During 2011 Doosan Power Systems started the deconstruction over a three and a half week period, however due to the proven time taken in 2011, Doosan Power Systems engaged the services of TDS Ltd to deconstruct a mirror copy project in just an eight-day window.
This projected and revised time scale (motioned by Doosan and agreed by TDS Ltd) required 24hour working by two individual teams.
Client: E. On
Contract: Demolition and structural dismantling
Contract start/end date: 8 Days and Nights (24- hour shiftwork)
Total project value: £100,000.00
Initial Project Brief
During initial tendering processes a management team was directed by Doosan to attend various clarification meetings and further planning meetings. As part of Doosan’s feasibility study of TDS Ltd a safety manager from Doosan visited an existing working site were TDS were the main contractor, to confirm and clarify that we were working to the highest safety standards expected. Further meetings with Doosan and the client, coupled with an excellent feedback report from the safety manager secured the project.
Due to the critical path program agreed and the multi million pound shut down immediately following our deconstruction exercise, an enormous amount of pre planning was required to enable the safe and time crucial conclusion of this project. Shift teams and supervisors were handpicked from our experienced resource pool to enable a safe and productive outcome, one of the biggest challenges with this project was the very short timescale.
Over a period of several weeks prior to starting, all team members were sent to the power station to be safety and CDM inducted in readiness for this known critical start date, several employees attended client led courses to achieve supervisor and nominated person status, as required by the client which included overhead crane training. The Management team and Directors of TDS were aware of the commitment required by all parties to achieve this reduced program, stand by personnel also received induction, CDM and supervisor training.
Method statements, risk assessments, lifting plans, safety plans, training certificates, procedures and COSHH assessments were required by the client 14 days prior to commencement. None notifiable asbestos rope was positioned between many of the panel faces, therefore based on the safe methods proposed, TDS were challenged to technically demonstrate and clarify that the methods suggested were in line with HSE guidelines, this was proven and confirmed using electronic monitoring techniques.
Pre-arranged low loaders were required at specific critic times to enable the removal of 32t impellors and 23t motors from the area following extraction. Pre-determined and controlled laydown areas for casings and apparatus were established prior to commencement.
Dismantling records were reviewed to enable recognition of safety learnings gathered. The 24- hour 8 -day program started on the 24th April 2012, following the installation of a fire-retardant curtain around the whole CDM area, that was approximately 100m perimeter x 15m high. The sequence of de- construction was complicated, as we had to ensure that the structural integrity of the apparatus was always maintained, in addition we had to be aware that all dismantled casings and apparatus were removed within the critical time frame that was set.
Scope of Work
- Erection of fire curtains
- Remove all associated stair casings and other apparatus.
- Create a material holding area by hot cutting away the impellor casing bottoms.
- Dismantle and remove impellor casings using the existing overhead crane.
- Hot cut impellors shafts at both ends then remove using the existing overhead crane.
- Remove motor covers then burn off all holding down bolts and remove using the existing overhead crane.
- Burn off holding down bolts of shaft bearing housing and remove using the existing overhead crane.
- Hot cut and dismantle using the existing overhead crane for the remaining fan casing.
- Hot cut and dismantle then removal using the existing overhead crane for the remaining fan lower casing.
An extensive interface operation between the main contractor, the client and all other contractors involved in this multi million pound shut down was required to enable the safe and productive execution of these works.
The TDS design team enabled the whole project to be completed in a safe yet timely manner, whilst considering the complex nature of the structure and designed lifts encountered.