1、Bottom Loading and Vapor Recovery for MC-306 however, theInstitute makes no representation, warranty, or guarantee in connection with this publicationand hereby expressly disclaims any liability or responsibility for loss or damage resultingfrom its use or for the violation of any federal, state, or
2、 municipal regulation with which thispublication may conflict.Suggested revisions are invited and should be submitted to the Standardization Manager,American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005.iiiCONTENTSPage1 GENERAL. . . . . . . . . . . . . . . . . . . . . . . . . . .
3、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4、 . . . . . . . . . 12 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 BOTTOM LOADING FO
5、R TANK MOTOR VEHICLES. . . . . . . . . . . . . . . . . . . . . . 24.1 Adapter Used for Bottom Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24.2 Tank Vehicles Used for Bottom Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 SECONDARY
6、SHUTOFF CONTROL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65.1 Liquid Flow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65.2 Secondary Control Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7、. . . . . . 65.3 Types of Secondary Control Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65.4 Required Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.5 Recommended Features. . . . . . . . . . . . . . . . .
8、. . . . . . . . . . . . . . . . . . . . . . . . . . . 116 VAPOR RECOVERY FOR TANK MOTOR VEHICLES. . . . . . . . . . . . . . . . . . . . . 156.1 When Vehicles are Bottom Loaded and Vapor Recovery Is Required . . . . . . . . 156.3 When Vehicles Are Top Loaded and Vapor Recovery Is Required. . . . . .
9、. . . . . 166.4 When Vehicles Are Unloaded and Vapor Recovery is Required . . . . . . . . . . . . 166.5 When Vehicles Equipped for Vapor Recovery Are Unloaded and Vapor Recovery Is Not Required. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166.6 Required Feature . . . . .
10、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 LOADING ISLANDS EQUIPPED FOR BOTTOM LOADING . . . . . . . . . . . . . . . . 177.1 Required Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177.2 Recomm
11、ended Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Figures1 Standard Tank Vehicle Adapter for Bottom Loading and Unloading . . . . . . . . . . . 32 Standard Interlock Control for Bottom Loading Adapter . . . . . . . . . . . . . . . . . . . . 43 Ho
12、rizontal and Vertical Spacing of Adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54A Functional Lane Shutdown Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74B Functional Rack Shutdown Diagram . . . . . . . . . . . . . . . . . . . . . . . . . .
13、. . . . . . . . . . 85A Side View of Trailer Showing Need for Different Sensor Depths . . . . . . . . . . . . . . 95B End View of Trailer Showing Various Levels and Two Methods of Mounting Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106A Co
14、nstruction Details for Thermistor Receptacle (Green). . . . . . . . . . . . . . . . . . . . 126B Construction Details for Thermistor Plug (Green). . . . . . . . . . . . . . . . . . . . . . . . . 127A Construction Details for Optical Receptacle (Blue). . . . . . . . . . . . . . . . . . . . . . . . 13
15、7B Construction Details for Optical Plug (Blue) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 Wiring Schematic for Thermistor System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Wiring Schematic for Optical System . . . . . . . . . . . . . . . . . . . . . . . . .
16、 . . . . . . . . . 1410 Coaxial Product Vapor Hose Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1711 Separate Product and Vapor Hose Connections with Manifold Vents . . . . . . . . . . 1812 Separate Product and Vapor Hose Connections . . . . . . . . . . . . . . . . . . .
