ISO 11540: 2014 Writing and Marking Instruments — Pen Cap Specification Testing
ISO 11540 Standard Testing for Preventing Children from Pen Cap Asphyxiation: Children often have the habit of sucking their fingers. After starting school, pen caps naturally become substitutes for their fingers, which is obviously very dangerous.
If children suck on pen caps and the size and shape of the pen caps are easy to be sucked and swallowed, they may suffocate as a result. The consequence may be fatal. This is a danger that cannot be ignored for lower-grade school-age children
ISO 11540: 2014 specifies the requirements for reducing the asphyxiation risk of the caps of writing and marking instruments.
It covers such instruments that may be used by children under 14 years old under normal or foreseeable circumstances.
ISO 11540: 2014 does not apply to the following situations: Writing and marking instruments designed for or only used by adults (such as jewelry pens, precious fountain pens, professional technical pens, etc.).