Tempest PAL-24 Industrial Ventilation Fan: High-Volume Airflow for Hazardous Locations

Walk any active industrial site long enough and you will find the same problem: a mid-size mobile fan that looked adequate on a spec sheet has been kicked, dropped, dragged over pipe yard grating, and now runs with a cracked shroud or a bent frame that throws the blade assembly out of balance. That vibration does not just shorten motor life, it creates a new hazard in an environment that already has enough of them. The Tempest PAL-24 is built to a different standard from the start, with a welded 1.5-inch circular steel tubing frame, a firefighting-grade aluminum shroud, and an explosion-proof configuration that carries a genuine Class I and Class II hazardous location rating. The details below explain exactly what those distinctions mean in operation.

What is the Tempest PAL-24 and what does it do?

The Tempest PAL-24 is a 24-inch diameter, mid-size mobile industrial ventilation fan designed for general ventilation in both standard and hazardous industrial locations. It moves high volumes of air across open distances using a powered axial-flow configuration, and it comes in three distinct build variants to match site conditions.

The three models cover the primary industrial demand spectrum. The PAL-24 single-speed unit runs a 1.0 HP TEFC electric motor and delivers 12,867 CFM at 115 lbs. The PAL-24-EP matches that motor and CFM output but adds a certified explosion-proof enclosure for hazardous atmospheres, weighing in at 120 lbs. The PAL-24-VSR steps up to a 2.0 HP variable-speed motor and pushes airflow to 15,663 CFM, with the added weight reflecting the heavier motor at 145 lbs. All three share identical frame dimensions of 31 inches wide by 23 inches deep by 40.75 inches tall, meaning they interchange on the same storage racks and transportation fixtures.

How does the PAL-24-EP explosion-proof rating work, and what hazardous locations does it cover?

The PAL-24-EP carries a Class I (Groups C and D) and Class II (Groups F and G) hazardous location rating, which authorizes its use in atmospheres containing flammable gases and vapors as well as combustible dusts. This is not a splash-resistant or weatherproof designation — it is a full explosion-proof electrical classification.

Class I Group C covers ethylene and similar vapors; Group D covers propane, natural gas, gasoline, and acetone vapors — the gases most commonly encountered in refinery, petrochemical, and pipeline maintenance environments. Class II Group F covers carbon black and coal dust; Group G covers grain dust and similar combustible particulates. The motor runs at 120V/60Hz standard with an approximate 14-amp draw. For cord length planning in large industrial structures, the PAL-24-EP supports up to 60 feet on 14 AWG wire, 95 feet on 12 AWG, 150 feet on 10 AWG, 240 feet on 8 AWG, and 380 feet on 6 AWG — allowing operators to reach remote confined spaces without voltage drop compromising motor performance. You can review the NFPA 70 National Electrical Code hazardous location classification framework for detailed guidance on matching equipment ratings to specific site atmospheres.

Why does frame construction matter for industrial fans, and how does the PAL-24 frame compare?

Industrial mobile fans take mechanical abuse that stationary HVAC equipment never encounters: being dragged by one handle, tipped into cargo beds, and run continuously on uneven concrete while hoses and cables snag the frame. A frame that flexes under load shifts the blade-to-shroud clearance, increasing both noise and the risk of blade contact with the shroud during high-vibration operating conditions.

The PAL-24 uses welded 1.5-inch circular steel tubing with a powder-coat finish — a heavier gauge than the square or thinner-walled tubing common on competing mid-size mobile fans. Circular tubing resists torque loading in multiple planes simultaneously, which matters when the fan is tilted at an angle to direct airflow into a confined space entry. The powder-coat finish protects against the chemical splash and corrosive atmospheres common in petrochemical and process plant environments. The 10-inch solid rubber wheels with high-strength polymer hubs are never-flat by design, eliminating pneumatic tire puncture issues on pipe yard surfaces where metal shavings and debris are routine.

What is the Turbo 2000 Tapered Aluminum Shroud and how does it increase airflow performance?

The Turbo 2000 is a tapered aluminum shroud originally developed for firefighting positive pressure ventilation (PPV) applications, where fast air penetration into a structure is critical. Tempest has carried this shroud forward into the PAL-24 industrial line because the aerodynamic geometry solves the same problem in both contexts: maximizing exit velocity without increasing blade diameter or motor power.

The taper accelerates the air column leaving the blade disc by reducing the effective exit area, concentrating the airflow into a tighter, faster-moving stream. Tempest documents a 30% increase in air velocity within a smaller profile relative to a standard straight-wall shroud of equivalent diameter. In practical industrial terms, this means the PAL-24 can achieve effective air changes at greater throw distances than its 24-inch blade diameter would otherwise suggest, which is relevant when ventilating long horizontal runs such as pipe galleries, tunnels, or below-grade process areas. The shroud is fabricated from aluminum, which keeps weight manageable while resisting corrosion in humid or chemically active atmospheres.

What are AirFlex blades and why does the disintegration design matter for safety?

AirFlex blades are eight-blade impeller assemblies manufactured from fiberglass-reinforced polyamide. The composite construction delivers the blade stiffness needed to maintain aerodynamic efficiency at high RPM while keeping rotational mass lower than aluminum or steel blade alternatives.

