Purging  & Allowable leakage rates      
  INSERT PIPE LENGTHS AND METER TYPE    Purge calculation only required if a length is inserted in one of the orange boxes 35mm copper, 32mm steel, 32mm MDPE or a U16 meter is used. Tightness testing drop limits are calculated if the leak is greater than 1mb for NG or 0.5 for LPG      
  Meter type G4 / U6 0.01          
  PUT AN X IN THE BOX BESIDE THE METER TYPE / No meter leave the boxes blank U16 / G10 0.03          
  E6 / E6S 0.0036          
  COPPER PIPE LENGTH IN M   STEEL PIPE LENGTH IN M   MDPE PIPE LENGTH IN M      
  15mm 0.00014 15mm     ½ 20mm         
  22mm 0.00032 20mm     ¾  25mm       
  28mm 0.00054 25mm      1 32mm          
  35mm 0.00084 32mm   1¼          
  Installation Volume IV   Purge Volume PV   Tightness testing IGEUP1B 2026    
  Total  Installation volume IV M3   PV purge volume M3   Natural Gas Sytem Leakage Allowance      
    PV imperial  ft3   LPG GAS Sytem Leakage Allowance      
      LPG GAS Testing with AIR Sytem Leakage Allowance    
  IV for leakage rates need only to be calculated if the drop is greater than 1mb for NG or 0.5 for LPG