NATURAL GAS DISTRIBUTION SYSTEM
Emergency shutdown of the fuel gas system or a portion of the system, due to firewould necessitate the isolation of the affected location by closing appropriate blockvalves and allowing the line to depressurize. If there is no fire, after isolation, depressurize the affected piping to a safe location and maintain firefighting equipment and supplies in a readily accessible location. It should be allowed to depressurize at the fire location after isolation valves are gas system to a safe location, preferably a vent header and to flare, and purge the system with nitrogen.

Не могу понять последнее предложение..
"Должна быть предусмотрена возможность сброса давления в месте возгорания...

Как будто что-то лишнее или перепутан порядок слов..

Спасибо.