1. Hwɛ sɛnea ɛte .
Paw dade nhama a ne kɔla yɛ pɛ, ɛyɛ mmerɛw ne nea ɛwɔ mu ne nea ɛwɔ akyi mpo, na ahurututu, ntini, efĩ, anaa sintɔ afoforo a ɛka nneɛma a ɛwɔ soro no yɛ adwuma.
2. Hwɛ nea wɔakyerɛw so .
Ɛsɛ sɛ dadeɛ paipu no nya nsɛm a emu da hɔ te sɛ afiri no din, nominal outer diameter, ne implementation standard number. Hwɛ sɛ labeling no ne paipu ankasa no hyia.
3. Hwɛ nea ɔyɛe no .
Nea ɔyɛ dade nhama nso ho hia sɛ wususuw ho bere a worepaw dade nhama no. Ɛyɛ papa sɛ wobɛpaw nneɛma a ɔyɛfo a ɔwɔ din pa ayɛ na ama woanya awerɛhyem kɛse.