User`s manual

FREQUENTLY ASKED QUESTIONS ON BLOWERS
Q: What is the main difference between the Axial and the Centrifugal Blowers?
A: The Centrifugal Blowers have the motor on the outside of the housing. The centrifugal design allows
them to push against greater dynamic back-pressure (higher static pressure) with extended lengths of
ducting compared to axial blowers.
The Axial Blowers have housed motors making them more compact, portable and less expensive.
They offer higher CFM in a free air configuration.
Q: How do I choose the correct blower to ventilate an area?
A: You first need to determine the total volume (cu.ft.) of the space to be ventilated. We recommend using
a blower that is capable of 20 exchanges of air per hour. You can find this information on our website
(www.allegrosafety.com) click on the Blower Selection icon (right hand side) to calculate the
recommended CFM requirement and find product matches. Also in the Blower section, click on
Ventilation Information (for a chart) or Blower Selection (same as above icon). For further assistance,
contact Allegro Technical Support at [phone].or [e-mail] .
Q: Is it better to positively ventilate or to evacuate air?
A: Any Confined Space must be positively ventilated; you may evacuate when fumes are being generated
in a specific location. (e.g. welding, grinding, etc.)
Q: How do I know an Explosion Proof (EX) Blower meets the Class, Division, and Group for my
hazardous confined space?
A: All of our EX Blowers are shipped with an approved Hazardous location motor. Each blower is
stamped with the approved Class, Division, and Group. They are also supplied with the appropriate anti-
spark fan wheel, and plug.
Q: Can you place the Explosion Proof Blower in an Explosive Atmosphere?
A: Yes, however the blower should be at least five feet away from the entrance, in order to bring fresh air
in and not just to re-circulate the contaminated air. (It is recommended that the area is monitored)
Q: Why do I need the Explosion Proof receptacle and plug with the Explosion Proof Blower?
A: The receptacle ( P/N 9503-03, sold separately) must be hard-wired to your power source (e.g. conduit,
flexible conduit) to meet explosion-proof standards. If you modify any part of the blower, cord, plug,
and/or receptacle, you will void the explosion proof certification.
Q; Can I use an explosion proof blower with a standard extension cord and/or receptacle?
A: If the plug can be used without alteration, the explosion proof blower may be used in a non-hazardous
area.
Q: Can the Air Driven Blower be used in an explosion proof atmosphere with statically conductive
ducting?
A: Yes, keeping in mind that it has steel parts and the unit is not certified as intrinsically safe.
Q: Can I use a blower to evacuate welding fumes?
A: Yes, you can have ducting directed at the working area with the blower in the extracting configuration.
Q: Why do I need to use statically conductive ducting with EX Blowers?
A: As a requirement for hazardous locations, this ducting is coated with Neoprene, which resists static
charge build up. It also is integrated with a grounding wire, to maintain the ground throughout your
system. A duct-to-duct connector may be used if the ground wire is continuously attached to a ground.
Q: Can I connect two pieces of ducting together?
A: Yes, you can use the optional duct-to-duct connector, P/N: 9500-01 (8"), 9550-01 (12”), 9600-01 (16"),
or 9650-01 (20”).
Q: What’s the maximum length of ducting?
A: Maximum duct lengths will vary for each blower and environment. Generally, increasing lengths will