PBG Plenum Box / NRG Neck Reducer to suit Grilles

    • Product Details


      The proprietary plenum boxes for Grilles constitute an easy and cost-effective way to connect the grilles back to ductwork. 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 can be fitted to the plenum box to help evenly distribute the airflow over the whole surface of the grille if used for Supply air.

      Product Description

      • PBGPlenum box for Grilles
      • NRGNeck Reducer
      • 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
      • BFLInternal perforated baffle plate (optional)
      • 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 (optional)


      • PBG / NRGGalvanised sheet steel


      • LengthExtract Grille length
      • WidthExtract Grille width
      • HeightSE – Spigot diameter or height + 100mm as standard

        TE – as specified by customer (200mm minimum recommended)


      When ordering plenum chambers please specify length width & 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

      3HF, 3HG, 3GJ  Exhaust Grilles

      GC5 - Eggcrate Grilles

      PER - Perforated Grilles

      Plenum Insulation Thermal & Acoustic specification

      Plenum lining foam Polyester

    • Product Images



    • Product Model Data