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PBSG Plenum Box / NRSG Neck Reducer to suit SG Security Grilles

    • Product Details


      The proprietary plenum boxes for our range of Security Grilles (SG1, SG2, SG3) 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 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, or prevent through vision for Return air.

      Product Description

      • PBSGPlenum box for Security Grilles (SG1, SG2, SG3)
      • NRSGNeck Reducer for Security Grilles (SG1, SG2, SG3)
      • 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)
      • BFLInternal perforated baffle plate (optional)


      • Thick 16 gauge galvanised steel, riveted construction
      • 1 or 2 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 / non-vision (optional)


      • PBSG/NRSG16 gauge galvanised sheet steel


      • LengthSecurity Grille length
      • WidthSecurity 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

      SG Security Grille range

      Plenum Insulation Thermal & Acoustic specification

      Plenum lining foam Polyester

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