Portable Blower for Confined Space Ventilation: 3000 m3/h Case Study

What the equipment supplier needed

An industrial equipment supplier wanted a portable blower for confined space ventilation, and it had already chosen the model. The request named our LWA-300(12″)U(S)M-04.

The electrical requirement stood out. Dual voltage, 115 and 230V, at 50 or 60Hz. Integrators selling into North America and abroad want one product that works everywhere, rather than two stock codes to manage.

Here the rest of the brief was specific.

• Fan diameter of 300mm, or 12 inches.
• Flexible PVC duct at exactly 0.35mm wall thickness, for durability.
• A 25-foot duct length, roughly 7.62 meters, rather than our standard 10-meter offering.
• Full drawings and specs for both the fan and the hose.
• Lastly, a quote for a sample order of two to four units.

A portable blower with flexible hose points at one family of jobs. Fume extraction from welding bays, fresh air into tanks and manholes, spot cooling for people working somewhere hot. In all of them the kit is a safety device, not a convenience.

Configuring the portable blower

This was a documents and quote project rather than a development one. No new tooling, and no NPI cycle. Even so, two questions needed answering properly.

Axial or centrifugal

We considered a small centrifugal blower and set it aside. It would make more static pressure, certainly. Equally, it would move far less air for the same footprint and the same input power.

Confined space work depends on air changes per hour rather than on pressure. Consequently the axial design wins, and our LWA-300 series is built for exactly this: high volume against the moderate backpressure of a long flexible hose.

AC rather than EC

We also weighed an EC variant with SmartEC controls, which would give variable speed and better efficiency. However, the customer wanted a plug-and-play single-speed unit. Consequently the extra cost buys nothing here.

Which fan shipped

Our LWA-300(12″)U(S)M-04 uses a single-phase AC asynchronous motor wound in 100% pure copper. Copper holds its temperature during continuous running, which matters on a portable blower left going all shift. That U in the model number is the dual-voltage capability, selected by rewiring inside the terminal box.

Sourcing a 25-foot duct

Genuinely non-standard here was the hose. Our catalog length is 10 meters, whereas the customer wanted 25 feet.

So our engineers took it to the supply chain team, who checked with our materials partner. A custom 25-foot run was possible without touching the 0.35mm wall specification. Afterwards, full drawings for both parts went out with the quotation.

Technical Specifications

Note the voltage row. Dual 115 and 230V capability is what lets one product ship to job sites on either side of the Atlantic.

Technical Documentation

LWA-300(12″)SM-04.pdf: This engineering drawing provides the dimensional and base performance data for the fan, which procurement managers use for initial fit-for-purpose validation.

LW-AD12″-10000-01.pdf: This document details the specifications for the flexible PVC ducting, including diameter and material, required by system integrators for compatibility checks.

quotation industrial axial blowerPVCflexible hose quotation.pdf: This is the final quotation provided to the customer, which includes pricing for both the fan units and the custom-length ducting for the sample order.

The customer’s initial inquiry included this image, highlighting the specific portable fan model and the required flexible ducting.

Final configuration of the Longwell LWA-300 series portable axial blower, featuring a full metal body and integrated carrying handle.

Why the enquiry converted quickly

In the end, four things turned a routine enquiry into an order.

• A non-standard hose confirmed same day. A custom duct length stops makers with rigid supply chains. However, local ties in Ningbo let us confirm sourcing and quote it at once.
• Cost that suits fleet buying. A matching portable blower from a leading European brand carries a heavy premium, yet adds no performance for standard industrial work. Ours has a full metal housing and a copper-wound motor at a price that scales.
• Drawings and quote inside 48 hours. The whole job, from enquiry to final documents, took under two days. Meanwhile the samples shipped from stock, where we usually hold 50 to 200 units of common models.
• UL files already open. Dual voltage usually hints at a UL need to come. We keep active UL 507 and UL 1004-1 files for our main lines, so the customer skips months of test work.

Browse our blower range, or the air mover section for smaller units. Confined space entry rules are published by OSHA.

Questions from the field

What is the lead time on 100 units?

A make-to-order quantity of 100 runs 15 to 25 days from purchase order confirmation. Below 50 units we can often ship from regional stock in 1 to 5 days. The two to four samples on this project left within three working days.

Can it handle hot air or light dust?

Yes, within limits. The standard LWA-300 is rated to +60C ambient and handles light, non-abrasive, non-flammable particulates such as workshop dust or welding fume. For potentially explosive dusts like fine wood dust or flour, you need an ATEX-certified fan from a different series to satisfy Zone 22 requirements.

How do I switch between 115V and 230V?

Inside the motor terminal box. Every fan ships with a wiring diagram showing the correct terminal connections for both supplies. A qualified electrician makes the change in under ten minutes.

Does duct length change the airflow?

Considerably. Every meter of flexible hose adds friction, and bends add more. Consequently a portable blower rated at 3000 m3/h in free air delivers less at the far end of 25 feet. Size against the pressure figure rather than the free-air figure whenever the run is long.