The critical safety feature is the engineered disintegration behavior on foreign object contact. In industrial environments, debris ingestion — a rag, a piece of insulation, a length of rope — is a realistic operational hazard. A steel or rigid aluminum blade hitting a solid foreign object at speed transfers enormous energy into the shroud and grille, potentially destroying both and creating high-velocity fragments. The AirFlex polyamide composition is specifically engineered to disintegrate on contact rather than transferring that kinetic energy outward. The external grille is constructed from continuous circular wound steel wire with 8 tie points and a zinc-plated, clear chromate finish — providing a first barrier against debris while the AirFlex design acts as a secondary safety layer if anything penetrates the grille opening.

When should you choose the PAL-24-VSR variable-speed model over the single-speed version?

The PAL-24-VSR is the correct choice when the ventilation task requires adjustable airflow rather than fixed maximum output. The 2.0 HP motor and variable-speed control deliver up to 15,663 CFM at full setting, but the variable range allows operators to reduce airflow for smaller spaces, for work near open flame sources where high velocity is undesirable, or during gas monitoring phases where slower, more controlled air movement provides more meaningful atmospheric readings.

The single-speed PAL-24 and the PAL-24-EP run fixed at 12,867 CFM, which is appropriate when the ventilation objective is straightforward purge-and-clear work at maximum rate. The 2,796 CFM difference between single-speed and full-variable output is not trivial in confined space entry timelines. The weight penalty for the variable-speed unit is 30 lbs over the single-speed model (145 lbs versus 115 lbs), a consideration when the fan must be carried up stairs or into elevated structures. For explosion-proof requirements combined with variable control, operators should evaluate whether the PAL-24-EP in combination with an external variable transformer fits the site’s electrical classification requirements, since the factory variable-speed unit is not listed in the explosion-proof configuration.

Where is the Tempest PAL-24 applied in industrial and energy sector operations?

The PAL-24 covers a wide range of ventilation demands across the energy, petrochemical, construction, and municipal sectors. Its Class I and Class II explosion-proof rating makes it directly applicable in refinery turnaround ventilation, tank entry and cleaning operations, pipeline maintenance access points, and natural gas compressor station work areas where flammable vapors are a routine presence.

For general plant ventilation where explosion-proof certification is not required, the standard PAL-24 and PAL-24-VSR handle warehouse cooling, large-bay air purging, construction site dust control, and post-fire or post-flood air restoration in industrial structures. Operations teams running larger facility ventilation campaigns can pair the PAL-24 with the Tempest Warehouse Cooling Kit for targeted high-volume cooling layouts across wide industrial floor plans.

Sites that need electric-powered ventilation in a different blade diameter or configuration can evaluate the Tempest 24-IND Electric Powered Fan as a comparable Tempest platform. For locations where electrical power is unavailable or where intrinsically safe gas-powered operation is preferred, the Tempest Special Operations Gas Power Blower provides an alternative drive configuration suited to remote or power-limited sites.

Operations comparing Tempest industrial fans against competing platforms should also consider the Super Vac V18-EX Valor Series Electric PPV for 18-inch applications and the Super Vac 716G4-H 7 Series Gas PPV for gas-powered positive pressure ventilation where site conditions favor that configuration. Both represent credible alternatives at different size and drive-type points on the selection matrix.

How does PAL-24 manufacturing origin affect procurement and long-term support?

The PAL-24 is designed, fabricated, and built in the USA at Tempest’s facility in Fresno, California. For operators under domestic procurement requirements or Buy American Act compliance frameworks, US manufacture is a non-trivial procurement criterion rather than a marketing detail.

US fabrication also shortens the supply chain for replacement parts. The shroud, blade assembly, grille, and wheel assemblies are sourced and stocked domestically, which reduces lead times for field replacements compared to fans whose components are manufactured overseas and imported. The Tempest official product and parts documentation covers component-level ordering for the PAL-24 line. The TEFC (Totally Enclosed Fan Cooled) motor specification means the motor enclosure is sealed against dust and moisture ingress — a relevant detail for the maintenance intervals in petrochemical and processing environments where airborne contamination is constant.

When the PAL-24 is the right call: The PAL-24 is the correct selection when a site requires a robustly framed, mid-size mobile industrial fan with genuine hazardous location certification, high-volume airflow above 12,000 CFM, and the durability to survive years of industrial handling without frame or shroud failure. The PAL-24-EP specifically belongs on any job site where Class I Group C or D vapors or Class II Group F or G dusts are present and where running an unrated fan creates an unacceptable ignition risk.

When it is not the right call: The PAL-24 is not the correct selection for ultra-remote operations with no AC power supply and no generator, where a gas-powered blower is the practical choice. It is also not sized for very large-volume industrial purge operations requiring fans above the 15,663 CFM range, where multiple units or a larger-diameter platform would be more appropriate. For smaller confined spaces where the 31-inch frame footprint creates access problems, a smaller-diameter fan with a more compact profile would be a better fit.

Tempest Industrial

PAL-24 Industrial High Volume Ventilation Fan

Most Robust Frame Available | Turbo 2000 Shroud | Made in the USA

Overview

The Tempest PAL-24 is the most robustly built mid-size mobile industrial fan in the Tempest lineup. Featuring a solid welded 1.5″ circular steel tubing frame, the PAL-24 is engineered to withstand the constant bumps, scrapes, and slams of industrial use — and keep performing for years.

Equipped with the Turbo 2000 Tapered Aluminum Shroud and AirFlex fiberglass-reinforced blades, the PAL-24 delivers up to 15,663 CFM (variable speed) for high-volume general ventilation in hazardous locations. Available in single-speed, explosion-proof, and variable-speed configurations.

Models & Ordering Information

Manufacturer: Tempest — 4708 N. Blythe Avenue, Fresno, California 93722 USA — tempest.us.com