The provisions contained in this appendix are not mandatory unless specifically adopted by a state agency, or referenced in the adopting ordinance.
CALIFORNIA PLUMBING CODE - MATRIX ADOPTION TABLE
APPENDIX A - RECOMMENDED RULES FOR SIZING THE WATER SUPPLY SYSTEM
(Matrix Adoption Tables are non-regulatory, intended only as an aid to the code user.
See Chapter 1 for state agency authority and building applications.)
Adopting Agency
BSC
BSC-CG
SFM
HCD
DSA
OSHPD
BSCC
DPH
AGR
DWR
CEC
CA
SL
SLC
1
2
1-AC
AC
SS
SS/CC
1
1R
2
3
4
5
Adopt Entire Chapter
X
X
X
X
X
X
X
X
X
Adopt Entire Chapter as amended (amended sections listed below)
This state agency does not adopt sections identified with the following symbol:† The Office of the State Fire Marshal's adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to
Section 1.11.0.
This appendix provides a general
procedure for sizing a water supply system. Because of the
variable conditions encountered, it is impractical to lay down
definite detailed rules of procedure for determining the sizes
of water supply pipes in an appendix, which shall necessarily
be limited in length. For an adequate understanding of the
problems involved, refer to Water-Distributing Systems for
Buildings, Report BMS 79 of the National Bureau of Standards;
and Plumbing Manual, Report BMS 66, also published
by the National Bureau of Standards.
Where the building supply is to be
metered, obtain information regarding friction loss relative to
the rate of flow of meters in the range of sizes likely to be
used. Friction-loss data is capable of being obtained from
most manufacturers of water meters. Friction losses for disk-type meters shall be permitted to be obtained from Chart A102.2.
CHART A102.2
FRICTION LOSSES FOR DISK-TYPE WATER METERS
FLOW (gallons per minute)
For SI units: 1 inch = 25 mm, 1 pound-force per square inch= 6.8947 kPa, 1 gallon per minute = 0.06 L/s
Obtain available local information
regarding the use of different kinds of pipe with
respect both to durability and to decrease in capacity with the length of service in the particular water supply.
Estimate the supply demand for
the building main, the principal branches and risers of the system
by totaling the fixture units on each, Table A103.1, and
then by reading the corresponding ordinate from Chart A103.1(1) or Chart A103.1(2), whichever is applicable.
2Appliances, appurtenances, or fixtures not included in this table shall be permitted to be sized by reference to fixtures having a similar flow rate and frequency of use.
3 The listedfixture unit values represent their total load on the cold water building supply. The separate cold water and hot waterfixture unit value for fixtures
having both cold and hot water connections shall be permitted to be three-quarters of the listed total value of the fixture.
4 The listed minimum supply branchpipe sizes for individual fixtures are the nominal (1.D.) pipe size.
5 For fixtures or supply connections likely to impose continuous flow demands, determine the required flow in gallons per minute (gpm) (L/s) and add it separately to the demand in gpm (L/s) for the distribution system or portions thereof.
7 Reduced fixture unit loading for additional hose bibbs is to be used where sizing total building demand and for pipe sizing where more than one hose bibb
is supplied by a segment of water distribution pipe. The fixture branch to each hose bibb shall be sized by 2.5 fixture units.
Estimate continuous
supply demands in gallons per minute (gpm) (L/s) for
lawn sprinklers, air conditioners, etc., and add the sum to the
total demand for fixtures. The result is the estimated supply
demand of the building supply.
Decide what is the desirable
minimum residual pressure that shall be maintained at the
highest fixture in the supply system. Where the highest group
of fixtures contains flushometer valves, the residual pressure
for the group shall be not less than 15 pounds-force per square
inch (psi) (103 kPa). For flush tank supplies, the available
residual pressure shall be not less than 8 psi (55 kPa).
Determine the elevation of the highest
fixture or group of fixtures above the water (street) main.
Multiply this difference in elevation by 0.43. The result is the loss of static pressure in psi (kPa).
Subtract the sum of loss in
static pressure and the residual pressure to be maintained at
the highest fixture from the average minimum daily service
pressure. The result will be the pressure available for friction loss in the supply pipes, where no water meter is used. Where
a meter is to be installed, the friction loss in the meter for the
estimated maximum demand should also be subtracted from
the service pressure to determine the pressure loss available
for friction loss in the supply pipes.
Determine the developed
length of pipe from the water (street) main to the highest fixture.
Where close estimates are desired, compute with the aid
of Table A104.4(1), Table A104.4(2), or Table A104.4(3),
whichever is applicable, the equivalent length of pipe for fittings
in the line from the water (street) main to the highest
fixture and add the sum to the developed length. The pressure available for friction loss in psi (kPa), divided by the
developed lengths of pipe from the water (street) main to the
highest fixture, times 100, will be the average permissible
friction loss per 100 feet (30480 mm) length of pipe.
TABLE A104.4(1)
ALLOWANCE IN EQUIVALENT LENGTH OF PIPE FOR FRICTION LOSS IN VALVES AND THREADED FITTINGS*
EQUIVALENT LENGTH OF PIPE FOR VARIOUS FITTINGS
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 degree = 0.017 rad
* Allowances are based on nonrecessed threaded fittings. Use one-half the allowances for recessed threaded fittings or streamlined solder fittings.
Knowing the permissible friction loss
per 100 feet (30 480 mm) of pipe and the total demand, the
diameter of the building supplypipe shall be permitted to be obtained from Chart A105.1(1), Chart A105.1(2), Chart A105.1(3), Chart A105.1(4) Chart A105.1(5), Chart A105.1(6), or Chart A105.1(7), whichever is applicable. The
diameter of pipe on or next above the coordinate point corresponding
to the estimated total demand and the permissible
friction loss will be the size needed up to the first branch from the building supplypipe.
