Hi Vis Thermal Jackets & Clothing

Understanding 3M Thinsulate and Quilted Insulation Technology

3M Thinsulate is a microfibre technology approximately 30% thinner in profile compared to standard polyester fill. The ultra-fine fibres (finer than human hair) create more air pockets per square inch, trapping warm air molecules and preventing cold air penetration. This thinner profile means thermal hi vis jackets don't restrict movement the way bulky padded coats do. Thinsulate comes in different weights: 80gsm suits mild cold for moderately active work, 100-150gsm provides serious insulation for general winter outdoor work, and 200gsm+ delivers extreme cold protection for arctic conditions or static outdoor roles where you're not generating much body heat through movement.

Quilted thermal jackets use polyester wadding stitched between fabric layers in diamond or square patterns. The quilting stitches prevent insulation shifting and clumping during wear and washing, maintaining even heat distribution. Whilst quilted insulation is bulkier than Thinsulate, it's economical and still provides excellent warmth for temperatures above -15°C. Some hi vis thermal coats feature removable quilted liners that zip out, creating a 3-in-1 system: wear the shell alone in autumn, add the liner for winter, or wear the liner independently as an insulated gilet.

EN342:2017 Certification and CLO Ratings Explained

Products in this collection include EN342:2017 certified options for protection against cold environments ≤-5°C; check individual listings for exact certification. The standard measures three parameters: Icler (thermal insulation in m².K/W—higher values mean better insulation, with typical ranges from 0.200 to 0.500+), air permeability (breathability rated Class 1 highest to Class 3 lowest), and optional water resistance. Testing uses a moving manikin calibrated per EN ISO 15831:2004. EN342 garments must be worn with thermal base layers to achieve stated temperature ratings.

CLO ratings measure thermal resistance—one CLO equals the insulation needed to keep a resting person comfortable at 21°C. Higher CLO values provide more warmth. Typical thermal hi vis jackets rate 1.5-2.5 CLO depending on insulation weight and whether worn with base layers. Combined with your activity level, this determines how long you can safely work at specific temperatures.

Care, Maintenance and When to Replace

Wash thermal garments at 30°C maximum using gentle cycle—hot water damages synthetic insulation fibres. Tumble dry on low heat to restore loft (the fluffiness that creates air pockets); air drying can leave insulation compressed. Store hanging rather than compressed in bags, as permanent compression reduces insulation effectiveness. Replace after 150-200 washes or when insulation feels permanently flat and no longer lofts after drying, reflective tape shows significant wear, or you notice cold spots indicating insulation has shifted away from certain areas.

Thermal vs Fleece: What's the Difference?

Fleece is the actual fabric material (brushed polyester creating warmth through air pockets in the fabric structure itself), whilst thermal refers to insulation type (synthetic fill sandwiched between outer shell fabric and inner lining). You can have a hi vis thermal jacket with fleece lining (combining both technologies) or a fleece-outer thermal hoodie, but they're different warming mechanisms. Thermal insulation works even when compressed (like under tool belts or when sitting), whereas fleece loses warming ability when compressed flat. Standard fleece jackets work for mild cold but lose effectiveness below freezing when wind chill intensifies.

• Winter highways maintenance and gritting operations in freezing conditions
• Utilities engineers working outdoors reading meters and inspecting infrastructure
• Building site operations continuing through cold weather
• Railway trackwork and infrastructure maintenance during winter
• Cold storage and freezer warehouse operations at sub-zero temperatures
• Winter landscaping and grounds maintenance
• Outdoor security patrols through overnight cold
• Emergency response and breakdown services operating in all conditions