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(guan)內介(jie)質的(de)(de)溫度(du)、壓(ya)力變化等原因，儲(chu)(chu)(chu)罐(guan)不能完全(quan)裝滿(man)，應留有(you)一(yi)定(ding)的(de)(de)空間，而(er)且(qie)液(ye)(ye)體(ti)儲(chu)(chu)(chu)罐(guan)工(gong)(gong)作時(shi)液(ye)(ye)面允許(xu)有(you)一(yi)個上(shang)下(xia)波動的(de)(de)范(fan)圍。這一(yi)上(shang)下(xia)波動范(fan)圍內的(de)(de)容(rong)(rong)量(liang)(liang)稱(cheng)為工(gong)(gong)作容(rong)(rong)量(liang)(liang)，儲(chu)(chu)(chu)罐(guan)實際允許(xu)儲(chu)(chu)(chu)存(cun)的(de)(de)最大容(rong)(rong)量(liang)(liang)稱(cheng)為儲(chu)(chu)(chu)存(cun)容(rong)(rong)量(liang)(liang)，所(suo)以，儲(chu)(chu)(chu)罐(guan)公稱(cheng)容(rong)(rong)量(liang)(liang)最大，工(gong)(gong)作容(rong)(rong)量(liang)(liang)最小，儲(chu)(chu)(chu)存(cun)容(rong)(rong)量(liang)(liang)居(ju)中。立式儲(chu)(chu)(chu)罐(guan)容(rong)(rong)量(liang)(liang)示意見(jian)圖(tu)12.3。液(ye)(ye)體(ti)儲(chu)(chu)(chu)罐(guan)工(gong)(gong)作時(shi)，其實際存(cun)量(liang)(liang)不得大于儲(chu)(chu)(chu)存(cun)容(rong)(rong)量(liang)(liang)，也不得小于儲(chu)(chu)(chu)存(cun)容(rong)(rong)量(liang)(liang)減去工(gong)(gong)作容(rong)(rong)量(liang)(liang)之差。