The only standard for civilians in Flag etiquette or flag standards is that the flag should be treated as a living thing. There are no other standards that apply to civilians. The standards stop at official honor guards, the concern with any further depth of regulations would be that spectators at events would not have the ability to show, hold, or present the US Flag in a show of patriotism. There are simple guidelines suggested for civilians which are listed below.
Simple flag respect:
Must be treated as a living thing.(This is a standard)
Must not be laid on, dragged over, or touch the ground.
Must be field of stars up.
Must not be torn or tattered.
Must be carried with respect.
Must not dip to a 45 degree angle or beyond.
When displaying the flag it must be free and can not be bound or restricted.
Below are a few reference links relating to flags.