Projects
Lower Liffey Valley Waste Water Treatment Works, Leixlip, Co. Kildare
Assignment
Internal scaffold access structures within cylindrical tanks.
Project Overview:
To design and construct internal scaffold access structures to provide operatives with full access to survey the integrity of the tank walls and roof sections carry out remedial works and apply a new coating system.
Figure 1. Anaerobic Digesting Tank
Activity Challenges
- Restricted means of entry and exit.
- Tank floor 4m below ground level and sloping downward.
- Operating in a confined space.
- Air ventilation to maintain oxygen levels.
- Development of a rescue and retrieval plan.
Project Solution
Adequate planning.
Develop and implement practical solutions without causing any health and safety issues.
- A cantilever platform structure with an integrated trapdoor was designed to project 2m through the tank side entry portal into the confined space. This innovative solution created limited internal access adequate for personnel to install temporary lighting and lower a fixed ladder to the tank floor via the trap door portal.
- This was the primary means of providing operatives with a safe passage to and from the tank floor.
- A davit arm was clamped onto the cantilevered structure for emergency rescue and retrieval.
Figure 2. Cantilevered Access
Project Conclusion
Given such potentially hazardous conditions, health and safety was central to the operations performed. The confined space Hazard Analysis and Risk Assessment was fundamental to the project prior to carrying out any work within the confined space.