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Cubic feet per minute per square meter (CFM) is a measure of the wind resistance or air permeability of a fabric. The higher the CFM, the greater the volume of air passing through. When hard shells dominated the landscape, discussions about CFM didn't come up. Traditional barriers like H2NO, Gore, Triple Point, Entrant, and other respectable waterproof breathable technologies all have a 0 CFM rating. They are absolutely windproof. With the advent of soft shells and more breathable fabrics, the air permeability argument becomes complicated, sometimes heated. Traditional layering has always taught the "vapor barrier warmth" concept. That is, maintain a (windproof) stable dead air space next to skin and you will stay warmer. That's true, if you're watching football game from the stands in November. But what happens when you're pounding uphill to the ridge before someone else sneaks into that untracked line of new powder? You can use a bit of convective heat loss; and you need more breathability to move the extra moisture you create through exertion. And a fabric with 0 CFM doesn't provide it. We've found that fabrics that measure as much as 5 CFM are still functionally windproof: that is, you don't feel the breeze come through. And they afford much greater comfort on the uphill. So we use 1-5 CFM as our standard for weather-protective soft shells (Mixmaster, Dimension, Dragonfly, etc.) Shells for higher exertion activities (e.g. Slingshot, Super Guide Pants, Talus Pants) must be even more breathable. For these products we hold to a comfortably wind-resistant, but not windproof, standard of 10-15 CFM. Beyond this, we don't go. We don't produce shell fabrics with a higher CFM (say, 15-20) because our field test shows that further gains in breathability don't offset the heat loss from wind penetration. (See Schoeller Dryskin on the chart on the next page- offering high breathability, but not enough wind protection) The goal is: both warm and dry. At the other end of the scale, as mentioned, we don't make 0 CFM soft shells. What's the point of a soft shell that doesn't breathe better than a hard shell?

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What does the CFM number on a ventilation fan mean?

CFM stands for cubic feet per minute, which is a measurement of the amount of air that the fan can move within one minute. It indicates the fan's airflow capacity, with a higher CFM number indicating a more powerful fan that can move more air. It is important to consider the CFM rating when choosing a ventilation fan to ensure it can adequately ventilate the space.


What are cfm?

CFM stands for cubic feet per minute, which is a unit of measurement used to quantify the volume of air that a fan or blower can move in a minute. It is commonly used in ventilation, air conditioning, and heating systems to describe the flow rate of air. A higher CFM rating indicates that the device can move a greater volume of air in a given time period.


How do you get cfm with a manometer?

To calculate CFM (cubic feet per minute) using a manometer, measure the pressure difference across a restriction in the airflow system. Use the manometer reading and the area of the restriction to determine the velocity pressure. Then, use the velocity pressure to calculate the airflow in CFM using the formula CFM = (Velocity Pressure * Area of the Restriction) / 4005.


What is more air flow 864 cfm or 864 cmh?

864 cfm (cubic feet per minute) represents air flow in terms of volume of air measured in cubic feet, whereas 864 cmh (cubic meters per hour) is air flow measured in cubic meters over an hour. The conversion factor from cfm to cmh is approximately 1 cfm = 1.7 cmh, so 864 cfm would have more air flow than 864 cmh due to the difference in volume units.


How to calculate cfm?

To calculate CFM (cubic feet per minute), you need to know the volume of the space in cubic feet and how many times you want to replace the air within one minute (air changes per hour rate). Multiply the volume of the space by the air changes per hour rate and divide by 60 to get the CFM required for that space. CFM = (Volume in cubic feet * Air changes per hour) / 60.

Related Questions

What is the recommended CFM rating for a range hood?

The recommended CFM rating for a range hood is typically between 150 to 300 CFM for every linear foot of the stove.


What is the recommended CFM rating for a range hood in a standard kitchen?

The recommended CFM rating for a range hood in a standard kitchen is around 300-400 CFM (cubic feet per minute).


What is the required CFM rating for a range hood?

The required CFM rating for a range hood typically ranges from 150 to 900 CFM, depending on the size and type of the stove. It is important to choose a range hood with a CFM rating that is appropriate for the size of your stove and kitchen space to effectively remove smoke, odors, and grease.


What cfm rating carburetor should I get for my 305 1984 Chevy?

600 cfm will be enough for that engine.


What is the recommended CFM rating for a bathroom fan?

The recommended CFM rating for a bathroom fan is typically between 50 to 100 CFM (cubic feet per minute) to effectively remove moisture and odors from the bathroom.


What is the recommended CFM rating for a bathroom fan to effectively remove moisture and odors?

The recommended CFM rating for a bathroom fan to effectively remove moisture and odors is around 50-100 CFM (cubic feet per minute).


What is the recommended CFM rating for a range hood based on the size and layout of my kitchen?

The recommended CFM rating for a range hood depends on the size and layout of your kitchen. As a general guideline, aim for a minimum of 100 CFM per linear foot of your range. For example, if your range is 30 inches wide, you would want a range hood with at least 250 CFM. However, for larger kitchens or kitchens with high ceilings, you may need a higher CFM rating. It's best to consult with a professional to determine the most suitable CFM rating for your specific kitchen.


What is the recommended CFM rating for a bathroom exhaust fan to effectively remove moisture and odors?

The recommended CFM rating for a bathroom exhaust fan to effectively remove moisture and odors is between 50 and 100 CFM (cubic feet per minute).


What is the recommended CFM (cubic feet per minute) rating for a bathroom fan to effectively remove moisture and odors?

The recommended CFM rating for a bathroom fan to effectively remove moisture and odors is around 50-100 CFM (cubic feet per minute).


What is the recommended CFM (cubic feet per minute) rating for a bathroom exhaust fan to effectively remove moisture and odors?

The recommended CFM rating for a bathroom exhaust fan to effectively remove moisture and odors is typically between 50 to 100 CFM (cubic feet per minute).


What is the CFM rating of a bathroom fan?

The CFM rating of a bathroom fan refers to the cubic feet of air that the fan can move per minute. It is a measure of the fan's airflow capacity and indicates how effectively it can remove moisture and odors from the bathroom.


What is the significance of CFM in bathroom fans and how does it impact their performance?

CFM, or cubic feet per minute, is a measure of the amount of air a bathroom fan can move in one minute. The higher the CFM rating, the more effective the fan is at removing moisture and odors from the bathroom. A higher CFM rating means the fan can quickly and efficiently ventilate the space, reducing the risk of mold and mildew growth and improving air quality. Therefore, CFM is a key factor in determining the performance of a bathroom fan.