94-11601. Safety Requirements Governing Production Platforms and Pipelines  

  • [Federal Register Volume 59, Number 93 (Monday, May 16, 1994)]
    [Unknown Section]
    [Page 0]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 94-11601]
    
    
    [[Page Unknown]]
    
    [Federal Register: May 16, 1994]
    
    
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    DEPARTMENT OF THE INTERIOR
    
    Minerals Management Service
    
    30 CFR Part 250
    
    RIN 1010-AB52
    
     
    
    Safety Requirements Governing Production Platforms and Pipelines
    
    AGENCY: Minerals Management Service, Interior.
    
    ACTION: Proposed rule.
    
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    SUMMARY: This rule proposes to revise various safety-related 
    regulations regarding the design and operating procedures of production 
    platforms and pipelines in the Outer Continental Shelf (OCS). The 
    purpose of the revisions is to reduce or prevent the unintentional 
    release of hydrocarbons from pipelines on or near offshore platforms 
    during emergency situations and thereby reduce the potential for 
    explosions or fires.
    
    DATES: Comments must be received or postmarked no later than July 15, 
    1994.
    
    ADDRESSES: Comments should be mailed or hand-carried to the Department 
    of the Interior, Minerals Management Service, Mail Stop 4700, 381 Elden 
    Street, Herndon, Virginia 22070-4817; Attention: Chief, Engineering and 
    Standards Branch.
    
    FOR FURTHER INFORMATION CONTACT: Paul Schneider, Technology Assessment 
    and Research Branch, telephone (703) 787-1559, or Bill Hauser, 
    Engineering and Standards Branch, telephone (703) 787-1600.
    
    SUPPLEMENTARY INFORMATION:
    
    Background
    
        The MMS is proposing to revise regulations governing design, 
    operation, and maintenance of oil and gas facilities in the OCS. These 
    revisions were recommended by an internal task group that reviewed 
    information on tow tragic offshore incidents in 1988 and 1989.
    
    Safety Review Task Group
    
        A safety review task group of MMS personnel was established to 
    review available information in the 1988 Piper Alpha platform fire in 
    the North Sea and the circumstances related to an interactive pipeline 
    and platform fire in 1989 at ARCO Oil and Gas Company's (ARCO) South 
    Pass 60 Platform ``B'' facility in the Gulf of Mexico. The group was 
    asked to make specific recommendations regarding regulations and 
    operating practices that would reduce the risk of such incidents 
    occurring in U.S. waters. Following is a capsule summary of each 
    incident.
    
    Explosion and Fire on Piper Alpha Platform, North Sea, 1988
    
        Piper Alpha was an oil and gas production platform in the United 
    Kingdom (U.K.) sector of the North Sea that was destroyed by fire in 
    1988. On July 6, 1988, a series of events and operational mistakes 
    caused an explosion and fires that ultimately destroyed the platform 
    and killed 167 people. Maintenance personnel mistakenly activated an 
    out-of-service injection pump causing a repair flange in the pipework 
    to rupture. Liquid condensate leaked into the production module for 
    several minutes. The gas ignited and exploded, damaging the electrical 
    power generator and the fire pumps. Eventually the fire ruptured the 
    shut-in gas pipelines releasing high pressure gas on the platform. The 
    fire burned for several hours until the pressure was relieved. The 
    platform was completely destroyed.
        The Public Inquiry into the Piper Alpha Disaster was published by 
    Her Majesty's Stationery Office, London, in November 1990. The report 
    confirmed the conclusions reached in the initial investigation report 
    published in September 1988. The report concluded that in all 
    likelihood the scenario of the leaking blind flange in the condensate 
    injector pump was the initial cause of the incident. The report lists 
    106 recommendations for improving safety in the U.K. North Sea. The 
    recommendations propose changes to the regulations, regulatory agency 
    realignment, and a call for renewed commitment to safety by industry.
    
    Summary of South Pass 60 Platform ``B'' Fire
    
        On March 19, 1989, an offshore contracting crew was ``cold-
    cutting'' an 18-inch gas line riser at the platform's 10-foot level in 
    preparation for the installation of a pig trap. ``Cold cutting'' is a 
    method of cutting through a section of pipe with a mechanical cutting 
    tool as opposed to using a blow torch. Upon penetration into the 
    pipeline riser, pressurized condensate began to spray from the cut 
    area. The condensate was ignited either by sparks generated on the 
    compressor skid on an attendant workboat or by hot exhaust pipes on the 
    above production deck. The fire raged upward from the riser, and the 
    emergency shutdown (ESD) system shut down both Platform ``B'' and 
    Platform ``E'' and all incoming and departing pipelines. Six of the 10 
    incoming and departing pipelines, including a high pressure gas line, 
    ruptured from the heat of the fire. The resulting explosions killed 
    seven people and destroyed the platform.
    
    Federal Register Notice on Subsea Pipeline Valves
    
        In support of the work of the task group, MMS published a Federal 
    Register Notice dated July 23, 1990 (55 FR 29860), seeking information 
    on subsea shutdown valve (SDV) technology and feasibility and offshore 
    emergency pipeline pressure reduction techniques. Thirty companies and 
    organizations representing oil- and gas-related industries responded to 
    the questionnaire. Their responses are discussed later in the preamble.
    
    Task Group Findings
    
        The MMS task group identified the following areas in the 
    regulations that should be revised:
    
        1. Identification and notification procedures for out-of-service 
    safety devices and systems.
        2. Location and protection of pipeline risers.
        3. Diesel and helicopter fuel storage areas and tanks.
        4. Approval of pipeline repairs.
        5. Location of ESD valves on pipelines.
    