CHART A105.1(1)
FRICTION LOSS IN HEAD (pounds-force per square inch) PER 100-FOOT LENGTH
For SI units: 1 inch = 25 nun, 1 gallon per minute = 0.06 L/s, I pound-force per square inch = 6.8947 kPa, 1 foot = 304.8 nun, 1 foot per second = 0.3048 m/s
CHART A105.1(2)
FRICTION LOSS IN HEAD (pounds-force per square inch) PER 100-FOOT LENGTH
For SI units: 1 inch = 25 mm, 1 gallon per minute = 0.06 L/s, 1 pound-force per square inch = 6.8947 kPa, 1 foot = 304.8 mm, 1 foot per second = 0.3048 m/s
CHART A105.1(3)
FRICTION LOSS IN HEAD (pounds-force per square inch) PER 100-FOOT LENGTH
For SI units: 1 inch = 25 mm, 1 gallon per minute = 0.06 L/s, 1 pound-force per square inch = 6.8947 kPa, 1 foot = 304.8 mm, 1 foot per second = 0.3048 m/s
CHART A105.1(4)
FRICTION LOSS IN HEAD (pounds-force per square inch) PER 100-FOOT LENGTH
For SI units: 1 inch = 25 mm, 1 gallon per minute = 0.06 L/s, 1 pound-force per square inch = 6.8947 kPa, 1 foot = 304.8 mm, 1 foot per second = 0.3048 m/s
CHART A105.1(5)
FRICTION LOSS IN HEAD (pounds-force per square inch) PER 100-FOOT LENGTH
For SI units: 1 inch = 25 mm, 1 gallon per minute = 0.06 L/s, 1 pound-force per square inch = 6.8947 kPa, 1 foot = 304.8 mm, 1 foot per second = 0.3048 m/s
CHART A105.1(6)
FRICTION LOSS IN HEAD (pounds-force per square inch) PER 100-FOOT LENGTH
For SI units: 1 inch = 25 mm, 1 gallon per minute = 0.06 L/s, 1 pound-force per square inch = 6.8947 kPa, 1 foot = 304.8 mm, 1 foot per second = 0.3048 m/s
CHART A105.1(7)
FRICTION LOSS IN HEAD (pounds-force per square inch) PER 100-FOOT LENGTH
For SI units: 1 inch = 25 mm, 1 gallon per minute = 0.06 L/s, 1 pound-force per square inch = 6.8947 kPa, 1 foot = 304.8 mm, 1 foot per second = 0.3048 m/s
Where copper
tubing or copper alloypipe is to be used for the supply
piping and where the character of the water is such that slight
changes in the hydraulic characteristics are expected, Chart A105.1(1) shall be permitted to be used.
Chart A105.1(2) shall be used for ferrous
pipe with the most favorable water supply in regards to
corrosion and caking. Where the water is hard or corrosive,
Chart A105.1(3) or Chart A105.1(4) will be applicable. For
extremely hard water, it will be advisable to make additional
allowances for the reduction of the capacity of hot-water lines in service.
The required size of branches and risers shall
be permitted to be obtained in the same manner as the building
supply, by obtaining the demand load on each branch or
riser and using the permissible friction loss computed in Section A104.0.
Where fixture branches to the building
supply are sized for the same permissible friction loss per 100
feet (30480 mm) of pipe as the branches and risers to the
highest level in the building and lead to the inadequate water
supply to the upper floor of a building, one of the following
shall be provided:
Selecting the sizes of pipe for the different branches so
that the total friction loss in each lower branch is approximately
equal to the total loss in the riser, including both
friction loss and loss in static pressure.
Throttling each such branch using a valve until the preceding balance is obtained.
Increasing the size of the building supply and risers
above the minimum required to meet the maximum permissible
friction loss.
Where a pressure-reducing
valve is used in the building supply, the developed
length of supply piping and the permissible friction loss shall be computed from the building side of the valve.
The allowances in Table A104.4(1) for fittings
are based on non-recessed threaded fittings. For
recessed threaded fittings and streamlined soldered fittings,
one-half of the allowances given in the table will be ample.
Assume an office building of four stories
and basement; pressure on the building side of the pressure-reducing
valve of 55 psi (379 kPa) (after an allowance for
reduced pressure falloff at peak demand); an elevation of
highest fixture above the pressure-reducing valve of 45 feet
(13716 mm); a developed length of pipe from the pressure-reducing
valve to the most distant fixture of 200 feet (60960 mm); and fixtures to be installed with flush valves for water
closets and stall urinals as follows:
Where the pipe material and water supply are such that
Chart A105.1(2) applies, the required diameter of the building supply is 31/2 inches (90 mm), and the required diameter
of the branch to the hot-water heater is 11/2 inches (40 mm).
The sizes of the various branches and risers shall be permitted
to be determined in the same manner as the size of the
building supply or the branch to the hot-water system, by estimating
the demand for the riser or branch from Chart A103.1(1) or Chart A103.1(2) and applying the total demand
estimate from the branch, riser, or section thereof to the
appropriate flowchart.
For SI units : 1 gallon per minute = 0.06 L/s, 1 pound-force per square foot = 6.8947 kPa
Allowing for 15 psi (103 kPa) at the highest fixture under the maximum demand of 252 gallons per minute (15.90 L/s), the pressure available for friction loss
is found by the following:
55 - [15 + (45 x 0.43)] = 20.65 psi (142.38 kPa)
The allowable friction loss per 100 feet (30480 mm) of the pipe is, therefore:
