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PSI is a type of pressure unit, defined as pound/square inch, 145psi = 1Mpa
Quality traffic unit SCCM, standard-state cubic centimeter per minute
DB is the unit of sound pressure level, which is recorded as DB and used to indicate the sound size.
The most faint voice that human ears can hear is about 1 decibel, the stable breathing sound and the leaf swinging sound are about 10 decibel, And the surging stream sound is about 20 decibel, the soft voice is about 20-30 decibels, the soft light music is about 40 decibels, the moderate voice is about 45 decibels, and the intermediate volume of the radio and TV is about 50-60 decibels, the loud noises and noise in the office are about 60 decibels, the noise in the city street is about 70 decibels, and the noise in the children is about 60 fo 80 decibels, the noise of busy streets is about 90 decibels, and the noise of heavy trucks is about 90-90 ~ 100 decibels, the roar of a motorcycle is about 105 decibels, the thunder is about 110 decibels, the sound of an amplifier is about 120 decibels, and the sound of a jet engine is about 150 decibels, about 140 ~ 170 decibels.
English unit of pressure
