ASTM symbols follow a simple scheme and a set order: wash (tub shape), bleach (triangle), dry (square), iron (iron) and special care (circle). A circle by itself usually means dry cleaning or wet cleaning. A circle (special care) inside a square (drying) changes "dry" to "tumble dry."
Adding lines, dots and other marks modify these base symbols and adds info. For example, a large X through a symbol negates it or offers a warning, whereas an empty symbol often means that any version of what the symbol represents is OK to use. Thus, a crossed-out triangle means do not bleach, whereas an empty triangle tells you that any bleach will do. Adding two parallel diagonal lines means to use only non-chlorine/oxygen bleach.
One, two or three dots used with the tumble dry and iron symbols indicate cold, medium and hot, respectively. But when used with the washer symbol, the number of dots relates to actual temperatures:
- Six: 200° F/95° C
- Five: 160° F/70° C
- Four: 140° F/60° C
- Three: 120° F/50° C
- Two: 105° F/40° C
- One: 65-85° F/18-30° C
An empty tumble dry symbol allows any heat, while a filled-in circle means no heat. Some tags use a tiny hand to mean hand washing — a bit on the nose, but effective.
Under the wash (tub) or dry (square) symbol, one line means permanent press, two lines indicate delicate or gentle cycle, and zero lines mean to use normal cycle. A single line beneath a dry clean symbol (a circle with a P or F) calls for a mild cycle, and two lines under a wet clean symbol (a circle with a W) means very mild cycle. By the way, the P or F indicate which dry cleaning solvent to use: tetrachloroethylene or petroleum (P) or petroleum solvent only (F).
And the list goes on. There's even a symbol for drying in the shade, which can combine with the symbols for line dry (square with a curved line), drip dry (square with three vertical bars) and lie flat (square with horizontal bar) [source: ASTM].
Clearly, care symbols pack a lot of data into a small space, but experts agree that there's room for improvement. As the need for this article demonstrates, most people don't understand the symbols. Moreover, the current lack of global standards makes providing care labels to other countries inconvenient, expensive and logistically maddening.
"Different standards per country make it difficult to manage and, if you sell your clothing globally, your care labels can become quite long with all required information," said Patrick McGuire, vice president of information technology for Nexgen Packaging. "A more global care-labeling system would help to make managing care labeling more efficient and reduce the required information."