Maximum Ceiling Fan RPMs
Published by: Greg Tillotson
Webmaster for Hansen Wholesale
Ever wonder why ceiling fans only go so fast? Ever think that if manufacturers just made ceiling fans spin faster, they would move more air? Well, maybe you don't think of these kinds of things, but as the webmaster for the Largest Ceiling Fan Website online, I can't help but have such thoughts.
The fact is: There are UL standards that place limitations on ceiling fan manufacturers that prevent them making fans that spin too fast. These limitations for safety purposes and are meant to minimize the risk of injury should a person raise their hands (or any other object) into the path of the ceiling fan blades while the fan is in operation. Imagine if some ceiling fan blades moved as fast as an airplane propeller and had blades like a machete! Well, UL standards prevent manufacturers from making such products...but they also present challenges to engineers who attempt design ceiling fans for maximum airflow and efficiency.
Maximum RPMS Allowed for Ceiling Fans
The first basic limitation is that no residential ceiling fans are allowed to be installed such that the blades are less than 7 feet from the floor. The second basic limitation has to do with the RPMs at which a fan can spin relative to the thickness of the blades. The concept is that thinner blades can cause more damage of laceration, so they are not allowed to spin as fast as those with thicker blades.
The RPMs allowed for any residential ceiling fan that can be installed on a ceiling less than 10 feet high are restricted by UL based on the blade span and thickness of the blades (see chart below). Any blade less than 3/16" thick cannot exceed the RPMs for 1/8" thick blades. Any blades 3/16" thick or greater cannot exceed the RPMs for 3/16" thick blades. In no case can the fan blades be less than 1/8" thick. No ceiling fan is allowed to be installed with the blades closer than 7 feet from the floor. These limitations are in place to minimize the risk of injury should a person raise their hands (or any other object) into the path of the fan blades while the fan is in operation.
How do RPMs affect airflow?
The amount of air that a ceiling fan produces is certainly affected by how fast is spins. Yet RPMs alone do not produce airflow. The aerodynamics of the blades is every bit as important as the RPMs. If a fan has blades that are straight and flat, it doesn't matter how fast it spins, it's not going to generate much airflow. Take the same blades and give them a 15 degree pitch and the fan will move air, but the RPMs will be slower since the angled blades are now having to perform some work, which puts drag on the motor. You can equate this to the difficulty of rowing a boat when you place the oars flat in the water compared to turning them at an angle. Flat is easy to row, but will not get you anywhere. Angling the blades just a few degrees makes it more difficult to row the boat, but you actually start moving. So imagine the difference in airflow between 2 fans that operate at the same RPM yet one has flat blades and the other has angled blades. The fan with angled blades must have a more powerful motor in order to maintain the same RPM as the fan with flat blades. So judging the airflow performance of a fan strictly by comparing RPMs is of little value. What you really need to know is how much airflow the fan will produce when operating at a particular RPM.
Maximum RPMS Reference Chart
The data below is based on ceiling fans that have a reverse function. Non-reversing ceiling fans are allowed to have slightly higher RPMs. UL actually states the limitations based on the maximum allowed speed of the tip of the fan blade at 3200 feet/minute for 3/16" thick blades and 2400 feet/minute for 1/8" thick blades. We have provided the following data by creating a formula that does this calculation based on the overall bladespan of any particular ceiling fan ranging from 24" to 84".
Based on UL 507 Standards (link to PDF removed by request of UL - 5/30/2013)
Ceiling Fan Maximum RPM Calculator
Enter the overall blade span of any fan and click calculate to determine the maximum RPM that any size fan can operate.
Details: Federal regulations limit the maximum RPM at which a ceiling fan safely operate in order to prevent potential bodily harm. The limitations are based on the above 2 blade thicknesses. Blades that are 1/8" thick and less than 3/8" thick must run slower than blades that are 3/8" thick or more. No residential ceiling fans are allowed to have blades less than 1/8" thick. Any ceiling fan that does not meet the maximum RPM requirement cannot be installed less than 10 feet from the floor, or must be enclosed in a cage.
Ceiling Fan Maximum RPM Table
|Span||3/16" Thick||1/8" Thick
Ceiling Fan Articles:
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Answers to Recent Ceiling Fans Questions Posted To This Page
- Question #9510 - Posted: 12/29/2016 6:01:26 PM
Ceiling Fans Question - Casablanca Model CA-59060
CA-59060 - http://www.hansenwholesale.com/ceilingfans/casablanca/model.asp?ProdNo=CA-59060
QUESTION: Casablanca Whitman Ceiling Fan Model 59060
Will this fan work with both the wall control and the remote? I do not want to find the remote when just walking out of the bedroom and prefer the wall switch, but would like the ability to use the remote feature while in bed. Do both control the dimmers? Do the dimmers work with the new LED dimmable bulbs?
ANSWER: The Casablanca Whitman fan comes with a wall control. Both the wall control and optional remote control can be used along with each other, so the answer is yes, you can use the remote from your bed and the wall control when you enter or exit the room. Both controls have full function of the fan including the fan speeds, reverse and, yes, dimming for the lights. The fan comes with two 50 watt halogen bulbs. There are currently no LED bulbs that you can buy to replace the halogen bulbs that will provide any more light than a couple of night lights, so it is not practical to use LED lights in this fan. Even if you did, the dimmer function would most likely not work since the wattage of the LED bulbs would be too low for the range of the dimmer. So, unfortunately I would have to say no to your last question.