    Identification and Notification Procedures for Out-of-Service Safety 
    Devices
    
        A contributing factor to both accidents was the lack of 
    communication and notification to personnel of the platform production 
    systems status. In the Piper Alpha incident, the production crew 
    attempted to start a condensate injection pump that was partially 
    dismantled for repairs during the previous shift. Leaking condensate 
    from the associated pipework of the pump caused the first of a series 
    of explosions and fires. The location of the pump control panel did not 
    allow the operator of the control panel to view the pump or detect the 
    leak. In the South Pass 60 incident, the platform operator and the 
    pipeline company did not provide for adequate planning and coordination 
    of the riser cutting operation. Platform personnel were apparently 
    unaware of the status of the riser cutting operation or the difficulty 
    the contractor was experiencing with the unexpected flow.
        Current regulations for identifying out-of-service devices are 
    found at:
        30 CFR 250.123(c), General platform operations. (1) Surface or 
    subsurface safety devices shall not be bypassd or blocked out of 
    service unless they are temporarily out of service for startup, 
    maintenance, or testing procedures. Only the minimum number of safety 
    devices shall be taken out of service. Personnel shall monitor the 
    bypassed or blocked-out functions until the safety devices are placed 
    back in service. Any surface or subsurface safety device which is 
    temporarily out of service shall be flagged.
        Requirements for out-of-service devices on pipelines are found at 
    30 CFR 250.154(c). If the required safety equipment is rendered 
    ineffective or removed from service on pipelines which are continued in 
    operation, an equivalent degree of safety shall be provided. The safety 
    equipment shall be identified by the placement of a sign on the 
    equipment stating that the equipment is rendered ineffective or removed 
    from service.
        The task group determined that the existing regulations do not 
    provide for adequate communication or warning of out-of-service 
    equipment and may not have prevented an accident similar to Piper Alpha 
    if the same set of circumstances existed in the OCS. The current rule 
    does not ensure that accidental flow of hydrocarbons will not be 
    initiated in process components that are taken out of service, 
    particularly if flow is initiated out of view of a flagged device or 
    control. Flagging requirements for out-of-service equipment and valves 
    need to be revised to ensure that control panels and certain equipment 
    upstream of process equipment or valves are also flagged and that the 
    procedure is documented. The task group recommended that the 
    regulations should include requirements identifying which individuals 
    have the authority to remove flags and to authorize equipment startup. 
    It also recommended that subpart A be revised to include a briefing 
    requirement to ensure that all workers on a production platform are 
    notified of all out-of-service equipment and safety concerns at the 
    beginning of each work shift or upon addition or replacement of 
    personnel.
    
    Location and Protection of Pipeline Risers
    
        From the evidence gathered on Piper Alpha, at least one of the 
    highly pressured risers ruptured when struck by debris falling from the 
    burning platform. The effect of gas escaping from the high pressure 
    pipeline was catastrophic. The escaping gas boiled to the surface, 
    exploded, and burned under the platform for several hours.
        Subpart J of the regulations currently requires risers to be 
    protected only from contact with floating vessels. Protection is 
    usually accomplished by locating risers between the jacket legs or by 
    reinforcing the risers with external protection. The task group 
    recommended that subpart J be revised to add a requirement to provide 
    for riser protection from falling objects as well and that MMS require 
    submission of piping drawings at an early stage in the platform design 
    approval process.
    
    Diesel and Helicopter Fuel Storage Areas and Tanks
    
        During the early stages of the Piper Alpha incident, fuel drums and 
    containers of lubricants and cleaners stored throughout the platform 
    exploded and burned when they were exposed to flames. These materials 
    are stored in a similar manner on U.S. facilities.
        There are no current MMS regulations for fuel storage. The task 
    group recommended that MMS revise the regulations to require operators 
    to store diesel and other flammable liquids on platforms in accordance 
    with the requirements contained in American Petroleum Institute (API) 
    Recommended Practice (RP) 500, Recommended Practice for Classification 
    of Locations for Electrical Installation at Petroleum Facilities. The 
    task group also recommended that the revised regulations require 
    operators to design fuel storage tanks in accordance with API RP 14C, 
    Recommended Practice for Analysis, Design, Installation and Testing of 
    Basic Surface Safety Systems for Offshore Production Platforms.
    
    Approval of Pipeline Repairs
    
        Upon examination of the events leading to the fire on the ARCO 
    ``B'' platform, the task group found that there was a lack of 
    communication and coordination between the platform operator and the 
    pipeline repair company. The task group recommended that the 
    regulations be strengthened by requiring MMS approval for pipeline 
    repairs. The Regional Supervisor, upon being notified that the lessee 
    or right-of-way holder is anticipating a pipeline repair, will consider 
    the complexity of the repair procedure in deciding whether or not to 
    require a written repair plan. Exceptions would be made for pipeline 
    repairs necessitated by imminent harm to the environment or to human 
    safety.
    
    Location of ESD Valves on Pipelines
    
        The Piper Alpha fire and the Arco ``B'' fire were greatly 
    intensified by released gas from pipelines associated with the 
    platforms. In the United States, incoming pipelines are required to 
    have emergency SDV's as a protective measure, but they are often 
    located onboard the platform to allow access for maintenance and 
    testing.
        Locating SDV's away from the process equipment, such as on the 
    seafloor or on the riser close to the waterline, may provide a greater 
    level of protection for the platform but would at the same time reduce 
    accessibility for repair and maintenance. This issue has major safety 
    and reliability implications; therefore, MMS published the advance 
    notice of proposed rulemaking in the Federal Register requesting more 
    information on this subject.
        Thirty responses to the questionnaire were received from the oil 
    and gas industry, including major oil and gas production companies, 
    pipeline operators, and equipment manufacturers. The first 13 questions 
    dealt with locating a pipeline SDV on the seafloor or just above the 
    splash zone. Approximately half of the respondents cited limited access 
    to a valve, particularly those located on the seafloor, for inspection 
    and maintenance purposes as a major area of concern. Nearly half of the 
    commenters suggested that the reliability of subsea valves is unknown 
    or nonexistent. Again, supporting data was very limited. The remaining 
    four questions dealt with pipeline pressure reduction during emergency 
    situations. The results of the questionnaire are discussed after this 
    section.
        For applications in the United States, the task group considered 
    three distinct riser locations for the placement of SDV's: On the 
    platform, on the seafloor, on the vertical portion of the riser below 
    the lowest production deck but above the waterline. The advantages and 
    disadvantages of each location are discussed below:
        The first location considered was ``on the platform.'' Subpart J--
    Pipelines and Pipeline Rights-of-Way, Sec. 250.154(b)(2) requires that,
    
    Incoming pipelines boarding to a production platform shall be 
    equipped with an automatic shutdown valve (SDV) immediately upon 
    boarding the platform * * *
    
