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Industrial Rooftop Exhaust Fans

Industrial rooftop exhaust fans serve buildings where the air volume is large, the heat load is continuous, and the fan must run as part of the building rather than as an add-on. The manufacturer publishes two industrial lines for that job: the FRP slope and elbow families for factory and agricultural buildings, and the DWT-I axial range for medium-to-low-pressure, high-airflow applications.

Which families serve industrial buildings

The slope-type page lists industrial workshops across textile, garment and hosiery, glass, molding, rubber, coating, toy, electronics, shoe, printing, food, dyeing and laundry trades. The elbow-type page lists the same industrial spread with textile mills, plastic molding, coating and painting, footwear, food processing and industrial laundry named. The carbon-steel DWT-I page lists warehouses, factories, power stations, bus stations and gymnasiums, and describes its applications as medium-to-low-pressure, high-airflow duty. The FRP DWT-I page lists industrial facilities, warehousing and logistics, transportation hubs, commercial and public buildings, and energy and infrastructure projects. Between the four pages, the industrial buyer is not short of application evidence; what the buyer still needs is the model-level match, and that comes from the tables, not from the application lists.

The DWT-I axial range, and its page-level claims

The carbon-steel DWT-I page states, as page-level claims, 17 machine numbers from 300 to 2400 mm impeller diameter, a series airflow of 15,000 to 220,000 m³/h, and a total pressure of 60 to 320 Pa. Those are series claims, not per-model specifications: the performance table on the same page lists eleven rows, DWT-I-3A to DWT-I-11.2A, and only those eleven rows carry per-model figures. The same page states that blades on machine numbers 12 and above are adjustable, that an explosion-proof version is available for flammable, explosive and corrosive-gas environments, and that a dual-speed motor or a variable-frequency motor and controller is available, with a recommended locked adjustment frequency of 25 to 50 Hz. Optional accessories listed on the page are a gravity or electric check valve, an anti-bird and insect net, a maintenance switch, and a centralized control box. Each of those statements is attributed to the page it stands on, and none of them is expanded into a specification for a model that has no table row.

FRP families in industrial service

The slope family brings a hand-laid glass-fibre-reinforced plastic shell with a secondary-treated smooth surface, SMC glass-fibre blades in a six-blade assembly, a 1.9-metre awning against rain, and a direct-drive design, with 7 nylon blades and 3 cast aluminium blades listed as options. Its two models run at 560 rpm on 380 or 220 V at 50 Hz, with rated powers of 1.1 and 0.75 kW and airflows of 45,000 and 28,000 m³/h. The elbow family brings an SMC fibreglass frame and blades, a direct-connected motor, PVC shutters against flies and backflow, and blade materials customizable to cast aluminium, nylon or stainless steel. Its four models run at 540 rpm, except the smallest at 680 rpm, on 380 or 220 V at 50 Hz, with airflows from 28,000 to 45,000 m³/h and noise figures from 55 to 65 dB. The elbow page describes its fan as creating a negative-pressure indoor environment while introducing fresh air, and as lightweight, easy to install, and low in energy consumption, with a smooth-surfaced FRP housing that is UV and weather resistant for indoor and outdoor use.

Voltage, and the customization note

Every slope and elbow model is tabled at 380 or 220 V and 50 Hz. The slope page adds a note that special voltage and power parameters can be customized. That note is reproduced here as a note, not as a promise covering any specific voltage: a buyer whose site voltage differs from the tabled figures should state the actual voltage in the inquiry and get the matching model confirmed in writing. The DWT-I tables list power and speed per operating point but no voltage column, so voltage for a DWT-I model is likewise a question to confirm, not a figure to assume from another family.

Sizes buyers ask about

Industrial buyers often ask about fan sizes in inches, because existing roof openings and curb sizes are commonly quoted that way. The slope table gives propeller diameters of 1250 mm (49 inch) and 890 mm (36 inch). The elbow table gives 1240 mm (50 inch), 1070 mm (43 inch), 880 mm (35 inch) and 650 mm (26 inch). The DWT-I tables give no inch figures; they give model numbers and dimension tables in millimetres, and the dimension tables differ between the carbon-steel and FRP pages, so a buyer matching an existing opening must use the dimension table of the family being ordered. The axial page carries the carbon-steel dimension table, and the FRP page carries the FRP dimension table, and neither table is carried onto the other page.

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