle and testing method of thermal manikin will to be further standardized, and the experiment results of different thermal manikins would be more comparable.

Not only would this work promote further development of the thermal manikins themselves and the innovation of relevant technologies but this also provides valuable information for the development and design of relevant products.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

References

Holmer

Thermal manikins in research and standards. In: Nilsson

Holmér

(eds) Thermal manikin testing. Stockholm: National Institute for Working Life, 2000, pp. 4–9.

Holmer

Thermal manikin history and applications. Eur J Appl Physiol 2004, 92(6): 614–618.

Wyon

DP.

Use of thermal manikins in environmental ergonomics. Scand J Work Environ Health 1989; 15(Suppl. 1): 84–94.

Belding

HS.

Protection against dry cold. In: Newburgh

(ed.) Physiology of heat regulation and the science of clothing. Philadelphia, PA: Saunders, 1949, pp. 351–367.

Silva

Coelho

Convection coefficients for the human body parts—determined with a thermal mannequin. In: Proceedings of the 8th international conference on air distribution in rooms, Copenhagen, 8–11 September 2002, pp. 277–280. Lyngby: Technical University of Denmark.

Konarska

Sołtyński

Sudoł-Szopińska

et al . Aspects of standardisation in measuring thermal clothing insulation on a thermal manikin. Fibres Text East Eur 2006; 14: 58–63.

Konarska

Sołtyński

Sudoł-Szopińska

et al . Comparative evaluation of clothing thermal insulation measured on a thermal manikin and on volunteers. Fibres Text East Eur 2007; 15: 73–79.

Wheldon

AE.

Energy balance in the newborn baby: use of a manikin to estimate radiant and convective heat loss. Phys Med Biol 1982; 27(2): 285–296.

Elabbassi

Belghazi

Delanaud

et al . Dry heat loss in incubator: comparison of two premature newborn sized manikins. Eur J Appl Physiol 2004; 92(6): 679–682.

10.

Sarman

Bolin

Holmer

et al . Assessment of thermal conditions in neonatal care: use of a manikin of premature baby size. Am J Perinatol 1992; 9: 239–246.

11.

Ostrowski

Rojczyk

Łaszczyk

et al . Infant care bed natural convection heat transfer coefficient measurements and estimation. Prz Elektrotechniczn 2014; 90(5): 122–125.

12.

Ostrowski

Rojczyk

Natural convection heat transfer coefficient for newborn baby. Heat Mass Transfer 2018; 54(8): 2395–2403.

13.

Martínez

Psikuta

Rossi

et al . Global and local heat transfer analysis for bicycle helmets using thermal head manikins. Int J Ind Ergonom 2016; 53: 157–166.

14.

Brühwiler

PA.

Heated, perspiring manikin head form for the measurement of headgear ventilation. Meas Sci Technol 2003; 14: 217–227.

15.

Brühwiler

Ducas

Huber

et al . Bicycle helmet ventilation and comfort angle dependence. Eur J Appl Physiol 2004; 92: 698–701.

16.

Brühwiler

Buyan

Huber

et al . Heat transfer variations of bicycle helmets. J Sports Sci 2006; 24: 999–1011.

17.

Brühwiler

PA.

Radiant heat transfer of bicycle helmets and visors. J Sports Sci 2008; 26: 1025–1031.

18.

Sun

Fan

. Comparison of clothing thermal comfort properties measured on female and male sweating manikins. Textile Research Journal 2017; 87(18): 2214-2223.

19.

Martinez

Psikuta

Corberán

et al . Multi-sector thermo-physiological head simulator for headgear research. Int J Biometeorol 2017; 61(2): 273–285.

20.

Fonseca

GF.

Sectional dry heat transfer properties of clothing in wind. Text Res J 1975; 45: 30–34.

21.

McCullough

Jones

Tamura

A data base for determining the evaporative resistance of clothing. ASHRAE Trans 1989; 95: 316–328.

22.

Mecheels

Umbach

KH.

Thermo-physiological properties of clothing system. Melliand Textil Int 1977; 57: 1029–1032.

23.

Olesen

Sliwinska

Madsen

et al . Effect of body posture and activity on the insulation of clothing. ASHRAE Trans 1982; 88: 791–805.

24.

Hanada

Studies on the regional thermal resistance of clothing system: part I—on sportswear. J Jap Res Assoc Textile End-Uses 1979; 20: 273–304.

25.

YS.

Development of a sweating fabric manikin with sedentary and supine postures. PhD Thesis, The Hong Kong Polytechnic University, Hong Kong, 2010.

26.

Wang

Kuklane

Gao

et al . Development and validation of an empirical equation to predict wet fabric skin surface temperature of thermal manikins. J Fiber Bioeng Inform 2010; 3: 9–15.

27.

Fan

Chen

YS.

Measurement of clothing thermal insulation and moisture vapour resistance using a novel perspiring fabric thermal manikin. Meas Sci Technol 2002; 13: 1115–1123.

28.

