What a shared duty means in daily practice
It means neither party can discharge its obligation by pointing at the other. A site that knows about a hazard has to tell the contractor about it. A contractor bringing equipment or chemicals into a workplace has to explain what that introduces. Where the two interact, such as cleaning during operating hours or working near plant, the arrangement has to be agreed rather than left to whoever is present.
The word that does most of the work is consultation. It is not a form. It is a conversation before the work starts and again when something changes, with a record that it happened. A walkthrough where the site's safety contact and the contractor walk the premises together and write down what they agreed is the practical form this usually takes, and it takes an hour.
