When the weather gets cold, add more CLO's


When working in cold environments, it can be difficult to accurately estimate how much warmth and insulation are needed based on just the temperature alone.

A big question we get is: "How do I compare insulation when there are different brands and levels?"

There’s a lot of information out there, so understanding the science behind CLOs can help you navigate Thinsulate™ and other cold-weather protection liners.

What is the CLO rating system?

The CLO system is used to measure the warmth levels of various materials. It’s determined based on the insulation levels needed to keep a person at a comfortable level while standing in a 70-degree room at 50 percent humidity.

The base is 0, which represents a completely unclothed person.

Example CLO ratings of garments:

  • Men’s briefs = .04 CLO
  • Sweatpants = .28 CLO
  • Thick sweater = .35 CLO
  • Winter coat = .70 CLO

Now, compare those to some of the most common thermal liners used in cold weather hand protection, like Thinsulate™ brand insulation, created by 3M.

Thinsulate™ liner CLO ratings:

  • C40 Thinsulate™ = 0.7 CLO
  • C100 Thinsulate™ = 1.3 CLO

The truth about "SUBZERO" gloves

When looking for cold weather PPE, beware of gloves and other products that give temperature or CLO ratings as "guarantees". Many factors play into body temperature, and one single solution can't guarantee the same results for every worker.

There are too many variables that impact whether or not a particular person is comfortable at a given temperature to guarantee performance.

These variables include:

  • Gender
  • Humidity
  • General metabolism
  • Wind speed
  • Specific activity level
  • Duration of exposure
  • Altitude
  • Body mass index

The list goes on. Every person is different, and some people will need more insulation than others for the same level of exposure.

Bottom line:

Field test gloves, use your best judgment and train your employees to understand the risks of working out in the cold. Don’t rely on manufacturers’ claims without validating them yourself.

HexArmor® can help

Have questions about what cold weather PPE may be right for you? Understanding the PPE you need for your workplace environment is imperative to any cold weather or cold stress safety program.

Download our cold weather work glove solutions and see what product may be the best for you and your application, or learn more about our cold-weather technology.

Let us know if you need help or if you're ready to start a trial - our Solution Specialists are ready to work with you. Call 1-877-MY ARMOR or send us a message.

Browse all HexArmor® cold weather hand protection

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