17、 . . . . . . . . 19vCONTENTSPage13 Location of Pressure Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2014 Typical Loading Rack Arm Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Tables1 Conversion of Customary Units in Figur
18、e 1 and 2 to SI Units . . . . . . . . . . . . . . . . 22 Color Coding for Thermistor System Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Color Coding for Optic System Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15vi1Bottom Loading and Vapor Recove
19、ry for MC-306 these items are listed as required features. Otherfeatures are desirable but are not essential to interchangeabil-ity; these are listed as recommended features.2.3For this edition of API RP 1004, all dimensions in cus-tomary units have been converted to the International System ofUnits
20、 (SI) and carried to decimal figures.3 ReferencesAPIRP 1007Loading and Unloading of MC306/DOT406 Cargo Tank Motor VehiclesRP 2003 Protection Against Ignitions Arising Out ofStatic, Lightning and Stray CurrentsNFPA170National Electrical CodeU.S. Military Specification2CID-A-A-59326Commercial Item Des
21、cription CouplingHalves, Quick-Disconnect, Cam-LockingTypeEPA3Standards of Performance for New Stationary Sources (40Code of Federal Regulations Part 60.501.“Definitions:” and Part 60, Appendix A,Method 27, “Determination of VaporTightness of Gasoline Delivery Tank UsingPressure Vacuum Test”)Standar
22、ds of Performance for Bulk Gasoline Terminals,(40 Code of Federal Regulations 60 Sub-part XX, 60.500)1National Fire Protection Agency, 1 Batterymarch Park, Quincy,Massachusetts 02269-91012U.S. Army Tank-automotive and Armaments Command, ATIN:AMSTAR D/210, Warren, Michigan 483673U.S. Environmental Pr
23、otection Agency, U.S. Government PrintingOffice, Washington, D.C. 204022 API RECOMMENDEDPRACTICE1004TTMA4RP No. 54-97External Work on Cargo Tank Motor Vehicles Which May Have Been in Service4 Bottom Loading for Tank Motor Vehicles4.1 ADAPTER USED FOR BOTTOM LOADING4.1.1 Required Features4.1.1.1 Type
24、To mate with loading couplers, the tank vehicle adaptermust have the basic configuration shown in Figure 1 (all tol-erances are provided in the appropriate figure). In the openposition, the adapter must have a clear, unobstructed opening2 in. (50.8 mm) in depth, measured from the outer face or clo-s
25、ure of the valve as shown in Figure 1. If a poppet device isused, the adapter poppet must have a travel of 2 in. (50.8 mm),measured from the sealing surface, as shown in Figure 1. Thefront face of the adapter poppet must be flat within 0.004 in.(0.102 mm), excluding the corner radius. No fastening d
26、eviceshall protrude above the general plane of the adapter face.If an interlock control is installed on the adapter, its dimen-sions must conform to those shown in Figure 2. Table 1 pro-vides equivalent SI values for the customary dimensionsshown in Figures 1 and 2.4.1.1.2 ActuationThe primary liqui
27、d control must be by means of the setstop meter on the loading island or a self-contained system onthe tank vehicle. The coupler may be opened for loading bymanual or automatic means.4.1.1.3 Size of Product OpeningThe adapter must have a product opening 4 in. (101.6 mm)in diameter at the exposed out
28、er face or closure of the valve.4.1.1.4 Pressure RatingThe adapter must be designed for a working pressure of 75pounds per square in. (psi) (517 kilopascals) and shall notleak at 1.5 times working pressure. 4.1.1.5 MountingThe mounting must be accomplished by using a TruckTrailer Manufacturers Assoc
29、iation (TTMA) standard, light-weight, 8-hole, 4-in. (101.6-mm) flange.4.1.1.6 Mating ActionThe mating action must be of the push type, with provisionfor locking without rotating the loading coupler body. The cou-pling range must permit mating of the coupler to the adapter inany position in a range o
30、f 360 degrees, without any couplercontacting an adjacent adapter spaced on 10-in. (254-mm)centers.A safety interlock or two-step action must be provided onthe coupler to prevent any liquid flow while coupling oruncoupling.4.1.1.7 Sealing SurfaceAs shown in Figure 1, the sealing surface must have a c
31、ir-cular finish of not more than 63 min. (see Table 1 for SI con-versions of customary units).4.1.2 RECOMMENDED FEATURES4.1.2.1 Overall SizeThe adapter should be as compact as is practicable for ade-quate design. The overall size of the adapter and the coupler,including the operation of any handles
32、or controls, shouldpermit adjacent adapters to be spaced on 10-in. (254-mm)centers. Adapters should be easy to operate with heavilygloved hands.4Tank Truck Manufacturers Association, 1020 Princess Street, Alex-andria, Virginia 22314Table 1Conversion of Customary Units in Figure 1 and 2 to SI UnitsEn
33、glish Dimensions (in.) SI Dimensions (mm) 0.002 0.051 0.005 0.127 0.015 0.381 0.0625 1.588 0.125 3.175 0.190 4.826 0.250 6.350 0.375 9.525 0.750 19.050 1.000 25.400 1.500 38.100 2.000 50.800 2.060 52.324 2.250 57.150 2.440 61.976 4.000 101.600 4.250 107.950 5.250 133.350 5.750 146.050 6.000 152.400