- Question #9509 - Posted: 10/1/2015 4:43:21 PM
Ceiling Fans Question - Emerson Model CF788VNB-72
CF788VNB-72 - http://www.hansenwholesale.com/ceilingfans/emerson/model.asp?ProdNo=CF788VNB-72
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ANSWER: When you click on the orange button for blades, look for blades that say "(Outdoor Damp)". Emerson specially makes the damp rated blades from solid hardwood (instead of cheap plywood) that is treated to resist cracking and warping from being outside. They will hold up much better than what you have experienced and are in fact rated for use in outdoor damp locations by the manufacturer.
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Ceiling Fans Question
QUESTION: I just bought a house with a Halsey ceiling fan and I want to add a light to it. The universal light kit only works sometimes! Where can I find Halsey light kits to fit models HC-HP and HG models?
ANSWER: I am sorry to report that Halsey went out of business several years ago, so finding parts for them is difficult. It is not a brand that we ever sold, so we would not have any fixtures on hand that were made by them. If you email me some pictures of your fan, I may be able to determine what types of universal fixtures will fit...if any. Email pictures to: firstname.lastname@example.org
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EM-CF766VS - http://www.hansenwholesale.com/ceilingfans/emerson/model.asp?ProdNo=EM-CF766VS
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ANSWER: Almost all of our ceiling fans with lights do not require a second hot wire, so they will work with a 1 wire pair...there are very few exceptions. If you give us a call, we will be happy to help you choose the best fan for your needs and make sure you can install it.
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Ceiling Fans Question - Savoy House Model SV-14-325-FD-SN
SV-14-325-FD-SN - http://www.hansenwholesale.com/ceilingfans/savoyhouse/model.asp?ProdNo=SV-14-325-FD-SN
QUESTION: How far down from the ceiling does the Seaside fan hang when installed with the flushmount option?
ANSWER: Thanks for your question: The Seaside fan from Savoy House comes with an 8" downrod as well as a flush mount adapter. The bottom of the fan cage hangs 16.3" from the ceiling when installed with the 8" downrod. Although the manufacturer does not specify the hanging distance with the flush mount option, after reviewing the installation instructions I have estimated that the flush mount option will reduce the distance by at least 6" to be safe...if not a bit more. That would put the bottom of the fan at about 10" from the ceiling.
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Ceiling Fans Question - Minka Aire Model F820-CT
F820-CT - http://www.hansenwholesale.com/ceilingfans/minkaaire/model.asp?ProdNo=F820-CT
QUESTION: I want to purchase the 36" Down rod DR536-CT (Cattera Bronze finish) $25.13 for the Santa Lucia Ceiling Fan I recently purchased from you. However, when I try to select it the website automatically adds the fan too. Please help
Sorry you are having trouble ordering a downrod. Here is what you can do: Simply delete the fan from your shopping cart to order just the downrod or use this link to add the downrod to your cart by itself:
Minka Aire DR536-CT Downrod
- Question #9502 - Posted: 7/6/2014 9:17:41 AM
Ceiling Fans Question
QUESTION: Do you happen to carry Hunter fan light fixtures that have a triangle base. These are not held in by screws but by a clip system.
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Ceiling Fans Question - Modern Fan Model VEL-HUG-BN-50-NK-NL-NC
VEL-HUG-BN-50-NK-NL-NC - http://www.hansenwholesale.com/ceilingfans/modernfan/model.asp?ProdNo=VEL-HUG-BN-50-NK-NL-NC
First off, I love all the consumer information Hansen Wholesale provides.
I'd love a clarification on something. You say that hugger fans don't work as well as regular ceiling fans. This makes total sense. However, why would the Modern Fan Velo Hugger be rated at the same 6650 CFM and 5.54 MPH wind speed as the regular Velo?
(Is it because the blades are installed as low as possible on the hugger fan, thus negating the height benefits?)
ANSWER: You are exactly correct. When installed with a standard downrod, the regular Velo hangs down the same distance as the Velo Hugger, so the airflow is the same.
- Question #9499 - Posted: 7/2/2014 11:30:33 PM
Ceiling Fans Question Model SV-58-819-5WA-37
Per the information on the site, the new DC motors, the Emerson K55XL, and other "induction" type motors are considered best quality. If that's the case, how do fans with smallish non-special motors (Say, Savoy House Indira, with 153 x 22mm motor) earn a 5 rating?
There are exceptions. A 5 rating is not just based on the motor inside the fan, but the overall consideration of the quality of the components and performance. Most 153mm motors are only 12mm to 15mm tall and tend to be overworked. The motor used in the Indra is 22mm tall, which is very unusual. This is a special motor that Savoy House had designed for this fan and the performance and quality of the motor are excellent. The 3-blade Indra produces a whopping 8517 CFM and runs very smooth and quiet. The entire fan was designed to produce maximum airflow while reducing noise. The blades have a very special aerodynamic design and the fan runs perfectly quiet. When I saw this fan introduced at the lighting show in Dallas, I was very impressed. Overall, one of the best fans I have rated in years. A DC motor would have been nice...but was not necessary to earn a 5 in my book.
Here is a link to the Savoy House Indra