superior glove winter webinar

Your Guide To Insulation and Winter Work Glove Selection

Bios

Bill Soellner, US Sales Manager Superior Glove Works Ltd.

• 24 years in the safety industry, having worked for four major manufacturers and a major safety specialty industrial distributor

• Bill has held positions in sales, sales management and product management with special emphasis on hand and arm protection.

• Bill has been published in leading trade publications such as ISHN, Cleanrooms Magazine and Compliance Magazine, writing articles on proper glove selection, clean environments products and chemical glove selection.

• He holds a BA from Western Michigan University.

Ken Cox, Lead Specialist Technical 3M Home Care Division

• Ken has worked at 3M (St. Paul, Minn.) for 40 years, of which he has spent 29 years in the non-woven insulation products related field.

• He holds a BS in Chemical Engineering from Purdue University and an MBA from the University of St. Thomas (St. Paul, Minn.).

• He is currently a member of both the American Apparel and Footwear Association and the American Association of Textile Chemists and Colorists.

History and Basic Understanding

©3M 2014. All right reserved.

History of “Warmth”

Ancient ways of keeping warm:• Bulky clothing• Wrappings around hands, arms, legs• Sleeping above / with livestock• Furs / Skins• Avoiding “out-in-the-open”• Caves (fairly constant underground temp)

The month of February in the Limburg Brothers' Très Riches Heures du Duc de Berry


Human Body “Warmth”• Human Metabolism acts as a “furnace” to generate needed heat.• Heat “flows” from higher temperature to lower temperature.• At temperatures higher than the body, excess heat

needs to be released• Sweating• Less Clothing• Lower the metabolism

• At cold environmental temperatures, heat needs to be retained

• Additional clothing• Higher metabolism• Increased Insulation


Human Body “Warmth” Mechanisms of Heat Loss

• Respiration & Perspiration• Convection

• Forced• Natural

• Conduction• Through confined air• Through, or along, a solid material (e.g., fiber, yarn, etc.)

• Radiation• Surface-to-environment• Surface-to-surface

Insulation helps control these losses.


What is Insulation?

• Anything that is a poor transmitter of heat (low thermal conductivity)

• Anything with a high thermal resistance •Anything that impedes the flow of thermal energy


What are the Risks to ChoosingInadequate Protection?


Cold Stress

Hypothermia• Normal body temperature

(98.6°F) drops to 95°F or less. • Mild Symptoms: alert but

shivering.• Moderate to Severe

Symptoms: shivering stops; confusion; slurred speech; heart rate/breathing slow; loss of consciousness; death.

Frostbite• Body tissues freeze, e.g., hands

and feet. Can occur at temperatures above freezing.

Symptoms: numbness, reddened skin develops gray/white patches, feels firm/hard, and may blister.

Trench Foot• Non-freezing injury to the foot,

caused by lengthy exposure to wet and cold environment.

• Symptoms: redness, swelling, numbness, and blisters.

Cold temperatures and increased wind speed (wind chill) cause heat to leave the body more quickly, putting workers at risk of cold stress.

Loss of Productivity• Slowed Productivity• Inaccurate & Incomplete Work• Lost time injuries from above conditions

Understanding Warmth Through CLO


Terminology

• “Clo Value” is a unit of thermal resistance used in describing the insulation of clothing ensembles

• Analogous to the thermal resistance unit of “R value” used in describing the insulation of houses and buildings

• 1.14 R value = 1.0 Clo value• Coined during Research leading up to

WW II on keeping soldiers warm (ref: Science Vol 94, No 2445, Nov 7, 1941)

• Metabolic Rates are measured in terms of the MET unit (see next slide)


Insulation Terms: Clo & MET values

• 1 Clo is the amount of thermal insulation required in clothing for a man to be comfortable in a:

• normally ventilated room at,• 70°F (21°C) and• <50% Humidity in a,• sitting/resting position

• The metabolic rate associated with this activity has been defined as 1 MET

• 1 MET = 58.15 W/m²• 1 MET = 50 Kcal/hr/m²


Clo & MET values

General Relationships:• The colder the environment, a greater amount

of “Clo” or clothing insulation will be required for comfort at the same level of activity (or MET)

• The higher the metabolic rate (MET) of a person, a lesser amount of “Clo” or clothing insulation will be required for thermal comfort at the same level of environmental temperature


Normal Clo Values

NUDE PERSONClo = 0.0

BUSINESS SUITClo = 1.0


General Rules of Insulation

• Insulation is approximately additive (but not exactly – Thermal Manikin testing would be necessary to be more exact)

• Humans are unique individuals, therefore, differences in insulation needs will occur for:

• Gender• Age• General / basal metabolic rate• Activity level / specific metabolic rate• Environmental conditions

•temperature•wind velocity•humidity•radiant exchange with surroundings

• Duration of exposure


Clo – How Much Do You Need? EXAMPLE:• Workers are doing Light Work (e.g. Ice

Fishing, Driving Tractor, Walking 2 mph)• Need to work at -10°F • With 2 Clo worth of clothing, they’ll be

comfortable for about 1 hr, 15 min • With an additional 0.5 Clo (2.5 Clo), they’ll

be comfortable for about 2 hrs, 45 min

• More than doubling their “allowable” time outside

• Potentially increasing productivity• Thinsulate™ Insulation can often provide

at least 0.5 more clo than current work-wear insulations

DLEneutral vs Ambient Temperature@ Activity Level: Light Work [2 MET = 116.4 W/m² °K]

-50

-40

-30

-20

-10

0

10

20

30

40

50

0 1 2 3 4 5 6 7 8 9Duration Limit Exposure, DLEneutral, Hrs.

