The Federation of Piling Specialists (FPS) has published new guidance for specifying crosshole sonic logging (CSL), to reduce harm to site personnel.

In accordance with their duty under Construction Design and Management Regulations, specifiers must eliminate, substitute or reduce safety risks and must do this when specifying CSL. This can be achieved in the following ways; CSL should be avoided in dry stable rotary piles and small diameter piles where the sonic logging tubes have <300mm clear separation. Consider alternative integrity testing methods. Where CSL must be used, limit its use to the top of the pile within a single cage length to eliminate the need to splice tubes, reduce testing frequency, limit the number of tubes (tube spacing as great as 1.5m is acceptable) and where applicable reuse inclinometer or base grouting tubes.

Further explanation and considerations can be found in the guidance note available for free download on the FPS website: FPS Guidance Note on Considerations for Specifying Crosshole Sonic Logging Test