Project Description

FP McCann ‘L’ Walls Form Flood Defence for Pembroke Substation

Status: Completed

Location: Pembroke

Division: Walling

Main Contractor: Trant Engineering Ltd

Market Sector: Commercial

The National Grid Substation Flood Defence Framework is a nationwide programme aimed at improving resilience of the electricity transmission power network to any type of floods; the objective being to significantly reduce the risk to the security of power supply and ensure the transmission network maintains electrical supply by preventing water entering these infrastructures. The Substation Flood Defence Framework programme started in 2008 and by 2021 all of National Grid’s 49 critical high and medium risk substations will be flood-proofed.

Within this programme of work is a substation located at Pembroke, South Wales. Southampton based Trant Engineering Ltd, is a nominated National Grid Framework contractor and has completed flood defence work at a number of National Grid sites. Traditional construction of substation concrete flood walls, typically involves the installation of steel piles around the perimeter of the site to the required height and in situ concrete cast to form the walls.At Pembroke however, following a review of flood wall options, Trant Engineering Ltd approached FP McCann to provide details of the precast concrete ‘L’ wall system on the understanding that such an off-site manufactured precast unit offers a fast, simple and effective solution compared to the more lengthy process of steel pile foundation, formwork and the pouring of wet concrete. To comply with the flood wall design height specification, FP McCann successfully quoted for supply of its 3.0m high tongue and groove ‘L’ Wall to cover the total perimeter length of 1278 metres The contract is in two phases, the first of which was completed in October 2020. The second phase is scheduled for March / April 2021.The L Walls are set out on an in situ formed concrete base slab. As well as speed of build, another major advantage of the ‘L’ Wall system is that props are not required during construction offering additional on-site health and safety benefits.

The precast concrete ‘L’ Walls are all being supplied from the Company’s Lydney manufacturing plant in Gloucestershire with the order comprising 852 no. 3.0 metre high units. Speaking on behalf of Trant Engineering Ltd, Contracts Manager Sean Sweeney says, “After quickly familiarising themselves with the anchoring and levelling method, the Trant Engineering team found the ‘L’ Walls simple to set down. The FP McCann precast concrete ‘L’ Wall flood defence units were the ideal solution to this substation flood protection project and we will certainly consider their use on future schemes within the power sector and on similar utilities infrastructure projects.”

FP McCann precast concrete ‘L’ Wall units are available in heights from 4.0 metres to 6.0 metres from Byley and units measuring 1.0 metre to 3.75 metres from FP McCann’s Lydney and Grantham depots. The ‘L’ Walls are ideal for bulk earth retention, flood defence work, and securing perimeters and boundaries around industrial and commercial property.

For sales enquiries contact James Hodgson on 07753 415817 or