A gate or ball type valve can be used or the isolation valve can be installed further upstream. 可以采用閘閥或球閥，或者可以將隔離閥安裝在更上游的地方。
A butterfly isolation valve cannot be installed directly to the valve inlet flange, as the disc will contact the orifice plate. 蝶閥隔離閥不能夠直接安裝在閥門(mén)進(jìn)口法蘭上，因為其閥瓣將會(huì )接觸到節流板。
Where piping being tested extends beyond the process unit limit without flanges, it shall be tested to the first block valve or set of flanges outside the unit limits. 如果試壓管道超出了工藝裝置界區而沒(méi)有法蘭時(shí)，則應試壓至裝置界區外的第一個(gè)隔斷閥或第一組法蘭。
