Nyob rau hauv ib lub sij hawm luv luv los muab qhov chaw ceev ceev rau loj ntawm cov khoom tsim, zoo rwb thaiv tsev thiab qhov chaw sau tag nrho kev tiv thaiv, xyuas kom meej tias cov khoom nyob rau hauv lub thauj cov kev tiv thaiv.Cov txheej txheem ntawm cia thiab loading, thiab unloading thiab txhim khu kev qha kev tiv thaiv.