        This regulation allows placement of the SDV on the deck where the 
    riser enters the platform. ``Immediately upon boarding'' means near the 
    edge of the platform. Accessibility for testing and maintenance is the 
    greatest advantage to this location since the valve is located within 
    the platform structure. Also, since the valve is located in close 
    proximity of the production processing equipment, there is little or no 
    hydrocarbon inventory between the valve and the process equipment that 
    needs to be vented in the event of an emergency. However, this location 
    also presents the greatest potential safety hazard. Since the valve is 
    located near the process equipment, it is vulnerable to damage from 
    explosions, extreme heat from fires, and falling debris during 
    emergency situations. The task group determined that the valve in this 
    location does not fulfill the intended purpose of an SDV in all 
    situations since failure of the SDV or pressured portion of the riser 
    would likely result in the release of a significant portion of the 
    pipeline inventory at the point of failure. This vulnerability was 
    demonstrated in the Piper Alpha disaster and the South Pass 60 fire.
        Next, the task group considered locating SDV's on the seafloor a 
    short distance from the platform. The safety advantage of this location 
    is obvious. The valve is isolated from the platform and is not 
    vulnerable to explosions or fire that may occur during an emergency 
    situation. However, a major drawback of this location is 
    inaccessibility for maintenance and testing, especially in deep water. 
    At this location, the valve would isolate the majority of the pipeline 
    inventory from the platform. However, there may be a significant 
    hydrocarbon inventory in the riser between the valve on the seafloor 
    and the process equipment. This inventory must be safely vented when 
    the pipeline is depressurized during an emergency after the valve is 
    closed.
        Lastly, the task group considered locating SDV's on the vertical 
    portion of risers below the lowest production deck of the platform but 
    above the waterline. This location offers several advantages. The valve 
    is removed from and placed below the hydrocarbon process areas within 
    the platform, thereby isolating it from potential explosion and fire 
    damage during emergency situations. Also, it effectively isolates the 
    entire inventory of the pipeline from the platform since there is a 
    minimal length of riser between the valve and the process equipment 
    that must be vented during emergency situations, and the valve is above 
    the waterline and is accessible for maintenance and testing.
        Considering the information gathered from the Federal Register 
    Notice and additional information regarding subsea valve installations 
    in the U.K. North Sea, the task group concluded that locating such 
    valves on risers or on the seafloor was technically feasible. Other 
    aspects of the current regulation were also reviewed. The task group 
    considered the current regulation which requires SDV's to be installed 
    on incoming pipelines only. Based on the events that occurred on Piper 
    Alpha, the task group determined that there is a significant potential 
    hazard from blackflow of pressured hydrocarbons from departing 
    pipelines. Therefore, the task group recommended requiring SDV's on all 
    new pipelines entering and departing production platforms. This 
    requirement should also apply to sulphur operations since sulphur is 
    also flammable and poses a significant threat to safety. This 
    requirement would cover bidirectional pipelines, crossing pipelines, 
    fuel lines, and pipelines carrying flammable or hazardous fluids. 
    Crossing pipelines that enter onto platforms but do not take on 
    production from those platforms pose an environmental risk, if not a 
    risk to human safety. Therefore, crossing pipelines should also be 
    required to have SDV's installed on the incoming and departing risers.
    
