Antistatic and explosion-proof flexible duct with a 12" diameter conductive link

12" Explosion-Proof Flexible Duct — Antistatic, Conductive Link, Explosive Atmospheres

The Allegro antistatic and explosion-proof flexible duct with a 12" / 30.48 cm diameter is the certified solution for ventilating confined spaces with an explosion hazard. It features a conductive link that continuously dissipates static electricity charges, eliminating the ignition risk from sparks in the presence of flammable gases or vapours. It is available in two lengths: 15 ft / 4.57 m and 25 ft / 7.62 m. This duct must be used exclusively with a 12" diameter explosion-proof blower, such as the RA9548-25EX kit. It operates in both directions for gas exhaust or fresh air ventilation. Allegro Industries manufacturer's codes are: 9550-15EX for the 15 ft model and 9550-25EX for the 25 ft model. Please select your length from the menu above.

This duct is manufactured from antistatic vinyl and polyester, materials specifically designed to prevent the accumulation of electrostatic charges. A neoprene coating provides enhanced heat resistance, allowing the duct to withstand temperatures up to 250°F / 121°C — well above the range of standard PVC ducts. The internal class 1 steel reinforcement maintains the circular cross-section at all times. This duct meets the flammability requirements of UL-94 V0, and its ohmic resistance is 100,000 Ohms or less per square inch, ensuring effective dissipation of static charges across the entire duct surface. Metal ground rods are present at each end. This duct also meets ASTM 227 standards.

Ducting Specifications

• Diameter: 12" / 30.48 cm
• Available lengths: 15 ft / 4.57 m, 25 ft / 7.62 m
• Material: antistatic vinyl and polyester
• Plies: 1
• Coating: neoprene (enhanced heat resistance)
• Maximum operating temperature: 250°F / 121°C
• Compressible for easy storage and transport
• Class 1 steel reinforcement
• Meets ASTM 227 standards
• Meets UL-94 V0 flammability requirements
• Ohmic resistance ≤ 100,000 Ohms per square inch
• Metal ground rod at each end for grounding
• Explosion-proof — for use with explosion-proof blowers only

Advantages of the RA9550X Explosion-Proof Duct for Your Job Sites

The Only 12" Explosion-Proof Duct in the Allegro Line

The RA9550X is the only 12" explosion-proof duct available in the Allegro range at Sylprotec. For any confined space with an explosion risk — hydrocarbon tanks, grain silos, solvent vessels, gas galleries — this duct is the only legal and safe option. Its standard counterpart RA9550 must never be used in these conditions.

Active Static Electricity Dissipation

The conductive link integrated into the duct body provides a low-resistance electrical path along the entire ventilation run. The ohmic resistance ≤ 100,000 Ω/sq in ensures that static charges generated by airflow or suspended materials (dust, vapours) are continuously dissipated to ground, never reaching the energy level needed to trigger ignition.

Superior Heat Resistance

The neoprene coating of the RA9550X raises the thermal limit to 250°F / 121°C, far above the 180°F / 82°C limit of standard PVC ducts. This is especially valuable in environments where elevated temperatures may be present near industrial processes.

Industries and Work Sites Where This Product Is Required

• Oil and gas — confined spaces containing flammable hydrocarbon vapours
• Chemical and petrochemical — tanks and reactors containing solvents or explosive vapours
• Agriculture — grain silos and confined spaces with explosive dust risk
• Mining — underground galleries and spaces with potentially explosive atmospheres
• Pharmaceutical — production tanks with flammable solvents
• Wastewater treatment — wells with biogas (methane) accumulation
• Any confined space classified Zone 1 or Zone 2 under ATEX / NEC standards

Installation, Grounding, and RA9550X Duct Selection

The RA9550X duct must be used exclusively with a 12" explosion-proof blower. Select the length appropriate for the distance between the confined space opening and the work zone. Always allow sufficient slack to avoid any tension on the duct, which could compromise the integrity of the conductive link.

Grounding — Complete Instructions (Vital)

After reviewing the instruction manual, we must add important information to clarify grounding concepts. When equipment is used in explosive environments, it is essential to ensure proper grounding. The slightest spark can cause a disaster.

There is 1 ground wire at each end of the RA9550X duct. This detail is not clearly visible in the manufacturer's product photo. One of these wires can be used to connect another duct of the same type to extend the total ventilation length. To do this, use the RACONN-12 connector and connect each duct's ground wire to the nearest end of the connector, so that the duct connector is integrated into the chain of grounded components.

Additionally, the duct ground wire must be connected to a bolt located on the side of the blower chassis, a few centimeters from the grill. By making this connection, electrical continuity is achieved between the duct (or ducts) and the blower.

To achieve proper grounding, all equipment connected together must have electrical continuity leading to ground. Zero or very low ohmic resistance is required. A competent electrician must verify that all equipment in the chain — from the end of the duct, through the blower, extension cords, explosion-proof plug, and electrical panel — is correctly grounded.

FAQ — Allegro RA9550X 12" Explosion-Proof Duct

Why is this duct conductive and antistatic?

In an explosive atmosphere, static electricity is as dangerous an ignition source as a visible spark. Airflow through a duct, combined with suspended particles or flammable vapours, can generate significant static charges. The antistatic materials of the RA9550X, combined with its ohmic resistance ≤ 100,000 Ω/sq in, allow these charges to continuously dissipate to ground, never reaching the energy level needed to trigger ignition.

Can this duct be extended with a standard RA9550 duct?

No. Combining the explosion-proof RA9550X duct with a standard RA9550 duct would break the continuity of the conductive link and void the explosion-proof protection of the entire installation. Use only two RA9550X ducts joined by the RACONN-12 connector with ground wire connection.

Why is grounding mandatory with this duct?

The conductive link of the RA9550X only dissipates static charges toward ground. If the duct, blower, extension cords, and electrical panel are not all connected to a common zero-continuity ground, static charges have nowhere to go and can accumulate to an energy level capable of causing an electrical arc or electrostatic discharge, triggering an explosion in an explosive atmosphere. Complete grounding of the entire chain is therefore a fundamental safety requirement, not optional.

Complementary Equipment Suggestions for Your Explosion-Proof Ventilation

The 12" explosion-proof axial blower kit with 25 ft conductive duct (RA9548-25EX) is the certified blower designed for this duct — using a non-explosion-proof blower in an explosive atmosphere is never acceptable. The RACONN-12 connector (RACONN) allows extending the installation while maintaining conductive link continuity. The manhole ventilation passage (RA9510) maintains airflow at the space entry, and the 50 ft weatherproof extension cord (RA9540-50) extends the power supply.

Before any entry into a potentially explosive confined space, the Altair 4X 4-gas detector kit (DETEC4GC) is essential for verifying the presence and concentration of flammable gases. The manhole barrier (EPTBB) secures the access perimeter above the opening, and the Peakworks 6 D-ring confined space harness (FPH2000APLE) protects the worker during descent, stored in its carry bag (FPBAG).

The texts coloured in green correspond to hyperlinks leading to specific safety equipment or to a general information link.