Calculations/Design Procedures Basic Fire …

1 CHEMGUARD204 S. 6th Ave Mansfield, Tx 76063 (817) 473-9964 FAX (817) DATA SHEET #D10D03212 REVISION: 09/2005 The primary purpose of this design manual is topresent a recommended calculation procedure todetermine Basic fire protection requirements forhydrocarbon hazards encountered in today's"typical" offshore 's offshore platform operator must be safetyand fire conscious, and concerned about minimizingfire losses and operational down time. Therequirements, type of equipment and quantity ofextinguishing agent for fire control on offshoredrilling platforms are dictated by to the different kinds of hazards encounteredon offshore platforms, it is recommended that twotypes of extinguishing agents be Chemical Protection should be provided toextinguish three-dimensional fires, pressure fedfires (both gaseous and liquid) and electrical Film Forming Foam should be providedto extinguish spill and pool fires and to secure andcool liquid hydrocarbon spills.

2 Systems of this type,combining the rapid fire extinguishing capabilities ofdry chemical as well as their ability to extinguishthree-dimensional fires with the sealing andsecuring capabilities of an aqueous film formingfoam, are of particular importance for protection offlammable liquid hydrocarbon PARAMETERSThe parameters of sizing fire -extinguishingequipment for any platform should include thefollowing points: Flow rate of extinguishing agent Minimum flow time of extinguishing agent Accessibility of equipment by platform personnelTHESE FACTORS DICTATET aking into consideration that offshore platformsnormally are designed with two levels.

3 The decksare normally connected by two stairways onopposite sides of the platforms. If a fire breaks outon a level where there are no operating personnel,the fire fighting personnel will have access to thedeck from only the two stairways. This dictates thepositioning of major fire fighting equipment at thepoint where the stairways connect to each deck. Ifoperating personnel are on the level where the fireoccurs, the first reaction is to run to the , the most accessible points for thelocation of the major fire fighting equipment is thestairway area of each flow rate of extinguishing agent from a handlineis effectively limited by the amount of reaction forceone man can withstand and still maintain accuratecontrol of the discharge nozzle.

4 The maximum flowrate of dry chemical a man can accurately control is5 to 8 lbs. /sec. The maximum flow rate of AFFF isapproximately 60 gpm per hand line using 1" maximum flow rate required from a given pieceof equipment is the flow rate per handline times themaximum number of handlines which could be usedto combat any single maximum flow rate should be reviewed as tothe maximum flow rate available vs. the potentialhazards on that particular deck. (Drip pan size etc.)In review, the following standards should be (Max area size in sq. ft.)x(.04 ) x (60 sec.)

5 Flow) = Unit sizeExample:(100 sq. ft.)x (.04 lbs. /sec. /sq. ft.)x (60 sec. flow) = 240 lbs. Unit CapacityTaking into consideration that based on a horizontalimpinging natural gas pressure fire each 8 , hand line can extinguish a fire fed at the rateof 8 mm This is based on data covering agas pressure range up to 750 psi. The informationis applicable for higher pressures since the primaryeffect of pressure in this case is an extension indetachment of the flame zone from the gas to the complexity of equipment, possible windCalculations/Design ProceduresBasic fire Protection Requirementsfor Hydrocarbon HazardsOffshore PlatformsCHEMGUARD204 S.

6 6th Ave Mansfield, Tx 76063 (817) 473-9964 FAX (817) DATA SHEET #D10D03212 REVISION: 09/2005conditions, presence of rapidly heated material(stainless steel tubing etc.), it is recommended thatthe unit capacity size be calculated by taking themaximum flow rate from the unit times a minimumflow time of one : FOUR-PILE PLATFORMOn a "typical" four-pile platform, there are twostairways on opposite sides of the platformconnecting the two decks. At these two locations,position both an AFFF and a dry chemical hosereel.

7 The dry chemical unit, which contains twohose reels, should be mounted on the sub-deck(where it will be least susceptible to damage). If theunit is placed adjacent to a stairway connection, itwill be necessary to furnish only one remote reel(via the other stairway) on the two remote reels by each stairway locationon the upper deck. There should be five drychemical hose reels on the platform. (2 on the drychemical unit and 3 remotes.) The maximumnumber, which would normally be used at one time,would be three on the lower deck.

8 With a maximumof three 8-lbs. /sec. reels being used at once, a totalflow rate from the unit of 24 lbs. /second would berequired. Taking a minimum flow time of 1 minute,we calculate the size of the unit to be: (24 lbs. /sec.) x (60 sec.) = 1,440 lbs. of closest size available dry chemical unit wouldbe a 1,500-lb. capacity, which will supply up to50/70-lbs. /sec. flow if review of the systems fire extinguishing ability platform hazards, the extinguishing capabilitiesare as follows:Max. Hazard Area (24 lb. /sec.) x (.04 ) = 600 Max. Pressure fire (24 lb.)

9 /sec.) x (8 mm scfd.) = 24 mm scfd. (8 lb. /sec.)Unless a four pilons platform has unusually largehazards, the above system should handle all thepressure and (3) three-dimensional fires that couldbe calculations determine that the system requiredon four-pile platform consists of the followingequipment: 1 - CDC1500 Lb. Capacity DC Unit 3 - Remote Reels with 100' x 1" Hose & Nozzle 3 - Remote Actuators Stations 1 - CPM150 AFFF Unit 4 - Remote Reels with 100' x 1" Hose & Nozzle 3 - Remote Actuators StationsCALCULATIONS: EIGHT-PILE PLATFORMOn a "typical" eight-pile platform, there are twostairways on opposite sides of the platform.

10 Thereis a multiple wellhead area separated from theproduction area by a both an AFFF and a dry chemical hose reelat the stairway connection points on both decks. Inaddition, due to the extremely large wellheadhazard area, position an AFFF and a dry chemicalreel on the production side of the firewall adjacentto both doors. The dry chemical unit contains twohose reels and should be mounted on the sub-deckif possible. With the unit placed adjacent to astairway connection it will be necessary to provideonly three remote reels on the sub-deck.