    Responses to the Questions in the July 23, 1990, Federal Register 
    Notice
    
        The following represents a summary of the responses received and 
    does not necessarily reflect the opinion of MMS.
        Question--If the SDV was located on the seafloor or just above the 
    splash zone, how would the following parameters be affected?
        (a) Maintenance.
        Response--Subsea maintenance poses a major problem, especially for 
    deep water which would be difficult during rough seas and winter 
    months. This jeopardizes the operation of the pipeline during those 
    periods. Preventative subsea maintenance would be impractical while 
    maintenance by divers would pose an additional safety risk. Minor and 
    major repairs of a valve would most likely require removal from the 
    pipe which is dangerous in itself and would require shutting down the 
    pipeline system for extended periods.
        The splash zone is the most corrosive offshore environment. The 
    cyclical wetting and drying of surface materials accelerate the 
    corrosion process and degrades protective coatings. At the splash zone, 
    increased maintenance would be required and most platforms have limited 
    access in this area. Splash zone maintenance could not be performed 
    during rough seas or winter months, thus jeopardizing the operation of 
    the pipeline during those periods. Control lines would also be exposed 
    to the corrosive wet/dry environment. Requiring SDV's to be located 
    subsea or at the splash zone increases the safety risk to personnel and 
    reduces the pipeline system's reliability.
        The diving cost alone to repair a subsea SDV in 180 feet of water 
    would run between $15,000 and $18,000 per day.
        (b) Inspection.
        Response--Subsea SDV inspection by a diver would be of minimal 
    value. Control systems for subsea valves are more complex than for 
    surface valves. The ability of divers to inspect and perform repairs 
    underwater is questionable and cannot be verified. Inspection and 
    repair operations would be limited by weather conditions.
        Inspection of an SDV above the splash zone is reliable since it can 
    be performed by an engineer or company representative. All inspection 
    information is first hand.
        A typical subsea SDV inspection in 300 feet of water could cost 
    between $20,000 and $30,000 per day.
        (c) Testing.
        Response--Testing subsea valves from a remote station is not 
    reliable and may indicate problems that may or may not exist.
        Dealing with a malfunction during testing could have serious 
    implications due to limited accessibility.
        The higher the SDV is located above the water, the greater its 
    accessibility, maintenance, and performance.
        Frequency of subsea SDV testing should be kept to a minimum in 
    order to maintain valve reliability.
        Testing would be complex. Remote monitoring or divers would be 
    necessary to confirm test results.
        (d) Reliability.
        Response--Reliability is dependent on the individual reliability of 
    all the components that make up the SDV and control system. Subsea 
    valve reliability statistics are not presently available and need to be 
    established.
        It is assumed that the reliability of an SDV functioning on the 
    seafloor would be less than at any other location. Access to the SDV 
    and control lines would be limited and equipment and personnel would be 
    exposed to adverse conditions.
        The reliability of an SDV functioning in the splash zone would be 
    slightly higher. Accessibility would be improved but the valve itself 
    and control lines would be exposed to more adverse conditions.
        (e) Pressure venting.
        Response--Subsurface SDV's would be limited by the static back 
    pressure of the seawater, or vent lines to the surface would be 
    required. This may cause a delay in response time.
        A splash zone SDV would not have back pressure, but gas exhaust 
    would need to be routed to the platform vent system.
        Underwater venting of pipelines is not recommended due to 
    environmental considerations.
        The volume of hydrocarbons vented through the platform flare system 
    would be greater for a subsea SDV than a platform SDV. This is a 
    serious safety consideration.
        The capability to vent pressure from a pipeline should never take 
    the form of bypassing the SDV but should be from the respective ends of 
    the pipelines.
        (f) Bidirectional operations.
        Response--Not affected.
        (g) Pigging operations.
        Response--Subsea valves should be fitted with remote position 
    indicators to ensure the valve is fully open during pigging operations.
        Question--What measures could be taken to enhance performance and 
    reliability--in particular, how could problems identified in response 
    to question one be alleviated?
        Response--Locating the SDV above the maximum wave height would 
    alleviate most problems described in question one. Control lines are 
    relatively short and the valve is readily accessible for maintenance 
    and repairs.
        There are designs where safety can be achieved by other methods. 
    There are also ``economical'' platforms where the producer accepts more 
    risk to reduce facility costs. The location of the SDV should be 
    commensurate with the level of protection afforded to other high-risk 
    facilities on the platform.
        The SDV's should be manufactured from materials which will avoid 
    valve replacement and offer reliable performance. The valve should have 
    manual actuators and quick connect ends to facilitate operation or 
    removal.
        Platform operating decks should be made of plate, not grating. 
    Plate acts as a fire wall. If the deck is made of plate, the SDV can be 
    safely located on the deck.
        The SDV's should be self-operating and fail-safe closed.
        Valves should be routinely inspected and tested as well as 
    continuously monitored.
        The SDV and control system should be protected from mechanical 
    damage.
        Placement of SDV's on the platform would improve reliability but 
    would also minimize their effectiveness.
        Redundant control and instrumentation systems may be desirable. 
    Standards should be established for value specifications and 
    certification. Quality control in manufacturing could also enhance 
    their reliability.
        Valve technology has advanced to the point that reliable subsea 
    operation is available. Advancement in the areas of a valve failure 
    data base and check valve technology could yield further reliability 
    and performance.
        Require a surface SDV as well as a subsea valve.
        Question--What types of SDV's are available that could be located 
    on the seafloor?
        Response--Any valve designed for subsea service such as a quarter 
    turn ball valve, check valve, or a gate valve could perform as an SDV.
        The use of hydraulically operated valves could present a pollution 
    problem.
        It is the actuator that needs to be scrutinized.
        No existing SDV would likely serve the purpose when located on the 
    seafloor.
        Hydraulic or pneumatic systems would be most practical. Some 
    manufacturers have devised an SDV for subsea service.
        Question--What specific limitations would be encountered with 
    regard to placing the SDV at the seafloor location with respect to the 
    following variables?
        (a) Size of valve.
        Response--For the most part, the size of the valve is not a major 
    factor. However, valves over 12 inches in diameter are cumbersome, 
    heavy and difficult to maneuver, and maintain. Valves greater than 36 
    inches in diameter are difficult to obtain.
        The valve and actuator may be quite large and may require 
    mechanical protection.
        (b) Pressure.
        Response--For the most part, pressure is not a major consideration 
    except in deep water. Very large actuators may be needed to overcome 
    extreme differential pressures in deep water.
        (c) Flow rate.
        Response--For low flow rates, the reduced flow may not justify the 
    placement of a seafloor SDV.
        (d) Water depth.
        Response--Water depth has a large effect on diver costs for 
    installation, maintenance, repairs, testing, etc. Deep-water locations 
    also require novel installation methods, additional complexity, and 
    further development of components and testing methods to achieve valve 
    reliability. Some SDV's may be designed for installation and 
    maintenance using a drilling rig. Beyond, 1,000 feet, diverless 
    maintenance and retrieval become major considerations. Common valve 
    operators are limited to water depths of less than 3,000 feet.
        In shallow water, subsea valves would be subjected to potential 
    damage from shipping vessels.
        (e) Types of fluids transported.
        Response--Gas lines that are pressurized contribute a higher risk 
    to platform safety than nonpressurized oil lines.
        (f) Other variables identified by commenters.
        Response--Repairing and replacing subsea SDV's would increase 
    pollution potential.
        Reliable valve operation is the biggest concern. Factors affecting 
    operation include water pressure and severe water forces on the valve 
    and operating lines, hydrate formation, wax build up, etc. Chemical 
    injection may be necessary to prevent hydrate or wax build up.
        The use of seafloor SDV's would preclude the use of J-tube methods 
    of riser installation since the valve could not be passed through the 
    J-tube.
        Sea-bottom conditions may dictate the location of SDV's.
