No employer shall require or permit the building of stacks which consist of successive tiers, one on top of another, unless -
(a) the stacking operation is executed by or under the personal supervision of a person with specific knowledge and experience of this type of work;
(b) the base is level and capable of sustaining the weight exerted on it by the stack;
(c) the articles in the lower tiers are capable of sustaining the weight exerted on them by the articles stacked above them;
(d) all the articles which make up any single tier are consistently of the same size, shape and mass;
(e) pallets and containers are in good condition; and
(f) any support structure used for the stacking of articles is structurally sound and can support the articles to be stacked on it.