(a) If you have an electro-hydraulic control system, you must:
(1) Design the subsea control system to meet the valve closure times listed in paragraphs (b) and (d) of this section or your approved DWOP; and
(2) Verify the valve closure times upon installation. The District Manager may require you to verify the closure time of the USV(s) through visual authentication by diver or ROV.
(b) You must comply with the maximum allowable valve closure times and hydraulic system bleeding requirements listed in the following table or your approved DWOP as long as communication is maintained with the platform or with the MODU or other type of workover vessel:
Valve Closure Timing, Electro-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) Pipeline 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 60 minutes after sensor activation. If you use a 60-minute manual resettable timer, you may continue to reset the time for closure up to a maximum of 24 hours total | [no requirements] | Initiate unrestricted bleed within 24 hours after sensor activation. | ||
| (3) ESD/TSE (Platform) | Close within 45 seconds after ESD or sensor activation | Close within 5 minutes after ESD or sensor activation. If you use a 5-minute resettable timer, you may continue to reset the time for closure up to a maximum of 20 minutes total | Close within 20 minutes after ESD or sensor activation. | Close within 20 minutes after ESD or sensor activation. If you use a 20-minute manual resettable timer, you may continue to reset the time for closure up to a maximum of 60 minutes total | Initiate unrestricted bleed within 60 minutes after ESD or sensor activation. If you use a 60-minute manual resettable timer you must initiate unrestricted bleed within 24 hours | Initiate unrestricted bleed within 60 minutes after ESD or sensor activation. If you use a 60-minute manual resettable timer you must initiate unrestricted bleed within 24 hours. | |
| (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 | Initiate unrestricted bleed within 60 minutes after ESD or sensor activation | Initiate unrestricted bleed within 60 minutes after ESD or sensor activation. | ||
| (5) Subsea ESD (MODU or other type of workover vessel, Dropped object) | [no requirements] | Initiate valve closure immediately. You may allow for closure of the tree valves immediately prior to closure of the surface-controlled SSSV if desired. | Initiate unrestricted bleed immediately | Initiate unrestricted bleed within 10 minutes after ESD activation. |
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(c) If you have an electro-hydraulic control system and experience a loss of communications (EH Loss of Comms), you must comply with the following:
(1) If you can meet the EH Loss of Comms valve closure timing conditions specified in the table in paragraph (d) of this section, you must notify the appropriate District Office within 12 hours of detecting the loss of communication.
(2) If you cannot meet the EH Loss of Comms valve closure timing conditions specified in the table in paragraph (d) of this section, you must notify the appropriate District Office immediately after detecting the loss of communication. You must shut-in production by initiating a bleed of the low pressure (LP) hydraulic system or the high pressure (HP) hydraulic system within 120 minutes after loss of communication. You must bleed the other hydraulic system within 180 minutes after loss of communication.
(3) You must obtain approval from the appropriate District Manager before continuing to produce after loss of communication when you cannot meet the EH Loss of Comms valve closure times specified in the table in paragraph (d) of this section. In your request, include an alternate valve closure timing table that your system is able to achieve. The appropriate District Manager may also approve an alternate hydraulic bleed schedule to allow for hydrate mitigation and orderly shut-in.
(d) If you experience a loss of communications, you must comply with the maximum allowable valve closure times and hydraulic system bleeding requirements listed in the following table or your approved DWOP:
Valve Closure Timing, Electro-Hydraulic Control System With Loss of Communication
| 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) Pipeline PSHL | Close within 45 seconds after sensor activation | Initiate closure when LP hydraulic system is bled (close valves within 5 minutes after sensor activation). | Initiate closure when HP hydraulic system is bled (close within 24 hours after sensor activation) | Initiate unrestricted bleed immediately, concurrent with sensor activation | Initiate unrestricted bleed within 24 hours after sensor activation. | ||
| (3) ESD/TSE (Platform) | Close within 45 seconds after ESD or sensor activation | Initiate closure when LP hydraulic system is bled (close valves within 20 minutes after ESD or sensor activation). | Initiate closure when HP hydraulic system is bled (close within 60 minutes after ESD or sensor activation) | Initiate unrestricted bleed concurrent with BSDV closure (bleed within 20 minutes after ESD or sensor activation) | Initiate unrestricted 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 | Initiate closure when LP hydraulic system is bled (close valves within 5 minutes after ESD or sensor activation). | Initiate closure when HP hydraulic system is bled (close within 20 minutes after ESD or sensor activation) | Initiate unrestricted bleed immediately | Initiate unrestricted bleed immediately, allowing for surface-controlled SSSV closure. | ||
| (5) Subsea ESD (MODU or other type of workover vessel), Dropped object | [no requirements] | Initiate closure immediately. You may allow for closure of the tree valves immediately prior to closure of the surface-controlled SSSV if desired. | Initiate unrestricted bleed immediately | Initiate unrestricted bleed immediately. | |||
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