        Protective coverage would be necessary to prevent trawl damage.
        Heavy valves, should they become suspended, will cause additional 
    stress on the pipeline.
        The SDV's located near the waterline would be vulnerable to 
    collisions and wave damage.
        Question--What actuation and control system options are available 
    for placement of the SDV on the seafloor (e.g., pneumatic, hydraulic, 
    electrical)? Would actuation backup capability be necessary or 
    desirable?
        Response--Actuators can be powered by line pressure, stored gas 
    pressure, or hydraulics. Fail-safe operation would be desirable. 
    Pneumatic and hydraulic systems are the most reliable for subsea 
    service. Manual operation is also necessary. Electrical systems could 
    be used, but a backup system would be desirable. It is also necessary 
    to provide manual diver valve actuation for emergency situations.
        Question--What emergency support systems (e.g., fire loop system, 
    ESD system, subsurface safety system) would activate the subsea SDV? 
    Should the conditions of actuation be different than for an SDV located 
    on the platform?
        Response--All ESD and fire loop systems could operate the SDV. 
    There would need to be a control line between the valve actuator and 
    the platform. This could pose a maintenance problem. Pressure sensors 
    could also be installed for the case of a ruptured or blocked line. 
    This would require a relief valve, which brings up the following 
    question. Where would the relief valve relieve to, the seafloor? The 
    foregoing provides yet another reason to have the SDV above water.
        Question--For seafloor placement of the SDV, what would be the 
    optimum location in distance from the platform?
        Response--Distance is not very important. The closer to the 
    platform, the better. This would keep the control lines the shortest. 
    Placing the valve 40 feet below the water surface on the riser would 
    make it accessible to divers while providing its structural protection.
        The location of an SDV relative to the platform should ideally be 
    decided by a quantified risk analysis. The optimum distance for 
    placement of an SDV should be determined on a case-by-case basis, 
    considering water depth, anchorage areas, fishing areas, and minimizing 
    the inventory between the platform and the SDV.
        Question--What effect would burial (either intentional or 
    unintentional) of the valve and actuator have on maintenance and 
    operational reliability?
        Response--Burial would not hurt the SDV, but it would make it 
    harder for divers to find it. Burial would increase the diving costs 
    associated with maintenance. Burial would preclude using a remotely 
    operated vehicle for inspection and maintenance and should be avoided.
        Question--What measures would be necessary to protect a subsea 
    valve and control system from the following effects?
        (a) Temperature.
        Response--The SDV and control system need to be designed to operate 
    in internal and external environments by selection of suitable 
    materials.
        (b) Hydrates.
        Response--Hydrate formation could prevent subsea SDV operation. 
    Glycol injection lines would be required in addition to control lines 
    supplemented with glycol tanks, pumps, and attendant equipment.
        (c) Permafrost.
        Response--Not feasible.
        (d) Hydrogen sulfide.
        Response--The effects of hydrogen sulfide could be controlled with 
    special alloys or inhibitors.
        (e) Carbon dioxide.
        Response--The effects of carbon dioxide could be controlled with 
    special alloys or inhibitors.
        (f) Stress cracking.
        Response.--The effects of stress cracking could be controlled with 
    special alloys.
        (g) Other effects identified by commenters.
        Response.--Control lines and connections could be damaged by boat 
    or fishing activity. Protection will be necessary to protect small 
    lines from being hooked by trawl boats and anchors.
        Sand production could jeopardize the operation of a subsea valve.
        Corrosion protection will be necessary for valve operators and 
    control lines.
        Question--Should SDV's be manufactured, maintained, and repaired in 
    accordance with a certification process similar to the process used 
    with surface and subsurface safety valves?
        Response--API Spec 6D, Specification for Pipeline Valves, is a 
    sufficient standard for valves, so certification is not necessary. 
    Pipeline SDV's are not critical to permanent containment of 
    hydrocarbons. However, proper maintenance of subsea valves may be a 
    bigger issue.
        Question--Would the use of flexible piping impose difficulties to 
    subsea valve?
        Response--Not so long as the pipeline is properly anchored at the 
    valve location. High seas could pose a difficult problem (keeping the 
    pipe still). Also, special support may be necessary for the SDV.
        Question--If an SDV is placed at an alternate seafloor location, 
    should an ADV also be placed on the platform?
        Response--An SDV installed on a platform has a different function 
    than a subsea SDV. The platform SDV mitigates consequences of a 
    hydrocarbon release from the process equipment by isolating the 
    pipeline from those facilities. Subsea SDV's mitigate the consequences 
    of a hydrocarbon release from the pipeline which may occur as a primary 
    or secondary event.
        In general, redundancy is always safer. However, redundancy costs 
    more for equipment and increases the chance for malfunction and 
    platform downtime. Placement of a surface SDV should not be required 
    but considered an option. In general, SDV's should not be placed on the 
    seafloor except in unusual circumstances.
        If an SDV is installed above the splash zone, there is no need for 
    another one on the seafloor.
        Question--Current regulations require SDV's on certain incoming 
    pipelines. What, if any, SDV's should be required on outgoing and 
    crossing pipelines?
        Response--There is no need to place SDV's on all outgoing or 
    crossing pipelines. Adding more valves is not necessary; however, 
    present valves may need to be relocated to safer locations.
        The SDV's should be placed on new outgoing and crossing pipelines. 
    A risk assessment should be performed on existing lines before making 
    such modifications.
        Flow safety valves are adequate and less likely to fail, due to 
    their simplistic design.
        Unmanned platforms that contain no production facilities, no 
    compression, and no power source should not require SDV's.
        Question--What options are available to allow rapid reduction of 
    pipeline pressure in an emergency, and what are the benefits and 
    drawbacks of the techniques?
        Response--Rapid reduction of pipeline pressure is a formidable 
    problem. Flaring at the platform can be a very slow method of reducing 
    pipeline pressure. Strategically located SDV's along the pipeline may 
    offer an alternative to depressurization. An outlying subsea vent is 
    probably safest since it distances the gas from the platform. However, 
    in most cases, rapid pressure reduction is expensive and of limited 
    use.
        There is the damage of the formation of hydrate plugs and liquid 
    plug flow as well as the need to prevent expanding vapor explosions.
        Blowdown on the seafloor or a platform could cause considerable 
    pollution due to entrained liquids and could feed a fire in some 
    instances.
        Blowing down a pipeline at a platform would require a scrubber 
    system to separate liquids. These liquids would need to be disposed of 
    safely which may be difficult during a platform emergency.
        Question--What are the benefits and shortcomings of subsea pipeline 
    diversion?
        Response--System dependability might be enhanced by subsea 
    diversion but not enough to offset additional cost over platform 
    diversion.
        Subsea diversion could place evacuating and rescuing personnel in 
    peril and could pose a significant pollution problem.
        Question--What are the advantages and disadvantages of having the 
    capability to blow down a pipeline from both ends?
        Response--It may be good engineering practice to locate blowdowns 
    at each end of a pipeline. One end may be inaccessible due to fire or 
    failure. If both ends are accessible, a more rapid blowdown can be 
    accomplished. However, the majority of damage and injuries on a 
    platform occurs during the first few minutes and before pressure could 
    be reduced. Actual damage is not likely to be significantly reduced.
        It would be necessary to bypass the check valve of the outgoing 
    line. The bypass would need to be maintained and tested. Facilities for 
    large scrubbing, liquid handling, and flaring would also be required.
        Question--Should pipelines be required to have the capability of 
    rapid reduction of pipeline pressure from either end and, if so, what 
    length of time should be specified as the maximum time for pipeline 
    pressure reduction in an emergency situation?
        Response--Rapid pressure reduction is impractical during 
    emergencies. Larger lines and volumes must be depressurized more 
    slowly.
        The pest solution is accident prevention and efficient platform 
    evacuation. Gas pipeline pressure cannot be reduced fast enough to 
    prevent early damage during a platform emergency.
        In an emergency, evacuation is the primary concern. Flaring large 
    volumes of gas could create a dangerous situation for aircraft and 
    boats.
    
