Flag Half-Staff History and Protocol
The term “half mast” is used in International English. In American English, “half staff” is used on land and “half mast” aboard ship.
The tradition of flying a flag at half-mast is believed to have begun in the XVII Century. The space above the national flag represents the “invisible flag of Death.”
There is confusion over where on a staff a flag should be positioned when it is at half-staff. British protocol specifies a flag should be not less than 2/3 the way up the staff.
In the United States, some people take the phrase “half staff” literally and fly the flag 1/2 the way up the staff. Vexillologists (people who study the history, symbolism, and usage of flags) hold the flag should be one flag width below the peak of the staff (the space above representing the invisible flag of Death).
In all nations, the flag is raised momentarily to the peak of the staff or mast, then lowered solemnly to the half-staff position.
In the United States Flag Code, there is no specific protocol for flags which cannot be lowered (those on a fixed staff such as an office or a church, those on a gaff such as a porch or a boat, or those displayed flat such as a wall).
For those flags, the American Legion recommends the following:
Fixed staff or gaff: Affix a black ribbon the width of one stripe and the length of the flag to the peak of the staff or gaff.
Wall: Affix a black bow to the centre of the flag, or three black bows across the top of the flag.