Trenching and excavation works make up a large and important part of the construction industry. Trench collapses can be attributed to several worker fatalities every year.
With regard to trenching, a common misunderstanding involves the depth at which benching or battering should begin. On many occasions duty holders who are responsible for the trenching works have begun the benches or battering at a depth of 1.5 metres, this is incorrect for work in Victoria.
Benching and battering should be started at a depth of 1 metre. The rule is one metre up and one metre back. This rule is depicted in WorkSafe’s Excavation Compliance Code.
The misunderstanding around whether to bench or batter at 1 metre or 1.5 metres has arisen from 2 reasons:
The information on high risk construction work contained in the OHS regulations 2017. The regulations state that high risk work is any work carried out in or near a shaft or trench with an excavated depth greater than 1.5 metres; At this depth or greater a written Safe Work Method Statement (SWMS) is a legal requirement and the work must be undertaken as per the SWMS.
WorkSafe require notification of excavation work involving a trench if the excavated depth is more than 1.5 metres (Note: this is not required if it part of works under an existing building permit)
Failing to bench or batter a trench at 1 metre can create a situation where, should there be a trench wall collapse, an additional half metre load of soil material could fall onto a worker crouched in the bottom of the trench. This additional soil load can weigh several hundreds of kilos and result in fatalities from crushing or suffocation.
So remember the rule. One metre up and one metre back. Happy digging.
Are your people competent?
Elliott Safety has developed a PowerPoint training presentation on Excavation and Trenching Safety that you can purchase and use as internal training for your site teams. Contact us for more information.
WorkSafe Victoria – Excavation Compliance Code 2019: https://content.api.worksafe.vic.gov.au/sites/default/files/2020-02/ISBN-Compliance-code-excavation-2019-12.pdf
SafeWork NSW – Code of Practice Excavation Work 2020