    Summary of Proposed Changes
    
        Based on the report of the task group and the analysis of the 
    responses received following the July 23, 1990, Federal Register 
    Notice, MMS proposes to:
        1. Revise Sec. 250.1, Documents incorporated by reference, to 
    incorporate API's Recommended Practice for Classification of Locations 
    for Electrical Installation at Petroleum Facilities, First Edition, 
    June 1, 1991 (API RP 500), into the regulations. This document replaces 
    API RP 500B, Recommended Practice for Classification of Areas for 
    Electrical Installations at Drilling Rigs and Production Facilities on 
    Land and on Marine Fixed and Mobile Platforms, Second Edition, with 
    Supplement. API RP 500 combined API RP 500A, 500B, and 500C into a 
    single document to provide guidelines for classifying locations at 
    petroleum facilities for the selection and installation of electrical 
    equipment. API RP 500 contains essentially the same information 
    contained in API RP 500B. API RP 500 is referenced in Sec. 250.51(i) to 
    classify fuel and other flammable liquid storage locations. Also, 
    references to API RP 500 replace API RP 500B in Secs. 250.53(b), 
    250.122(e)(4)(i), 250.123(b)(9)(i), 250.291(b)(3) and (d)(4)(i), and 
    250.292(b)(4)(i).
        2. Add a new Sec. 250.27, Safety of operations communication, that 
    requires operators of offshore production platforms to notify incoming 
    or new personnel arriving on the platform of the status of repairs of 
    process equipment, safety systems, or other systems that are out of 
    service. The new regulation also requires operators to maintain records 
    of all communications.
        3. Revise Sec. 250.51, General requirements, to include 
    requirements for fuel storage on offshore facilities.
        4. Revise Sec. 250.123, Additional production system requirements, 
    to be more specific on identifying and deactivating process equipment 
    and controls when safety systems are out of service and maintaining 
    records.
        5. Add a new paragraph, Sec. 250.153(a)(5), that requires operators 
    to protect horizontal sections of pipeline risers from damage by 
    falling objects.
        6. Revise Sec. 250.154 to require pipeline shutdown valves to be 
    located below the lowest production deck on all new pipelines entering 
    and departing OCS platforms. This rule also applies to all pipelines 
    under the jurisdiction of MMS, including production flow lines, 
    gathering lines, sulphur pipelines, fuel lines, bidirectional lines, 
    and crossing pipelines. For existing platforms and pipelines, the rule 
    requires installation or relocation of valves when significant riser 
    repairs or maintenance is performed.
        7. Revise Sec. 250.158 to give the Regional Supervisor authority to 
    require operators to submit written pipeline repair procedures for 
    approval. The preparation and approval of written plans ensure that an 
    operator adequately considers the repair activity.
    
    Author
    
        The principal authors of this proposed rule are Elmer P. 
    Danenberger, Chief, Engineering and Technology Division, and Paul 
    Schneider, Technology Assessment and Research Branch.
    
    Regulatory Flexibility Act
    
        The DOI has also determined that this proposed rule will not have a 
    significant economic effect on a substantial number of small entities 
    because, in general, the entities that engage in activities offshore 
    are not considered small due to the technical complexities and level of 
    financial resources necessary to safely conduct such activities.
    
    Paperwork Reduction Act
    
        This proposed rule adds new information collection requirements to 
    subparts A and J. The information collection requirements contained in 
    this rule have been submitted to the Office of Management and Budget 
    (OMB) for approval as required by the Paperwork Reduction Act (44 
    U.S.C. 3501 et seq.). The collection of this information will not be 
    required until it has been approved by OMB. Public reporting burdens 
    for the new information collection requirements contained in subparts A 
    and J are estimated to average 8 hours per response, including the time 
    for reviewing instructions, searching existing data sources, gathering 
    and maintaining the data needed, and completing and reviewing the 
    collection of information. Send comments regarding these burden 
    estimates or any other aspects of this collection of information, 
    including suggestions for reducing the burden, to the Information 
    Collection Clearance Officer; Minerals Management Service; Mail Stop 
    2053, 381 Elden Street; Herndon, Virginia 22070-4817, and the Office of 
    Management and Budget; Paperwork Reduction Project (1010-0030) for 
    subpart A and (1010-0050) for subpart J; Washington, DC 20503, 
    telephone (202) 395-7340.
    
    Takings Implication Assessment
    
        The DOI certifies that the proposed rule does not represent a 
    governmental action capable of interference with constitutionally 
    protected property rights. Thus, a Takings Implication Assessment need 
    not be prepared pursuant to E.O. 12630, Government Action and 
    Interference with Constitutionally Protection Property Rights.
    
    E.O. 12778
    
        The DOI has certified to OMB that this proposed regulation meets 
    the applicable civil justice reform standards provided in sections 2(a) 
    and 2(b)(2) of E.O. 12778.
    
    National Environmental Policy Act
    
        The DOI has determined that this action does not constitute a major 
    Federal action significantly affecting the quality of the human 
    environment; therefore, preparation of an Environmental Impact 
    Statement is not required.
    
    E.O. 12866
    
        This rule was reviewed under E.O. 12866. The rule was determined to 
    not be a significant rule under the criteria of E.O. 12866 and, 
    therefore, was not reviewed by OMB.
    
    List of Subjects in 30 CFR Part 250
    
        Continental shelf, Environmental impact statements, Environmental 
    protection, Government contracts, Incorporation by reference, 
    Investigations, Mineral royalties, Oil and gas development and 
    production, Oil and gas exploration, Oil and gas reserves, Penalties, 
    Pipelines, Public lands--mineral resources, Public lands--rights-of-
    way, Reporting and recordkeeping requirements, Sulphur development and 
    production, Sulphur exploration, Surety bonds.
    
        Dated: April 4, 1994.
    Bob Armstrong,
    Assistant Secretary, Land and Minerals Management.
    
        For the reasons set forth in the preamble, 30 CFR part 250 is 
    proposed to be amended as follows:
    
    PART 250--OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER 
    CONTINENTAL SHELF
    
        1. The authority citation for part 250 continues to read as 
    follows:
    
        Authority: Sec. 204, Pub. L. 95-372, 92 Stat. 629 (43 U.S.C. 
    1334).
    
        2. In Sec. 250.1, paragraphs (d)(9) and (d)(15) are revised as 
    follows:
    
    
    Sec. 250.1  Documents incorporated by reference.
    
    * * * * *
        (d) * * *
    
        (9) API RP 14C, Recommended Practice for Analysis, Design, 
    Installation and Testing of Basic Surface Safety Systems for 
    Offshore Production Platforms, Fourth Edition, September 1, 1986, 
    API Stock No. 811-07180, incorporated by reference at 
    Secs. 250.51(i); 250.122 (b) and (e)(2); 250.123(a), (b)(2)(i), 
    (b)(4), (b)(5)(i), (b)(7), (b)(9)(v), and (c)(2); 250.124 (a) and 
    (a)(5); 250.152(d); 250.154(b)(12); 250.291 (c) and (d)(2); 250.292 
    (b)(2) and (b)(4)(v); and 250.293(a).
    
    * * * * *
        (15) API RP 500, Recommended Practice for Classification of 
    Locations for Electrical Installations at Petroleum Facilities, 
    First Edition, June 1, 1991, API Stock No. 811-06005, incorporated 
    by reference at Secs. 250.51(i), 250.53(b), 250.122(e)(4)(i), 
    250.123(b)(9)(i), 250.291(b)(3) and (d)(4)(i), and 250.292(b)(4)(i).
    * * * * *
        3. A new Sec. 250.27 is added to subpart A to read as follows:
    
    
    Sec. 250.27  Safety of operations communication.
    
