The Triad of Comfort

A garment can often feel comfortable if it feels soft or warm but the test comes when you face physically exerting yourself or experiencing a change in weather conditions. 

If the insulation is poor, this can result in either feeling too hot, feeling too cold or sweating without moisture escaping, which results in a garment becoming very uncomfortable. Thus, with a vision to create the experience of true outdoor comfort, Clo® Insulation, along with industry experts, researched and developed the optimum breathable insulation to drive your comfort up to an altogether new level.

You’ll absolutely love the top-level performance of our breathable insulation achieved through intensive research and development of the triad of comfort. With any type of clothing for either use in sports activities, country lifestyle or for a fashion item, the key to ultimate comfort is to bring together the attributes below:

To maintain your body temperature in cool and extremely cold conditions.

To allow for moisture to disperse away from body heat maintaining a constant body temperature without sweating. All the above exist separately in many materials, but, the real secret to ultimate comfort is the combination of all 3 to maintain that delicate balance between breathability and warmth.

To give your garments great feel and comfort.

The science of breathability

Breathability is a measure of how quickly moisture vapour generated from your body can pass through a fabric from the inside of your waterproof jacket to the outside environment.

Breathability can be measured in several different ways, most commonly by using a Moisture Vapour Transmission Rate (MVTR) which is a measure of the speed in g/m²/day at which moisture passes through a fabric or other substance, i.e. the mass of moisture that passes through a square metre of fabric in 24 hours. Using this method:

Fabric breathability can slow down for the following reasons…

Moisture may not move through the fabric fast enough.

If this occurs, the wearer will get wet from the inside the garment via trapped perspiration. In dry environments, most “breathable” fabrics work well. In semi-humid environments, waterproof-breathable fabrics struggle. In very humid environments, nothing will keep anyone dry.

The “outside” humidity is too high.

If the outside air is nearly saturated with water vapor already, there is simply no capacity for it to absorb additional vapor generated by activity. Thus perspiration, being unable to evaporate, remains next to the skin.

Importance of breathable insulations

As humidity is almost always a higher percentage on the inside of a jacket than the outside, it is very important for the insulation to be truly breathable as this is in a lot of cases the barrier to moisture escaping. This means for moisture to escape freely away from the body heat, it needs to travel right through the insulation to keep the wearer drier during exertion rather than get trapped inside the garment resulting in moisture build‑up and clothing becoming wet.

If you get wet, you will get cold and uncomfortable very easily. Breathable fabrics let water vapour through, meaning perspiration can escape. Having breathable clothing can hugely increase comfort, as no‑one wants to have a damp layer next to their skin all day. It is important with a breathable jacket that all the layers are breathable so the jacket will work effectively.

The Clo® Vivo insulation innovation

How can something so simple make such a vast difference? Concept Vivo was a light bulb moment when our Clo® Insulation development team came across a unique innovation that will change the insulation world.

Vivo insulation comprises of a series of small apertures set within the insulation to enhance the breathability without decreasing the thermal performance.  The holes are a unique size which are visible enough to notice a difference but too small to allow air to circulate thus trapping the air to maintain the insulation properties.  A number of tests carried out have demonstrated that the Vivo concept increases the breathability of the insulation by up to 30% which brings about a massive uplift in comfort when in use between breathable fabrics of a jacket or garment.

The small series of holes allow the free flow of moisture to escape through the insulation and away from the body heat, this not only increases the breathability but speeds the process up so the insulation is no longer the barrier to moisture escaping. The small holes also allow for a 4 way stretch within the insulation with a fast recovery action which allows the insulation to be combined with performance fabrics of your choice.

Vivo breathes life into your insulation to further promote the triad of comfort.

Clo® Insulation fibres

Clo‑i fibres

Clo‑i fibres have a unique shape which effectively combines all the properties of current insulation fibres and creates a unique all-in-one solution for a superior clothing insulation material.

Hollow fibres

Hollow fibres have a channel down the centre of the fibre to trap extra air for a more efficient insulation.

Solid fibres

Solid fibres are the most basic of synthetic fibres made for strength and anti-migration and used for general commercial applications.

Micro fibres

Micro fibres are synthetic fibres finer than one denier or decitex/thread.  The shape, size, and combinations of synthetic fibres are selected for specific characteristics, including softness, toughness, absorption, water repellence, electrostatics, and filtering capabilities.

