Case Study: Case Study – NDT Blast Preparations at a UK Biomass Power Station on a Planned Shutdown
Over the Summer, KUE Group have attended a major UK Biomass Power Station to carry out NDT (Non Destructive Testing) Blast Preparations. KUE have carried out NDT Blast Preparations on all of the UKs large power generation sites for many years, but 2020 was particularly challenging to meet our safety obligations due to COVID-19.
Why Do Power Stations Plan Outages
Power stations, whether they are fossil fuel, biomass or nuclear, all plan to shut down some or all of their energy production to carry out essential inspection and maintenance activities. Traditionally, these were carried out during the Spring and Summer months, however, with the increasing use of air conditioning in the last decade, outages can be scheduled all year round, depending on demand and the price of wholesale energy.
An outage is often a hive of activity within a condensed programme of work, with over a thousand personnel from a wide range of differing disciplines arriving on site to carry out their own planned works at the same time alongside other trades.
NDT is the usual method for testing for operational or mechanical damage to working plant. It can be achieved by grinding and other hand preparation methods, but grit blasting is the most cost effective method, ensuring that the inspections do not deviate from critical path schedules.
A key item of any work schedule is comprehensive planning and preparation being carried out months before a blast hose is pressurised.
Prior to attending site, we received an initial scope of work. Method Statements, Risk Assessments and COSHH Assessments were submitted showing our intentions to carry out the works safety.
Site supervisors loaded the self-contained blasting rigs, extraction equipment, blast hoses and abrasives. All necessary site safety inductions were carried out by all attending operatives.
On mobilisation, the KUE self-contained blasting rig, extraction equipment and abrasives were taken to and set up on site. The blast rig was situated as close to the Boiler House as possible, the blast hoses connected to the compressor and parallel with communications lines, were routed into the blast areas.
KUE performed NDT Blast Preparations on multiple items on during the outage, including:
- High Pressure Pipework
- Fan Impellors
- Internal Furnace Pipework
For safety reasons, certain pieces of plant could only be accessed with a permit. This ensures that KUE were working on the correct piece of plant, that KUE had exclusive use of that piece of plant and that most importantly – it was not live at the time of working and therefore safe to access.
As only permit acceptors can take out a permit, KUE had a number of operatives trained to be able to receive these permits.
Once all access, scaffold and background lighting was in place, KUE could begin grit blasting. To ensure visibility was kept to an optimum level and remove potential airborne contaminants, KUE utilised our high volume dust extraction systems.
To mitigate conflicts with other trades in adjacent work areas, in accordance with normal practice, KUE carried out grit blasting on night shift where there was less opportunity to interface with others.
Once all the works were completed and cleaned down to an acceptable standard they were passed off by site engineers. This process continued over 33 labour intensive nights.
On completion, we demobilised from site, ensuring that the client was happy and more importantly that all the works that we were associated with were completed in a timely manner, most crucially of all – safely.