Panel Filters – Inter-Fold


Suitable for all air conditioning and ventilation applications. The Inter-Fold is a compact and economical air filter which features low operating costs along with a high dust holding capacity.


Filter Media
Designed to achieve medium efficiency and dust holding capacity, Inter-Fold’s filter media comprises of high performance, non-woven, reinforced cotton/poly fabric. When tested against the ASHRAE procedure the Inter-Fold will has an average efficiency of 30-35% + and an arrestance of 92%.

Radial Pleat Design
Inter-Fold’s exclusive radial ‘V’ pleat design guarantees total use of the filter media, as well as maximum dust holding capacity and extended service life.

Enclosing Frame
The enclosing frame is constructed of rigid, heavy-duty and moisture resistant kraft board. The filter pack is bonded to the inside of the periphery of the frame to eliminate the possibility of air by-pass. Importantly, the support members are bonded to each pleat on the upstream and downstream side to ensure pleat spacing and stability.

Media Support Construction of an Inter-Fold Filter
The unique media support is an expanded diamond grid with 98% open area. The filter media is chemically bonded to the support to ensure pleat stability throughout the life of the filter.

The Inter-Fold is totally disposable. A simple retro-fit can upgrade any new or existing air filtration system to incorporate IFC’s Inter-Fold. Its greater dust holding capacity extends replacement intervals, and used as a pre-filter, considerably lengthens the service life of any other secondary filters in the system.


The Inter-Fold may be operated at varying velocities up to 2.54m/s for the 25mm and 50mm filters, and up to 3.17m/s for the 100mm filter.

Filter Media Area:

  • 25mm deep filter: 2.3m2 of media per 1m2 of face area. 49 pleats per linear metre.
  • 50mm deep filter: 4.6m2 of media per 1m2 of face area. 46 pleats per linear metre.
  • 100mm deep filter: 7.0m2 of media per 1m2 of face area. 34 pleats per linear metre.


Air Filters

Inter-Fold air filters are medium efficiency, pleated disposable type. Each filter consists of a non-woven cotton/poly fabric media, media support grid and enclosing frame.

Filter Media

Filter media is reinforced, non-woven cotton/poly fabric. The filter media has an average efficiency of 30-35%, and an average arrestance of not less than 92%.

Media Support Grid

The media support is an ‘expanded diamond’ grid with an effective open area of not less than 98%. The grid is chemically bonded to the filter media to eliminate the possibility of media oscillation and media pull away. The media support grid is formed in such a way that it forms a radial ‘V’ design, allowing total use of the filter media.

Enclosing Frame

The frame is constructed of a rigid, heavy duty kraft board with diagonal support members bonded to upstream and downstream side of each pleat to ensure pleat stability. The filter pack is bonded to the periphery of the enclosing frame, thus eliminating the possibility of air bypass.

Holding Frame

Holding frames are factory fabricated of 1.6mm galvanized steel and equipped with gaskets and spring type positive sealing fasteners. Fasteners are capable of being attached and removed without the use of tools.

Spare Filters - New installations

It is recommended that two complete sets of spare filters are supplied for use during the construction, testing and balancing period. A complete set of new filters should be installed after testing and balancing, bringing the total number of filter sets to three (3).

Due to ongoing research & development, Clyde-Apac reserves the right to modify the product & specifications without notice.

Clyde-Apac Laminar Air Flow equipment & HEPA filter products available from authorised dealers and distributors