An exit route must meet minimum height and width requirements. [29 CFR 1910.36(g)] The ceiling of an exit route must be at least seven feet six inches (2.3 m) high. Any projection from the ceiling must not reach a point less than six feet eight inches (2.0 m) from the floor.
4. adjective. In Britain, first-class postage is the quicker and more expensive type of postage. In the United States, first-class postage is the type of postage that is used for sending letters and postcards. Two first class stamps, please. The price of mailing a first-class letter will not be increasing this year.
In order to qualify as a postcard and get the lower rate, however, it must be within certain size limits and of a specific shape. In the US, first class postage for a postcard is about 40% less than first class postage for a letter. Postcards for personal use are typically sent using this standard first class postcard rate.