The job
Removal of part of the roof for careful storage on site to allow it to be reconstructed. Lifting out of the existing valves and positioning in of new valves provided by National Grid. Reconstruction of the roof.
Our involvement
The whole job with the exception of the disconnection of the existing valves by a National Grid engineer.
The challenge
The compressor roof was a flat roof made out of concrete precast beams and structural flags. The flags were in two sizes, 400mm and 600mm, so they had to be carefully numbered to allow easy reassembly.
We also had to be aware that part of the structure was to be retained for a footbridge replacement scheme at Edale Street/Mill Lane.
Our solution
We created a set of RAMS Risk assessment and Method statements for the work. These covered specific measures we had put in place to avoid damaging the structure or services and the stability of the building or pipe work in the compressor station.
To avoid falling from a height once the flags had been removed we created a working platform and crash deck with a design temporary work ( DTW) scaffold.
We invested in pre-planning and engaged with the scaffolders and National Grid ‘’NG’’ in the early stages.
This significantly reduced the time on site, ensured minimal disruption and with virtually no waiting time.
We had six months to complete the work against a complex timeline:
- mark out the extent of the roof to be removed
- construct crash deck under the existing flat roof
- marking every flag to be removed with an identifiable number linked to the location of the flags for reassembly
- remove and store the flags using mechanical aid
- remove the precast beams after having named then
- alliteration of scaffold and crash decking to allow lifting in and out of the valves
- construction of barriers around the hole where the crash deck had been removed
- crane lift out the existing valve and secure the valve to be taken off site to a local recycling centre
- crane lift in the new valve (connection by National Grid engineer)
- removal of crane from site
- re-build crash deck
- carefully reconstruct roof structure