Mattle

Use sweating articulated manikin SAM for thermophysiological assessment of complete garments. In: Proceedings of the third international meeting on thermal manikin testing (3IMM), Stockholm, 12–13 October 1999, pp.100–101. Stockholm: National Institute for Working Life.

29.

Meinander

Extraction of data from sweating manikin tests. In: Proceedings of the third international meeting on thermal manikin testing (3IMM) Arbete och Hälsa, Stockholm, 12–13 October 2000, pp. 95–99. Stockholm: National Institute for Working Life.

30.

Yasuhiko

Yoshio

Toshitada

et al . A model of sweating thermal manikin. J Tex Mach Soc Jpn 1992; 37: 101–112.

31.

Fukazawa

Lee

Matsuoka

et al . Heat and water vapour transfer of protective clothing systems in a cold environment, measured with a newly developed sweating thermal manikin. Eur J Appl Physiol 2004; 92: 645–648.

32.

Barker

Deaton

AS.

Evaluating the effects of material component and design feature on heat transfer in firefighter turnout clothing by a sweating manikin. Text Res J 2007; 77(2): 59–66.

33.

Wang

Measurements of clothing evaporative resistance using a sweating thermal manikin: an overview. Ind Health 2017; 55(6): 473–484.

34.

Nilsson

HO.

Thermal comfort evaluation with virtual manikin methods. Build Environ 2007; 42(12): 4000–4005.

35.

Goldman

RF.

Thermal manikins: their origins and role. In: Fan

(ed.) Thermal manikins and modelling. Hong Kong: The Hong Kong Polytechnic University, 2006, 6–15.

36.

Meinander

Evaluation of functional clothing systems with a sweating thermal manikin. In: Proceedings of the international symposium on textile and composite (VTT symposium 133), Tampere, 15–18 June 1992, pp. 289–295. Tampere: Technical Research Centre.

37.

Richards

MGM

Mattle

. Development of a sweating agile thermal manikin. In: Proceedings of the fourth international meeting on thermal manikin (4IMM EMPA), St. Gallen. 27–28 September 2001.

38.

Qian

Fan

The application and technology of walking fabric sweating thermal manikin. In: Proceedings of the 7th functional textiles and nanotechnology symposium, St. Gallen, Switzerland, 27–28 September, 2007.

39.

Fan

Chen

Zhang

. A perspiring fabric thermal manikin: its development and use. In: Richards

MGM

(ed.) Proceedings of the 4th international meeting on thermal manikin (5IMM). 2001, St. Gallen: EMPA.

40.

Hammarlund

Nilsson

Öberg

PÅ

et al . Transepidermal water loss in newborn infants I. Relation to ambient humidity and site of measurement and estimation of total transepidermal water loss. Acta Paediatr 1977; 66(5): 553–562.

41.

Belghazi

Tourneux

Elabbassi

et al . Effect of posture on the thermal efficiency of a plastic bag wrapping in neonate: assessment using a thermal “sweating” mannequin. Med Phys 2006; 33(3): 637–644.

42.

Museux

Cardot

Bach

et al . A reproducible means of assessing the metabolic heat status of preterm neonates. Med Phys 2008; 35(1): 89–100.

43.

Décima

Stéphan-Blanchard

Pelletier

et al . Assessment of radiant temperature in a closed incubator. Eur J Appl Physiol 2012; 112(8): 2957–2968.

44.

Ostrowski

Rojczyk

Łaszczyk

et al . Infant care bed natural convection heat transfer coefficient–measurements and estimation. Physiology 2014; 7: 8.

45.

Ostrowski

Rojczyk

Szczygieł

et al . Dry heat loses of newborn baby in infant care bed: use of a thermal manikin. J Phys Conf Ser 2016; 745(3): 032087.

46.

Kang

Tamura

Evaluation of clo values for infant’s clothing using an infant-sized sweating thermal manikin. Els Erg B S 2005; 3: 409–415.

47.

Tourula

Isola

Hassi

et al . Infants sleeping outdoors in a northern winter climate: skin temperature and duration of sleep. Acta Paediatr 2010; 99(9): 1411–1417.

48.

Tourula

Fukazawa

Isola

et al . Evaluation of the thermal insulation of clothing of infants sleeping outdoors in northern winter. Eur J Appl Physiol (2011); 111(4): 633–640.

49.

Satsumoto

Havenith

Evaluation of overall and local ventilation in diapers. Text Res J 2010; 80(17): 1859–1871.

50.

Guo

Hui

et al . Heat and mass transfer of adult incontinence briefs in computational simulations and objective measurements. Int J Heat Mass Tran 2013; 64: 133–144.

51.

Ozen İ Çinçik

Şimşek

. Thermal comfort properties of simulated multilayered diaper structures in dry and wet conditions. J Ind Text 2016; 46(1): 256–278.

52.

Mecheels

Thermophysiological properties of clothing systems. Melliand Textil 1976; 57: 1029–1032.

53.

