Standard ARc-FLash Hazard Lable Size

[Humble2000]

Assuming no size limitation, what is the standard (specified) size of these labels (eg 4 x 6 inches)?
Is there a code or regulation to print these labels on a specific size?

 

[Zogzog]

No sixw requirements, the standard is 4x6 for detailed and 4x4 for generic labels, the NEC requires them to be "clearly visiable" to the person operating the equipment.