New Cross Substation Fire Man

29th March 2022

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The project consisted of the provision of a new fire water main to connect to a new fire hydrant and existing fire protection system water storage tank within National Grid’s 275Kv New Cross Substation. The main was partially routed through shallow tunnels totalling 100 metres across the site and the new fire main, totalling 230 metres including the external sections was also installed to provide fire protection to National Grid’s assets and to replace their existing defunct system. The works comprised:

External Fire Main - Ormside Street to Tunnel

  • Installation, testing and commissioning of a new potable water 150mm nominal bore HDPE blue water main pipework
  • Excavation and installation of new fire main in trench 750mm wide, backfilling and reinstatement
  • Core drilling through tunnel wall

Tunnel Internal Fire Main

  • Provision, installation, testing and commissioning of seamless steel pipework for 16 bar pressure including steel pipe support brackets to allow pipe expansion and contraction
  • Modifications of existing escape ladder to allow for steps over new fire main
  • Insulation of exposed pipework at tunnel entry and 30 metres into the tunnel
  • Pressure testing of the entire tunnel internal pipework section

External Fire Main - Tunnel to new Fire Hydrant

  • Provision, installation, testing and commissioning of new potable water blue HDPE 16 bar pipework between Tunnel and new Fire Hydrant.
  • Excavation and installation of new fire main in trench 750mm wide, backfilling and reinstatement
  • Core drilling through tunnel wall

Works were originally planned for a 13-week duration, but actually commenced 3 weeks later than scheduled due to access issues and other contractors being on site. Through accelerating the programme, we still met the original completion date.

We utilised our in-house Survey Team to identify charted and uncharted services within the old electricity substation and used vacuum excavation techniques to quickly and safely excavate around them.

To mitigate the risk of damaging cables and ease of handling inside the tunnels, 3m pipe lengths were used due to access restrictions with 6m lengths.

Confined space working within the tunnel was managed by a confined space management company that had expertise in deep tunnel working providing adequate lighting, ventilation, gas detection, drainage / water pump requirements, standby power provision, radio communication and emergency escape arrangements.

As a direct result of our collaborative working relationship with National Grid to complete this project on programme, we were awarded another project on the framework with a further scheme negotiated on the Iver Pipeline.

 

CLIENT: National Grid
PROJECT VALUE: £0.3m 
START DATE: February 2019
COMPLETION DATE: April 2019
FORM OF CONTRACT: NEC option A