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PBHLB / PBLLB Plenum Box to suit CSB Barrel Slot Diffusers

    • Product Details


      The proprietary plenum boxes for our Barrel Slot Diffusers are designed to guarantee a good distribution of the air prior to diffusion through the terminals. Available with Side or Top Entry connections to customer-specific diameter/shape, these can be fitted with Spigot flap dampers FD, cord- or quadrant-operated, as well as 6mm acoustic lining (optional) reaction to fire class
      C-s3-d0 to EN 13501-1: 2007 to avoid noise generation.

      An internal baffle plate is fitted as standard to the plenum box to help evenly distribute the airflow over the whole slot length. Also available with rivet fix (hem fix as standard).

      Product Description

      • PBHLBHigh-line Plenum box to suit CSB Barrel Slot Diffusers
      • PBLLBLow-line Plenum box to suit CSB Barrel Slot Diffusers
      • SESide Entry spigot
      • TETop Entry spigot
      • CCCircular connection
      • RCRectangular connection
      • FOFlat Oval connection
      • FDCCord-operated Flap damper (optional)
      • FDQQuadrant-operated Flap damper (optional)
      • LINED6mm acoustic lining (optional) reaction to fire class C-s3-d0 to EN 13501-1: 2007
      • BLACKPlenum painted black to prevent through vision (optional)


      • Galavnised steel, stitch fixed
      • Available in High-Line or Low-Line to accommodate larger spigot sizes
      • 1 to 4 connections – Circular, Rectangular or Flat Oval (reduced plenum height)
      • Side or Top entry spigots with optional airflow control damper
      • Oblong holes on top plate for easy drop rod installation
      • Internal baffle plate for optimum air distribution


      • PBHLBGalvanised sheet steel


      • LengthLinear Slot diffuser length
      • WidthNumber of slots
      • HeightSE – Spigot diameter or height + 100mm as standard
        TE – as specified by customer (200mm minimum recommended)


      When ordering plenum chambers please specify length, number of slots & height, spigot size and position (top or side entry) and control options. Please note that the plenum height should in general be 100mm greater that the spigot diameter (side entry applications).

      Product Specification

      Related links

      Plenum boxes installation and maintenance

      CSB Barrel Slot Diffusers

      Installation and Maintenance Instructions for CSB

      Plenum Insulation Thermal & Acoustic specification

      Plenum lining foam Polyester

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