WorkSafe High Hazard Unit are looking for input on a set of guidelines for pipe jacking pipes under 3 metre diameter with reference to the UK pipe jacking Association "guidance for designers". A copy of this document is attached (refer particularly to the table in Appendix 2). Essentially this is a table that describes permissible length and diameter for pipe jacking techniques. WorkSafe are looking to adopt this in the form of a best practice guideline.
A workshop was held recently in Auckland which was attended by 24 industry representatives including contractors, consultants and asset owners, I am waiting on a reply from WorkSafe if other workshops are proposed around the country, I will pass on if any are planned.
The possible consequence of adopting such a guideline is that current techniques used for hand excavation of short length, small diameter pipelines may become restricted or prohibited. This would mean mechanised methods would effectively become mandatory with consequential time and cost implications. Please note that the guidelines would only apply to those works deemed to fall under the HSE (Mining Operations and Quarrying Operations) Regulations 2013.
The Australasian Tunnelling Society (New Zealand chapter) has agreed with WorkSafe to solicit and compile feedback from the industry representatives.