ILBF In-Line G4 Filter Box – 350Ø

The Airflow ILBF In-Line Filter Box is a galvanised steel filter housing designed to be installed directly into circular ventilation ductwork.

Supplied complete with a replaceable G4 panel filter, the unit filters dust and larger airborne particles from supply or extract air, helping protect fans and other downstream HVAC equipment.

The removable access lid is secured with toggle latches, allowing quick access to the filter for routine inspection and replacement without removing the filter box from the duct system.

Features

• Supplied complete with replaceable G4 panel filter
• Suitable for supply or extract air
• Galvanised sheet steel construction
• 350mm round duct connections
• Removable access lid with toggle latches
• Filter removable without disconnecting ductwork
• Designed for installation directly into circular ductwork

Filter Box Specifications

Specification	Details
Product Type	In-Line Filter Box
Duct Size	350mm
Filter Box Size	400 × 400mm
Spigot Size	350mm
Spigot Length	100mm
Construction	Galvanised Sheet Steel
Filter Type	Replaceable G4 Panel Filter
Air Direction	Supply or Extract
Access	Removable Lid with Toggle Latches
Installation	In-Line with Circular Ductwork

G4 Filter Specifications

Specification	Details
Filter Size	392 × 392 × 45mm (16 × 16 × 2")
Frame	Rigid Cardboard Frame
Filter Media	Synthetic
Filter Class	G4 according to EN 779:2012
Recommended Final Pressure Drop	250 Pa
Maximum Temperature	70°C
Maximum Relative Humidity	90%

Applications

• Pre-filtration for in-line fans
• Protection of fans and downstream HVAC equipment
• Supply air filtration
• Extract air filtration
• Residential ventilation systems
• Commercial ventilation and air conditioning systems

Filter Maintenance

The G4 panel filter should be inspected regularly and replaced when visibly dirty or when airflow becomes noticeably restricted.

Filter replacement frequency will vary depending on the application, operating hours and level of airborne dust and contaminants. Do not allow the filter to become excessively loaded, as increased filter resistance will reduce airflow through the ventilation system.

Always switch off connected fans or ventilation equipment before opening the filter box for maintenance.