Offshore facilities containment

While RP14C provides guidance on the need for process safety devices, it is desirable to perform a complete hazards analysis of tlie facility to identify hazards that are not necessarily detected or contained by process sLifety devices and that could lead to loss of containment of hydrocarbons or otherwise lead to fire, explosion, pollution, or injury to personnel. The industry consensus standard, American Petroleum Institute Recommended Practice 14J, Design and Hazards Analysis for Offshore Facilities (RP14J), provides guidance as to the use of various hazards analysis techniques. 

All fixed fire suppression system control valves should be located out of the fire hazard area but still within reach of manual activation. For high hazard areas (such as offshore facilities), dual feeds to fire suppression systems should be considered from opposite areas. For onshore facilities, firewater isolation valve handles should not be contained within a valve pit or a below grade enclosure within the vicinity of hydrocarbon process facilities, since heavy process vapors travel from the process and may settle inside. 

When it is determined Uiat tlie installation of containment and/or di ersionary structures or equipment to prevent discharged oil from reaching navigable waters is not practicable from any onshore or offshore facility, the owner/operator should clearly demonstrate such impracticability and provide the following ... 

Fire and explosion accidents are of major concern to the owners and operators of refineries and petrochemical, gas processing, terminal, and offshore facilities. Statistics have shown that the majority of monetary loss in these types of complexes is due to fire and explosion. According to statistics (www.ohsonline.com, December 2010), 77 percent of the monetary loss in refinery and petrochemical complexes is due to fire and explosion. The breakout of accidents due to fire and explosion is 65 percent vessel (container) and vapor cloud explosion and 35 percent fire. The causes of these accidents are mostly attributed to mechanical issues, process upset, and operator error. 

Produced oil and gas frequently contains toxic chemicals that are hazardous to the health of those working on offshore facilities, and that can cause corrosion of equipment and instrumentation. It is critical that these chemicals be handled in a proper manner. 

To avoid common failure incidents, prime mover and backup fire pumps preferably should not be located immediately next to each other and ideally should be housed at separate locations at the facility. They should feed into the firewater distribution at points that are as remote as practical from each other. In practical applications, except for offshore installations, most small to medium sized facilities contain a single firewater storage tank, requiring the siting of all firewater pumps close to it. Even in these circumstances it may be wise to segregate the main and backup fire pumps from each other with tie-in points to the firewater distribution loops. This mostly depends on the hazard level of the facility and... 

An example of the distinction between safety and health can be seen in some offshore facilities. These facilities often use produced gas to drive turbines or in fired heaters. If the gas contains hydrogen sulfide (H2S) then, when it is burned, the H2S will be converted to sulfur dioxide (SO2). The concentration of SO2 in the exhaust plume will be very low because it is extensively diluted with the other gases such as nitrogen and carbon dioxide. Hence it does not pose a safety threat. However, over a long enough period of time, the SO2 can have a health effect on those working on the platform. 

The disposal of dredged spoil in an environmentally friendly manner poses difficulties from the perspective of the normally large volumes of spoil involved and the modern requirements of environmental sustainability of such spoil disposal facilities. These driving forces have led to offshore spoil containment facilities being developed for wetlands habitats. 

Based on the information contained in these figures it is possible to draw an area classification diagram of the facility. Figure 17-15 shows an example for a typical offshore production platform. 

Many producing facilities are located offshore or in other environmentally sensitive areas. In these areas, the use of dry (versus liquid-filled) transformers will eliminate the necessity of providing curbing and other containment systems to prevent pollution. Dry transformers are normally preferred for most production facility applications. Liquid-filled transformers should be considered, however, for high voltage and large units (particularly over several hundred kVA). 

All hydrocarbon process areas containing materials with gaseous materials that are not adequately ventilated (i.e., would not achieve a minimum of six air changes per hour or would allow the build up of flammable gas due to noncirculating air space). Typically applications include compressor enclosures, process modules in offshore platforms and enclosed arctic facilities. 

In chemical laboratories or similar facilities at the time of an earthquake, chemicals may leak that produce an irritating or corrosive gas. For instance it was reported that, in the Miyagi Offshore Earthquake in a chemical laboratory of the Prefectural Sendai Technical High School, a bottle containing an acid dropped from a table and filled the room with an odor so irritating that people could not enter the room 4 c 1. It was also reported that, in a chemistry lecture room of Tohoku University, vapors of pyridine and tetrahydrofuran filled the room to the extent that restoration work could not be started until two days after the earthquake 3 5 . ... 

Processes that contain unusual, complicated or extremely hazardous materials should be reviewed by the detailed HAZOP method to ensure major possible events have been accounted for which may not be familiar to the team. This may also be true when a high employee or public population may be exposed to potential hazards (such as may be the case with some offshore oil production facilities). 

The safety case should contain sufficient information about the facility to verily that the design and operating philosophy is consistent with the SMS and with the assumptions and outputs of the formal risk analysis. Using an offshore platform as an example, the safety case will generally contain the following minimum information. 

The common scope of application for all the regulations is generally defined by reference to Sect. 1-4 of the Petroleum Act, with some adjustments following from the parallel provisions contained in the other acts upon which the decree is based (see Subsection 5.3.1). This implies that the basic criterion is whether the matter in question is petroleum activit , defined in the Petroleum Act as all activities associated with subsea petroleum deposits , and further defined by examples of such activities (Sect. 1-6 (c) and (e)-(i)). We need not go further into this for our purpose it suffices to note that the decree covers all aspects of activities that reasonably can be considered to have such a link to offshore petroleum activities that they may be relevant for safety in that activity, ° including activities related to certain facilities onshore. 

Offshore production platforms and drilling rigs are generally arranged into Safe and Hazardous Areas. The two areas should be separated from one another and may have physical barriers between them. The Safe Area will include accommodations, the control room, UPS (uninterruptible power supply), emergency power generation equipment, and nonhazardous platform utilities such as water and compressed air. The Hazardous Area contains the flare, derricks, gas compression, hydrocarbon separation, the wellhead, and drilling facilities. 

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