"Double block-and-bleed system" means two block valves connected in series with a bleed valve or line that can vent the line between the two block valves.
06- 096 C.M.R. ch. 100, § 42
"Double block-and-bleed system" means two block valves connected in series with a bleed valve or line that can vent the line between the two block valves.
06- 096 C.M.R. ch. 100, § 42