Page 6 - LMD Vacuum Excavation - Annual Review 2021/22

Gas connections and mains replacement productivity nearly doubled by new approach to planning and excavations
LMD has been working in partnership with specialist contractor, Utility Solutions Provider (USP), Trinity, Cadent and Cadent’s local delivery partners to ensure gas mains replacement targets are successfully met.
The initial impetus for the initiative came from Jonathan Smith, Head of Programme and Engineering at Trinity. Jonathan
had worked with vacuum excavators on earlier projects and understood their potential impact on productivity.
Although the approach adopted is radical and innovative, the question it addresses is very simple: Can we create a work methodology that ensures skilled gas teams are able to focus their time on gas mains replacement work rather than ancillary activities such as digging out their own pushes? The vision is to mobilise a two-man dig team (USP) and a two-man vacuum excavator team (LMD) to site ahead of
the gas connections and mains replacement teams. The vacuum excavator is used to excavate trial holes and locate the main. The USP team drills the main and inserts a camera. The camera is used to pinpoint and mark up the location of services, back feeds and valves within an accuracy of 50mm. This eliminates the cost of missed digs and associated reinstatement.
Once the services are located and marked up, the USP team uses floor saws to cut through the road or pavement surface. The size of the excavation is tightly controlled (to minimise reinstatement costs). Having broken up the top layer, USP hands over to the LMD team which completes the excavation to the level of the service connection using the vacuum excavator. The use of the vacuum excavator ensures that the volume of excavated material is minimised, and all existing services are exposed without the risk of, for example, a cable strike or mains burst. Site safety and compliance is paramount. Whilst LMD exposes the service connections, the USP team switches to locating mains pits to facilitate the replacement
of iron gas mains with polyethylene pipes. Replacement is typically undertaken using dead or live insertion techniques.
Carl Edwards leads USP’s operations:
‘The new approach has proved to be very successful. Overall gas connections and mains replacement activity has increased by around 50% on normal levels. Once the processes and procedures had been trialled and formalised, we found that the USP dig team and LMD vac ex team were moving so fast that the gas replacement team was sometimes struggling to keep up.
Co-ordination was facilitated by the creation of a dedicated WhatsApp group. The initial plan was to have two vacuum excavator and two dig teams but this soon increased to four and, at its peak, reached nine rigs.
The success of the approach has already led to interest from other gas networks.’
Mick Dysart is LMD’s Managing Director:
‘The close working partnership with USP was central to our success; it’s really all about communication and planning. What looks simple on paper is often more complex when the reality of life on site is added to the mix.
The use of vacuum excavators brings efficiency, productivity and safety. We’re looking forward to working on further phases of work in the months to come.’
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