MOJAQMD RULE 910 STD. FOR STOR.VESSELS FOR PETRO.LIQUIDS          
LAST REVISED 12/03/76

          
          (Adopted: December 3, 1976)

                                       Rule 910
                             Standard of Performance for
                        Storage Vessels for Petroleum Liquids


          (a)  Definitions

               (1)  CONDENSATE  means  hydrocarbon  liquid  separated  from
                    natural  gas  which  condenses  due  to  changes in the
                    temperature  and/or  pressure  and  remains  liquid  at
                    standard conditions.

               (2)  CUSTODY   TRANSFER   means  the  transfer  of  produced
                    petroleum and/or condensate,  after  processing  and/or
                    treating  in  the  producing  operations,  from storage
                    tanks or automatic transfer facilities to pipelines  or
                    any other forms of transporation.

               (3)  DRILLING AND PRODUCTION FACILITY means all drilling and
                    servicing  equipment,  wells,  flow  lines, separators,
                    equipment,   gathering   lines,   and  auxiliary   non-
                    transportation related equipment used in the production
                    of  petroleum  but  does  not include natural  gasoline
                    plants.

               (4)  FLOATING ROOF means a storage  vessel  cover consisting
                    of   a  double  deck,  pontoon  single  deck,  internal
                    floating  cover  or  covered floating roof, which rests
                    upon and is supported  by  the  petroleum  liquid being
                    contained, and is equipped with a closure seal or seals
                    to close the space between the roof edge and  tank wall
                    (see Rule 463 of these rules and regulations).

               (5)  HYDROCARBON   means  any  organic  compound  consisting
                    predominantly of carbon and hydrogen.

               (6)  PETROLEUM means  the  crude  oil removed from the earth
                    and the oils derived from tar sands, shale, and coal.

               (7)  PETROLEUM LIQUIDS means petroleum,  condensate, and any
                    finished  or  intermediate products manufactured  in  a
                    petroleum refinery  but does not mean Numbers 2 through
                    6 fuel oils as specified  in ASTM-D-396-69, gas turbine
                    fuel oils Numbers 2-GT through  4-GT  as  specified  in
                    ASTM-D-2880-71, or diesel fuel oils Numbers 2-D and 4-D
                    as specified in ASTM-D-975-98.

               (8)  PETROLEUM   REFINERY  means  any  facility  engaged  in
                    producing gasoline,  kerosene,  distillate  fuel  oils,
                    residual  fuel  oils,  lubricants,  or  other  products
                    through    distillation   of   petroleum   or   through
                    redistillation,  cracking,  or  reforming of unfinished
                    petroleum derivatives.

               (9)  REID VAPOR PRESSURE is the absolute  vapor  pressure of
                    volatile  crude  oil and volatile non-viscous petroleum
                    liquids,   except   liquified   petroleum   gases,   as
                    determined by ASTM-D-323-58 (reapproved 1968).

               (10) STORAGE VESSEL means  any tank, reservoir, or container
                    used for the storage of petroleum liquids, but does not
                    include:

                    (A)  Pressure vessels which  are designed to operate in
                         excess  of 776 mm HG (15 pounds  per  square  inch
                         gauge) without  emissions to the atmosphere except
                         under emergency conditions.

                    (B)  Subsurface caverns or porous rock reservoirs, or

                    (C)  Underground tanks if the total volume of petroleum
                         liquids added to  and  taken  from a tank annually
                         does not exceed twice the volume of the tank.

               (11) TRUE  VAPOR  PRESSURE  means  the  equilibrium  partial
                    pressure exerted by a petroleum liquid as determined in
                    accordance with methods described in American Petroleum
                    Institute Bulletin 2517 "Evaporation Loss from Floating
                    Roof Tanks," 1962.

               (12) VAPOR  RECOVERY SYSTEM means a vapor  gathering  system
                    capable  of collecting all hydrocarbon vapors and gases
                    discharged  from  the storage vessel and vapor disposal
                    system capable of processing  such  hydrocarbon  vapors
                    and  gases  so  as  to  prevent  their  emission to the
                    atmosphere.

          (b)  Emission Standard

               This  rule applies to storage vessels for petroleum  liquids
               the construction,  modification  or  reconstruction of which
               commenced after March 8, 1974, of more  than  150,000 liters
               (39,630 gallons) storage capacity except it shall  not apply
               to  storage  vessels  for  petroleum  or  condensate stored,
               processed,  and/or  treated  at  a  drilling and  production
               facility prior to custody transfer.

               The owner or operator of any storage  vessel  to  which this
               rule applies shall store petroleum liquids as follows:

               (1)  If the true vapor pressure of the petroleum liquid,  as
                    stored, is equal to or greater than 78 mm Hg (1.5 psia)
                    but  not greater than 570 mm Hg (11.1 psia) the storage
                    vessel  shall be equipped with a floating roof, a vapor
                    recovery system, or their equivalents.

               (2)  If the true  vapor  pressure of the petroleum liquid as
                    stored is greater than  570  mm  Hg  (11.1  psia),  the
                    storage  vessel shall be equipped with a vapor recovery
                    system or its equivalent.

          (c)  Monitoring

               The owner or operator  of  any  storage vessel to which this
               rule applies shall for each such  storage  vessel maintain a
               file  of each type of petroleum liquid stored,  the  typical
               Reid vapor pressure of each type of petroleum liquid stored,
               and the  dates  of  storages.   Dates  on  which the storage
               vessel is empty shall be shown.

               The owner or operator of any storage vessel  to  which  this
               rule  applies  shall  for each such storage vessel determine
               and record the average  monthly storage temperature and true
               vapor  pressure  of  the petroleum  liquid  stored  at  such
               temperature if:

               (1)  The petroleum liquid  has  a  true  vapor  pressure, as
                    stored, greater than 26 mm Hg (0.5 psia) but  less than
                    78  mm Hg (1.5 psia) and is stored in a storage  vessel
                    other  than  one equipped with a floating roof, a vapor
                    recovery system or their equivalents; or

               (2)  The petroleum  liquid  has  a  true  vapor pressure, as
                    stored, greater that 470 mm Hg (9.1 psia) and is stored
                    in  a  storage  vessel other than one equipped  with  a
                    vapor recovery system or its equivalent.

                    The  average  monthly   storage   temperature   is   an
                    arithmetic  average calculated for each calendar month,
                    or portion thereof if storage is for less than a month,
                    from bulk liquid  storage  temperatures  determined  at
                    least once every seven days.

                    The  true  vapor  pressure  shall  be determined by the
                    procedures  in  API Bulletin 2517.  This  procedure  is
                    dependent upon determination of the storage temperature
                    and the Reid vapor pressure, which requires sampling of
                    the petroleum liquids  in  the storage vessels.  Unless
                    the control officer requires in specific cases that the
                    stored  petroleum  liquid be sampled,  the  true  vapor
                    pressure may be determined by using the average monthly
                    storage  temperature   and   the   typical  Reid  vapor
                    pressure.   For  those  liquids  for  which   certified
                    specifications limiting the Reid vapor pressure  exist,
                    that  Reid  vapor  pressure  may  be  used.   For other
                    liquids,   supporting  analytical  data  must  be  made
                    available  on  request  to  the  control  officer  when
                    typical Reid vapor pressure is used.