Laboratory testing and certification

In order to ascertain that our products perform and to certify them to the relevant European standards we test them in various different ways in both physical garment tests and controlled tests in laboratory environments.
Some of these are detailed below.

Different test methods to test breathability

There is no industry standard for testing breathability, therefore at Clo® Insulation we have tested our breathable insulations across a variety of tests.

BS7209 / ASTM E 96 (upright cup method)

Tests are conducted in a wind tunnel which is housed in an environmental chamber. The air temperature in the chamber is 23±0.5˚C, and the dew point temperature is 12±1˚C (50% relative humidity). The air velocity in the wind tunnel is 2.8±0.25 m/s. Six circular specimens of 7.4 cm diameter are cut from the fabric. Each specimen is placed on a 155 ml aluminium cup that is filled with 100 ml of distilled water, covered with a gasket, and then clamped into position. Coated or laminated fabrics are placed with the coated or laminated side facing the water in the cup. Each cup is first weighed to the nearest 0.001g and then placed inside the wind tunnel. Subsequent weighings are made at 3, 6, 9, 13, 23, 26, and 30 hours after placement in the chamber. The water vapor transmission rate (WVTR) is calculated using the following formula, where = weight change (g), t = time during which G occurred, G/t = slope of the straight line for weight loss per unit time (g/h), and A = test area (m²).

WVTR   =G/t

Evaporative resistance
(ISO 11092, ISO 1999, and ASTM F 1868)

This test measures the amount of power it takes to keep the plate heated to skin temperature when water vapor is evaporating from the surface of the plate and diffusing through the fabric to the environment. 

Three 50.8 cm x 50.8 cm square specimens are cut from fabric. A PTFE liquid barrier is placed on the plate to prevent water from contacting the fabric, ensuring that only water vapor contacts the fabric sample. Each test specimen is placed on the horizontal and flat plate orientated with the side of fabric normally encountering more water vapor facing the hot plate. 

The plate temperature and the air temperature are controlled at 35 ± 0.5°C by a main heater and a set of guard and bucking heaters that eliminate both lateral and axial flow from the main heater. A dew point temperature of 19°C is used to achieve 40% relative humidity. A vertical flow of air from a hood is maintained at 1.0 m/s. 

Figure 2. Sweating Hot Plate  

When the system reaches steady state, the test setup stays at equilibrium for 1 hour. The basic equation for calculating the total resistance to evaporative heat transfer provided by the liquid barrier, fabric, and air film is:

R e,t  =(Ps – P· A

where Re,t = total resistance to evaporative heat transfer provided by the fabric system and air (m²Pa/W), A = area of test specimen (m²), Ps = water vapor pressure at the plate surface (Pa), Pa = water vapor pressure in the air (Pa), and H = power input.

EN 15496:2004 or JIS L 1099
(desiccant inverted cup method)

A solution of potassium acetate is used to fill two-thirds of a cup. The solution acts as a desiccant and generates 23% humidity on one side of the fabric. Once the potassium acetate solution is added, PTFE film is placed over the cup and fixed into place. 

Three 20 cm x 20 cm square specimens are then cut from the fabric. Each specimen is placed on the test piece supporting frame. Coated or laminated shell fabric are placed such that the coated or laminated side faces away from the desiccant. Another piece of the PTFE film is placed on top of the fabric specimen and secured to the frame. The test piece frame assembly is placed in a floating position in a water tank of temperature 23˚C. 

Figure 1. Desiccant inverted cup assembly (fabric is between water and desiccant)

The mass of the test body with the film side upwards is measured. Then, the test body is im-mediately overturned and placed in the supporting frame. The entire assembly is placed in a constant temperature apparatus that circulates air at 30±2°C. After 15 minutes, the test body is taken out of the constant temperature apparatus and weighed. 

The WVTR is calculated using the following formula.

P   =4(a₁ – a₀)

where a₁ = mass of the test body after the test (g), a₀ = mass of the test body before the test (g), P = rate of water vapor transmission (g/h/m²), and S = water vapor permeable area (m²). The results are averaged from three specimens and converted to g/24h/m².

Bespoke laboratory testing

To give your garments edge in development, Clo® Insulation can also offer bespoke testing comparisons of your product to ensure we can take your garments to the next level. 

Highly Breathable Insulation
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