        At the beginning of each crew shift and upon addition or 
    replacement of personnel, incoming workers shall receive safety 
    information relative to activities and repairs underway on the facility 
    and any process or safety equipment that is out of service. This 
    information may be provided through a safety meeting, a notice provided 
    to each employee, or a posted notice that must be read by each 
    employee. A record of this communication shall be kept and maintained 
    at the facility.
        4. In Sec. 250.51, a new paragraph (i) is added to read as follows:
    
    
    Sec. 250.51  General requirements.
    
    * * * * *
        (i) Diesel and other fuel storage tanks, drums containing 
    lubricants, cleaners, and other flammable liquids shall be clearly 
    labeled and located as far as practicable from ignition sources. 
    Storage locations shall be classified in accordance with the American 
    Petroleum Institute (API) Recommended Practice (RP) for Classification 
    of Locations for Electrical Installations at Petroleum Facilities (API 
    RP 500). Tanks shall be adequately vented or equipped in accordance 
    with API RP for Analysis, Design, Installation and Testing of Basic 
    Surface Safety Systems for Offshore Production Platforms (API RP 14C). 
    Fire detection devices, such as fusible plugs, shall be installed in 
    fuel and flammable liquid storage areas.
        5. In Sec. 250.53, paragraph (b) is revised to read as follows:
    
    
    Sec. 250.53  Electrical equipment.
    
    * * * * *
        (b) All areas shall be classified in accordance with API RP 500, 
    Recommended Practice for Classification of Locations for Electrical 
    Installations at Petroleum Facilities.
    * * * * *
        6. In Sec. 250.122, the introductory text of paragraph (e)(4)(i) is 
    revised to read as follows:
    
    
    Sec. 250.122  Design, installation, and operation of surface 
    production-safety systems.
    
    * * * * *
        (e) * * * 
        (4) * * * 
        (i) A plan of each platform deck outlining all hazardous areas 
    classified in accordance with API RP 500, Recommended Practice for 
    Classification of Location for Electrical Installations at Petroleum 
    Facilities, and outlining areas in which potential ignition sources, 
    other than electrical, are to be installed. The area outline shall 
    include the following information.
    * * * * *
        7. In Sec. 250.123, paragraphs (b)(9)(i) and (c)(1) are revised to 
    read as follows:
    
    
    Sec. 250.123  Additional production system requirements.
    
    * * * * *
        (b) * * *
        (9) Fire- and gas-detection system. (i) Fire (flame, heat, or 
    smoke) sensors shall be installed in all enclosed classified areas. Gas 
    sensors shall be installed in all inadequately ventilated, enclosed 
    classified areas. Adequate ventilation is defined as ventilation that 
    is sufficient to prevent accumulation of significant quantities of 
    vapor-air mixture in concentrations over 25 percent of the lower 
    explosive limit (LEL). One approved method of providing adequate 
    ventilation is a change of air volume every 5 minutes or 1 cubic foot 
    of air-volume flow per minute per square foot of solid floor area, 
    whichever is greater. Enclosed areas (e.g., buildings, living quarters, 
    or doghouses) are defined as those areas confined on more than four of 
    their six possible sides by walls, floors, or ceilings more restrictive 
    to air flow than grating or fixed open louvers and of sufficient size 
    to allow entry of personnel. A classified area is any area classified 
    Class I, Group D, Division 1 or 2, following the guidelines of API RP 
    500.
    * * * * *
        (c) General platform operations. (1) Surface or subsurface safety 
    devices shall not be bypassed or blocked out of service unless they are 
    temporarily out of service for startup, maintenance, or testing 
    procedures. Personnel shall monitor the bypassed or blocked-out 
    functions until the safety devices are placed back in service. Any 
    surface or subsurface safety device that is temporarily placed out of 
    service shall be flagged. When conducting repairs or maintenance that 
    expose the production safety system to the atmosphere or to conditions 
    that constitute a potential danger to safety of personnel or protection 
    of the environment, the system shall be purged of hydrocarbons and flow 
    shall be blocked from the area under repair or maintenance. Valves, 
    pumps, or other equipment that could initiate flow through the 
    designated area shall also be flagged and removed from service. The 
    activation of such equipment from the control panel shall be 
    temporarily precluded. Only the person in charge of the repair or 
    maintenance may authorize the resumption of service. This authorization 
    may not be given until the repair or maintenance action is completed.
    * * * * *
        8. In Sec. 250.153, a new paragraph (a)(5) is added to read as 
    follows:
    
    
    Sec. 250.153  Installation, testing, and repair requirements for DOI 
    pipelines.
    
        (a) * * *
        (5) Risers shall be designed to prevent damage from falling debris. 
    Horizontal sections of risers shall be of minimal length and protected 
    to prevent damage from falling objects.
    * * * * *
        9. In Sec. 250.154, paragraphs (b) and (c) are revised to read as 
    follows:
    
    
    Sec. 250.154  Safety equipment requirements for DOI pipelines.
    
