Air Valve Plenum Box, 125mm Valve x 1 Spigot 90mm EPP

Description

The Casavent AVA-125-90-1-V-EPP is an EPP air valve plenum box that connects a single 125mm ceiling or wall air valve to one 90mm radial semi-rigid duct, forming the room-end termination for a 90mm radial MVHR or MEV system. The larger 90mm duct bore means a single spigot can often deliver the airflow that would need two 75mm ducts, simplifying the ductwork at that valve position.

Moulded from Expanded Polypropylene, the box shares the same insulating, corrosion-free construction as the rest of the Casavent EPP plenum range.

125mm Air Valve Neck

1 x 90mm Duct Spigot

EPP Material

168mm Length (A)

λ 0.0038 Thermal Conductivity

-25 to +80°C Service Temperature

System Component This plenum box is a system component — it connects a 125mm air valve to 90mm radial ductwork and does not include the valve, ducting, or manifold. These are sold separately.

Single 90mm Duct Simplicity The larger 90mm bore lets one duct run carry airflow that would otherwise need two 75mm ducts, simplifying routing where a single wider duct is preferable to twin narrower ones.	Compact Footprint At just 168mm long, this is the most compact plenum box in the range, useful where valve-end installation space is tight.
Insulating EPP Construction The Expanded Polypropylene body provides thermal insulation (λ = 0.0038 W/(m·K)) around the connection point, reducing condensation risk.	Aerodynamic Internal Profile The profiled internal shape keeps pressure drop low, helping the connected 90mm duct run operate efficiently.
Double Duct Fixing The spigot uses a male connection with an internal gasket and EPP outer casing for a secure, airtight fit.	Corrosion-Free As a moulded plastic component, the box is immune to corrosion, suited to long-term loft and ceiling void installation.

Product Overview
Brand	Casavent
Product Code	AVA-125-90-1-V-EPP
Description	Air Valve Plenum Box, 125mm Valve x 1 Spigot 90mm, Vertical, EPP
Orientation	Vertical
Dimensions
Air Valve Neck Diameter	125mm
Duct Spigot Diameter	90mm (x1)
Length (A)	168mm
Width (B)	233mm
Height (C)	90mm
Spigot Length (L)	36mm
Technical Data
Material	Expanded Polypropylene (EPP)
Thermal Conductivity	λ = 0.0038 W/(m·K)
Service Temperature	-25°C to +80°C
Reaction to Fire	Class E (EN 13501-1)
Microbial Resistance	Rating 1a, Method A (EN ISO 846:2019)
Air-Tightness	Suitable for ATC2 (D) air-tightness class systems (EN 17192:2018)

What does this plenum box connect?

It connects a single 125mm ceiling or wall air valve to one 90mm radial semi-rigid duct.

Why choose a single 90mm duct over two 75mm ducts?

A single 90mm duct can carry a comparable or greater airflow to two 75mm ducts while simplifying routing and reducing the number of holes and fixings needed at the valve position.

What is the box made from and why?

Expanded Polypropylene (EPP) — lightweight, insulating, corrosion-free, with good acoustic properties.

How is it fixed in place?

Using either screws and wall plugs, or 17–25mm-wide perforated mounting tape.

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