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)
|Span||3/16" Thick||1/8" Thick
Answers to Recent Ceiling Fans Questions Posted To This Page
- Question #9482 - Posted: 4/15/2014 9:07:09 AM
Ceiling Fans Question - Casablanca Model CA-55061
CA-55061 - http://www.hansenwholesale.com/ceilingfans/casablanca/model.asp?ProdNo=CA-55061
QUESTION: The add shows a 4 speed wall control with a lite control. Is that included in the price of the 55061 Casablanca fan?
ANSWER: The Panama Gallery fan does include the 4 speed wall control at the price published on our site. The optional 99020 hand held remote control is also included FREE for a limited time. (That offer may have expired by the time other visitors read this posting).
- Question #9480 - Posted: 4/8/2014 1:41:59 AM
Ceiling Fans Question
QUESTION: how big of a fan will I need for a room this big 20 feet wide 30 feet long and 26feet hith
ANSWER: Your room is too large for any single ceiling fan. I would recommend 2 60" to 72" fans and you will most likely need to purchase two 6 foot long downrods and a downrod coupler for each fan so you can join the downrods together to create 12 foot long downrods. If you can only install a single ceiling fan, I would suggest using an 80" fan. Please call us so we can go over your options and help you select the best fan(s) for your application. Call: 1-800-201-1193. You can also email pictures of your room to firstname.lastname@example.org.
- Question #9473 - Posted: 4/4/2014 8:12:01 AM
Ceiling Fans Question
QUESTION: We have a small office, 9 feet by 11 feet. We just put in a wall to wall, floor to ceiling built in cabinet. The ceiling fan, which centered in the center of the ceiling, is not now. It is closer to the built in and it seems more air is being pushed toward the built in. Is this the effect of the built in? Can anything be done to push more air to the desk, which is opposite the built in?
ANSWER: The built in cabinet is likely impeding the natural airflow pattern of the fan, which can cause it to move less air. Several options: 1) Relocate the fan closer to the desk. 2) Buy a larger fan. 3) Buy a more powerful fan of the same size. The amount of airflow a fan is capable of producing is measured in CFM (Cubic Feet of Airflow per Minute). You will find it easy to compare the CFM between all of the fans on our site (where CFM is available). Give us a call and we will be happy to go over these options in more detail. If you can email me some pictures of your room, I will be happy to take a look and see if there is anything else I can suggest. Email pictures to: email@example.com
- Question #9472 - Posted: 4/3/2014 8:30:36 AM
Ceiling Fans Question - Emerson Model CF955WW
CF955WW - http://www.hansenwholesale.com/ceilingfans/emerson/model.asp?ProdNo=CF955WW
QUESTION: Is it possible to use dimmable CFL bulgs in Midway Eco and will remote allow them to dim?
Unfortunately the Emerson Midway Eco remote does not have a dimming function, so although you could install dimmable CFL bulbs, you would not be able to dim them. As I have mentioned previously, the lack of dimming capability is the only complaint we get about this fan...and rightfully so. This is a problem for virtually ALL ceiling fans with lights from ALL brands that meet Energy Star requirements. If you really need dimming capability and are looking for a ceiling fan that has a DC motor, I would suggest you consider the Casablanca DC Stealth. The DC Stealth does not meet Energy Star requirements because it incorporates a 100 watt halogen bulb, but it does have a super efficient DC motor. Casablanca chose to go that way in order to meet the needs of people looking for a high quality contemporary style ceiling fan with a super efficient DC motor and a dimmable light. Here is a link to the: Casablanca DC Stealth Model 59105 in White
- Question #9470 - Posted: 4/3/2014 8:17:20 AM
Ceiling Fans Question - Emerson Model CF787ORB-72
CF787ORB-72 - http://www.hansenwholesale.com/ceilingfans/emerson/model.asp?ProdNo=CF787ORB-72
QUESTION: Model CF787ORB comes with a 4 speed wall control. How does it reverse the fan blades direction ? It is located at 20feet off the ground
The Emerson Carrera Grande has a manual reverse switch on the motor housing. Because your ceiling is so high, reversing the fan manually is obviously not going to happen. Emerson makes a special remote control transmitter and receiver that is capable of reversing the fan. This remote can be installed as a wall control and also be used as a hand held remote. Here is a link to the components: SR650-RC212
. They also have another remote only option with a receiver that cannot be used as a wall control. Here is a link to that system: SR600-RC212
. Although the receiver is not shown in the picture, it is included in the model that we are selling.
Keep in mind that in order for these to work, you must install the receiver unit in the canopy of the fan when you install the fan. If you do not install it then, you will have to get up there to do it later...so be sure to purchase these components along with your fan. Also, rather than using the links above to purchase these parts, you can simply add them to your original fan purchase by clicking on the orange button labeled "Controls" below the picture of the fan on the main product details page...or just give us a call and we will make sure you get everything you need.
- Question #9469 - Posted: 4/3/2014 8:02:18 AM
Ceiling Fans Question
QUESTION: Where can I find a replacement globe for my harborside breeze Wakefield ceiling fan?
ANSWER: Harbor Breeze ceiling fans are sold only by Lowes, so you will need to contact them to see if they can supply you with the globe you need.
- Question #9468 - Posted: 4/3/2014 8:01:15 AM
Ceiling Fans Question - Emerson Model CF875SPB
CF875SPB - http://www.hansenwholesale.com/ceilingfans/emerson/model.asp?ProdNo=CF875SPB
QUESTION: I am looking for an Emerson crystal LX ceiling fan CF875SPB that I understand has been discontinued. Can you find one for me?
It has been about 10 years since Emerson made that fan...so we ran out of stock many years ago. I am pretty confident that you will not find any dealers that have one. It was a nice looking fan with the illuminated crystal motor housing, but compared to fans made today, it did not move enough air (the motor was too small in order to accommodate the lights that lit up the crystal). Here is a link to view all of the flushmount/hugger ceiling fans that we currently have available: Flushmount Ceiling Fans
- Question #9466 - Posted: 4/3/2014 7:45:49 AM
Ceiling Fans Question - Minka Aire Model F803-TL
F803-TL - http://www.hansenwholesale.com/ceilingfans/minkaaire/model.asp?ProdNo=F803-TL
QUESTION: How do I reverse my Minka Aire Model F803-TL ceiling fan without the wireless remote. The remote unit has begun to fail and will not power up. I have switch the wireless unit to a regular wall mounted fan control. However, I need to change the direction of the blade spin and I do not see a direction switch on the fan itself. How do I rectify this issue. Many thanls
There is no method of reversing the Minka Aire Artemis ceiling fan other than with the remote control or wall control that was/is made for the fan. Generic remotes do not have a compatible reverse function and there is no reverse switch on the fan motor housing. Please contact Minka Aire customer support so they can determine the correct replacement parts (remote transmitter and receiver) for your fan since they have changed them over the years. Once you have determined the part numbers you need, you can call us to order them. Here is a link to their contact info: Minka Aire Customer Support