Simms ColdWeather long sleeve shirt now a all time favorite for fall and spring fly fishers. The ColdWeather shirt features wicking UPF50 protection, two large fly box compatible chest pockets with a hook loop design, off shoulder seaming for both comfort and articulation. The Simms cold weather shirt comes as a traditional slim fit with a slight drop tail. Also a great piece to wear off river into town or even working in the yard.
FABRIC TECH: 100% polyester flannel shell; 100% polyester
FEATURES & BENEFITS:
• Wicking & UPF50
• Two fly box compatible chest pockets with hook-&-loop closure
• Off-shoulder seaming for comfort & articulation
• Slight drop tail
APPROX. WEIGHT: 18 oz.
STYLE FIT: Traditional Fit
* These are body measurements
About ColdWeather Insulation
There are three kinds of heat transfer: conduction (exchange of heat through contact), convection (movement of air), and radiation.
Air has a low thermal conductivity but is very mobile. There are thus two elements that are important in protecting from the cold:
Another important factor in ColdWeather insulation is humidity. Water is a good conductor of heat, thus if clothes are damp — because of sweat, rain, or immersion — water replaces some or all of the air between the fibres of the clothing, causing heat loss through conduction and/or evaporation.
Thermal ColdWeather insulation is thus optimal with three layers of clothing:
The three layers of air between the skin and the exterior layer also play an insulating role. If the clothing is squeezed tight (as by the straps of a backpack), insulation will be poorer in those places.
Clothing coldweather insulation may be expressed in clo units. The clo has the same units as the R value used to describe insulation used in residential and commercial construction. The clo value is also similar in magnitude to the R value.
This is the amount of insulation that allows a person at rest to maintain thermal equilibrium in an environment at 21°C (70°F) in a normally ventilated room (0.1 m/s air movement). Above this temperature the person so dressed will sweat, whereas below this temperature the person will feel cold.
There are a number of ways to determine clothing coldweather insulation provided by clothes, but the most accurate according to ASHRAE Fundamentals are measurements on heated manikins and on active subjects. Equations may then be used to calculate the thermal insulation. Because clothing insulation cannot be measured for most routine engineering applications, tables of measured values for various clothing ensembles can be used. According to ASHRAE-55 2010 standard, there are three methods for estimating clothing insulation using the tables provided.
Another coldweather unit which is used is the "tog":
The word "togs" is a British slang term for clothes.