Am

bien

t Tem

pera

ture

, °F

1. Clo

1.5 Clo

2. Clo

2.5 Clo

3. Clo

Clo Value is that of garment alone, but Duration lines assume 0.7 Clo for ancillary clothing

Light Work

The same example of clothing ensembles, but at 0°exposure rather than at -10 exposure, would more than Quadruple their time outside, going from 2 hours to much more than 8 hours!


Warm Fabrics & Layers of Warmth/Insulation

How material choices help achieve warmth in a Winter Work Glove

A well designed glove has 3 layers: the outer-layer of the glove, the middle insulating layer, and the inner, next to hand layer.

Outer layer: Should be of a material or combination of materials with high abrasion resistance, water and wind repellence, cut resistance, good grip, etc. In the correct proportion to what work you are going to be doing.

Middle layer: An insulating layer. Something with high loft, that traps a lot of air, for warmth.

Inner layer: A next to skin layer, that ideally is moisture wicking and soft against the skin.

3M™ Thinsulate™ Insulation


How does 3M™ Thinsulate Insulation function?

Fibrous Structure Traps Air • Low Thermal Conductivity gas• Air is a good insulator = impedes conductive

heat loss• The thicker (bulkier) an insulation, the

more air entrained (many insulations ONLY depend on this mechanism)

• 3M™ Thinsulate™ Insulation for hand wear is between 97% and 99.5% air



Fibrous Structure Helps Block Radiant Heat Loss • A major heat loss mechanism; Fibers impede radiant heat loss• The smaller the fiber diameters used, the more fibers per

insulation weight and the more “opaque” an insulation• 3M™ Thinsulate™ Insulation for apparel employs microfibers

(< 10µm) and/or fine fibers(< 15µm) coupled with larger fibers

• Analogous to radiation from fireplace – where the chain-mail screen blocks a large amount of the radiation

• Like fibers block radiation heat loss from the body



How does 3M™ Thinsulate Insulation function?Thermal energy is blocked by microfibers or fine fibers • A major heat loss mechanism; Fibers impede radiant heat loss

Can you read the text under the insulation?

70 g/m² - TYPE CS



Thermal energy is blocked by microfibers or fine fibers • A major heat loss mechanism; Fibers impede radiant heat loss

Can you read the text under the insulation?

70 g/m² - TYPE CS 70 g/m² - GENERIC FIBERFIL

What To Look For/What To AvoidWhen Selecting Winter Gloves

What To Look For & Avoid

If you are looking for a good winter work glove, consider the following:• Fully Sock Lined• CLO knowledge and understanding values • High Loft Insulation – like 3M™ Thinsulate ™• Palm coating and/or liner if some water is a threat• Full coating if immersed in water• Good Fit – tight gloves reduce circulation and make your hands colder• NO cotton linings• NO compression palm if handling cold material• Appropriate cuffs - be sure the cuff fits over your jacket or parka sleeve• Wind protection

Advertised winter glove. Cotton napped fabric lining @ 240 gsm.

In most cases, the lining will not cover the sides of the fingers. Remember you lose most of the heat in your hands through the fingers, and only insulating the front and back, but not the sides, is a recipe for cold hands.

This picture shows a very well designed and constructed glove with a high CLO value ( 1.19 ). The glove shows up as almost all purples and blues, with NO reds and very little yellow. So no thick spots in the lining, and the glove is well sewn and constructed.

A very good manufacturer of winter gloves will use Thermal imaging to show the weak spots of their glove construction, and work to improve them.

This glove from a different manufacturer shows a similar style glove, but with some manufacturing issues. Note the parts of the glove with heat loss ( the red and yellow areas ). There is a major problem on the thumb. The red portion on the back of the thumb suggests a very thin spot on the lining.

Battle of Warmth vs. Dexterity

Offers great warmth butlittle dexterity.

Better dexterity but still not great for warmth.

Thicker, more layers = less dexterity

More warmth and better dexterity.

Great dexterity and impact protection but not great for warmth.

Waterproof, windproof and dexterous but not great for warmth.

Great dexterity, grip and cut-resistance but not great for warmth.

More dexterity = less insulation

Measuring Warmth Fabric weight or density is one indicator of how warm the material is going to be. This is measured in ounces per square yard or grams per square meter. Shortened to oz/sq yd and gsm.

Convert from oz per sq yard to the metric gsm. Just multiply by 33.9.

So if you wanted to figure out the total lining weight of a glove that was quoted as having a 6 oz napped polyester lining with a 100 gram Thinsulate lining, the total lining weight would be -

(6 x 33.9) + 100 grams = 303.4 gsm

What is going to be warmer, a glove with a 6 oz fleece cotton lining or a 180 gsm lining?

Answer: the 6 oz is 203 gsm so it will be warmer.

Questions?