8.41. If the water table is reached during excavation work to install an underground tank, the contractor or owner-builder must comply with the following requirements:(1) the up-lift stress of the tank must be calculated and a copy of the calculation must accompany the analysis documents and be sent to the owner to be filed in the petroleum equipment installation register that the owner must make available to the Board in accordance with Chapter VI of the Safety Code (chapter B-1.1, r. 3) made under the Building Act (chapter B-1.1); (2) the calculation must be based on the highest estimated water-level elevation;
(3) if the calculation indicates that the up-lift stress is such that an empty tank could be displaced, the tank must be anchored by anchor straps attached to a reinforced concrete slab or to anchor weights under the tank, by ground anchors or by use of a reinforced concrete slab above the tank;
(4) the size of the slab or anchors must be designed on the basis of the up-lift stress to which the empty tank will be submitted and in a manner to prevent it from lifting;
(5) the tank must be separated from a concrete slab or anchor weight by a layer at least 300 mm thick of a backfill material referred to in section 8.33;
(6) every anchor strap or ground anchor must be electrically insulated from the tank, be installed in such a manner that it does not damage the tank’s protective coating, and be tightened by hand in the case of a strap; and
(7) the strength of the anchor straps and ground anchors must be determined on the basis of the factors mentioned in paragraph 4.