Allegro 8" Manhole Ventilation Passthru (MVP)

The Allegro 8" Manhole Ventilation Passthru (MVP) is a compact confined-space ventilation accessory designed to maintain and redirect airflow into manholes, sewers, tanks, utility vaults, and similar vertical-entry spaces while minimizing obstruction at the entry point. Its integrated design combines a low-profile air vent, 90-degree elbow, and built-in mounting system into a single portable assembly.

The low-profile elbow is designed to fit beneath the lower crossbar of a compatible manhole guardrail, helping preserve access for workers while ventilation is operating. Flat channeled corners allow the manhole cover to help stabilize the assembly during use.

An integrated collapsible 8-inch duct deploys directly into the confined space. The duct compresses to allow easier worker entry and then springs back into shape after the worker passes. When not in use, the duct stores in an integrated storage bag with a quick-release drawstring for compact transport and storage.

The MVP body is constructed from recyclable linear low-density polyethylene (LLDPE) in high-visibility yellow. The ducting uses vinyl and polyester with a PVC coating and is heat resistant up to 180°F.

Duct Diameter: 8 in.

Duct Type: Collapsible

Duct Material: Vinyl/polyester with PVC coating

Maximum Duct Temperature: 180°F (82.2°C)

Housing Material: Linear Low-Density Polyethylene (LLDPE)

Color: High-Visibility Yellow

Length with Duct Stored: Approximately 32 in.

Length Deployed: Approximately 62 in.

Width: Approximately 20 in.

Height: Approximately 23 in.

Weight: Approximately 11 lb.

Manufacturer Part Number: 9510-50

Standards/Compliance: ASTM 227 ducting specification; UL 94V-0 flame-retardant ducting