If the operation of the system will produce a flammable mixture in the piping which will carry it to the storage tanks, an approved flame arrestor, tested in accordance with the applicable provisions of Article 7, shall be properly installed in vapor return piping between the shear section and the storage tank.
EXCEPTION: An approved automatic fire check may be installed in lieu of an approved flame arrestor.
Cal. Code Regs. Tit. 19, § 1918.61
Note: Authority cited: Section 41956, Health and Safety Code. Reference: Sections 41956 and 41958, Health and Safety Code.