34、6.500 165.100 7.250 184.150BOTTOMLOADINGANDVAPORRECOVERYFORMC-306 however, an electrical interface between the loadingisland and the vehicle is necessary when loading at a rack.5.3 TYPES OF SECONDARY CONTROL SYSTEMS5.3.1 GeneralIn systems discussed in 5.3.2 and 5.3.3, the sensor must bedeep enough i
35、n each of the tank vehicle compartments toassure that once the sensor has been activated, product flowstops before the compartment is completely full. Determina-tion of the proper depth must take into account the maximumproduct flow rate, shutoff valve response times and tank com-partment volume (th
36、at is, the available outage).5.3.1.1Maximum product flow rate at the loading rack.For bottom loading racks, this typically ranges from 600 900 gallons per minute (gpm) (2.27 3.40 cubic meters perminute (m3pm) per loading arm. At 900 gpm (3.400 m3pm)the flow is 15 gallons per second (gps) (0.057 cubi
37、c metersper second (m3ps). This flow rate may be different dependingupon product and facility, however, tankers should be pre-pared to load safely at any facility.5.3.1.2Shutoff valve response time.Normal flow shutdowntime with a properly functioning preset loading meter control(PSC) valve is 1 2 se
38、conds. In the rare case when the PSCvalve is not functioning properly, the loading flow will bestopped by the independent secondary shutoff (SSC) systemand 2 4 seconds is typically required. This 2 4 second timeincludes the overfill protection systems activation time andtime for the independent valv
39、e (SSC) to close. 5.3.1.3Tank Compartment Volume. The minimum outagerequirement for each compartments sensor setting is 60 gal-lons (0.227 m3). Combining the 900 gpm (15 gps) 34.07m3pm (0.057 m3ps) maximum flow rate and the 4-secondmaximum shutdown time requires an empty space (outage) of60 gallons
40、(0.227 m3) above the high level point, which iswhere the sensor senses liquid. To accommodate a 60-gallonBOTTOMLOADINGANDVAPORRECOVERYFORMC-306 & DOT-406 TANKMOTORVEHICLES7Figure 4AFunctional Lane Shutdown DiagramTankTankValvePumpActuatedRiser Valve(SSC)ActuatedRiser Valve(SSC)PresetMeterControlValv
41、e(PSC)PresetMeterControlValve(PSC)Overfill SensorTerminalAutomationSystemLane #1 Lane #2Upon high level signal, all Control Valves (PSC)& the Independant Actuated Riser Valves (SSC)on a Single Lane shutdown.Note:Rack OverfillController8 API RECOMMENDEDPRACTICE1004Figure 4BFunctional Rack Shutdown Di
42、agramTankTankValve(SSC)PumpManualRiser ValveManualRiser ValvePresetMeterControlValve(PSC)PresetMeterControlValve(PSC)TerminalAutomationSystemLane #1 Lane #2Upon high level signal, all Control Valves(PSC)& the Entire Loading Rack (All TankValves (SSC) & Pumps) is shutdown.Note:Overfill SensorRack Ove
43、rfillControllerBOTTOMLOADING AND VAPOR RECOVERY FOR MC-306 & DOT-406 TANK MOTOR VEHICLES 9(0.227 m3) outage, the overfill sensor placement is critical andvaries widely due to the range in tank truck/trailer compart-ment sizes (typically 300 9,000 gallons (1.13 34.07 m3).Unlike the typical outage req
44、uirement of 3% for thermalexpansion, the 60 gallon (0.227 m3) outage quantity is notbased on a percentage of the total compartment size. Forexample the 60 gallon (0.227 m3) outage is 6% of a 1,000 gal-lon (3.79 m3) compartment, but only 1.5% of a 4,000 galloncompartment (15.14 m3). To safely accommo
45、date the outagethe high-level sensor must be installed at the correct depthdepending upon tank compartment size, see Figure 5A. Theexact sensor depth should be determined by reference to thetanks actual capacity chart (available from the tank vehiclemanufacturer). Since sensors can be mounted direct
46、ly into thetop of the tank shell, or in the dome lid cover, an allowance forthe added height must be made when mounting in the domelid cover (the sensor must be longer, to offset the highermounting), see Figure 5B.Note: Inspection of the sensor depth can be accomplished during theannual vapor tightn
47、ess testing.5.3.2 Thermistor SystemA thermistor system uses a thermistor sensor (a tempera-ture-sensitive resistor) that is heated by an intrinsically safeelectrical signal from the loading rack. When in air, the sensoris warmer than the highest expected product temperature.When product comes in con
48、tact with the sensor, the ther-mistor is cooled, causing a change in resistance. This changeis detected by the rack overfill controller, which shuts downthe PSC valve and the independent SSC valve.5.3.3 Optical SystemAn optical system uses a beam of light that is internallyreflected from an exposed
49、glass/air interface when the sensoris in air. An electrical photodetector intercepts this reflectedlight and produces a signal that is used to energize the loading-valve control system. When liquid touches the glass sensor,the beam is refracted into the liquid and is not reflected backinto the photodetector. The control unit, which grants permis-sive control only when it receives a signal from the photode-tector, shuts down the PSC valve and the independent SSCvalve.5.4 REQUIRED FEATURES5.4.1 Electrical RequirementsAny electrical system used for secondary shutoff controlmu
