儲罐的容量與其幾何尺寸有關。按鋼材耗量最小的原則，對大型的立式儲(chu)罐，當公稱容量在1000～2000mm³時，取高度約等于直徑；對3000mm³以上的儲罐取高度等于3/8～3/4的直徑較為合理。儲罐的公稱容量是指按幾何尺寸計算所得的容量，向上或向下圓整后以整數表示的容量。

  由于罐內介質的(de)(de)(de)溫度、壓(ya)力變化(hua)等原因，儲(chu)(chu)罐不能完全裝滿，應留有一定的(de)(de)(de)空間，而(er)且液體(ti)儲(chu)(chu)罐工(gong)作(zuo)時液面允許有一個上(shang)下波(bo)動(dong)的(de)(de)(de)范(fan)圍(wei)(wei)。這一上(shang)下波(bo)動(dong)范(fan)圍(wei)(wei)內的(de)(de)(de)容(rong)(rong)量稱為工(gong)作(zuo)容(rong)(rong)量，儲(chu)(chu)罐實際允許儲(chu)(chu)存(cun)(cun)的(de)(de)(de)最(zui)(zui)大容(rong)(rong)量稱為儲(chu)(chu)存(cun)(cun)容(rong)(rong)量，所以，儲(chu)(chu)罐公稱容(rong)(rong)量最(zui)(zui)大，工(gong)作(zuo)容(rong)(rong)量最(zui)(zui)小，儲(chu)(chu)存(cun)(cun)容(rong)(rong)量居(ju)中。立式儲(chu)(chu)罐容(rong)(rong)量示意見圖12.3。液體(ti)儲(chu)(chu)罐工(gong)作(zuo)時，其實際存(cun)(cun)量不得大于儲(chu)(chu)存(cun)(cun)容(rong)(rong)量，也不得小于儲(chu)(chu)存(cun)(cun)容(rong)(rong)量減(jian)去工(gong)作(zuo)容(rong)(rong)量之差。