MacroAir Technologies Airvolution Installation Manual - page 9

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MacroAir Technologies Inc.    www.macro-air.com    Toll Free: 866-668-3247    Build: January 9 2009 

2.1 Weight 

A standard 20 foot 6-blade fan weighs about 230 pounds, the 10-blade version about 325 pounds, 

including the standard mounting hardware.  In inverted-blade applications designed to blow air upward 

(very unusual), there is an additional down force of about 100 pounds due to fan thrust.  We recommend 

that a building structure be capable of holding approximately twice the stated hanging weight of the 

fan.  If there is some doubt of this, a professional contractor or architect should perform a thorough 

evaluation of the building prior to purchasing fans. 

2.2 Torque 

The maximum torque (twisting force) that must be handled by the mounting system, including building 

structure, occurs at fan startup.  For a 20 foot fan, maximum potential starting torque is 300 ft-lbs.  When 

standard electrical controls are installed, the fan will never begin to approach this maximum because the 

standard variable-speed control system uses soft-start technology.  However, should the soft-start fail, or 

when a fan is installed as a single-speed model without the variable speed control system (rare), full 

torque might be applied to the mounting system, so it is important that it be adequate to withstand 300 ft-

lbs torque. 

2.3 Safety Cable

A MacroAir fan should never be run without a properly installed safety cable, which is supplied with every 

fan along with all required hardware.  You must install safety cable for warranty to be in effect. 

2.4 Close Clearances

The area within three feet of the blade tips when the fan is at rest is considered “close clearance”.  It is 

EXTREMELY DANGEROUS to mount the fans within “close clearance” of any object.  We strongly 

recommend not mounting the fan closer than 15% of its diameter to any object.  If this is an issue, 

mounting extensions and smaller fans are available from MacroAir. 

2.5 Guy Cables

A running fan can sway due to a minor imbalance or because of wind.  “Wind” may be only the air 

movement the fan itself generates, or it may be actual wind if the fan is mounted outdoors or in open  

areas.  Since the mounting system is free swiveling, it will not stop fan movement, so it is imperative that 

guy wires be properly installed.  The primary considerations are angle and tension of the guy wires.  See 

Step 10 for more information. 

2.6 Guards 

(except standard eco6 fan with integral guard) 

If there is potential for people or objects to come in contact with a running fan, it is best to construct a 

guard from angle iron and steel mesh, attaching it securely to the building structure.  The guard should be 

mounted with sufficient clearance so that no part of it can be pushed into the fan, with at least 18 inches 

of clearance on all sides.  We recommend 2” x 2” x 3/16” angle-iron for the frame, and, in most cases, 2” x 

2” x 11” gage weldmesh (1/8” diameter wire on 2” centers) for the screen.  However, mesh size should be 

dependent on what objects might come in contact with the fan — if, for example, employees on lifts can 

inadvertently get a finger into a fan, use smaller mesh or greater spacing — OSHA guidelines state that a 

finger guard must prevent a finger entering into the guard within four (4) inches of the moving device, the 

fan blades in this case.  Refer to OSHA guidelines, paragraph 1910.212(a) (5) for more information.