Gao

Holmer

Fan

et al . The comparison of thermal properties of protective clothing using dry and sweating manikins. In: Proceedings of the 3rd European conference on protective clothing (ECPC) and (NOKOBETEF), vol. 8,Gdynia, 10–12 May 2006, pp. 1–6. Gdynia: Central Institute for Labour Protection.

54.

Farrington

Rugh

Bharathan

et al . Use of a thermal manikin to evaluate human thermoregulatory responses in transient, non-uniform, thermal environments. SAE technical paper no. 2004-01-2345. 2004.

55.

Rugh

Bharathan

Predicting human thermal comfort in automobiles. SAE technical paper no. 2005-01-2008. 2005.

56.

Rugh

Lustbader

Application of a sweating manikin controlled by a human physiological model and lessons learned. United States Department of Energy, (2006), https://www.nrel.gov/docs/fy07osti/40435.pdf

57.

Psikuta

Richards

Fiala

Single-sector thermophysiological human simulator. Physiol Meas 2008; 29(2): 181–192.

58.

Psikuta

Wang

Rossi

RM.

Prediction of the physiological response of humans wearing protective clothing using a thermophysiological human simulator. J Occup Environ Hyg 2013; 10(4): 222–232.

59.

Richards

Psikuta

Fiala

Current development of thermal sweating manikins at Empa. In: Fan

(ed.) Thermal manikin and modeling. 2006, pp. 173–179. Hong Kong: Hong Kong Polytechnic University.

60.

Fiala

Havenith

Bröde

et al . UTCI-Fiala multi-node model of human heat transfer and temperature regulation. Int J Biometeorol 2012; 56(3): 429–441.

61.

Fiala

Lomas

Stohrer

A computer model of human thermoregulation for a wide range of environmental conditions: the passive system. J Appl Physiol 1999; 87(5): 1957–1972.

62.

Fiala

Lomas

Stohrer

Computer prediction of human thermoregulatory and temperature responses to a wide range of environmental conditions. Int J Biometeorol 2001; 45(3): 143–159.

63.

Psikuta

Development of an “artificial human” for clothing research, 2009, https://www.dora.dmu.ac.uk/xmlui/handle/2086/2765

64.

Curran

Peck

Hepokoski

et al . Physiological model control of a sweating thermal manikin. In: Proceedings of the 10th manikin and modelling meeting, Tampere, 7–9 September 2014.

65.

Burke

Curran

Hepokoski

Integrating an active physiological and comfort model to the Newton sweating thermal manikin. In: Proceedings of the 13th international conference on environmental ergonomics, Boston, MA, 2–7 August 2009.

66.

Schellen

Loomans

MGLC

Kingma

BRM

De Wit

et al . The use of a thermophysiological model in the built environment to predict thermal sensation: coupling with the indoor environment and thermal sensation. Build Environ 2013; 59: 10–22.

67.

Turnow

Knochenhauer

Kewitz

et al . Coupling of human thermoregulation and URANS computation for investigation of local heat transfer and flow structures in a generic car cabin. Flow Turbul Combust 2016; 97(4): 1281–1296.

68.

Murakami

Kato

Zeng

Combined simulation of airflow, radiation and moisture transport for heat release from a human body. Build Environ 2000; 35(6): 489–500.

69.

Pichurov

Angelova

Simova

et al . CFD based study of thermal sensation of occupants using thermophysiological model: part I: mathematical model, implementation and simulation of the room air flow effect. Int J Cloth Sci Tech 2014; 26(6): 442–455.

70.

Cropper

Yang

Cook

et al . Coupling a model of human thermoregulation with computational fluid dynamics for predicting human-environment interaction. J Build Perform Simu 2010; 3(3): 233–243.

71.

Zhu

Kato

Ooka

et al . Development of a computational thermal manikin applicable in a non-uniform thermal environment—part 2: coupled simulation using Sakoi’s human thermal physiological model. HVAC&R Res 2008; 14(4): 545–564.

72.

Gao

Niu

Zhang

Coupling CFD and human body thermoregulation model for the assessment of personalized ventilation. HVAC&R Res 2006; 12(3): 497–518.

73.

Voelker

Alsaad

Simulating the human body’s microclimate using automatic coupling of CFD and an advanced thermoregulation model. Indoor Air 2018; 28(3): 415–425.

74.

Yang

Weng

Modelling heat transfer and physiological responses of unclothed human body in hot environment by coupling CFD simulation with thermal model. Int J Therm Sci 2017; 120: 437–445.

75.

Weng

Yuan

Combined effects of moisture and radiation on thermal performance of protective clothing: experiments by a sweating manikin exposed to low level radiation. Int J Cloth Sci Tech 2015; 27(6): 818–834.

76.

Havenith

Wang

den Hartog

et al . Interaction effects of radiation and convection measured by a thermal manikin wearing protective clothing with different radiant properties. In: Proceedings of the third international conference on human-environmental system (ICHES 05), Tokyo, Japan, 12 September 2005.

77.

Shi

Wang

Qian

Effect of non-uniform skin of “Walter” on the evaporative resistance and thermal insulation of clothing. Int J Cloth Sci Tech 2017; 29(5): 686–695.