Kev lag luam tseem ceeb suav nrog cov ntaub pua plag, pem teb thiab lwm yam khoom siv hauv tsev, ua haujlwm rau cov tsev so hnub qub, qib A cov chaw ua haujlwm, cov tsev siab thiab cov tsev nyob. raws li muaj ntau cov khoom lag luam ntawm cov ntaub pua plag, SPC yas nias plank nrog nraub qaum, ntaub pua plag khoom siv, thiab lwm yam.