Project overview
Omega Red was contracted by a company that specialises in anaerobic biodigesters across the UK, to fit a lightning protection system at its anaerobic digestion facility.
Project execution
Omega Red carried out a risk assessment of the site, which houses several concrete anaerobic digester tanks and a mechanical plant and identified the need for a system that safely discharges the current into the earth’s core, should a direct strike occur.
Owing to height restrictions applied to the planning consent, the initial concept of 30-40m high stainless-steel masts was rejected. Through collaboration with the client and manufacturer, a design and plan to install a series of strategically placed High-Voltage Insulation (HVI) lightning protection systems around the tanks was devised.
The complete design required the installation of four fixed masts, HVI antennas with coaxial cables, and standalone tripod masts connected to a bare copper earth ring around the tanks and plant area.
This lightning protection system prevents lightning flashing into any danger zones by attaching itself to the HVI antennae and travelling safely down to the earthing network under the concrete floor slab.
During the design phase, the team had to take the site into consideration and the solution had to accommodate the volume of machinery on site, ensuring that there was enough space for vehicular plant to safely move around.
The team usually put an earth ring 600mm deep into ground below the frost levels expected in the UK. However, the bunded area of the site was built upon a membrane to prevent pollution egress into the soil below and close agreement with the owners was needed to determine timing and depth of installation prior to ground level concrete slabs being poured and cast.
The land around the site is primarily made of chalk which added an additional challenge as chalk is primarily poor for earth resistance readings. The team needed need to achieve under 10Ω for the lightning protection system and under 1Ω for the power earthing which was calculated by our Nottingham Branch Power Earthing Division.
Project result
The system was designed and installed in 40 weeks to the client’s specification, within the client’s budget and in close coordination with the client’s construction programme.
