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(jie)質(zhi)的溫(wen)度、壓(ya)力變化等原因，儲(chu)(chu)(chu)(chu)(chu)罐不能完全裝滿，應留(liu)有一定的空間，而且液(ye)體(ti)儲(chu)(chu)(chu)(chu)(chu)罐工(gong)作時液(ye)面允(yun)許有一個(ge)上下波(bo)動的范圍。這一上下波(bo)動范圍內的容(rong)(rong)量(liang)(liang)稱(cheng)為(wei)工(gong)作容(rong)(rong)量(liang)(liang)，儲(chu)(chu)(chu)(chu)(chu)罐實際允(yun)許儲(chu)(chu)(chu)(chu)(chu)存(cun)(cun)的最大容(rong)(rong)量(liang)(liang)稱(cheng)為(wei)儲(chu)(chu)(chu)(chu)(chu)存(cun)(cun)容(rong)(rong)量(liang)(liang)，所以，儲(chu)(chu)(chu)(chu)(chu)罐公稱(cheng)容(rong)(rong)量(liang)(liang)最大，工(gong)作容(rong)(rong)量(liang)(liang)最小(xiao)，儲(chu)(chu)(chu)(chu)(chu)存(cun)(cun)容(rong)(rong)量(liang)(liang)居(ju)中。立式(shi)儲(chu)(chu)(chu)(chu)(chu)罐容(rong)(rong)量(liang)(liang)示(shi)意見圖(tu)12.3。液(ye)體(ti)儲(chu)(chu)(chu)(chu)(chu)罐工(gong)作時，其實際存(cun)(cun)量(liang)(liang)不得大于儲(chu)(chu)(chu)(chu)(chu)存(cun)(cun)容(rong)(rong)量(liang)(liang)，也不得小(xiao)于儲(chu)(chu)(chu)(chu)(chu)存(cun)(cun)容(rong)(rong)量(liang)(liang)減去工(gong)作容(rong)(rong)量(liang)(liang)之差。