    * * * * *
        (b) All new oil, gas, or sulphur pipelines approved or modified 
    after the effective date of these regulations shall comply with this 
    section, where applicable.
        (1)(i) Incoming pipelines to a platform shall be equipped with a 
    flow safety valve (FSV).
        (ii) For sulphur operations, incoming pipelines delivering gas to 
    the power plant platform may be equipped with high- and low-pressure 
    sensors (PSHL), which activate audible and visual alarms in lieu of 
    requirements in paragraph (b)(1)(i) of this section. The PSHL shall be 
    set at 15 percent or 5 psi, whichever is greater, above and below the 
    normal operating pressure range.
        (2) Incoming pipelines boarding to a production platform or 
    delivering gas to a power plant platform shall be equipped with an 
    automatic shutdown valve (SDV) below the lowest production deck of the 
    platform. The SDV shall be connected to the automatic- and remote-
    emergency shut-in systems.
        (3) Departing pipelines receiving production from production 
    platforms shall be protected by PSHL to directly or indirectly shut in 
    all production facilities. The PSHL shall be set not to exceed 15 
    percent above and below the normal operating pressure range. However, 
    high pilots shall not be set above the pipeline's maximum allowable 
    operating pressure.
        (4) Departing pipelines from a production platform shall be 
    equipped with an SDV below the lowest production deck of the platform. 
    The SDV shall be connected to the automatic- and remote-emergency shut-
    in systems in a manner that allows the safe shut in of the platform 
    prior to SDV closure.
        (5)(i) Crossing pipelines on production or manned nonproduction 
    platforms shall be equipped with an SDV on both the incoming and 
    departing lines below the lowest production deck. These SDVs shall be 
    connected to the automatic- and remote-emergency shut-in systems.
        (ii) Crossing pipelines on unmanned nonproduction platforms shall 
    be equipped with an FSV.
        (6) Bidirectional pipelines servicing production or manned 
    nonproduction platforms shall be equipped with a PSHL and an SDV on all 
    risers.
        (7) All SDV's shall be operable locally and connected to the 
    automatic- and remote-emergency shut-in systems. The SDV shall be 
    protected from fire, explosion, and impacts from falling objects and 
    marine vessels. The SDV shall be accessible for inspections, 
    maintenance, repairs, and testing. The SDV shall be inspected and 
    tested at least once each calendar month, but the interval shall not 
    exceed 6 weeks.
        (8) For facilities and pipelines installed prior to the effective 
    date of these regulations, an SDV shall be installed when riser 
    maintenance or repair is performed.
        (9) The Regional Supervisor may require that oil pipelines be 
    equipped with a metering system to provide a continuous volumetric 
    comparison between the input to the line at the structure(s) and the 
    deliveries onshore. The system shall include an alarm system and shall 
    be of adequate sensitivity to detect variations between input and 
    discharge volumes. In lieu of the foregoing, a system capable of 
    detecting leaks in the pipeline may be substituted with the approval of 
    the Regional Supervisor.
        (10) Pipelines incoming to a subsea tie-in shall be equipped with a 
    block valve and a FSV. Bidirectional pipelines connected to a subsea 
    tie-in shall be equipped with only a block valve.
        (11) Gas-lift or water-injection pipelines on unmanned platforms 
    need only be equipped with an FSV installed immediately upstream of 
    each casing annulus or the first inlet valve on the wellhead.
        (12) Pipeline pumps shall comply with Section A7 of API RP 14C. The 
    setting levels for the PSHL devices are specified in paragraph (b)(5) 
    of this section.
        (c)(1) If the SDV or other required safety equipment is rendered 
    ineffective or removed from service on pipelines that are continued in 
    operation, an equivalent degree of safety shall be provided. The 
    affected safety equipment shall be identified by the placement of a 
    sign on the equipment stating that the equipment is rendered 
    ineffective or removed from service.
        (2) When conducting repairs or maintenance to the pipeline system 
    components that expose the pipeline to the atmosphere or to conditions 
    that constitute a potential danger to safety of personnel or protection 
    to the environment, the system shall be purged of hydrocarbons and flow 
    shall be blocked from the area under repair or maintenance. Valves, 
    pumps, or other equipment that could allow or initiate flow through the 
    designated area shall also be flagged and removed from service. 
    Activation of this equipment from the control panel shall be 
    temporarily precluded. Only the person in charge of the repair or 
    maintenance may authorize the resumption of service. This authorization 
    may not be given until the repair or maintenance action is completed.
        10. In Sec. 250.158, paragraph (e) is revised to read as follows:
    
    
    Sec. 250.158  Reports.
    
    * * * * *
        (e)(1) Except for emergency repairs necessary to prevent or 
    minimize pollution or the loss of human life, the lessee or right-of-
    way holder shall notify the Regional Supervisor prior to the repair of 
    any pipeline or pipeline component. Based on the nature of the repair, 
    the Regional Supervisor may require the lessee or right-of-way holder 
    to submit detailed pipeline repair procedures for approval before 
    conducting repairs. The repair procedures shall include the types of 
    equipment and specifications of components used in the repair.
        (2) A detailed report of the pipeline repair shall be submitted to 
    the Regional Supervisor within 30 days after completion of the repair. 
    The report shall include the following:
        (i) Type of damage sustained and cause:
        (ii) Type and volume of hydrocarbons lost due to damage;
        (iii) Specifications of components utilized in the repair and a 
    detailed repair procedure;
        (iv) Results of pressure and other verification tests; and
        (v) Date pipeline or component returned to service.
    * * * * *
        11. In Sec. 250.291, paragraphs (b)(3) and (d)(4)(i) are revised to 
    read as follows:
    
    
    Sec. 250.291  Design, installation, and operation of production 
    systems.
    
    * * * * *
        (b) * * *
        (3) Electrical system information, including a plan of each 
    platform deck that shows:
        (i) All hazardous areas classified in accordance with API RP 500, 
    Recommended Practice for Classification of Locations for Electrical 
    Installations at Petroleum Facilities; and
        (ii) All areas in which potential ignition sources are to be 
    installed;
    * * * * *
        (d) * * *
        (4) * * *
        (i) A plan of each platform deck, outlining all hazardous areas 
    classified in accordance with API RP 500 and outlining areas in which 
    potential ignition sources are to be installed;
    * * * * *
        12. In Sec. 250.292, paragraph (b)(4)(i) is revised to read as 
    follows:
    
    
    Sec. 250.292  Additional production and fuel gas system requirements.
    
    * * * * *
        (b) * * *
        (4) Fire- and gas-detection system. (i) Fire (flame, heat, or 
    smoke) sensors shall be installed in all enclosed classified areas. Gas 
    sensors shall be installed in all inadequately ventilated, enclosed 
    classified areas. Adequate ventilation is defined as ventilation that 
    is sufficient to prevent accumulation of significant quantities of 
    vapor-air mixture in concentrations over 25 percent of the LEL. One 
    approved method of providing adequate ventilation is a change of air 
    volume every 5 minutes or 1 cubic foot of air-volume flow per minute 
    per square foot of solid floor area, whichever is greater. Enclosed 
    areas (e.g., buildings, living quarters, or doghouses) are defined as 
    those areas confined on more than four of their six possible sides by 
    walls, floors, or ceilings more restrictive to air flow than grating or 
    fixed open louvers and of sufficient size to allow entry of personnel. 
    A classified area is any area classified Class I, Group D, Division 1 
    or 2, following the guidelines of API RP 500.
    * * * * *
    [FR Doc. 94-11601 Filed 5-13-94; 8:45 am]
    BILLING CODE 4310-MR-M
    
    
    

Document Information

Published:
05/16/1994
Department:
Minerals Management Service
Entry Type:
Uncategorized Document
Action:
Proposed rule.
Document Number:
94-11601
Dates:
Comments must be received or postmarked no later than July 15, 1994.
Pages:
0-0 (1 pages)
Docket Numbers:
Federal Register: May 16, 1994
RINs:
1010-AB52
CFR: (11)
30 CFR 250.1
30 CFR 250.27
30 CFR 250.51
30 CFR 250.53
30 CFR 250.122
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