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(you)于(yu)罐(guan)(guan)內介質的(de)溫(wen)度、壓力變(bian)化等(deng)原因，儲(chu)(chu)(chu)罐(guan)(guan)不(bu)能完(wan)全裝滿(man)，應(ying)留有(you)一(yi)定的(de)空間，而且(qie)液體儲(chu)(chu)(chu)罐(guan)(guan)工作(zuo)(zuo)時(shi)(shi)液面允許有(you)一(yi)個上下波(bo)動的(de)范(fan)圍。這一(yi)上下波(bo)動范(fan)圍內的(de)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)稱為工作(zuo)(zuo)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)，儲(chu)(chu)(chu)罐(guan)(guan)實(shi)際允許儲(chu)(chu)(chu)存(cun)的(de)最(zui)大(da)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)稱為儲(chu)(chu)(chu)存(cun)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)，所以，儲(chu)(chu)(chu)罐(guan)(guan)公稱容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)最(zui)大(da)，工作(zuo)(zuo)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)最(zui)小(xiao)，儲(chu)(chu)(chu)存(cun)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)居中(zhong)。立式(shi)儲(chu)(chu)(chu)罐(guan)(guan)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)示意(yi)見圖(tu)12.3。液體儲(chu)(chu)(chu)罐(guan)(guan)工作(zuo)(zuo)時(shi)(shi)，其實(shi)際存(cun)量(liang)(liang)(liang)不(bu)得大(da)于(yu)儲(chu)(chu)(chu)存(cun)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)，也不(bu)得小(xiao)于(yu)儲(chu)(chu)(chu)存(cun)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)減去(qu)工作(zuo)(zuo)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)之差。