An employer must require or permit the building of stacks which consist of successive tiers, one on top of another, unless -
- the stacking operation is executed by or under the personal supervision of a person with specific knowledge and experience of this type of work;
- the base is level and capable of sustaining the weight exerted on it by the stack;
- the articles in the lower tiers are capable of sustaining the weight exerted on them by the articles stacked above them;
- all the articles which make up any single tier are consistently of the same size, shape and mass;
- pallets and containers are in good condition; and
- any support structure used for the stacking of articles is structurally sound and can support the articles to be stacked on it.