Scaffold platforms must be fully planked or decked, and generally the gap between planks or between the platform and uprights must not exceed:

解析

Platforms must be fully planked or decked between the front uprights and the guardrail supports, and the space between the platform and the uprights must be no more than 1 inch. The only relief runs the other way from what candidates expect: the gap may open to 9 1/2 inches where the employer can demonstrate that a wider space is necessary to fit the platform around the uprights, and the space between adjacent planking units must still be closed up. Two, three and six inches are each wide enough to drop a hammer through onto the crew below or to catch a boot, and none of them appears in the standard as a general allowance.