Valve Closure Timing, Direct-Hydraulic Control System
If you have the following. . . | Your pipeline BSDV must. . . | Your USV1 must. . . | Your USV2 must. . . | Your alternate isolation valve must. . . | Your surface-controlled SSSV must. . . | Your LP hydraulic system must. . . | Your HP hydraulic system must. . . |
(1) Process upset | Close within 45 seconds after sensor activation | [no requirements] | [no requirements] | [no requirements] | [no requirements] | ||
(2) Flowline PSHL | Close within 45 seconds after sensor activation | Close one or more valves within 2 minutes and 45 seconds after sensor activation. Close the designated USV1 within 20 minutes after sensor activation. | Close within 24 hours after sensor activation | Complete bleed of USV1, USV2, and the AIV within 20 minutes after sensor activation | Complete bleed within 24 hours after sensor activation. | ||
(3) ESD/TSE (Platform) | Close within 45 seconds after ESD or sensor activation | Close all valves within 20 minutes after ESD or sensor activation. | Close within 60 minutes after ESD or sensor activation | Complete bleed of USV1, USV2, and the AIV within 20 minutes after ESD or sensor activation | Complete bleed within 60 minutes after ESD or sensor activation. | ||
(4) Subsea ESD (Platform) or BSDV TSE | Close within 45 seconds after ESD or sensor activation | Close one or more valves within 2 minutes and 45 seconds after ESD or sensor activation. Close all tree valves within 10 minutes after ESD or sensor activation. | Close within 10 minutes after ESD or sensor activation | Complete bleed of USV1, USV2, and the AIV within 10 minutes after ESD or sensor activation | Complete bleed within 10 minutes after ESD or sensor activation. | ||
(5) Subsea ESD (MODU or other type of workover vessel), Dropped object | [no requirements] | Initiate closure immediately. If desired, you may allow for closure of the tree valves immediately prior to closure of the surface-controlled SSSV. | Initiate unrestricted bleed immediately | Initiate unrestricted bleed immediately. |
30 C.F.R. §250.839